GI Tract Cancer Flashcards
what are clinical signs of oral tumors?
- bleeding from mouth
- halitosis
- decreased appetite
- blood on toys, water bowl, etc.
- decreased desire to play with toys, pain while playing
- weight loss
- facial deformity
- resistance to manipulation near the mouth
- pain or resistance to opening the mouth
- nasal discharge
describe the approach to a new oral mass
- document!!
-measure
-dental chart
-take a picture
-hopefully an incidental finding - can start with FNA:
-frequently acellular
-OMM can sometimes get a dx - biopsy: incisonal
-why documentation = so important because if remove for biopsy, send off and it’s bad then refer, specialists need to know where to look too
describe the most common malignant oral tumors
dogs:
1. oral malignant melanoma (OMM): most common
2a. squamous cell carcinoma (SCC)
2b. fibrosarcoma (FSA)
3. acanthomatous ameloblastoma
feline:
1. SCC: VERY most common
2. FSA
benign differentials: peripheral odontogenic fibroma, ginigival hyperplasia, papilloma
appearance of any of these is NOT diagnostic in anyway!! need biopsy
describe the behavior of canine OMM, SCC, FSA, and acanthomatous ameloblastoma
OMM:
-locally invasive
-highly metastatic: regional LNs, lungs
SCC:
-locally invasive
-low metastatic rate
FSA:
-locally invasive
-low metastatic rate
acanthomatous ameloblastoma:
-locally invasive
-does NOT metastasize
describe oral tumor staging
- imaging: determine extent of disease
-local: skull CT is best
–also used for SX or RT planning
–dental rads are an okay starting point
-thoracic rads: to see metastasis
- regional LN FNA: also for metastasis
-mandibular: most common
-retropharyngeal
describe feline oral tumor behavior
- SCC:
-VERY locally invasive
-VERY fast growing
-low met rate because so invasive and fast growing it just doesn’t have enough time to met before death - FSA:
-locally invasive
-low met rate
describe canine oral tumor treatment
- OMM:
-local control: surgery (need to take bone) vs radiation
-systemic therapy: melanoma vaccine
-chemo completely ineffective so use vx (not prophy, vx used as tx once dz present) - SCC, FSA, acanthomatous ameloblastoma: surgery; need to take bone
describe feline oral tumor treatment
- SCC:
-surgery: need to take bone; only perform is mass is small and wide margins are possible
-palliative care if not small; most common since very fast growing and cats hide symptoms - FSA: surgery; need to take bone
describe canine oral tumor prognosis, presuming no metastasis and treated with surgery (or RT for OMM)
- OMM:
-approx 6-12 months
-life limiting: local recurrence, development of metastasis - SCC, FSA, acanthomatous ameloblastoma:
-long survival expected if no recurrence
describe feline oral tumor prognosis, presuming no metastasis
- if complete resection (rare), long survival is possible
- more commonly, wide margins not possible so palliative care only and <3 months
describe salivary gland tumors
- rare
- most commonly adenocarcinoma (ACA)
- most common gland:
-cat: parotid (can look like an ear-based mass)
-dog: mandibular - treatment: surgery
- prognosis: up to 18 months
describe gastric neoplasia
- rare in dogs and cats
- most common histotypes:
-dogs: adenocarcinoma (ACA)
-cats: lymphoma - clin signs: usually acute/progressive
-vomiting: including hematemesis
-hyporexia/anorexia
-weight loss
-melena - prognosis: generally poor in both species
describe intestinal neoplasia
- rare in dogs
- increased incidence in cats over last 20-30 years (LSA)
- LSA most common in dogs and cats
- others:
-adenocarcinoma
-leiomyosarcoma
-GI stromal tumor (GIST)
-mast cell tumor
-extramedullary plasmacytoma (esp rectal)
describe clinical signs and imaging of intestinal neoplasia
clin signs:
1.V/D
2. weight loss
3. hyporexia
imaging:
1. contrast radiographs: filling defects
2. ultrasound: loss of layering, wall thickening
describe differentiation of intestinal tumor types
- imaging characteristics: unreliable
- cytology:
-high yield: large cell LSA, mast cell tumor, extramedullary plasmacytoma
-variable yield: carcinoma, leiomyosarcoma, GIST
-low yield: small cell LSA - histopathology:
-best diagnostic
-+/- IHC
describe feline GI lymphoma
- most common feline GI cancer!
- SI 4x more common than LI
- intestine +/- LNs, liver
- 2 subtypes:
-small cell: low grade, mucosal depth, less aggressive, T-cell predom, more common, chronic onset, diffusely thickened intestines
–biopsy is best sample (FNA will be low yield)
-large cell: high grade, transmural depth, more aggressive, B and T cell, less common, acute onset, discrete masses more common
–cytology is high yield diagnostic with abnormal lymphocytes
what is the best way to try to differentiate between small cell GI lymphoma and IBD inc ats?
need histopath, IHC, but still unreliable and treat basically the same so whatevs
no biochemical markers exist to differentiate!!! (no blood tests), imaging won’t help, cytology won’t help
recall compare and contrast endoscopic vs surgical biopsy
endoscopic:
-pros: less invasive, maybe shorter anesthesia, can view mucosal surface
-cons: small superficial samples!!, can’t reach whole GIT, can’t see rest of abdomen
surgical:
-pros: full thickness samples, visualize entire abdomen, can biopsy other structures, including LNs
-cons: more invasive, can only view serosal surface
recall treatment and prognosis of the 2 types of feline GI LSA
large cell: COP/CHOP, 30-40% respond, survival 6-9 months if respond
small cell: chlorambucil + prednisolone, >90% respond, survival is >18 months
describe intestinal adenocarcinoma
- in SI, colon, or rectum
- clin signs:
-V/D, weight loss, hyporexia
-distal colorectal tumors: straining to defecate, hematachezia - 40-60% metastatic rate
-LNs: most common
-local extension: omentum/mesentery/carcinomatosis
-liver/spleen
-lungs - staging:
-abd ultrasound or CT and chest rads
describe treatment and prognosis of canine intestinal carcinoma
- surgery: 5cm margin orad and aborad
- prognosis:
-surgically resected (non-metastatic): wide variation (3 mos - over 1 year); adjuvant chemo NOT proven to extend survival, longer for colorectal CA
-metastatic: <3 months; sx not recommended (unless osbtructed/perforated),
–palliative: intraperitoneal chemo for carcinomatosis + malignant effusion (carboplatin)
compare leiomyosarcoma to GIST
- similar histological appearance
-leiomyosarcoma: smooth muscle
-GIST: enteroschromaffin cells (AKA interstitial cells of cajal/GI pacemaker cells) - in 2005, pathologist recognized that many leios were actually GIST based on IHV
-important differentiating factor: most GIST are c-kit positive so may respond to drugs that target kit (Palladia)
describe leiomyosarcoma treatment and prognosis
- met rate for both: 35-50%
- staging: abd US (or CT) and chest rads
- treatment:
-surgery is treatment of choice (5cm margins orad and aborad)
-non-resectable GIST: palladia (chemo not helpful for leiomyosarcoma)
- prognosis for surgically resected:
-1 year on average
describe colorectal neoplasia
- most common dx:
-benign polyps
-colorectal adenocarcinoma
-lymphoma - clin signs:
-rectal prolapse
-hematochezia
-tenesmus
-diarrhea - frequently ID on rectal exam
-ALWAYS rectal!! - staging:
-CXR
-CT to eval regional LNs (caudal LNs, hard to see on US)
-colonoscopy to ID extent of disease
describe treatment and prognosis of colorectal neoplasia
treatment:
1. rectal eversion, pull through
2. endoscopic removal of masses
3. lymphoma: chemo (CHOP/COP)
prognosis:
1. polyps: long survival times
2. carcinoma: survival of over 1 year with successful surgery
3. lymphoma >2 years possible
