Tumors of the Urinary System

Question 1

describe incidence and signalment of urothelial carcinoma (formerly transitional cell carcinoma)

Answer 1

1. most common bladder/urethral tumor!
2. affects older, smaller dogs:
   -scotties, westies, shelties
3. females > males

Question 2

describe the biologic behavior of urothelial carcinoma in dogs

Answer 2

1. primary sites:
   -trigone of bladder!
   -urethra
   -prostate
2. metastatic sites:
   -lymph nodes
   -lungs
   -bones
3. locally invasive:
   -most invade the bladder wall and/or adjacent organs (urethra, prostate)
   -carcinoma in situ is rarely diagnosed in dogs (finding cells only in tumor site, earlier diagnosis, harder to do)
4. moderate metastatic rate:
   -LN mets: 16%
   -distant mets: 14%
   -distant mets at necropsy: 50%

Question 3

describe the risk factors for urothelial carcinoma in dogs

Answer 3

1. obesity
2. topical flea and tick dips
3. herbicides and insecticides
4. cytoxan: chemotherapy agent that can irritate the bladder
5. breed
6. sex (female)
7. diet: leafy greens decrease risk?

Question 4

describe common presenting clinical signs of urothelial carcinoma in dogs

Answer 4

urinating in the house

Question 5

describe diagnostic plan for urothelial carcinoma in dogs

Answer 5

1. obtain history/ask:
   -when first notice urinary signs?
   -small amounts versus large amounts? (LUT versus UUT)
   -staining, blood, etc.
   -better, same, or worse
   -V/D, C/S, PU/PD
   -meds, travel history
2. common problem list formed from history and physical exam is:
   -stranguria, pollakuria, hematuria, possibly thickened urethra on rectal
3. ddx:
   -UTI, stones/crystalluria, tumor (UC, other, polyp), FIC (CATS), trauma
4. diagnostics:
   -UA: be careful interpreting presence of transitional cells (esp if lots of inflammation, could make TCs look neoplastic instead of just dysplastic)
   -urine culture: usually negative so move on

-imaging:
–abdominal rads: rule out stones (Piss on Cornell U); contrast cystography
-abdominal ultrasound: rule out neoplasia, tumor location/size, hydroureter/hydronephrosis, intra-abdominal metastases

-once find mass have more specific diagnostics (see next)

Question 6

describe diagnostics once rule out UTI and find bladder mass

Answer 6

1. collect urine for CADET BRAF test:
   -detects BRAF mutation in urine; detected in >85% of UC cases
   -pros: easy, minimally invasive/min equipment, relatively inexpensive (just need 40ml of urine, a lot)
   -cons: false negatives/false positives possible, but eval in context of presentation/signalment
2. FNA and cytology:
   -pros: easy, min invasive, requires min equipment, inexpensive
   -cons: RISK OF TUMOR SEEDING!!; inflammation can make dysplastic cells look neoplastic
   -try to AVOID doing this (last ditch effort)
   -tumor seeding is why the cystocentesis you did to try to diagnose UTI can increase risk
3. traumatic cath and cytology:
   -pros: easy/min invasive, min equipment, inexpensive, may obtain tissue for histopath
   -cons: small sample size, requires skill in female dogs, inflammation can confound results again
4. cystoscopy and histopathology:
   -pros: min invasive, obtain tissue for histopath, allow visualization of entire LUT (urethra)
   -cons: requires skill and equipment, expensive, small tissue samples
5. cystotomy and histopathology:
   pros: allow visualization of tumor, obsain nice big samples for histopath, therapeutic if tumor is apical
   -cons: invasive, RISK OF TUMOR SEEDING (must be careful and use oncologic surgical principles)

Question 7

describe a general therapeutic plan for urothelial carcinoma in dogs

Answer 7

1. piroxicam (feldene)
   -NSAID, non-selective COX inhibitor
   -0.3mg/kg PO ONCE daily
   -narrow margin of safety! GI and nephrotox
   -response: objectively, less than 20%, subjectively, greater than 75% (alleviate clinical signs)
   -MST: 6 months
   -should ALWAYS be considered in management of UC
2. RT
3. chemo: various protocols used = none super effective
4. complete surgical excision/partial cystectomy: generally NOT possible due to tumor location
   -only really possible if at apex of bladder
5. palliative/salvage:
   -urethral stenting!
   -permanent cystostomy catheter
   -complications: incontinence, increase risk of secondary UTIs

Question 8

describe the general goals of UC therapy/treatment

Answer 8

palliation/slow tumor growth; we rarely make these tumors go away!

-most die due to urinary obstruction; most euth bc of primary tumor not necessarily metastasis

Question 9

describe negative prognostic factors for UC

Answer 9

1. tumor size: bigger is worse and less responsive to therapy
2. urethral/prostate involvement

Question 10

describe renal lymphoma in cats

Answer 10

biologic behavior: systemic disease!!

1. BILATERALLY enlarged kidneys
2. historically FeLV+ cats
3. azotemia: acute renal failure

diagnosis: cytology usually diagnostic

Question 11

describe treatment of renal lymphoma in cats

Answer 11

1. supportive care: IV fluids
2. chemotherapy (NOT surgery)
3. prednisone: once dx made and if owner not interested in chemo

Question 12

describe mammary gland tumors (FYI)

Answer 12

1. spaying is protective! risk increases with how many heat cycles
2. biologic behavior:
   -50/50 rule of dogs: 50% benign, 50% malignant; of the 50% that are malignant, only 50% of those metastasize

-85/15 rule in cats: 85-90% malignant, 10-15% benign

3. epithelial neoplasia: most common
4. metastatic sites: lymph nodes, lung, occasionally bone
5. diagnosis: cytology
   -difficult to determine benign vx. malignant; need histopathology!
   -excellent place to start though to rule out tother tumors, sarcoma, MCT, etc.

Question 13

describe treatment of mammary gland tumors (FYI)

Answer 13

1. surgery!!
   -EXCEPTIONS: inflammatory carcinomas, distant metastases
   -dogs: remove entire tumor using the simplest procedure necessary to get clean margins
   -cats: chain or radical mastectomy recommended
   -OHE at time of tumor removal is controversial!
2. chemo?