Outcome and prognostic factors in medically treated canine prostatic carcinomas: A multi‐institutional study

Abstract

Literature describing medical treatment of canine prostatic carcinoma (PC) is sparse. The aims of this study were to assess outcomes, including time to progression (TTP) and median survival time (MST), of canine PC treated with non-steroidal anti-inflammatory drugs (NSAIDs) and/or chemotherapy, and to identify prognostic factors. Records from 8 institutions were searched for dogs with cytologically or histologically confirmed PC without bladder involvement: 67 dogs were included. Presenting signs were urinary (25), gastrointestinal ([GI], 11) and systemic (3); 16 dogs had GI and urinary signs, 7 dogs had systemic signs with concurrent GI or urinary signs and in 5 dogs the tumour was an incidental finding. Out of 27 dogs, 9 (33%) had positive urine culture. Metastases were identified in 26 dogs to lymph nodes (19), lungs (10), bone (2) and liver (1). Treatment included NSAIDs and chemotherapy (32), NSAIDs alone (31) and chemotherapy alone (4). The overall MST was 82 days (range 9-752) and median TTP was 63 days (range 9-752). Dogs receiving NSAIDs combined with chemotherapy experienced a significantly longer MST (106 vs 51 days; P = .035) and TTP (76 vs 44 days; P = .02) compared to dogs receiving NSAIDs alone. Intact dogs and those with metastatic disease had significantly shorter MST (31 vs 90 days, P = .018 and 49 vs 109 days, P = .037, respectively); intact dogs also had significantly shorter TTP (25 vs 63 days, P = .0003). This study suggests that a combination of NSAIDs and chemotherapy may improve outcomes in canine PC. Metastatic disease and being entire negatively influenced prognosis.

Prostatic Neoplasia in the Intact and Castrated Dog: How Dangerous is Castration?

“…Canine carcinomas are typical of elderly age [19] and it has been hypothesized that physiological changes due to aging may have an impact on the initiation of CPN development [20]. Although the median or mean body weight is rarely mentioned, medium to large size breeds are more frequently affected by CPN than small or miniature breeds [1,21,22]. No breed predilection has ever been confirmed.…”

“…Prostatic neoplasia in both men and dogs is often associated with bone metastasis, giving the tumor the reputation to metastasize fast and frequently to the skeletal system [20]. However, when considering the reports on metastasis in dogs affected by CPN, lungs and regional (iliac) lymph nodes are affected more frequently than bones [1,22,27,30,32,34,43] (see Table 4). The overall incidence of metastasis in dogs with CPN ranges from 16% [18] to 80% [32].…”

“…Prostatic tumors in the dog which stained positively for CK7 were reported to have both a higher overall metastatic frequency (p = 0.04) and a higher frequency of bone metastasis (p = 0.03), compared to CK7-negative CPN [34]. Surprisingly, lung metastasis has been reported to have no negative impact on median survival time (MST) [22]. Further research is needed to reevaluate the importance of the presence or absence of metastatic disease on treatment-choices and prognosis.…”

“…However, because of diffuse metastatic disease at the time of diagnosis, the above treatment protocols are rarely applied [30,32,48]. Recently, Ravicini et al [22] treated 67 dogs with various degrees of prostatic neoplasia either with nonsteroidal anti-inflammatory drugs (NSAIDs) (46%), with chemotherapy (6%), or with a combination of both (48%) ( Table 5). None of the dogs in this study received surgical treatment or radiotherapy, yet 33% of these dogs showed improvement in clinical signs.…”

Characterization of six canine prostate adenocarcinoma and three transitional cell carcinoma cell lines derived from primary tumor tissues as well as metastasis

“…Canine prostate adenocarcinoma (PAC) and transitional cell carcinoma (TCC) both show highly invasive growth and metastatic behavior that limit treatment options [7,8]. Several cytostatic drugs and cyclooxygenase 2 (COX-2) inhibitors appear to prolong survival times in TCC patients [8,9], whereas few studies support slight effects of COX-2 inhibitors solely or combined with chemotherapeutic agents against canine PAC [10,11]. Comparable to human castrate-resistant prostate cancer, canine PAC is mostly androgen-independent and therefore refractory to androgen depriving or suppressing treatments [7,12].…”