CANINE BLADDER AND URETHRAL TUMORS - A RETROSPECTIVE STUDY OF 115 CASES (1980-1985)

One hundred and fifteen dogs with neoplasms of the lower urinary tract (bladder and/or urethra) were retrospectively evaluated at five referral institutions participating in ongoing studies by the Veterinary Cooperative Oncology Group. Most tumors were malignant (97%) and of epithelial origin (97%). Lower urinary tract tumors were more common in older dogs weighing greater than 10 kg. The following significant (P < 0.05) statistical associations were found using the University of Guelph hospital population as control; there was no sex predisposition although the female: male ratio was 1.95:1. Neutered dogs were predisposed as were Airedale Terriers, Beagles, and Scottish Terriers, whereas German Shepherds were significantly under-represented among dogs with lower urinary tract tumors. These statistical associations should be interpreted cautiously because of possible demographic differences in hospital populations among the University of Guelph and other cooperating institutions. There were no significant correlations between age, gender, weight, breed, response to therapy, and survival time. Clinical signs were indicative of lower urinary tract disease and included hematuria, stranguria, and pollakiuria. The laboratory data were nonspecific except for urinalysis test results. hematuria and inflammatory urinary sediments were most commonly reported; neoplastic cells were identified in the urine sediment of 30% of dogs with lower urinary tract tumors. Contrast cystography was a useful noninvasive diagnostic method since 96% of the dogs had a mass or filling defect in the lower urinary tract demonstrated by this technique. Regional or distant metastases were evident in 37% of the dogs at the time of initial diagnosis whereas at necropsy, 48% of dogs had regional and juxtaregional lymph-node metastasis and 51% had distant metastasis. One or more tumor types, in addition to the lower urinary tract tumor type, were discovered in 22% of dogs. The prognosis for dogs with lower urinary tract tumors was poor; only 16% of the dogs treated had a survival time of 1 year or more. Dogs with complete surgical excision of nonmetastatic bladder tumors had the longest median survival time - 365 days. Dogs with bladder or urethral tumors had significantly longer median survival times than dogs with tumors located in both the bladder and urethra. Surgery and radiotherapy in nine dogs resulted in survival times of 30 to 630 days. The survival times for 15 dogs treated with chemotherapy ranged from 7 to 315 days.