Lecture 10 2/19/25 Flashcards
What does “a chance to cut is a chance to cure” refer to?
-surgery is the most important component of treatment for solid tumors in dogs and cats
-first attempt at removal is best chance at a cure
What are the aspects of client education surrounding surgical oncology?
-cancer diagnosis is difficult news for owner; consider counseling surrounding news/decisions
-provide owners with options/explain the potential outcomes of each option
-explain the expected goals of treatment, including cure/survival time, complications, cosmesis, and pain level
What are the characteristics of cancer staging?
-PE and history eval. can indicate co-morbidities; indicates health for anesthesia, surgery, and recovery
-standard staging protocol involves thoracic radiographs, abdominal ultrasound, and regional/distant lymph node evaluation
-advantaged imaging including nuclear scintigraphy, CT, and MRI can be used
What are the components of tumor anatomy?
-gross tumor
-pseudocapsule
-microscopic tumor
What are the characteristics of the pseudocapsule?
-fibrous tissue in reaction to growing mass
-limit of many benign tumors
-malignant tumors will continue to grow beyond this
What are the characteristics of microscopic tumor?
-satellite cells or tumor fingers/tendrils
-found in the reactive zone
Which tissue planes are resistant to tumor penetration?
-fascia
-joint capsule
-cartilage
-bone
What is FNA used to diagnose?
-mast cell tumor
-lymphoma vs reactive lymph node
-melanoma
-inflammation vs sarcoma
When is biopsy indicated?
when FNA results are:
-inconclusive
-non-diagnostic
-not fitting with clinical picture
What information can be provided by biopsy?
-benign or malignant
-grade of neoplasia
-median survival time
-response to surgical treatment
-need for radiation and/or chemo
What are the risks of biopsy?
-tumor metastasis to local tissues
-hemorrhage
-tissue rupture
What are the characteristics of tru-cut/needle biopsy?
-most commonly performed for tumors within body cavities
-require heavy sedation or anesthesia
-can be percutaneous and ultrasound guided, laparoscopic/thoracoscopic, or via laparotomy/thoracotomy
What are the steps to taking a tru-cut/needle biopsy?
-sterile skin prep
-blind or ultrasound guidance
-insert inner needle
-advance cutting sheath
-extract device
-remove sample from channel with a needle
What are the characteristics of incisional biopsy?
-sharp incision; wedge or punch biopsy
-removal of portion of tumor; majority still intact, but taking more than a needle biopsy
-heavy sedation w/ local anesthesia for dermal tumors; general anesthesia for body cavity and deep subcutaneous tumors
-used for large tumors in bad locations
-second procedure needed to remove full tumor
-location very important; do not want to go central, but must stay within confines of tumor tissue; poorly planned biopsy leads to larger margin for later removal
What are the modifications made for large and/or deep tumors with regards to incisional biopsy?
-large tumors may require multiple biopsy sites to ensure appropriate diagnosis
-deep tumors require an approach to the mass that involves incisions and dissecting down to the tumor
What are the characteristics of excisional biopsy?
-sharp incision around the periphery of the tumor
-removal of all gross disease and small barrier of normal tissue; pseudocapsule is removed but satellite tumor cells may remain
-heavy sedation and local anesthesia for small tumors; GA for large tumors and tumors around head/ears
What are the pros and cons of excisional biopsy?
pros:
-can be curative for benign tumors with only one procedure
-provides best chance for cure since it is the first cut
cons:
-may increase margin necessary for malignant tumors
-may have higher grade, rapid tumor regrowth
What are the characteristics of bone biopsy?
-done on suspicious bone lesions
-typically require small surgical approach under GA
-can use jamshidi needle or michele trephine; based on bone size
What are the characteristics of surgical intent?
-outcome the oncology team wishes to achieve
-based on tumor type, tumor stage, advanced imaging, and tumor location
In which instances might a tumor-free surgical margin not be attempted?
-would not benefit quality of life
-disfiguring or non-cosmetic
-no advantage for treatment
-not compatible with life
What are the characteristics of curative intent surgery?
-goal is to achieve tumor-free margin and cure patient
-cannot be done if metastatic disease present
-big procedure requiring GA, removal of lots of tissue, and potentially amputation
-may require major reconstruction
-must have a plan in the event of a “dirty” margin
What are the characteristics of palliative intent surgery?
-goal is to improve quality of life through improved function and/or pain relief
-done when curative intent is not possible
-may prolong good QOL and delay euthanasia
What are the characteristics of surgical dose?
-amount of surgical resection planned
-based on intent of surgery, invasiveness of tumor, and anatomy of the area
When is wide or radical excision used?
curative intent surgery in which the goal is to remove both gross and microscopic disease
What is radical excision?
-removal of a body “compartment”
-can include removal of entire organ or limb
What is wide excision?
removal of a large amount of predetermined normal tissue around tumor; multiple cm of healthy tissue margin
What are the characteristics of marginal excision?
-planned excisional biopsy
-included removal of gross disease and pseudocapsule
-performed to avoid curative intent surgery, such as due to cosmesis, owner decision, or presence of metastasis
-may require adjuvant therapy such as radiation or chemo
What are the characteristics of cytoreduction/debulking?
-residual gross disease is left behind; can undergo rapid regrowth
-gross disease left behind is not typically responsive to radiation and chemo
-generally not recommended; not effective and leads to complications with hemorrhage and dehiscence
What are the characteristics of lymph nodes?
-FNA of local lymph nodes is recommended for nearly all externally palpable tumors
-surgical excision can be done with confirmation of metastasis
-often removed during limb amputations and separated out for path. eval.
What are the general surgical concepts when performing surgical oncology?
-excise ALL previous biopsy tracts; assume presence of tumor within them
-early vascular ligation can minimize distant metastasis
-try not to directly handle tumor; considered DIRTY
-change gloves and instruments between tumor removal and closure
-use absorbable monofilament suture
-insert hemoclips if considering radiation
-primary closure is preferred over reconstructive techniques
-avoid drains
What is to be expected during post-op care?
-mast cell tumors can take longer than 10-14 days to heal due to inflammatory mediators
-seromas may occur, especially with amputations and wide exicisons
-seromas should be treated with warm packing and compression bandages
-seromas should NOT be drained unless patient is uncomfortable or infection
-dehiscence can occur due to tension on closure or excessive activity
-necrosis at tips of skin flaps is common
What are the characteristics of path. submission?
-anything important enough to remove should be submitted
-mark margins in different colors of ink (NOT red) prior to placing in formalin
-provide thorough history and surgical report
What are the characteristics of mast cell tumors?
-most common skin tumor in dogs and one of the most common in cats
-boston terriers, boxers, and pugs at increased risk
-surgery is treatment of choice
-curative intent surgery is wide excision
-want 2 cm lateral to tumor and 1 fascial plane deep for margins
-recurrence at dirty margin is only 30%
What are the characteristics of soft tissue sarcoma?
-slow growing and locally invasive
-clean margins are most important prognostic indicator for local disease
-recurrence is grade dependent
-curative intent surgery is wide excision
-want 2-3 cm lateral to tumor and 1 fascial plane deep for margins
-radical excision needed for recurrent or high grade tumors
What are the characteristics of injection site sarcomas in cats?
-associated with trauma and inflammation
-seen with vaccines, long acting medication injections, and non-absorbable sutures
-more commonly high grade
-aggressive local behavior, but metastasis in less than 25%
-most effective therapy is surgery
-want 5 cm lateral to tumor and 2 fascial planes deep for margins
When should surgery be considered in cats for suspected injection site sarcoma?
-masses at injection sites for 3+ months
-masses that grow in size over 4 weeks
-masses greater than 2 cm in diameter
What is the follow up for cats with injection site sarcoma?
-radiation therapy
-monitor frequently for metastasis
What are the characteristics of malignant melanoma?
-dermal melanoma can be benign or malignant
-oral melanoma is malignant and is the most common malignant oral tumor
-malignant melanoma should have curative intent surgery
-malignant melanoma requires 2+ cm lateral margin, digit amputation, maxillectomy, or mandibulectomy depending on location
-can use marginal excision for smaller, benign masses
