Oncology: Approach to the Cancer Case Flashcards

1
Q

Why do patients die of cancer?

A
  • Delayed/erroneus diagnosis
  • Failure to treat- primary disease, metastatic spread
  • Ineffective treatment
  • Owner decided not to treat
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2
Q

What basic diagnostics can be done for cancer?

A
  • History
  • Physical examination
  • Minumum database- blood count, biochem, urinalysis
  • Biopsy- cytology, histoloy
  • Imaging
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3
Q

What advanced diagnostic tools can be used for cancer?

A
  • Immunochemistry- cytochemistry and histochemistry
  • Flow cytometry
  • PCR
  • Electrophoresis
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4
Q

What are the AVMAs signs of cancer?

A
  • Abnormal swelling that persists or continues to grow
  • Sores that do not heal
  • Unexplained weight loss
  • Loss of appetite
  • Bleeding or discharge from any body opening
  • Bad odor- especially mouth
  • Difficulty eating or swallowing
  • Reluctance to excercise or loss of stamina
  • Difficulty breathing, urinating, defecating
  • Change in behaviour
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5
Q

What should be noted when examining a potential lesion?

A
  • Measure and record size and location of all lesions
  • Assess invasiveness and attachment to underlying tissues
  • Look for characteristics associated with malignancy
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6
Q

If cancer is suspected what should be checked on a general examination?

A
  • General condition and BCS
  • Palpation over the whole body
  • Palpation of LNs especially draining nodes
  • Palpation looking for signs of pain, especially over bones and spine
  • Oral and rectal examination
  • Assessment of CVS and respiratory systems
  • Abdominal palpation
  • Mentation and neuro assessment
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7
Q

What can haematology and biochemistry show for cancer patients?

A

Haematology- only diagnosis if patient has leukaemia
* required prior to chemo

Biochem is never diagnostic
* concurrent disease

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8
Q

How is cancer diagnosed?

A
  • FNA- cytology
  • Tissue biopsy- histopathology
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9
Q

What are the pros and cons of cytology vs histopathology

A

Cytology
* Not as invasive
* Only manual restaint
* Cheaper
* Limited assessment of tumour type/grade

Histopathology
* GA required
* More accurate tumour type/grade
* Invasive

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10
Q

What is generally the purpose of cytology vs histopathology and vice versa?

A

Strength of cytology is generally guiding diagnostics and treatment planning- prior to surgery

Histolopathology- final diagnosis and guiding post surgical treatment

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11
Q
  1. When is needle off FNA indicated? (not aspirated)
  2. What do you need to be careful of?
A
  1. Lymph nodes, suspected round cell tumours
  2. Do not go through lesion (seeding)

Multiple directions, cover needle hub as you with draw

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12
Q
  1. When is FNA with aspiration indicated?
  2. How much pressure is indicated?
A
  1. Suspect solid tumuors, when the needle off gave poor yield
  2. 1cc of negative pressure (1ml)

Multiple directions, don’t go through lesion, release suction before taking needle out

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13
Q

What are contraindications for FNA?

A

Bleeding
* if platelet count normal and no evidence of coagulpathy then ok

Risk of pneumothorax/urine

Tumour transplantation deeper into tissue

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14
Q

How is a smear made from an FNA?

A

5ml air to expel sample
Use weight of slide to spread the sample

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15
Q

How can cytology samples be taken?

A
  • Intra-op or PM
  • Ulcerated superficial lesions
  • Nasal biopsies
  • Airway lesions
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16
Q

Describe the technique for cytology impression smears

A
  • Collect sample
  • Blot surface- remove debris if ulcerated lesion, remove blood
  • Dab against slide- make multiple spots
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17
Q

What are the problems of FNA?

A

None diagnostic
None representitive- heterogenous lesions

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18
Q

What are the different tissue biopsy techniques?

A
  • Needle core biopsy
  • Incisional biopsy
  • Surface and pinch biopsies
  • Punch biopsy
  • Excisional biopsy
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19
Q

What are the risks of biopsy?

A
  • Haemorrhage
  • Transplantation of tumour cells
  • Compromise of future surgery
  • Damage to adjacent structures
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20
Q

How can a needle core biopsy be taken?

A

Trucut needles- two handled operation, needle assistance

Cooks/Arnolds biopsy needled- semi-automated

21
Q

What are the advantages and disadvantages of needle core biopsies?

A

Adv
* Comparatively inaccessible tissues can be accessed percutaneously
* Larger samples
* Multiple samples can be taken
* Superficial lesions can be biopsied under sedation and local anaesthesia

Dis
* Small samples compared to other biopsied
* Greater risk of FNA
* Operator skill required- US guided

22
Q
  1. What needle is needed for bone core biopsy?
  2. What is the risk?
A

Jamshidi needle

Pathological fracture risk

23
Q

What is incisional biopsy?
What is the most common technique?

A
  • Surgical removal of segment of solid tissue
  • Technique varies with tissue/lesion
  • Wedge biopsy most common
24
Q

What are the advantages and disadvantages of incisional biopsy?

A

Adv
* Good evaluation of architecture
* Histopathological grading
* Surgical approach
* More tissue

Dis
* GA normally required
* Increased time
* Both increase costs

25
Q

What are the ‘rules’ of incisional biopsy?

A
  • Position incision so entire biopsy tract can be removed on subsequent surgery
  • Make incision large enough to harvest the sample without excessive tissue manipulation
  • Minimise instrumental manipulation of biopsy
  • Avoid diathermy
  • Include normal tissue if possible
  • Ensure adequate fixation
26
Q

What accessible surfaces can pinch and grap biopsies be used?

A
  • Respiratory tract
  • Gastrointestinal tract
  • Urogenital tract

Direct visualisation
Endoscopy
Blind
Laparoscopy/thoracoscopy

27
Q

How can surface pinch and grab biopsies be done for nasal tumours?

A
  • Measure distance to insert from radiographs
  • No further then medial canthus (eyes)
  • Cats- cut off urinary catheter
28
Q
  1. When are endoscopic biopsies mainly used?
  2. When are punch biopsies used?
A
  1. Mainly mucosa- very small
  2. Cutaneous/superficial- rotate in one direction
29
Q

What is an excisional biopsy?

A

Attempted surgical extirpation of a lesion or mass followed by removal of biopsies of whole sample

Often results inadequate excision

30
Q

When is excisonal biopsy indicated?

A
  • Haemorrhaging splenic masses
  • Mammary tumours
  • Pulmonary tumours

Widely used in treatment of skin tumours

Submit whole lesion- tag/label/pain questionable margins

31
Q

What are the contraindications of excisional biopsies?

A
  • Rapidly growing mass
  • Ill defined or poorly demarcated lesion
  • Peritumoural oedema or erythema
  • Skin ulceration
  • Injection site masses in cats
  • FNA suspicious for MCT or STS
  • Non-diagnostic FNA
32
Q

What is the ideal first diagnostic step for this case?

A

FNA and Cytology

33
Q

What is the ideal first diagnostic sample for this lesion

A

Exisional biopsy after staging

34
Q

What is followed after diagnosis of cancer?

A
  • Client communication
  • Active monitoring
  • Staging
  • Tumour related complications
  • Comorbidities and general health
35
Q

How are solid tumours clinically staged?

A

Process by which we assess the extent of disease
* T- primary tumour
* N- metastatic disease in local and regional lymph nodes
* M- distant metastatic

Grade does not mean stage
Usually further divided- T1-4 which gives prognosis

36
Q

How can T be clinically staged?

A
  • Clinical exam
  • Location and palpable
  • Fixed- to deep tissues/skin
  • Ulceration
  • Imaging
37
Q

How much bone lysis is needed before it can be identified on radiographs?

A

60%

38
Q

How can T stage be imaged?

A
  • Plain radiographs
  • Contrast- urogen, GI, CNS
  • Ultrasound- abdomen
  • Direct visualisation- endocsope, laparoscope
  • Advanced imaging- CT/MRI
39
Q

How are tumour metastasis divded?

A
  • Haematogenous- blood
    sarcomas, melanoma
    Lung, kidneys
  • Lymphatic- lymphatic system
    Mast cell tumours, carcinomas, melanomas
    Lymph nodes
40
Q

How can N be clinically staged?

A
  • Palpation
  • Imaging
  • Cytology/histology
    FNA/biopsy
41
Q

How can clinical stage N be imaged?

A
  • Thoracic radiograpy- moderate to marked enlargment of nodes
  • Abdominal radiography- medial iliac lymph node enlargment
  • US- mesenteric lymph nodes
  • Lymphangiography- sentinel nodes- inject contrast find what nodes drain
42
Q

What route do most lymph node metastasis follow?

A

Spread by the lymphatic route go to the nearest node towards the centre of the body (towards the thoracic duct)

can skip a node
affected nodes can be resected ‘en bloc’

43
Q

What are common sites for distant metastasis (M)

A
  • Lung
  • Parenchymatous organs- liver, spleen, kidney
  • Bone
  • Skin
  • CNS
  • Distant nodes

Clinical signs are difficult to identify

44
Q

How can metastasis to parenchymatous organs be clinically staged to M?

A

US superior
Confirm by FNA

45
Q

What are the limitations of the TNM system?

A
  • Animals do not always present with the primary disease
  • Metastatic disease- bony mets, LN in tonsillar carcinoma
  • Paraneoplastic syndromes
46
Q

When should referral be considered?

A
  • Specialist expertise
  • Advanced treatments
  • Odd tumours/uncertain diagnosis
  • Tricky clients
  • More aggressive tumours
47
Q

How likely are the following cancers to metastasise?
* Oral/mucosal malignant melanoma
* Visceral and some other soft tissue haemangiosarcoma
* Appendicular oesteosarcoma
* High grade MCTs

A

Highly

48
Q

How likely are the following neoplasms to metastasise?
* Subungual malignant melanoma
* Poorly differentiated mammary tumour
* Most mammary carcinomas
* Anal sac adenocarcinoma
* Prostatic carcinoma
* Digitial squamous cell carcinoma

A

Highly

49
Q

What cancers do not metastasise?

A
  • Oral acanthamatous ameoblastomas
  • Haemangiopericytoma
  • Schwannaoma
  • Benign tumours