SA approach to cancer case

Define cancer

uncontrolled proliferation of abnormal cells

• impaired cellular differentiation

Why do patients die of cancer

• delayed dx

• lack of tx

  • primary disease

  • metastatic spread

• ineffective tx

• owners decision to no tx

List principles of oncology

• cancer won't self self

• specific dx is important for tx

• Understanding and management of owner's expectations

• early tx =best chance for cure

• good tx plan

  • mal-management = poorer prognosis

List AVMAs signs of cancer

• abnormal swelling that persists or continually grows

• sores that don't heal

• unexplained weight loss

• loss of appetite

• bleeding or discharge from any body opening

• bad odour, esp. from mouth

• dysphagia

• reluctance to exercise or loss of stamina

• dyspnoea

• difficulty urinating or defaecating

• behavioural changes

List tests for biopsy sampling

• cytology

• Histology

  • grading

List advanced/ molecular diagnostics for cancer

• immunochemistry

  • cytochemistry and histochemistry

• PCR

• Flow cytometry

• PCR

  • Antigen receptor rearrangement

  • KIT mutation

• electrophoresis

List basic diagnostics for cancer

• hx

• physical exam

• biopsy

  • cytology/ histology

• imaging

Outline important hx for a suspected cancer case

• general

  • diet, meds. travel

• tumour (/s)

  • duration

  • size- growth

  • appearance

  • location- invasiveness/ attachments

• other clinical signs

Outline important clinical exam for a suspected cancer case

• whole body palpation

  • assess for other lumps

  • LNs

  • for signs of pain

• CVS and resp assessment

• mentation and neuro assessment

• BCS + musculature

Outline uses of blood tests in cancer patients

• haematology

  • needed prior to chemo

  • concurrent disease

  • paraneoplastic syndromes

• infectious diseases

What are the preliminary diagnostics done on a suspicious lump?

• fine needle aspirates

• cytology

What sampling is needed for cytology

fine needle aspirate

What sampling is needed for histopathology

tissue biopsy

Outline the pros and cons of cytology

• relatively non-invasive

• only physical restraint needed

• rapid and cheaper

• no architectural detail

• small sample of cells

• limited assessment of tumour type and grade

Outline the pros and cons of histology

• invasive

• GA or sedation

• time consuming sampling and results

• expensive

• architecture apparent with larger sample size

• more accurate tumour type and grade

What are the uses of cytology?

• initial dx

• guiding diagnostics

• guiding tx planning

What are the uses of histopath?

• definitive dx

• guiding adjuvant tx

When may FNA and biopsy be needed?

• tumours needed high morbidity surgery

• cytology doesn't align with clinical picture

When to use the needle off approach for a fine needle aspirate

(fine needle biopsy)

• LNs

• suspected round cell tumours

When to use the needle on approach for a fine needle aspirate

(fine needle aspirate biopsy)

Suspected solid tumours

List complications for fine needle aspirates

• bleeding

• risk of fluid leakage after sampling hollow organs

• risk of tumour transplantation deeper into tissue

  • do not go through lesions

Outline the different cytology techniques

• smear

  • expel FNA contents and smear using clean slides

• Impression smear

  • blot cut surface of sample to remove debris and blood

  • dab surface against clean slide

Outline problems with FNAs

• 1 in 5 have no diagnostic value

• None representative samples

take several samples to reduce issues

List types of tissue biopsy techniques

• needle core biopsy

• incisional biopsy

• surface and pinch biopsies

• punch biopsy

• excisional biopsy

List the risks of biopsy

• haemorrhage

  • internal organs>>

• transplantation of tumour cells

• compromises future surgeries

• damage to adjacent structures

Outline the types of needles used in a needle core biopsy

• trucut needle

  • 2 handed

• cook's/ Arnolds biopsy needles

  • semi automated

both can be cold sterilised

What is this

Tru cut needle for a needle biopsy

What is this

Cook's/ Arnolds biopsy needle for a needle core biopsy

List advantages of needle core biopsies

• larger sample than a FNA

• some evaluation of architecture

• inaccessible tissues are accessed percutaneously

• only sedation and local anaesthesia for superficial lesion

List the disadvantages of needle core biopsies

• smallest sample size compared to other biopsies

• increased complication risk compared to FNA

• not good for LNs

Summarise the technique for a needle core biopsy

• restraint, asepsis, immobilise mass

• can be US guided by person with reasonable skill

• stab incision and introduce needle

  • advance central obturator

  • rotate 90 degrees

  • advance outer cannula

• remove from mass

• retract outer cannula

  • biopsy in notch

  • flush with saline or gently use needle to remove

Outline a bone core biopsy

• jamshidi needle

• risk of pathological fracture if bone damaged

  • don't penetrate far cortex

• multiple samples needed

What is this

Jamshidi needle used in bone core biopsies

Define an incisional biopsy

Surgical removal of a segment of solid tissue

• inverted wedge technique most common

  • easy closure

List the advantages of incisional biopsies

• good evaluation of architecture

• histopathological grading

• surgical approach allows selection of biopsy site

  • controls risks to neighbouring structures

• more tissue to carry out stains

List the disadvantages of incisional biopsies

• GA needed

• increased time

• higher cost

• slower answer vs cytology

Outline the rules of an incisional biopsy

1. plan you site

2. avoid major structures

3. avoid necrotic, haemorrhagic or infected areas

4. Position biopsy so whole biopsy tract can be removed in subsequent surgery

5. Incision to be large enough for sample but without excessive tissue manipulation

6. Do not include normal tissue

7. ensure adequate fixation

Outline surface pinch and grab biopsies

How do you determine depth of surface pinch and grab biopsies for nasal tumours

• radiographs

• do not insert further than medial canthus

Outline endoscopic surface pinch and grab biopsies

• superficial biopsies: mucosal

• very small biopsies

  • take multiple

• full thickness biopsies for GI tract

Outline uses of punch biopsies

• cutaneous and other superficial lesions

• not LNs

• Sedation +/- local

• rotate punch in same direction to prevent shearing of layers

What is an excisional biopsy

surgical removal of a lesion followed by

• removal of biopsies from it for histopathological evaluation

• or whole sample submitted

Outline uses of excisional biopsy

• haemorrhaging splenic masses

• mammary tumours

• pulmonary tumours

Outline contraindications for excisional biopsies

• rapidly growing mass

• ill-defined or poorly demarcated lesion

• peritumoural oedema

• skin ulceration

• mass fixed to underlying tissue

When is monitoring appropriate

• Active monitoring

• for benign lesions or after surgery with low chance of recurrence

• may need nurse checks if owner not confident

What factors of a tumour affect treatment decision making

• tumour type

• grade

• stage

• signalment

• co-morbidities

Summarise the TNM staging system

For solid Malignant tumours

• T- TUMOUR

  • primary tumour

• N- NODES

  • metastatic disease in local and regional LNs

• M- METASTASES

  • Distant metastatic disease

Outline the limitations of the TNM system

• animals do not always resent with primary disease

• paraneoplastic syndromes

Outline the T stage of the TNM classification system

• clinical exam

• location and palpation

  • demarcation, fixation, ulceration

• imaging

  • plain/ contrast radiograph

  • US

• Direct visualisation

  • -scopy / ex lap

  • Take biopsies at same time

• Advanced imaging

  • CT, MRI

    • good for Surgical planning

Can there still be bone involvement if not seen on radiograph

Yes

lysis is not seen until 60% loss in bone mineralisation

Traditionally how would you classify tumour metastasis

By their metastatic patterns

• Haematogenous

• Lymphatic

Outline haematogenous tumour metastasis

dissemination via the circulatory system

• sarcomas

• malignant melanoma

Outline lymphatic tumour metastasis

dissemination via the lymphatic system

• local and regional lymph node spread

• mast cell tumours

• carcinomas

• malignant melanomas

Outline the route of metastases through the lymphatics

spread by lymphatic route to the nearest node towards the centre of the body i.e. towards the thoracic duct

What role do lymph nodes have in preventing metastases

healthy LNs act as barrier

Outline the regional staging during the N stage of the TNM system

• palpation

  • size, texture, fixation

• imaging

  • radiographs

  • US

  • Lymphangiography

• cytology/histology

  • FNA

  • Biopsy

What LNs can be detected in thoracic radiography

• moderate to marked enlargement of nodes

• lateral

  • suprasternal

  • cranial mediastinal

  • tracheobronchial

• DV

  • increases sensitivity

What LNs can be detected in abdominal radiography

• medial iliac (sublumbar)

• unlikely to detect enlargement of mesenteric nodes unless massively enlarged

What LNs can be detected in abdominal US

• subtle enlargements

• iliac (sublumbar)

• mesenteric

Outline lymphangiography

Contrast is injected into a tumour and a CT is taken to see which LNs it drains into to

• detects sentinel LNs

• Doesn't detect metastases only draining nodes

What cancer in considered disseminated by fault

Lymphoma

What are common sites for metastases

• lung

• parenchymatous organs

  • liver, spleen, kidney

• bone

• skin

• CNS

• distant nodes

What are the best modes for identifying metastasis

• inflated x-rays x 3 views

• +/- US

  • preferred for parenchymal organs

• good interpreter

What should you provide when giving a prognosis

Range rather than median

compare cases to literature

List some highly metastatic