Cancer therapies surgery in the management of the oncology patient

What needle do you use for a FNA biopsy?

21G 1” needle + 2 or 5ml syringe

Why should cytology & FNA slides not be put in same packaging

Formalin from cytology damages cells of FNA

Describe the process of carrying out a tru-cut biopsy?

• GA / Sedation + LA @ stab incision over mass

• Aseptic Prep

• 1-3mm Stab incision

• Multiple needle cores

• Gently remove

• Formalin +/- Impression smear

• Consider Culture as well

  • fungal / mycobacterial infection?

Describe the process of an incisional biospy?

• Wedge of tissue

• Ideally composite

  • near edge —> more likely to have normal tissue

  • don’t extend beyond edge of tumour

  • compare normal to tumour tissue

• Keep within future field of Tx

What are the different ways you can stage tumours?

• Blood test

• Urine test

• FNA local LNs

• Thoracic imaging for distant mets —> rads (2 views to confirm) & abdo U/S

  • liver, spleen, LNs mets of mast cell tumours

• Bone marrow aspirates

Why should you check both lateral views when checking for lung mets?

Can only see the lesions when they are surrounded by air filled lung —> contrast more visible

What is the TNM staging for tumours?

Describe surgery as a tx for tumours

• Complete excision / no detectable dx

  • primary closure

• Cytoreduction + adjunct tx

• Palliation

What borders would you use when removing a mast cell tumour?

• Mod grade —> 2cm lateral margin & deep facial plane

• High grade —> 3cm lateral margin & deep margin

do margins meet? if yes = primary closure

What can help you when you are carrying out a primary closure?

Towel clamp —> use this before placing suture —> shouldn’t be tearing through tissues

Take bite through fascia to subdermal fascia on top, take towel clamp off & should hold

What should be done after primary closure of leg after tumour surgery?

• Bandaged in extended position for 2 weeks (robert jones bandage) —> changed twice a week

  • Secures fibrous tissue → then restricted exercise

What is this showing?

Bright red granulation tissue + pale pink ep tissue migrating across —> heals but takes 8-12wks ish

What do you need to consider when healing by second intention?

• Second intention healing is better than Incomplete excision

• Work out the costs of sedation & rebandaging twice a week (poss w/ sedation)—> may be the same as referral

What type of tumour is this?

Mast cell tumour

Cannot get deep plane margins to excise → cytoreductive surgery

What is this showing?

Haemangiosarcoma on GI body wall

What is the role of surgical palliation?

• Relieve clinical signs

• Improve function

• Prolong / improve quality of life

What are the different cytoreductive options?

• Radiotherapy (1x per week for 4 weeks OR 3x per week for 4 weeks)

• Chemotherapy

• Electrochemotherapy

• Immunotherapy - vaccine for malignant melanoma

What are some examples of paraneoplastic Syndromes?

• Hypercalcaemia —> anal sac adenocarcinoma

• Hypoglycaemia

• Anaemia —> splenic haemoangiosarcoma

How should the patient be prepped for tumour surgery?

• Wide clipping —> wider than you need just in case

• Local n. blocks

• Gentle scrub technique —> avoid metastasis / degranulation

  • metastatic cells can be released

  • mast cell tumour —> proteases interfere w/ healing, histamine release

• Peri-op ABs

  • 20 mins pre-op

  • q. 2hrs intra-op

  • up to 24hrs post-op

What are halstead’s principles of surgery?

• Gentle tissue handling

• Accurate haemostasis

• Preserve local blood supply

• Aseptic technique

• Close tissue w/o tension

• Careful tissue approximation

• Avoid dead space

Surgical margins

• What is the goal when removing a tumour?

• Which Halstead principle is most important to follow when considering tissue margins?

• What tissues are resistant to invasion?

  • What tissues are easier for tumours to infiltrate?

Surgical margins

• Goal= complete excision

  • & closure tissues without tension

  

Surgical margins

• List the 4 different surgical margins that can be used for tumour removal

Intracapsular margin

• What does this involve?

• What types of tumours is it used for?

• Why might tumour reoccur?

Intracapsular margin

• Piecemeal removal

  • intracapsular dissection

• Used for benign disease

• Failure due to microscopic tissue

Marginal margins

• What does this technique involve?

• Why might failure occur?

• In what situations would you do this?

Marginal margins

• en bloc removal

  • both mass and pseudo capsule

• Failure d/t satellite or skip metastases

• Used for benign tumours or cytoreduction

Wide margins

• What does this involve?

• Why might failure occur?

• What types of tumours is it good for?

Wide margins

• En bloc excision

  • mass + pseudocapsule + reactive zone + margin

• Failure d/t skip metastasis

• Good for skin & S/C tumours

Radical margins

• What does this involve?

• Why might failure occur?

• What types of tumours is it good for?

Radical margins

• en bloc removal

  • mass + entire tissue compartment

• failure due to distant metastases

• Used for poorly localised or high grade malignancies

When would surgery with wide margins fail?

• Skip metastasis

• Outgrowths of tumour (scattered cells & satellite mets —> branching down BV / lymphatic)

• Generally good for skin & S/C tumours

How do you avoid tumour seeding?

Change gloves & instruments before closing so don’t spread tumour cells elsewhere

When would you remove LNs?

• only remove if evidence mets (may be movement towards removal of tumours when staging)

• enlarged, firm or fixed

• microscopic confirmation (FNA)

What must you do once you have removed the mass?

• Mark margins - will tell you if you have a clean edge once it gets to histopath

• Bread slice (2cm) if it is large

What wound protection can you utilise?

Modified SPICA

Robinson Sling (stops backwards movement of hindlimb for any wounds in the flank area)

(for both don't use vet wrap which is too stretchy)

When would you re-examine the animal?

• 1, 2, 3 months

• 6, 9 & 12 months

• then every 6 months

evaluate surgery site & regional LN