Surgical Oncology Flashcards
What roles does surgery play in the management of cancer? What ancillary procedure is commonly done?
- diagnosis with biopsy
- resection for sure
- palliation of clinical signs
- cytoreduction prior to adjunctive therapy
- prevention/reduce risk of recurrence
vascular access port placement for chemotherapy and radiation therapy
What is the purpose of tumor staging? What system is used?
establishes extent of disease and provides information to prognosticate for clients
TNM system
- T = (primary) tumor size
- N (regional) node involvement
- M = metastasis
Once a tumor is found, what is important to evaluate?
regional lymph nodes —> size, mobility, consistency
know body mapping for drainage compared to the tumor
When is cytology especially useful? In what 2 cases is it not?
round cell tumor malignancies that exfoliate well - MCT, histiocytoma, lymphoma, plasmacytoma, TVT
- sarcomas and spindle cell tumors - fibrous, do not exfoliate well
- lipoma - washes off with preparation
What can resemble malignancy on cytology? What is done if a sample is not diagnostic?
inflammation
pursue biopsy
Whan is diagnostic imaging especially helpful for diagnosing tumors? What can be used?
- intercavitary tumors
- firm, non-mobile tumors
- staging for metastasis
radiography, U/S, CT/MRI, nuclear scintigraphy, PET scan
What should not influence aggressiveness of surgeons with intent to cure cancer? What should be minimized?
ability to close wound —> need to know margins for tumor types
handling of tumors and penetration of capsules —> protects normal tissues from seeding
How can seeding of healthy tissue be avoided?
- avoid handling tumors
- do not penetrate capsule
- lavage tissues, change gloves and instruments, and lavage again before closing
- avoid using open drains
What are 3 specific indications for biopsies?
- to indicate treatment protocol based on tumor type
- tumor in a difficult location for surgical reconstruction
- knowledge of diagnosis would alter owner’s desire to treat
What are some biopsy techniques?
- impression smears of ulcerated masses or other exfoliated cells
- FNA
- needle core biopsy
- punch biopsy
- incisional
- excisional
What are 5 keys to obtaining diagnostic biopsies?
- proper sample size
- number of samples - multiple areas for larger masses
- take it near the junction of normal/abnormal tissue
- handle biopsy gently, moisten, and put in fixative ASAP to avoid artifacts
- give the pathologist detailed history and information
What are 3 indications of incisional biopsies? Why does it need to be planned carefully?
- large, superficial lesions
- lesion located in an area where achieving margins and closure might be difficult
- when less invasive techniques fail to yield diagnosis
biopsy sites should be selected so that the biopsy tract can be included with the definitive surgical procedure
What makes a proper incisional biopsy?
narrow, but deeper wedge - facilitates closure of the biopsy site, especially if tumor is firm and attached to skin
Why do FNAs even need to be planned and done carefully?
can result in seeding of biopsy tracts if the tumor exfoliates cells easily —> TCC
What are 2 indications for excisional biopsies?
- type of treatment would not be altered by tumor type
- re-excision with wider margins possible without significant morbidity
What cures the most patients with cancer?
complete surgical resection
- first chance is the best chance
What margins are recommended for most tumors? What are 2 exceptions?
removal of normal tissue completely around the mass
- benign masses with low risk of recurrence - lipomas
- masses in body cavities
What are 3 types of excisional biopsies?
- marginal
- wide - 2-3 cm of normal tissue three-dimensionally
- radical - entire compartment, like an amputation
What is the most common neoplasm that calls for a marginal excision?
lipoma
What typically influences required margins?
biological activity —> tumor grade based on mitotic index, differentiation, etc.
- MCT require wide excisions
What should be done if a tumor is fixed to a structure?
assume that tissue is also invaded and remove it
- removal of mammary gland and the entire chain
What should be done if a tumor is invaded during a procedure?
surgical field should be thoroughly lavaged, gloves changed, and different instruments used for the remainder of the procedure
- invasion associated with recurrence
How are lymph nodes commonly assessed with tumor removal? What else is commonly indicated when sampling later is expected to be difficult?
cytology - FNA, removal, even if they are normal on palpation —> lung of GI tumors
removal of the draining lymph node - also helps with more accurate staging
What is the purpose of palliative surgery for tumors? What are 3 examples?
improve QoL, not necessarily length of life - weight expected morbidity vs. gain
- amputation in animals with painful bone tumors
- splenectomy for HSA
- mastectomy for infected mammary tumors
What is the purpose of debulking and cytoreduction surgery? What are some examples?
enhance efficacy of other treatments with the goal to reduce tumor burden to microscopic levels prior to chemotherapy or radiation therapy
- chemotherapy
- radiation therapy
- photodynamic therapy
- cryotherapy
When is surgery for metastatic disease indicated? In what patients does it typically prolong survivial?
solitary for few metastatic lesions on the lung, liver, or brain
can prolong survival in dogs with OSA, insulinomas, and perianal/anal sac AdCA
What is required for assessing completeness of excision?
differentiating processing (sectioning) margins for surgical margins —> communicate with pathologist, mark cut edges or questionable areas with indelible dye (India ink) or sutures
- allow ink to dry before placed in fixative
Surgical margins:
Histopath, inked surgical margin:
pathologist will indicate if the margins are clean, close, or dirty
What should happen if a pathologist determines the margins to be dirty?
- re-excision
- adjunctive therapy - radiation, chemotherapy
What dogs most commonly have anal sac disease?
SMALLER DOGS —> Poodles, Chihuahuas
(rare in cats)
What should be done before an anal sacculectomy? Where are the anal sacs found?
manage infected or abscessed glands medically until inflammation resolves and the excision can be performed
within the external anal sphincter
What equipment is required for closed anal sacculectomies? How is this method performed?
blunt probe/instrument, paraffin injection (palpable), catheter
(OUT to IN)
How is an open anal sacculectomy performed?
- insert one blade of scissors into sac
- apply upward pressure to tips to minimize tissue cut
- insert groove director or probe through duct into anal sac
- incise over instrument with caudal tension on instrument to minimize damage to sphincter
- dissect anal sac from anal sphincter
What are the 3 most common complications associated with anal sacculectomies?
- infection
- draining tract formation due to incomplete removal - secretory lining is able to regrow, must go back in and remove remaining tissues
- fecal incontinence
What are the 2 most common perianal gland tumors?
- adenomas - intact males, castration and resection indicated (neuter can cause involution on its own, too)
- adenocarcinomas - females, poor prognosis (look for hypercalcemia)
What is the most common anal sac tumor? What 3 signs are associated?
apocrine gland adenocarcinomas
- paraneoplastic hypercalcemia
- PU/PD
- renal failure
