Abstracts

Question 1

Adrenal tumors treated by adrenalectomy following spontaneous rupture carry an overall favorable prognosis: retrospective evaluation of outcomes in 59 dogs and 3 cats (2000–2021)

Answer 1

Question 2

Adverse events and outcomes in dogs with appendicular osteosarcoma treated with limb amputation and a single subcutaneous infusion of carboplatin

Answer 2

Question 3

Assessing major influences on decision-making
and outcome for dogs presenting emergently
with nontraumatic hemoabdomen

Answer 3

Question 4

Blood glucose monitoring during surgery in dogs to assess completeness of surgical resection of insulinoma: 11 cases

Answer 4

Question 5

Cavitary pulmonary lesion wall thickness, presence of additional nodules, and intralesional contrast enhancement
are associated with malignancy in dogs and cats

Answer 5

These findings suggest that lesions with wall thicknesses > 39.6 mm at their thickest points and 1.9 mm at their thinnest points are more likely to be malignant in origin.
In lesions that have heterogenous contrast enhancement, additional nodules, and wall thickness > 40 mm at its
thickest point, it would be reasonable to consider
malignant neoplastic disease higher on the list of dif-
ferentials than other causes.

Question 6

Characteristics and outcomes for 61 cats that underwent either surgery or stereotactic radiotherapy as treatment for intracranial meningioma (2005–2017)

Answer 6

Question 7

Clinical and pathological findings of rabbits with lymphoma: 16 cases (1996–2019)

Answer 7

Question 8

*****Clinical experience with next-generation sequencing–based liquid biopsy testing for cancer detection in dogs: a review of 1,500 consecutive clinical cases

Answer 8

Question 9

Clinical presentation and treatment of lymphoma in companion rats (Rattus norvegicus; 2008–2020)

Answer 9

Question 10

A prospective, randomized, placebo-controlled, double-blinded clinical trial comparing the incidence and severity of gastrointestinal adverse events in dogs with cancer treated with piroxicam alone
or in combination with omeprazole or famotidine

Answer 10

Question 11

Clinical validation of a blood-based liquid biopsy test integrating cell-free DNA quantification and next-generation
sequencing for cancer screening in dogs

Answer 11

Lastly, the integrated test described in this study
provides results indicating the likelihood that cancer
is present at the time the patient’s blood was drawn.
Neither cfDNA quantification analysis nor NGS anal-
ysis currently provides information about a patient’s
genetic risk for developing cancer in the future.

Question 12

Comparison of lateral surgical margins
of up to two centimeters with margins
of three centimeters for achieving tumor-free
histologic margins following excision
of grade I or II cutaneous mast cell tumors in dogs

Answer 12

Question 13

Complications and outcomes associated with unilateral thyroidectomy in dogs with naturally occurring thyroid tumors: 156 cases (2003–2015)

Answer 13

Factors that were associated with the overall com-
plication rate included duration of hospitalization and
whether the mass was assessed as fixed or mobile
during physical examination. The odds of develop-
ing complications for dogs with a fixed mass were 5.4
times the odds for dogs with a mobile mass. For each additional day of hospitalization, dogs had increased odds (2.2) of developing complications.

The 2 factors that were significantly associated
with a shorter progression-free interval were mitotic
index and the maximal dimension of the tumor. Factors
that were significantly associated with survival time
were mitotic index and perioperative complications.

Measures of tumor size should not be used for de-
termination of surgical resectability and that greater importance should be placed on accurate measures of
tumor invasiveness.

Only 9% of patients died from thyroid carcinoma.

Question 14

Conventionally fractionated radiation therapy is associated with long-term survival in dogs with infiltrative lipomas

Answer 14

Consistent with previously reported cases,11 and
in contrast to many other tumor types, gross disease
did not result in shorter survivals.

Question 15

Computed tomographic findings and clinical features in dogs with canine cutaneous lymphoma: 10 cases (2007–2018)

Answer 15

Of the 9 dogs that received chemo-
therapy, 5 had a complete response and 4 did not re-
spond. Median survival time for the nonresponders
was 13 days (range, 7 to 25 days). Median survival
time for dogs that responded to treatment was 561
days (range, 18 to 1,345 days).

Question 16

Diagnostic utility of abdominal ultrasonography for evaluation of dogs with nontraumatic hemoabdomen:
94 cases (2014–2017)

Answer 16

Differences between AUS and gross find-
ings were common. The greatest sensitivity (87.4%)
of AUS was found for detection of splenic lesions,
with substantially lower values for hepatic (37.3%)
and mesenteric (31.3%) lesions, and the least sensi-
tivity was found for diffuse nodular metastasis (0%).

Question 17

Doxorubicin for treatment of histiocytic sarcoma in dogs: 31 cases (2003–2017)

Answer 17

The median TTP for dogs that received doxorubicin as frontline therapy was 42 days, compared with a median TTP of 33 days when doxorubicin was used in a rescue setting; these times were not significantly (P = 0.75) different.

As an alternative to dividing the study popula-
tion into frontline and rescue groups, dogs could
also be categorized according to the initial extent
of their disease and the modalities used for treat-
ment as follows: group 1, disseminated disease with
multimodality therapy (surgery or radiation therapy
or both in addition to chemotherapy; n = 9); group
2, disseminated disease with chemotherapy alone
(15); and group 3, local disease with multimodality
therapy (7).

Median survival time, determined on the basis of
data for 29 dogs, was 169 days. Median sur-
vival time was 147 days for dogs in group 1, 113 days
for dogs in group 2, and 525 days for dogs in group 3.

Question 18

Doxorubicin for treatment of histiocytic sarcoma in dogs: 31 cases (2003–2017)

A number of inherent and acquired cellular mechanisms of cancer resistance
to anthracyclines have been described:

Answer 18

Among the most important is enhanced drug efflux by ATP-binding cassette (ABC) transporters, including ABCB1 (p-glycoprotein [P-gp] or MDR1), ABCC1 (multidrug-
resistance–associated protein 1), and ABCG2 (breast cancer resistance protein). Doxorubicin-induced activation of extracellular signal-regulated kinases may lead to ABC transporter upregulation, as does over-
expression of transcription factors associated with epithelial-mesenchymal transition. These 3 major ABC transporters are operative in canine cancers.

Additional doxorubicin resistance mechanisms include altered topoisomerase II activity and enhanced detoxification of drug-generated free radicals. One group has investigated mechanisms of doxorubicin chemoresistance specifically in canine HS, finding HS
lines to be generally more doxorubicin-resistant than representative B- and T-cell non-Hodgkin lymphoma lines, with increased ABCB1 and ABCG2 messages. However, neither P-gp expression nor enhanced
dye efflux activity was found in HS cells, suggesting that the other abnormality they identified, low TP53 gene expression, might be the culprit. Indeed, a TP53 frameshift mutation causing loss of p53 expression has been found in many HS clinical specimens and is
functionally associated with enhanced doxorubicin resistance in vitro.

Question 19

Evaluation of neutrophilia as a prognostic factor in dogs with multicentric lymphoma treated with a cyclophosphamide, doxorubicin, vincristine, and prednisone–based chemotherapy protocol

Answer 19

The N:L ratio has also been used as a prognostic
tool for human patients with lymphoma. This ratio
serves as a representation of the inflammatory re-
sponse evoked by the cancer, relative to the immune
response, with higher ratios having been linked to
poorer prognoses in human lymphoma patients.

The percentage of substage b patients in the
study population (19/30 [63%]) was significantly greater than the percentage of substage b patients in the historical control population (10/37 [27%]).
Additionally, the percentage of dogs in the study population with stage V disease (8/30 [27%]) was higher than the percentage in the historical control population (8/37 [22%]), although not significantly so.

In addition to neutrophilia, immunophenotype was also significantly associated with PFST;

Question 20

Evaluation of the validity of the double two-thirds rule for diagnosing hemangiosarcoma in dogs with nontraumatic hemoperitoneum due to a ruptured splenic mass: a systematic review

Answer 20

In total, 1,150 dogs were diagnosed with hemo-
peritoneum secondary to a ruptured splenic mass.
Overall, 73.0% (840/1,150) of dogs were diagnosed
with a malignancy and 27.0% (310/1,150) were di-
agnosed with a benign lesion. Of the malignancies,
87.3% (733/840) were hemangiosarcoma.

The double two-thirds rule seems to have originated
from all dogs presenting with a splenic mass, regard-
less of the presence of a concurrent hemoperitone-
um. The authors chose to analyze cases diagnosed
specifically with hemoperitoneum secondary to a rup-
tured splenic mass due to recent studies that report
improved odds of a benign diagnosis in dogs with-
out hemoperitoneum.

Question 21

Evaluation of variables associated with outcomes in 41 dogs with incompletely excised high-grade soft tissue sarcomas treated with definitive-intent radiation therapy with or without chemotherapy

Answer 21

The points based system of tumor grading (grade 1, 2, 3 STS) was not prognostic for OST or TTP, but that MI, duration of RT (ie if delays were necessary), and surgical scar length (as a stand in for tumor size) were prognostic. As the MI increased, so did the hazard of disease progression over the study period. Similarly, as the duration of RT increased, so did each of the hazards for disease progression or death during the study period. Further, as the surgical scar length increased, so did
the hazard of death over the study period.
Neither OST nor TTP was meaningfully impacted by
other variables analyzed.

Therefore the MI should be considered as an independent prognostic indicator of the biologic behavior of STS.

Administration of chemotherapy did not measur-
ably improve outcomes for dogs in the present study.
Our finding was consistent with that of a previous
study.

Question 22

2 STS grading systems in dogs

Answer 22

Bostock and Dye et al classifies STSs as low versus high grade solely on the basis of MI (sum of mitotic figures in 10 hpf). Tumors with an MI < 9 are classified as low grade, whereas tumors with an MI ≥ 9 are classified as high grade.

Kuntz et al10 more recently published
a grading system (grades 1 [low], 2 [intermediate], and 3 [high]) that is widely used and involves points assigned to each of 3 histologic criteria: cell differentiation, MI, and tumor necrosis.

Question 23

Factors influencing complications following mastectomy procedures in dogs with mammary gland tumors: 140 cases (2009– 2015)

Answer 23

In light of these several non-insignificant complications requiring surgical correction, it may be reasonable to consider staging the surgeries if both chains are involved and avoid making the surgery dose larger than necessary.
Prophylactic mastectomy on unaffected mammary
glands should probably not be performed without a
compelling reason to do so.

Question 24

Clinical, diagnostic, and pathologic features
and surgical outcomes of combined hepatocellular-cholangiocarcinoma in dogs: 14 cases (2009-2021)

Answer 24

The MST for all 14 cHCC-CCA cases was 700 days
(range, 10 to 869 days). The MST of the
well-differentiated type was 700 days (range, 10 to
821 days), and that of the poorly-differentiated type
was 740.5 days (range, 315 to 869 days), indicat-
ing no significant difference in survival
based on the degree of bile ducts differentiation. The MST was 612 days (range, 10 to 821 days) when all
lesions were removed and 784.5 days (range, 315
to 869 days) when all were not removed, which was
also not significantly different (P = 0.1477).

The above indicates that hyperattenua-
tion in the arterial phase and prominent cyst-like lesions may form part of the differential diagnosis of
cHCC-CCA from HCC.

Although prognosis did not differ significantly based
on the differentiation of biliary components, all 2
cases with postoperative metastases were poorly-
differentiated group;

Question 25

Histopathologic findings and survival outcomes of dogs undergoing liver lobectomy as treatment for spontaneous hemoabdomen secondary to a ruptured liver mass: retrospective analysis of 200 cases (2012–2020)

Answer 25

## Footnote Dogs with an increased ALT were 10.7 times more likely to have a diagnosis of WD-HCC compared to a benign mass. Conversely, with an increased ALT, the odds of being diagnosed with HSA or a malignant tumor decreased by 95% or 89%, respectively, compared to a benign mass. Additionally, when the ALT was increased, the odds of being diagnosed with either HSA or a malignant tumor decreased by 97%. Unlike with SH associated with ruptured splenic masses, for ruptured hepatic masses, the presence of concurrent liver or splenic nodules should not be interpreted as advanced/metastatic disease or as a diagnosis of HSA without histopathology.

Question 26

Fluoroscopy-guided fine-needle aspiration of deep-seated pulmonary masses in dogs and cats appears safe and accurate

Answer 26

## Footnote In our study, for the 3 cats (cats 1, 2, and 5) that had samples consistent with necrotic tissue or inflam- mation, survival times were 36, 18, and 26 months, respectively. When compared to cats in which FNA results were consistent with carcinoma, cats with inflammatory/necrotic lesions survived 6.3 times longer (798 vs 126 days). The reported survival time in cats with pulmonary carcinoma without metastatic disease following lung lobectomy is between 11 and 115 days. Hence, the survival time of the 3 cats with “nondiagnostic samples” was not consistent with cats with pulmonary adenocarcinoma. In addition, at the time of diagnosis, 30% to 53% of cats with pulmonary carcinoma have evidence of intrathoracic metastatic disease while 16% have extrathoracic metastases. In our study, none of the cats had evi- dence of intra- or extrathoracic metastatic disease. Therefore, in cats, a solitary pulmonary nodule has the potential to be benign in nature. This strengthens the argument that sampling should be performed prior to contemplating surgical options.

Question 27

Genomic tumor analysis provides clinical guidance for the management of diagnostically challenging cancers in dogs | What types of mutations are identified with this next gen sequencing?

Answer 27

## Footnote This genomic assay is a tumor-only, next-generation sequencing canine gene panel covering 120 genes associated with canine or human cancer. Mutation types identified include single-nucleotide variants (SNV), copy number variants (CNV), and internal tandem duplications (ITD).

Question 28

How many patients could the genomic assay diagnosis with either a broad histologic class or specific histology of cancer? How many patients was it able to differentiate between benign and malignant? For the group 2 patients that it was not able to diagnosis, how many could it provide prognostic and/or therapeutic information for?

Answer 28

The genomic assay was diagnostically sup- portive of either a broad histologic class or specific histology in 45% (31/69) of patients, and it was able to differentiate malignant versus likely benign neoplasia in 9% (6/69) of patients. Even for patients in which the diagnosis remained elusive (group 2), genomic analysis provided prognostic and/or therapeutic information in the majority (69% [22/32]) of those patients.

Question 29

Goats diagnosed with neoplasia display variability in clinical presentations, treatments, and outcomes

Answer 29

Question 30

Grade shifts in recurrent canine soft tissue sarcomas and mast cell tumors

Answer 30

Question 31

What is the basis for assigning a grade in MCT and STS?

Answer 31

For cutaneous MCT, the following 2 main grading schemes are used: 3-tier, which assigns a grade of 1 to 3 on the basis of disease extent, cellularity and cellular morphology, mitotic count, and stromal reaction, and 2-tier, which assigns a grade of low or high on the basis of mitotic count, multinucleated cells, bizarre nuclei, and karyomegaly. For cutaneous and subcutaneous STS, a grade of 1 to 3 is assigned on the basis of cellular differentiation, mitotic count, and percentage of tumor necrosis

Question 32

Distribution of histopathologic types of primary pulmonary neoplasia in dogs and outcome of affected dogs: 340 cases (2010–2019)

Answer 32

## Footnote Mitotic count, intrathoracic lymph node metastasis, distant metastasis, and presence of pleural effusion at diagnosis remained significant prognosticators on multivariable analysis. Tumor size and completeness of margins did not. Presence of clinical signs prior to diagnosis was not prognostic. Survival time following disease progression was significantly (P = 0.021) shorter for dogs that received chemotherapy (MST, 306 days) than for dogs that did not receive any additional treatment (MST, 419 days). This did not remain true when stratified by tumor grade.

Question 33

Indications, complications, and mortality rate following craniotomy or craniectomy in dogs and cats: 165 cases (1995–2016)

Answer 33

## Footnote This study identified greater odds of complications during surgery and vwithin 24 hours after surgery, with rostrotentorial and other approaches, compared to the caudal tentorial approach; Surgical approach, preoperative seizures, and administration of fentanyl postoperatively were associated with complications during surgery and within 24 hours postoperatively. Total IV anesthesia with propofol and timing of feeding were associated with odds of complications within 10 days of surgery.

Question 34

Ionized calcium-to-phosphorus ratio predicts neoplasia in azotemic dogs: a retrospective study of 105 cases

Answer 34

## Footnote The high number of patients with neopla- sia in our study population would suggest that in a hypercalcemic, azotemic, and normophosphatemic dog, there should be an effort to rule out neoplasia prior to assuming that the hypercalcemia is second- ary to renal dysfunction in these cases. In conclusion, the total calcium and Ca:P were higher in azotemic, normophosphatemic dogs with neoplasia; however, the low sensitivity and specificity of this ratio made it an unreliable tool to predict neo- plasia in this specific study population.

Question 35

Describe the process of calcium homeostasis

Answer 35

Calcium homeostasis is closely regulated along with phosphorus via parathyroid hormone (PTH), calcitriol (1,25-dihydroxyvitamin D3), and calcitonin. During periods of hypocalcemia, PTH secretion increases plasma calcium via mobilization of calcium and phosphorus from bone, increased renal absorption of calcium, and increased urinary excretion of phosphorus as well as increased calcitriol synthesis. Calcitriol has similar functions in addi- tion to resulting in increased intestinal absorption of calcium and phosphorus. Increased calcitriol results in negative feedback to inhibit PTH synthesis. Hypercalcemia suppresses PTH and upregulates calcitonin secretion to inhibit osteoclastic bone resorption.

Question 36

Age- and breed-matched retrospective cohort study of malignancies and benign skin masses in 660 dogs with allergic dermatitis treated long-term with versus without oclacitinib

Answer 36

## Footnote The cumulative incidence of malignancy did not differ significantly between the exposed group (16.5% [56/339]; 95% CI, 12.6% to 20.5%) and the nonexposed group (12.8% [41/321]; 95% CI, 9.1% to 16.4%). The relative risk of malignancy was 1.3 (95% CI, 0.9 to 1.9) for dogs in the exposed group versus the nonexposed group. The cumulative incidence of benign skin masses was significantly lower for the exposed group versus the nonexposed group. The relative risk of a benign skin mass was 0.7 for dogs in the exposed group, compared with those in the nonexposed group. The incidence rate of benign skin masses did **not** differ significantly between the exposed group (71 new cases/1,000 patient years) and the nonexposed group (91 new cases/ 1,000 patient years). The mean duration between onset of treatment and euthanasia or death was significantly longer for dogs in the nonexposed group (39 months;range, 4 to 110 months), compared with dogs in the exposed group (30 months; range, 6 to 56 months). Dosage of oclacitinib did not significantly affect odds of malignancy or benign skin masses.

Question 37

MOA oclacitinib

Answer 37

Oclacitinib inhibits the function of pruritogenic and pro-inflammatory cytokines that depend on JAK1 or JAK3 enzyme activity. It primarily targets JAK1, with a lesser effect on JAK3. By inhibiting these kinases, oclacitinib reduces the activity of various cytokines involved in allergy, inflammation, and itch, including IL-2, IL-4, IL-6, IL-13, and IL-31.

Question 38

Marginal excision of cutaneous mast cell tumors in dogs was not associated with a higher rate of complications or prolonged wound healing than marginal excision of soft tissue sarcomas

Answer 38

Question 39

Neoplasia of the tubular genital tract in 42 goats

Answer 39

Question 40

Outcome in dogs with invasive adrenal gland tumors that did not pursue adrenalectomy

Answer 40

## Footnote -dog with palladia survived greater than 800 days so don't understand median survival time range

Question 41

Outcomes following balloon dilation for management of urethral obstruction secondary to urothelial carcinoma in dogs: 12 cases (2010–2015)

Answer 41

## Footnote Compare with MST of 78 days with stent placement to relieve obstruction.

Question 42

Outcomes for dogs with functional thyroid tumors treated by surgical excision alone

Answer 42

## Footnote The MSTs for dogs with malignant and benign tumors were 970 and 1,072 days, respectively; these were not significantly (P = 0.65) different. ST for the dog with mets at dx was 87 days.

Question 43

Comparison of treatment with I131, RT, and surgery for thyroid tumors in dogs

Answer 43

Iodine 131 has been used to treat primary thy- roid tumors and metastatic disease, and survival times were similar to those obtained with external beam radiation therapy. Worth et al compared surgery, 131I, and a combination of both approaches as treatment for thyroid carcinomas in 65 dogs, of which 11 had hyperthyroidism. Three of the 11 dogs with hyperthyroidism underwent surgery alone, and 8 underwent 131I treatment alone. An MST for dogs undergoing surgery alone was not reached, and serum total T4 concentration was not reported to besignificantly associated with MST.

Question 44

Perioperative ventricular arrhythmias are increased with hemoperitoneum and are associated with increased mortality in dogs undergoing splenectomy for splenic masses

Answer 44

## Footnote Body weight was also significant for the pres- ence of both intra- and postoperative VAs in the pres- ent study, with each increase in body weight of 5 kg increasing the odds of intraoperative VAs by 16% and postoperative VAs by 24% on multivariable analysis. Previous studies have identified a link between increas- ing body weight and the presence of hemoperitoneum and also increasing body weight and a diagnosis of hemangiosarcoma. These historical findings are consistent with the findings of this study that heavier dogs were more likely to have a diagnosis of heman- giosarcoma and that for each 5 kg increase in body weight, the odds of hemoperitoneum increased by 22%. In conclusion, dogs with hemoperitoneum, a high- er body weight, and a higher heart rate on presentation were more likely to experience intra- and postoperative VAs. Presence of such VAs was associated with an in- creased odds of in-hospital mortality. Despite this, the overall in-hospital mortality rate was low (6.5%), indi- cating a good prognosis for survival of surgery in dogs with splenic masses, regardless of the presence of VAs or hemoperitoneum.

Question 45

Postoperative thrombocytosis and thromboelastographic evidence of hypercoagulability in dogs undergoing splenectomy for splenic masses

Answer 45

## Footnote A recent study of critically ill dogs failed to estab- lish an association between evidence of thrombosis at necropsy and thromboelastography parameters measured during the previous 7 days. The large pro- portions of dogs with postoperative thrombocytosis and thromboelastography parameters suggestive of hypercoagulability in the present study, combined with the comparatively low incidence of clinically apparent thromboses in dogs undergoing splenecto- my, imply that other important factors are involved

Question 46

# **Important article Prevalence of malignancy and factors affecting outcome of cats undergoing splenectomy

Answer 46

Question 47

What are some risk factors for cats undergoing splenectomy that have been inconsistently reported as negative prognostic factors?

Answer 47

Risk factors for cats undergoing splenectomy have not been clearly defined. Weight loss, anorexia, mastocytemia, administration of a blood product, metastasis to regional lymph nodes and a concurrent or historical neoplasia have inconsistently been reported as negative prognostic factors in cats undergoing splenectomy for MCTs.

Question 48

Survival times based on final diagnosis (MCT, LSA, HSA, nonneoplastic lesions) in 62 cats undergoing splenectomy

Answer 48

Question 49

Prevalence of malignancy in masses from the mammary gland region of dogs with single or multiple masses

Answer 49

Question 50

Which mammary glands in dogs are most commonly affected with masses?

Answer 50

In the present study, the fourth and fifth mammary glands were the most commonly affected (59% of masses identified in these glands), which is consistent with what has been previously reported

Question 51

Prevalence of pulmonary nodules suggestive of metastasis at presentation in dogs with cutaneous or subcutaneous soft tissue sarcoma

Answer 51

Question 52

What type of peripheral nerve sheath tumors are typically excluded from the STS group based on biological behaviour?

Answer 52

peripheral nerve sheath tumors arising from the brachial or lumbosacral plexus are typically excluded from the STS group

Question 53

Radiographic features of histologically benign bone infarcts and bone infarcts associated with neoplasia in dogs

Answer 53

Question 54

Retrospective analysis of carboplatin-induced cumulative neutropenia in cancer-bearing dogs

Answer 54

## Footnote In other words, all dogs that experienced multiple neutropenic events developed a neutropenic event by the second prechemotherapy CBC.

Question 55

Short- and long-term outcomes associated with anal sacculectomy in dogs with massive apocrine gland anal sac adenocarcinoma

Answer 55

## Footnote Age, body weight, hypercalcemia, largest mass dimension on CT, adjuvant chemotherapy, and adjuvant radia- tion therapy were not associated with PFI nor identi- fied as confounders on the main effects. No variables were associated with OST. Lymph node metastasis at the time of surgery was a negative prognostic indicator for PFI but not OS in these dogs. NOTE: The only risk factor that has been pre- viously associated with local recurrence is the pres- ence of lymphovascular invasion, which was unable to be evaluated in this study

Question 56

Procedural description and prospective evaluation of short-term outcome for the use of prostatic artery embolization in dogs with carcinoma of the prostate

Answer 56

## Footnote All dogs had decreased prostate volume (on the basis of results from CT performed before and 30 days after PAE) and improved clinical signs (on the basis of results from owner questionnaires completed before and 30 days after PAE). Although technically challenging, PAE was successfully performed for all 20 dogs and complications were uncommon.

Question 57

Single high-dose radiation therapy and liquid fiducial markers can be used in dogs with incompletely resected soft tissue sarcomas

Question 58

Stereotactic radiotherapy (10 Gy X 3) for canine nonlymphomatous intranasal tumors is associated with prolonged survival and minimal risk of severe radiotoxicity

Answer 58

## Footnote Interestingly, there is no evidence from this study that diagnosis with chondrosarcoma is a positive prognostic factor; in fact, to the contrary, as compared with other histologies, senior dogs in this population had a more than 7-fold higher risk of dying (P =0.007) when they had chondrosarcoma.

Question 59

What are several factors that are prognostic for OST that have been described for dogs treated with conventional full-course protocols.

Answer 59

Several factors that are prognostic for OST have been described for dogs treated with conventional full-course protocols. Dogs with adenocarcinomas and well-differentiated carcinomas reportedly survive longer than dogs with poorly differentiated, anaplastic, or squamous cell carcinomas, and dogs with chondrosarcomas fare better than dogs with adenocarcinomas. By contrast, and regardless of tumor histotype, dogs with tumors causing lysis of the cribriform plate have shorter OST times than those without calvarial involvement.

Question 60

Stereotactic body radiation therapy for treatment of soft tissue sarcomas in 35 dogs

Answer 60

Question 61

Incidence, survival time, and surgical treatment of parathyroid carcinomas in dogs: 100 cases (2010–2019)

Answer 61

Question 62

Suspected primary bone marrow T-cell lymphoid neoplasia causing paraneoplastic hypercalcemia in 11 dogs (2014–2021)

Answer 62

## Footnote Flow cytometry was also useful to characterize the neoplasm as CD4+ or CD4– CD5– T cell in origin, rather than a CD34+ ALL,

Question 63

The promise of immunotherapeutic strategies to advance cancer treatment in pet dogs

Answer 63

Question 64

Multimodality treatment including ONCEPT for canine oralmelanoma: A retrospective analysis of 131 dogs

Answer 64

## Footnote Response ratesto hypofractionated RT are >80%, with complete remission ratesbetween 44% and 70%. Response rates to hypofractionated RT are >80%, with complete remission rates between 44% and 70%. None of the dogs had distant metastasis or receivedchemotherapy.

Question 65

What are positive prognostic indicators for oral melanoma?

Answer 65

Prognostic indicators that predict a better outcome after treatment include small primary tumor size, lower clinical stage, absence of metastasis, rostral location in the oral cavity, absence of bonelysis, tumor site (lip), and histologic features including well-differentiated histology, low mitotic index (MI), low Ki67index, and low nuclear atypia.

Question 66

What are response rates for oral melanoma to hypofractionated RT?

Answer 66

Response rates to hypofractionated RT are >80%, with complete remission rates between 44% and 70%.

Question 67

Thoracoscopic resection of lung masses is associated with excellent survival to discharge and good long-term outcomes

Answer 67

Question 68

Timing of adjuvant chemotherapy after limb amputation and effect on outcome in dogs with appendicular osteosarcoma without distant metastases

Answer 68

## Footnote On multivariable analysis, a TIamp-chemo > 5 days and duration of clinical signs > 28 days were significantly associated with an increased risk of tumor progression. The TIamp-chemo was the only variable that retained a significant association with OST on multivariable analysis.

Question 69

Treatment of retroperitoneal sarcoma results in improved outcomes

Answer 69

Question 70

Tumor size as a predictor of lymphatic invasion in oral melanomas of dogs ## Footnote Note: Lymphatic invasion has been described as the gold standard for identification of malignancy of melanocytic neoplasms of the mouth.

Answer 70

## Footnote A sensitivity of 100% was seen at a tumor size ≥ 6.5 mm in diameter, and specificity of 100% was obtained at a size ≥ 24.5 mm in diameter. Although significant (P = 0.047), the area under the ROC curve for tumor size in predicting lymphatic invasion was 0.678 (95% con- fidence interval, 0.521 to 0.835) and was considered poor. The Youden index was used to determine the optimal tumor size with the highest combined sen- sitivity and specificity to detect lymphatic invasion. The Youden index was maximized at a tumor size of ≥ 16.5 mm in diameter, with a sensitivity and specificity of 42.2% and 92.9%, respectively.11

Question 71

# **Important article Ultrasonographic liver nodules are more often benign lesions in dogs with hemoperitoneum secondary to splenic tumor rupture

Answer 71

## Footnote Note: Recently we reported on a small cohort of dogs with splenic tumor rupture and found that only 33% of liver nodules found on preoperative ultrasonogra- phy were subsequently histologically confirmed to be metastatic hemangiosarcoma lesions. There were no discernable differences in ultrasonographic appearance to differentiate between benign and malignant lesions. Our study contributes significantly to this discus- sion by reporting an overall prevalence of liver metas- tasis in dogs with hemoperitoneum secondary to a ruptured splenic tumor at a markedly lower rate of only 12%, indicating a notable departure from previously re- ported figures. An explanation for this difference could be the prospective nature of this study, compared to the retrospective nature of most of these previous studies, demonstrating the potential impact of under- lying biases inherent within retrospective data. Eleven of the 12 (92%) dogs diagnosed with hepatic metastasis had hemangiosarcoma and the remainder had carcinomatosis. Furthermore, we showed that only 15% of liver lesions identified on preoperative ultrasonography were histologically confirmed to be metastatic, whereas the remainder of the lesions were determined to be benign lesions. Similar findings have been noted in another study.

Question 72

Vinblastine/prednisolone chemotherapy leads to hematological toxicity in dogs with high-grade or metastatic mast cell tumors

Answer 72

Question 73

What ails the pet rat? A retrospective study of more than 300 biopsy samples of externally palpable masses submitted from pet rats for histopathology (2013e2021)

Answer 73

Question 74

Lumpy, bumpy guinea pigs: a retrospective study of 619 biopsy samples of externally palpable masses submitted from pet guinea pigs for histopathology

Answer 74

Question 75

Activation of the Akt signalling pathway as a prognostic indicator in canine soft tissue sarcoma

Answer 75

## Footnote The phosphatidylinositol 3-kinase (PI3K)/Akt/mammalian target of rapamycin (mTOR) is one of the signalling pathways that contribute to cell proliferation and regulates many important cellular processes such as tumour growth, differentiation, meta- bolism and anti-apoptosis in various types of tumours [15]. Akt is a type of serine/threonine kinase [16] and is activated when Ser473 residue is phosphorylated by the mTORC2 complex in response to growth factor stimulation. Activated Akt regulates cell proliferation, survival and motility through phosphorylation of the effector proteins 4E-BP1 and S6 kinase (S6K), the latter of which further phosphorylates S6 (phospho-S6) [17,18]. Expression of phospho-S6 has also been used as an indicator to determine activation of the PI3K/mTORC1/S6K pathway [19e21]. Some reports suggest that elevated expression of phospho-S6 is associated with metastasis and cancer cell invasion [22e26]. Furthermore, in human STS, expression of phosphorylated Akt (phospho-Akt) and its downstream proteins has been found to be increased, suggesting that it could potentially be a new therapeutic target for STS [27]. There- fore, high expression of phospho-Akt could be related to metastasis in STS and activation of the Akt signalling pathway may potentially be associated with grading and prognosis in canine STS.

Question 76

Significance of Angiogenic Growth Factors in Bovine Ocular Squamous Cell Carcinoma

Answer 76

## Footnote The most common lesion in dogs was gingival hyper- plasia, followed by peripheral odontogenic fibroma, while in cats lymphoplasmacytic stomatitis was most common. Boxers appear predisposed to peripheral odontogenic fibroma. Young age may be a risk factor for calcinosis circumscripta and viral papilloma in dogs. The most common oral cavity malignancy in dogs and cats is high-grade melanoma and squamous cell carcinoma, respectively. Feline oral melanoma is a rare disease. Due to the wide spectrum of observed oral cavity tumours and tumour-like lesions and their macroscopic similarity, clinical diagnosis may be challenging, therefore histopathological examination is recommended in each case.

Question 77

Canine and Feline Oral Cavity Tumours and Tumour-like Lesions: a Retrospective Study of 486 Cases (2015e2017)

Answer 77

Question 78

# **Important What factors have been suggested to cause the development of canine and feline oral tumors?

Answer 78

It has also been suggested that canine and feline oral cavity tumours can develop due to passive tobacco smoke inhalation, flea control collars and dietary and environmental factors. Several factors have been described that can lead to the development of oral squamous cell carcinoma in cats, including contact with carcinogens in flea collars, topical tick and flea medications or grooming behaviour. Chronic stomatitis has also been proposed as a predisposing factor for squamous cell carcinoma in both dogs and cats

Question 79

Canine Cancer Cells Activate Platelets via the Platelet P2Y12 Receptor

Answer 79

Question 80

# **Important Article Canine Non-Angiogenic, Non-Myogenic Splenic Stromal Sarcoma: a Retrospective Clinicopathological Analysis and Investigation of Podoplanin as a Marker of Tumour Histogenesis

Answer 80

## Footnote Biological behaviour has been most closely correlated with the mitotic count (MC) of these tumours, with a MC greater than or equal to 9 associated with a significantly longer survival time (7 months versus 1-2 months). Categorization of a subset of these tumours into distinct histotypes based on standard light microscopy is exceptionally difficult, as there is significant histo- morphological overlap between fibrosarcoma, leiomyosarcoma, histiocytic sarcoma and undifferen- tiated sarcoma (Spangler et al, 1994). Additionally, the appearance of splenic complex nodular hyperpla- sia (CNH), which can be dominated by stromal cells or histiocytes, can complicate attempts at classifica- tion (Moore et al, 2012). Not only can lesions of CNH and stromal sarcoma overlap morphologically with histiocytic sarcoma and lymphoma (collectively described as splenic fibrohistiocytic nodules [SFHNs]) (Spangler and Kass, 1998) but specifically, differentiating CNH with prominent fibrohistiocytic stromal expansion (ie, grade II SFHNs) from genuine but well-differentiated and inflamed stromal sar- comas (ie, grade III SFHNs) is particularly difficult.

Question 81

# **Important Chart Proposed diagnostic algorithm for histopathological evaluation of splenic tumours in dogs. After

Answer 81

Question 82

Canine ovarian epithelial tumours: histopathological and immunohistochemical evaluation with proposed histopathological classification system

Answer 82

## Footnote The currently established criteria of malignancy for OETs in domestic animals are increased mitotic activity, invasion into the ovarian stroma and extension into the ovarian bursa [2], but there is no specified cut-off value for mitotic activity. In this study, an OET was classified as an OvCa if it exhibited at least extensive effacement of ovarian tissue, invasion of ovarian stroma or extension into the ovarian bursa, whereas an ovarian adenoma could not have any of these three features. Ovarian adenomas had simple branching papillae lined by one or two layers of uniform, cuboidal or tall columnar neoplastic cells with basally located nuclei, whereas the arrangement in papillary OvCas was less orderly. This study provides refined morphological criteria for differentiating benign OETs and OvCas, as well as the description of several histopathological patterns of OvCas, namely papillary, solid with tubular differentiation, micropapillary, cystic and sarcomatous. The application of this classification scheme is proposed for further studies of canine OETs, especially OvCas, since significant prognostic differences may be discovered between different subtypes in the future. Our results also highlight a mitotic count of two as apotential cut-off value between benign OETs and OvCas. Since there can be morphological overlap between OvCas and sex cord-stromal tumours, CK7 expression can be helpful in con- firming ovarian epithelial origin in ambiguous cases. Furthermore, based on its frequent expression, 14-3-3s appears to have a role in canine OETs since it is not expressed in normal canine ovaries. The infrequent expression of COX-2 suggests that it is a poor candidate as a potential therapeutic target in canine OvCas.

Question 83

CD117 expression in canine ovarian tumours

Answer 83

## Footnote The most prevalent canine ovarian tumours are carcinomas and granulosa cell tumours (GCTs) [10]. Ovarian carcinomas (OCs) arise from the ovarian surface epithelium and surface epithelial structures (SES) [10]. They are the most common and aggressive and have metastatic rates of up to 48% [3]. Histologically, OCs contain tubular, cystic and papillary growth patterns, characterized by large cuboidal or columnar cells with scant or moderate amounts of cytoplasm and basal nuclei [11,12]. GCTs derive from sex-cord stromal tissue and are unlikely to metastasize [1,3], but they have a greater variety of histological patterns, making accurate diagnosis difficult. Cytokeratin 7 (CK7) is a type II intermediate filament found in ovarian surface epithelium and thus can be used to differentiate epithelial from sex-cord derived tumours [13]. Normal ovarian tissue did not express CD117 but positive CD117 immunolabelling was found in both GCTs and OCs and, although not statistically significant, OCs generally had more intense expression in comparison with GCTs.

Question 84

CDX-2 Protein and mRNA Expression in Canine Intestinal Adenocarcinoma

Question 85

Characterization of 22 Canine Pancreatic Carcinomas and Review of Literature

Answer 85

## Footnote In summary, the clinical findings in canine pancre- atic carcinomas are non-specific and simultaneous inflammation can mask the underlying neoplasm, so pancreatic carcinomas may be misdiagnosed as un- successfully treated pancreatitis. Consequently, diag- nosis of pancreatic carcinomas in dogs requires detailed histopathological characterization of pancre- atic biopsy samples.