Ch 82 Tumor surgery Flashcards
(48 cards)
1
Q
considerations
A
- first surgery has the best chance of complete removal and should therefore be well planned.
- Incomplete resection > only diagnostic purposes (biopsy) because regrowth of the tumor will usually occur quickly > partly in response to enhanced (neo)vascularization of the tumor bed
- central (bulk) portion of tumor relatively indolent and slow growing,
- tumor edge contains cells displaying a “migratory or invasive phenotype” > micro-environment that facilitates aggressive growth behavior
2
Q
common skin tumours
A
3
Q
surgical margins
A
- most important factor in local tumor control is the surgical wound margin
- debulking
- marginal
- wide
- radical
- depends on tumor type and grade (i.e., invasiveness) and on the type of tissue (e.g., fat versus fascia)
- high probability of local recurrence, depth = at least one tissue plane away from the tumor
- considerable variation in published data about what is considered a complete tumor excision on histologic margin evaluation
4
Q
surgical principles
A
biopsy
- histologic type and grade often predictive for biologic behavior = important for treatment planning
- incisional biopsy prefered
- Fine needle aspiration biopsy tracts are of less importance in regard to tumor spread.
- Contamination of needle tracts > transitional cell carcinomas and pulmonary adenocarcinomas
principles
- Open wound management after wide excision of distal extremity tumors can have very good functional and oncologic outcome > can be slow, relatively fragile new skin and wound contracture
- Faster wound healing with better skin quality with graft
- Careful and correct tissue handling must be applied to avoid spreading of tumor cells
- Early ligation of larger, tumor-associated blood vessels
- if tumor bed was incised during surgery, instruments and gloves should be changed +/- lavage of wound bed
- 5% to 10% formaldehyde;
- 2 cm scar revision margin
5
Q
Factors Affecting Wound Healing
A
- chemo
- radiation
- tumour related (residual neoplastic tissue infiltrating, cytokines and bioactive substances (e.g., mast cell degranulation), cancer cachexia, and other paraneoplastic syndromes
6
Q
Likewise, full-thickness intestinal surgery (gastrotomy/enterotomy and/or resection-anastomosis) in 70 cats with alimentary lymphoma was not associated with an increased risk for wound dehiscence.
A
7
Q
What tissue appears most sensitive to healing issues with chemotherapy?
At what stage post-op is it generally recommended to start chemotherapy?
A
- Intestinal tissue
- 7-10 days after surgery > arbituary as sudies in human have shown no heling consequnces with peri-op chemo and potentially interferes with metastatic pathways
8
Q
What is the gereral recommendation of timing of radiation therapy before and after surgery?
A
- After surgery: 1-3 weeks (Effects on wound healing most distinct in the acute inflammatory and proliferative phase, less severe during granulation and remodeling)
- Before surgery: Discontinue for 3-4 weeks
9
Q
List tumour-related factors which may impact wound healing
A
Residual neoplastic tissue
Tumour-related cytokines
Cancer cachexia
Paraneoplastic syndromes
Tumour size
10
Q
Tumor Staging
A
- uses the tumor-node-metastasis (TNM) system
- size and invasiveness (T),
- involvement of regional lymph nodes (N),
- presence of distant metastases (M).
- routine blood work
- signs of possible paraneoplastic syndromes
- All skin and subcutaneous masses should be investigated cytologically by fine needle aspiration biopsy
- Most tumors can be diagnosed cytologically.
- definitive diagnosis of tumor type and grade (malignancy) should be confirmed through histology.
11
Q
List the 4 classifications of tumours based on cell origin
A
- Mesenchymal: (mesoderm) connective tissue, endothelial, hematopoietic, lymphoid, and muscle origin. Fibrosarcomas, hemangiopericytomas, peripheral nerve sheath tumors, myxosarcomas, liposarcomas, lipomas, hemangiosarcomas, vaccine-induced sarcomas
- Epithelial: (endoderm, mesoderm, ectoderm) papillomas, squamous cell carcinoma, basal cell tumors, sebaceous and sweat gland tumors, perianal adenomas and adenocarcinomas, apocrine gland adenocarcinomas, hair matrix tumors, and mammary gland tumors
- melanocytic
- round cell: Lymphoma, plasma cell tumor, histiocytoma, mast cell tumor, transmissible venereal tumor, and malignant histiocytosis
12
Q
What is the estimated diagnostic accuracy of FNA cytology of skin neoplasms as compared to histo?
FNA has a high predictive value
A
over 90%
13
Q
How do epithelial and mesenchymal neoplasms tend to metastasise?
A
- Mesenchymal - haematogenous
- Epithelial - Lymphatics
Exceptions: osteosarcoma, synovial cell sarcoma spead to lymph nodes
14
Q
L.n. FNA
A
Fine needle aspiration cytology can be very sensitive to diagnose lymph node metastasis, compared to manual palpation, which has much lower sensitivity
15
Q
CT/MRI
extent of disease
A
- to establish better insight into tumor margins and invasiveness
- assess l.n.
- screening for thoracic metastasis
16
Q
What technique can be used for real-time intra-op margin assessment?
A
Near-infrared fluorescense imaging
17
Q
What sized thoracic nodules can be detected on CT and rads?
A
CT: 1-2mm
Rads: 5-9mm
18
Q
Lymphatic System
A
- functions: transport and immune response
- part of the cardiovascular system
- part of the host immune defense system
lymphatics
- initial lymphatics are present as blind-end sinuses
- no tight junctions between the cells,> permit extracellular fluid, macromolecules, and cells to drain
- lymphatics > collecting ducts > lymph nodes > thoracic duct
- lymph flow is active and passive
lymph node
- one or two at each nodal station.
- capsule (smooth muscle fibers), septa and trabeculae, the hilus and Internally, a cortex and medulla.
- B cell, T cells, macrophages and plasma cells
19
Q
What cells make up the germinal centers of a lymph node?
A
B-lymphocytes and plasma cells
20
Q
Lymphadenectomy
A
- Evidence of metastasis in local lymph nodes is an important indicator of systemic metastasis and predictive for prognosis for many cancers
- role of positive nodes in tumor metastasis is still largely unclear, and how to deal with tumor-positive local lymph nodes remains a controversial subject
- classic theory: represents the first location of metastasis before systemic spread has long been debated
- lymph node staging in humans is based on biopsy of the sentinel
- made visible using blue dye, contrast material, and/or a low dose of radionuclide injected in or near the tumor.
- The first draining node is detected visually or by hand-held gamma detector and removed for histology.
- presence of micro (<2mm) or macrometastasis determines risk of more l.n. being involved and reduced DFI
- however, melanomas in humans metastasize to distant sites irrespective of lymph node status
- In dogs lymph drainage is frequently not confined to the closest draining lymph center + removing lymph nodes with microscopic disease may be therapeutic > sentinel lymph node (excisional) biopsy may be warranted in veterinary patients
- mammary tumor STUDY: dogs with macrometastasis in the draining lymph node (>2 mm) had significantly worse outcome than if micro
21
Q
List some benefits of lymphadenectomy
A
- LN mets may act as a source for further spread
- Could slow down rate of mets
- May reduce paraneoplastic disease
- Part of debulking procedure
- Lymphadenectomy pf positive nodes concurrent with excision of grade 2 MCT significantly improved survival
22
Q
List some disadvantages of lymphadenectomy
A
- tumor sites are commonly drained by more than one set of local lymph nodes > metastasis can occur in nodes, making elective lymphadenectomy a serious and invasive procedure.
- lymphadenectomy of normal nodes is potentially harmful ( Lymphedema)
- possibly interferes with an important immunologic host response against the tumor
23
Q
Lymphangitis
A
- inflammation of lymph vessels) is usually caused by infectious agents
- locally swollen and painful
- Chronic > results in mesenchymal cell proliferation, which may cause irreversible thickening of skin and subcutis
- Conservative therapy using moist, warm, local compresses or soaks
- infectious agent is diagnosed or suspected, systemic antimicrobial therapy is indicated
24
Q
What is lymphedema?
Lymphedema can be primary or secondary.
A
Interstitial oedema characterised by an imbalance between net capillary filtration and lymphatic return of interstitial fluid
With lymphatic stasis, macromolecular proteins and metabolites accumulate in the interstitial space. This increased oncotic pressure draws more water out causing a subsequent increase in interstitial hydraulic pressure. Dilation of lymph vessels may also lead to valve insufficiency
chronic > processes lead to progressive subcutaneous fibrosis
25
List underlying abnomalities of primary lymphoedema
Hypoplasia, aplasia or hyperplasia of distal lymphatics
Lymphatic valve incompetence
hypoplastic or fibrotic lymph nodes
- onset of clinical signs (usually at birth)
-
26
Secondary Lymphedema
neoplasia, trauma, surgery, radiation therapy, parasitic infection, and chronic lymphangitis
veterinary literature on secondary lymphedema in companion animals is limited
dx
- As fibrosis increases, pitting may not occur
- High lymphatic load (inflammation, hypoproteinemia, cardiac dysfunction, venous obstruction, arteriovenous fistula) must be ruled out
- investigated by direct contrast lymphangiography
27
fascial plane mapping for superficial tumour resection in the canine hindlimb
| Latifi 2024
type 1 fascia (discrete sheets) – lumbodorsal fascia, lateral gluteal region, fascial lata,
lateral crus
- type 2 fascia (associated with thin muscles) – internal/external abdo oblique, sartorius
tensor fascia lata, distal biceps and fascia
lata, superficial gluteal
- type 3 fascia (associated with thick muscles) – biceps femoris, semimembranosus,
semitendinosus, middle gluteal
- type 4 fascia (associated with periosteum) – iliac wing, ischium, patella, tibial tuberosity,
medial tibia, distal crus and pes
- questionable fascial planes – ischiorectal fossa, femoral triangle, extensor mechanism
medial and distal crus and pes
- intersections and margins of ventral perineum → difficulty maintaining deep margin
28
fascial plane mapping for superficial tumour resection in the canine forelimb
- type 1 fascia (discrete sheets) – antebrachium, prox scapula, small area of biceps fascia
- type 2 fascia (associated with thin muscle) – majority of scapula, trunk, medial brachium
- type 3 fascia (associated with thick muscle) – lateral brachium over triceps, medial biceps
- may require partial muscular resection
- type 4 fascia (associated with periosteum) – scapular spine and olecranon
- questionable fascial planes – elbow joint, distal ¼ of antebrachium, carpus
29
fascial plane mapping for superficial tumour resection in the canine neck and trunk
type 1 fascia (discrete sheets) – lumbodorsal fascia, tendinous portion of trapezius
- type 2 fascia (associated with thin muscle) – majority of trunk and neck
- type 3 fascia (associated with thick muscle) – lateral brachium
- may require partial muscular resection
- type 4 fascia (associated with periosteum) – muscles of the caudal thorax to 13th rib
dorsal spinous processes T6-L6
- questionable fascial planes – area surrounding 13th rib, junction between latissimus dorsi
and external abdominal oblique
30
Ranganathan 2021 – intersurgeon agreement for 3cm margins of excision of subcutaneous tumours
- prediction interval for margin measurement 6mm
- 95% surgeons expected to delivery 2.4-3.6mm margins → clinically relevant variation
31
Milovancev 2018 – margin length reductions occur at every step of processing for MCT and STS
- in grII MCT and grI-II STS
- physical factors: tissue elasticity, myofibril contraction, processing
- biological factors: microscopic tumour infiltration into grossly normal margins
- expected reduction in margins: MCT median 8.8mm, STS median 5.0mm
- upper 75% quartile: 12.3mm and 9.6mm
- max reduction: MCT 29.6mm, STS 24.2mm
32
sentinel lymph node mapping
| SLN, the first LN draining the tumour bed
- lack of comparative studies between different techniques, a standardized approach for SLN mapping is lacking in dogs and cats
- removing the RLN (anatomically closest LN to the primary tumour) or only enlarged or cyto-positive l.n. may lead to an undertreatment of potentially metastatic LNs
- studies confirm a discrepancy of **28%–63% between RNL and SLN** using different mapping techniques
mapping tehcniques
- Radiographic indirect lymphography
- CT indirect lymphography
- Contrast-enhanced ultrasound (CEUS) indirect lymphography
- Lymphoscintigraphy and methilene
blue
- Near-infrared (NIR) fluorescence
33
Annoni 2023 – SLN of canine MCT with pre-op radiographic indirect lymphography
| VCO
peritumoural injection of iomeprole 1ml per 1cm2 of tumour base
- 151/168 (90%) detected at first radiograph 1min post-injection
- different to RLN in 57%
- multiple SLN in 26%, multiple lymph centres in 31%
34
Comparison of indirect computed tomographic lymphography and near-infrared fluorescence sentinel lymph node mapping for integumentary canine mast cell tumors
Alvarez-Sanchez 2023
at least 1 SLN identified = 80%
- different nodes identified by different techniques – complementary rather than exclusive
- 95% low-intermediate grade tumours bu 95% had metastatic LN
Detection of
ICTL-SLN and NIRF-SLN failed in 1/20 (5%) and 4/20 (20%), respectively.
Tumors were grade II/low-grade in 19/20 (95%) > Nineteen out of 20 (95%) dogs had mets present
Intermediate to low grade tumors had a high metastatic
LN rate regardless of the tissue layer the primary
MCT was located to, suggesting a greater aggressiveness
of lower grade tumors than previously reported.
35
Surgical complications following sentinel lymph node biopsy guided by γ-probe and methylene blue in 113 tumour-bearing dogs
| vco
postoperative: overall 21.2%
- 2/113 (2.8%) major → severe seroma requiring revision 1/2
severe lymphoedema 1/2
- minor: lymphoedema, seroma, hematoma, dehiscence
36
Development of a minimally invasive endoscopic technique for excisional biopsy of the axillary lymph nodes in dogs
Kuvaldina 2023
incise between superficial pectorial and lat dorsi
37
Near-infrared fluorescent image-guided lymph node dissection compared with locoregional lymphadenectomies in dogs with mast cell tumours
P Beer 2022
NIRF → higher degree (83%) of identification of nodes targeted based on pre-op mapping
- more metastatic nodes diagnosed (69% vs 33%) with NIRF
38
Lymphatic drainage from the head and neck is variable with significant crossover, therefore sentinel lymph node (SLN) mapping can help ensure the appropriate lymph node(s) are sampled
Wan 2021 – CTL + indocyanine green NIRF + meth blue → 100% SLN for oral tumours in dogs
- IG-NIRF 91%, MB 50.8%, CTL 42.1% identification
- CTL + intraoperative lymphography recommended
39
Chiti 2021 – SLN mapping recommended for canine malignant head and neck tumours
- lymphoscintigraphy and blue dye → sens 88.9%, spec 100% for SLN for biopsy
- biopsy → 42% positive, 4/8 positive nodes were different to regional LN
- ipsilateral mandibular lymphocenter affected in only 22% dogs
40
Randall 2020 – intra- or peri-tumoural contrast injection for indirect CT-L
- 4-quadrant peritumoural more effective for highlighting draining vessels and SLN (11/20)
vs intratumoural (5/18)
- less successful vs vital dye injection (17/18) and lymphoscintigraphy (20/20)
- variable lymphatic vessel drainage to Lns and variable number of nodes receiving
drainage in a basin observed
41
Detecting LN metastasis is problematic in veterinary clinical practice: LN size or asymmetry on palpation is unreliable for detection of metastasis11; there are significant patient anatomical variation in the number and location of LNs within a lymphocenter (LC)12; and complex, variable LN drainage patterns have been described.13 Not all LNs are palpable or readily accessible for sampling (e.g., medial retropharyngeal and parotid LCs), which further complicates preoperative decision making.4 For this reason, extirpation of all bilateral mandibular and retropharyngeal LCs for histopathology has been recommended to avoid understaging patients,14, 15 but this is invasive and the therapeutic benefit remains unknown.
42
Diagnostic accuracy of contrast-enhanced computed tomography for assessment of mandibular and medial retropharyngeal lymph node metastasis in dogs with oral and nasal cancer
O. T. Skinner
ensitivity of CT was 12.5% and 10.5%, specificity was 91.1% and 96.7%, and accuracy was 67.5% and 76.3% for mandibular and medial retropharyngeal lymph nodes respectively. No individual CT findings were predictive of nodal metastasis. Given the low sensitivity of CT, this modality cannot be relied upon alone for assessment of cervical lymph node metastasis in dogs.
43
Prevalence of pulmonary nodules suggestive
of metastasis at presentation in dogs with cutaneous
or subcutaneous soft tissue sarcoma
Villedieu 2021
146 client-owned dogs, retro
nodules present in 16 (11.7%)
dogs (5/77 [6%] with grade 1 STSs, 2/36 [6%] with grade 2 STSs, and 9/24
[38%] with grade 3 STSs).
recurrent tumors (5/22 [23%])
pulmonary staging was a low-yield diagnostic procedure
for dogs with grade 1 or 2 cutaneous or subcutaneous STSs, especially when tumors
had been present for ≤ 3 months
44
Clinical experience with next-generation sequencing–based liquid biopsy testing for cancer detection in dogs:
a review of 1,500 consecutive clinical cases
Allison L. O’Kell,
The relative observed sensitivity was 61.5% (67/109) and specificity was 97.5% (311/319). The positive predictive value was 75.0% (21/28) for screening patients and 97.7% (43/44) for aid-in-diagnosis patients,
involves analyzing circulating tumor DNA (ctDNA) in blood samples to detect and monitor cancer-related genomic alterations.
45
Percutaneous ultrasound-guided anchor wire
placement aids in the intraoperative localization
of nonpalpable, superficial foreign bodies and abscesses in dogs
Grace Thomas 2024
| Rossanese et al: use for lymph nodes
Computed tomography and ultrasound revealed an abscess cavity and suspected foreign body in 9 dogs and an abscess cavity without evidence of a foreign body in 2 dogs. Anchor wires were placed in close proximity to the foreign body or inside the abscess. All documented foreign bodies were successfully located and retrieved.
use of an anchor wire for minimally invasive localization has been demonstrated to be a successful, safe, and effective method of facilitating superficial inguinal lymph node excisions in dogs without perioperative complications.21 Rossanese et al22 determined that this method more successfully localized nonpalpable lymph nodes in dogs and reduced surgical time when compared to methylene blue or unassisted lymphadenectomy.
46
Ultrasound-guided placement of an anchor wire or injection of methylene blue to aid in the intraoperative localization and excision of peripheral lymph nodes in dogs and cats
Rossanese 2021
ultrasound-guided placement of an anchor wire (AW) or injection of methylene blue (MB)
94% for group AW, 87% for group MB, and 72% for group None
Both lymph node localization techniques were highly successful and reduced surgery time, compared with unassisted lymphadenectomy.
47
Abdominal CT evaluation of the liver and spleen for staging
mast cell tumors in dogs yields nonspecific results
Jonathan R Hughes
| VRU
Computed tomographic evaluation of the liver showed
no consistent pattern associated with mast cell metastasis and did not predict cytology results.
Multifocal splenic hypoattenuating lesions more commonly coincided with mast cell metastasis.
Sampling of the liver and spleen remains to be considered in the absence of abnormal CT findings
for full staging.
48
Superficial anatomic landmarks can be used to triangulate the location of canine peripheral lymphocentrums:
superficial cervical, axillary, and superficial inguinal
Natalie J. Worden
the superficial landmarks to each lymphocentrum were as follows:
(1) superficial cervical: wing of atlas, acromion process of scapula, greater tubercle of humerus;
(2) axillary: caudal border of transverse head of superficial pectoral muscle, caudal triceps muscle, ventral midline; and
(3) superficial inguinal: origin of pectineus muscle, ipsilateral inguinal mammary gland, ventral midline.
