I'm sorry to hear of this with Cory. The cancer was most likely a transitional cell carcinoma. Here's a very thorough review of this cancer from Clinical Veterinary Advisor, 3rd Ed., Cote', 2015. It's designed for the veterinarian but I'd be pleased to answer any questions and address any concerns you may have after reading the review. Please make sure that you scroll down and note the prognosis for these patients:
Transitional Cell Carcinoma
Neoplasms of epithelial origin that arise in the bladder parenchyma; relatively common in dogs but rare in cats
Species, Age, Sex
- Dogs: typically, older adults (median age 11 years). Females appear to be at higher risk than males.
- Cats: affects older adults rarely; males at increased risk
Genetics and Breed Predisposition
Scottish terriers (up to 20-fold increased risk), Shetland sheepdogs, West Highland white terriers, wirehaired fox terriers, Airedales, beagles, and collies have higher incidence.
- Dogs: female predominance. Exposure to herbicides and insecticides associated with an increased risk; worsened in the presence of obesity, possibly due to accumulation of “inert ingredients.” Spot-on flea products do not appear to increase risk. Cyclophosphamide administration may increase risk.
- Cats: possibly associated with chronic urinary tract infection (UTI). Older cats at greatest risk.
- Bacterial cystitis
- Hypertrophic osteopathy
- Urethral obstruction
- Bladder atonia/hypotonia
- Most common form is invasive cancer into muscularis, most often in trigone region.
- Early form of superficial cancer may be identified that may be more responsive to therapy.
History, Chief Complaint
- Pollakiuria (common)
- Hematuria (common)
- Stranguria (common)
- Tenesmus (occasional)
- Abdominal pain (occasional)
- Abdominal distention (occasional)
- Lameness and joint thickening (rare; associated with hypertrophic osteopathy)
Physical Exam Findings
- Abdominal tenderness +/−
- Caudal abdominal mass +/−
- Urethral mass on rectal exam +/−
- Distended urinary bladder +/−
- Abdominal distention with fluid wave if bladder ruptured (rare)
Etiology and Pathophysiology
- Bladder mass most commonly occurs in trigone region (dogs).
- Urethral or prostate involvement is common, often leading to obstruction.
- Lymph node metastasis present in ≈15% of cases at the time of diagnosis
- Distant metastasis common (49% at death)
- Metastatic sites include lymph node, lung, liver, kidney, spleen, uterus, gastrointestinal (GI) tract, bone, muscle, cystocentesis needle tracts.
- Secondary bacterial urinary infection common
Middle-aged to older animals with signs of recurrent UTI should be screened for bladder masses, and dogs of at-risk breeds—particularly Scottish terriers—should be screened early. Diagnosis should be made as early as possible to achieve the best outcome.
Pollakiuria, stranguria, hematuria:
- Feline lower urinary tract disease/interstitial cystitis
- Other bladder tumor such as botryoid rhabdomyosarcoma (in young, large-breed dogs) or leiomyosarcoma
Abdominal distention/tenderness or abdominal mass:
- Mass in spleen, mesenteric lymph node, or retroperitoneal space
- Ruptured splenic or hepatic mass with hemoperitoneum
- Abdominal trauma or coagulopathy with peritoneal or retroperitoneal bleeding
- Rectal mass
- Prostatic abscess, cyst, or neoplasia
- Hydronephrosis or hydroureter
- Other bladder neoplasm or radiolucent urolithiasis
- Ruptured splenic, renal, or hepatic mass with hemoperitoneum
- Traumatic bladder rupture
- Papillary cystitis
- Botryoid rhabdomyosarcoma
- Lymphoma (rare)
- Other rare carcinomas or sarcomas
- Other bladder tumor
- Idiopathic renal hematuria
- CBC, serum biochemistry profile: no specific findings. Azotemia and hyperkalemia may occur with urethral or ureteral obstruction.
- Urinalysis: proteinuria and hematuria are most common. May be complicated by secondary bacterial UTI with pyuria, bacteruria. Cystocentesis has been associated with needle-tract neoplastic cell implantation and should be avoided if TCC is suspected or confirmed; recommend catheterization or free-catch.
- Veterinary bladder tumor antigen test (VBTA): ≈85% sensitive for TCC but only 45% specific in the presence of other urinary tract disease. As such, it can be used as a screening test (negative result is 85% reliable) but a positive result does not equal TCC.
- Abdominal radiographs: visualization of bladder mass is uncommon. Bladder distention may be seen, and with rupture, possible peritoneal or retroperitoneal fluid may be present.
- Thoracic radiographs: metastasis may be present. Pulmonary lesions may be nodular interstitial, unstructured interstitial, cavitated, or alveolar in appearance; bone lesions possible.
- Abdominal ultrasound: bladder mass or wall thickening with possible metastasis to abdominal organs or nodes; prostate or urethra are commonly involved. Insensitive for monitoring tumor size.
- Computed tomography (CT; see p. 1130): useful for identifying and monitoring total tumor volume and staging for metastasis to lymph nodes and lungs
Advanced or Confirmatory Testing
- Cytologic analysis from guided diagnostic catheterization or biopsy from cystoscopy necessary for diagnosis (see p. 1136)
- Contrast cystography/ureterography (see p. 1134) or CT scan may be used for delineating ureteral involvement and impending urethral obstruction.
The therapeutic goals are to alleviate clinical signs, control the primary mass, and prevent or delay metastasis.
Acute General Treatment
- Surgically manage urinary bladder rupture if present (see pp. 1037 and 1039)
- Surgically remove lesions at bladder apex if operable. Surgery may be of greater benefit in cats. Surgery reduces clinical signs, but may not extend survival.
- Address complicating bacterial UTI with culture and MIC-guided antimicrobials (see p. 252).
- Begin chemotherapy to palliate clinical signs and address metastatic disease:
- Piroxicam 0.3 mg/kg PO q 24h if renal function is normal or firocoxib 5 mg/kg PO q 24h. For cats, meloxicam 0.02-0.05 mg/kg PO q 24h has been evaluated. Can be used alone or in combination with:
- Mitoxantrone 5 mg/m2 IV q 21 days for 4 cycles; or
- Doxorubicin 30 mg/m2 IV q 21 days for 4 cycles (dogs); or 1 mg/kg IV q 21 days (cats and small dogs); for body surface area conversion charts, see pp. 610 and 618.
- CBC and blood urea nitrogen (BUN)/creatinine/urine specific gravity should be checked before each dose, and CBC checked 1 week later.
- Cisplatin cannot be recommended in combination with piroxicam due to nephrotoxicosis.
- Intravesicular therapy of BCG or thiotepa used in humans has been poorly effective in veterinary patients.
- If bladder distended initially, maintain urinary drainage to avoid detrusor hypotonia (see p. 96).
- Address metabolic imbalances if present secondary to obstruction (see pp. 509 and 1032).
- Continue piroxicam indefinitely barring adverse GI or renal effects.
- May repeat mitoxantrone after first four doses if clinical signs recur.
- Cumulative doxorubicin dosages greater than 180-240 mg/m2 are associated with increased risk of cardiotoxicosis.
- Urinary diversion surgery or intraluminal stenting may prolong life if urethral or ureteral obstruction is imminent.
Feeding vegetables may help prevent bladder TCC.
- Avoid combining drugs with similar toxicity profiles, such as cisplatin and piroxicam.
- Piroxicam should not be given in combination with corticosteroids or other nonsteroidal antiinflammatory drugs.
- Neutropenia, thrombocytopenia, sepsis, and renal injury secondary to chemotherapy
- GI ulceration or nephrotoxicosis secondary to piroxicam
- Urethral or ureteral obstruction secondary to tumor growth
- Monitor CBC before every chemotherapy treatment and 7-10 days later.
- Monitor BUN, serum creatinine, and urine specific gravity for renal function every 3-12 weeks.
- Monitor frequently for UTI.
Prognosis & Outcome
This disease is locally aggressive with a significant metastatic potential.
- Median reported survival treated with piroxicam alone is ≈6-7 months.
- Median reported survival treated with piroxicam and mitoxantrone is ≈12 months, with or without surgery.
- Median reported survival treated with surgery alone is ≈3.5 months.
- Median reported survival ≈8.5 months
- Surgical resection may improve prognosis significantly in cats.
Pearls & Considerations
- Repeated urinary tract signs or infection, especially in older animals, warrants screening for TCC.
- Early detection is critical for best response to treatment.
- VBTA test may allow early detection in geriatric at-risk breeds of dogs with lower urinary tract signs.
- Definitive diagnosis necessary for prognosis and therapeutic decisions; requires cytologic examination or biopsy.
- Bacterial UTI is a frequent complication.