Griffin MA, Culp WTN, Giuffrida MA, Ellis P, Tuohy J, et al. Lower urinary tract transitional cell carcinoma in cats: Clinical findings, treatments, and outcomes in 118 cases. J Vet Int Med. 2019 Oct 14; 1-9.
To date, information on prognosis and treatments for cats with bladder cancer (transitional cell carcinoma; TCC) has been limited, owing to a lack of data. In contrast to TCC in dogs, the incidence of TCC in cats is low. TCC is the second most common site of urinary tract neoplasia in cats (after renal lymphoma). The largest retrospective study published on TCC in cats to date reported on 20 documented cases, however it was not possible to determine survival advantage for any specific treatment (which included piroxicam administration, chemotherapy, and surgical excision) due to an insufficient number of cats receiving any given treatment protocol.
The objective of the present study was to describe the common clinical characteristics, treatments, and outcomes in a cohort of cats with TCC of the lower urinary tract, and to identify variables of prognostic relevance. The retrospective observational study included 118 client-owned cats with lower urinary tract carcinoma selected by medical record database review between 1991 and 2018 from 11 different referral institutions. Cats were required to have either cytological or histopathological confirmation of carcinoma from a mass in either the bladder or urethra to be included in the study.
The median age of included cats was 15.0 years (range 5.0-20.8 years). Spayed females represented 46.2 % of cats, and castrated males represented 46.2 %.
A history of urinary tract infection was present in 28 of 118 (23.7%) cats, feline idiopathic cystitis in 17 of 118 (14.4%) cats, and urolithiasis in 12 of 118 cats (10.2%). Most cats (78.0%; 92 of 118) had previously been presented to a veterinarian for signs of urinary tract disease. At least one clinical sign was noted in 111 of 118 (94.1%) of cats, and the median duration of clinical signs was 30 days (range 0-730 days). The remaining 7 of 118 (5.9%) of cats had TCC incidentally diagnosed while undergoing imaging for assessment of other conditions.
Diagnosis was achieved by ultrasound-guided FNA alone in 28% of cats, surgical biopsy alone in 25.4% of cats, necropsy alone in 14.4%, urine cytospin alone in 11.9%, and traumatic urethral catheterization alone in 5.1%. Metastatic disease was estimated in 12.7% of cats at initial evaluation, based on imaging, cytology, and histopathology results.
Treatments were grouped into three populations for analysis: no treatment, treatment with cystectomy, and treatment without cystectomy. No cats underwent radical cystectomy. For those cats undergoing partial cystectomy, excision was reported as complete in 9 of 28 (32.1%) cases, incomplete in 12 of 28 (42.9%) cases, and not reported in 7 of 28 (25 %) of cases.
Non-steroidal anti-inflammatory drugs (NSAID) were administered to 49 of 118 (41.5%) cats, and 15 of 49 (30.6%) were treated only with NSAIDs. The remaining 34 of 49 (69.4%) cats received NSAIDs as part of a multi-modal treatment plan. NSAIDs administered included piroxicam, meloxicam and robenacoxib. Chemotherapy was administered to 33 of 118 (28%) cats; 6 of 33 (18.2%) cats were treated with only chemotherapy, and 27 of 33 (81.8%) cats were treated with chemotherapy as part of a multi-modal treatment plan. The most common chemotherapy protocol was mitoxantrone alone. Radiation therapy was administered to 3 of 118 (2.5%) cats on once weekly fractionated basis for 2 to 6 treatments. Based on multivariate analysis, trigonal disease and a presenting complaint of lethargy were associated with increased likelihood of not receiving treatment.
Median progression-free survival time for all cats was 113 (range 69-153) days. The median time to tumor recurrence in cats that underwent partial cystectomy was 205 days (range 42-459).
Median survival time (MST) for all cats was 155 days (range 110-222). MST for untreated cats was 46 days (8-82), 176 days (113-240) for cats that were treated without partial cystectomy, and 294 days (212-626) for cats treated with partial cystectomy with or without other treatment modalities.
Excerpt from article showing Kaplan-Meier survival estimates for different treatment groups
The results of the present study demonstrate a benefit of treatment with cystectomy and NSAIDs in cats with TCC, where significantly longer survival times were associated with these treatment modalities. The authors conclude that to promote improved outcomes, surgical excision and NSAID administration should be the primary treatment recommendations for cats with lower urinary tract TCC. Data indicate that NSAIDs were generally well tolerated by cats and carry a low risk of complications when used appropriately. The study highlights TCC as an important differential in cats with a history of other forms of lower urinary disease, particularly when cases are recurrent or refractory to treatment.
Several limitations exist in the present study, including its retrospective nature and inherent potential for incomplete clinical information. Moreover, there was significant variation in the treatment protocols and anatomic locations for disease, precluding valid comparisons across subgroups of cats. Many cases were lost to follow-up, and a likely selection bias influenced by both patient and client factors is speculated. Previous treatment performed at referring practices was also not accounted for in this study. Lastly, the long inclusion period may have resulted in bias toward certain recommended treatment modalities, based on available data at the time.
In conclusion, this study represents that largest performed to date on cats with TCC of the lower urinary tract. Additional studies are required to evaluate larger numbers of cats undergoing various treatments, to allow meaningful comparisons across subgroups of cats. (HM)
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