Surgery & Radiation Therapy Flashcards
When is surgery considered the best treatment? What are 5 contraindications?
solitary lesions
- surgical procedure is too invasive or disfiguring
- high risk of rapid tumor growth
- patient is an anesthetic risk
- gross metastasis found on staging tests
- tumor is highly likely to metastasize quickly
What is a surgical margin?
amount of normal tissue between the edge of the sample and closest to tumor cells
- serial cross sections analyzed by pathologist
- better to have large margins, as cross sections can only tell so much
What is an incisional/wedge biopsy? What are 3 indications?
small sample taken from a mass
- large masses that cannot be removed in their entirety
- masses in areas that are difficult to access (oral masses)
- if cytology is not conclusive and owners want to know the tumor type prior to aggressive procedures
What is a major con associated with incisional/wedge biopsies as diagnostic tools?
may not be a representative sample —> some tumors can have superficial ulceration (oral masses, SCC) or are heterogeneous
What is the major indication of excisional biopsies? How does it compare to incisional biopsies?
anatomic locations that don’t allow for larger surgery (not attempting wide surgical margins), like the muzzle, oral cavity, or distal limb
more representative - whole mass available for evaluation —> grade can be more accurate
When are skin/SQ masses removed as treatment? What helps for planning?
in a location that is amendable to wide resection (may need amputation) due to potential regrowth at surgery site
cytology of the mass prior to surgery
- MCT, soft tissue sarcoma: wider margins
- plasma cell, cutaneous melanoma, lipoma: wide margins less important
What is the most common approach to surgically treating splenic tumors? When is this not necessary?
splenectomy - malignancy appearance or active bleeding common (HSA)
benign splenic nodules commonly seen in older dogs
How do primary liver tumors act?
hepatocellular carcinoma or hepatomas rarely metastasize, but they can be large and press on surrounding tissue (stomach!) resulting in decreased appetite and vomiting
What cancer is commonly seen in the bladder? When can surgery be used as treatment?
TCC
often not resectable, but can be considered if found on the apex + can improve hematuria
How are small intestinal, kidney, and pancreatic tumors surgically approached?
SI - resection and anastomosis to improve GI signs
KIDNEY - very commonly malignant, can remove one entire kidney (most likely nonfunctional anyways) to improve hematuria and prevent intra-abdominal hemorrhage
PANCREAS - surgery not common, will most likely cause pancreatitis (abdominal pain, vomiting) and not improve clinical signs
How is surgery used as palliative therapy? What is the goal of this approach?
debulking, cytoreductive - mass removed/reduced to help control current clinical signs in cases where wide surgical margins cannot be reached or metastasis is already present
immediate (temporary) relief - will likely regrow quickly, metastasis is the cause of systemic disease
In what situation can a biopsy not be submitted?
surgery as palliative therapy - most likely already took it off once before, owners unlikely to change course of treatment based on information gained
What is the unit of measure, linear acceleration, and fraction in radiation therapy?
Gray (Gy)
treatment delivered
one radiation treatment
local therapy for local disease
(Gy/fraction = dose at a single treatment)
What type of radiation treatment offers the best tumor response? What is a major con to this?
high cumulative dose or high dose per fraction
more side effects —> surrounding tissues will be affected
What is the difference between definitive and palliative radiation therapy?
DEFINITIVE = aggressive radiation with curative intent
- finely fractionated = little bits of radiation a day for a high cumulative dose without affecting surrounding tissue
- stereotactic (coarse) = larger dose with decreased frequency
PALLIATIVE = just enough to improve QoL
(all require anesthesia for each dose)
How is radiation dermatitis/moist desquamation treated?
- E-collar
- keep area clean with daily nolvasan wash
- salves - radiocare gel, cortisone
- pain control - NSAIDs, tramadol
- severe cases = steroids
How do patients commonly respond following hair loss after radiation therapy?
- may or may not grow back
- usually grows back in a different color
What are some chronic (late) effects seen following radiation therapy?
(9-12 months or more post-treatment —> typically permanent and potentially fatal)
- full-thickness skin necrosis
- bone necrosis
- brain/spinal cord necrosis
- cataracts
- secondary tumors (OSA)
- hyperpigmentation and alopecia
What is anterior caval syndrome?
group of symptoms that occur when there is pressure on the superior vena cava, or it is partially blocked and blood can’t flow back to the heart normally
- can be cause by tumors!
- AKA frog face
