Malignant melanoma in 63 dogs (2001-2011): the effect of carboplatin chemotherapy on survival.

AIMS: The aim of the study was to compare the effect of carboplatin chemotherapy on the survival of canine patients diagnosed with malignant melanoma after loco-regional control or as a sole therapy. METHODS: A retrospective study of 63 dogs with oral, digital or cutaneous malignant melanoma treated with surgery and/or chemotherapy was undertaken. Dogs were grouped based on the anatomical site of melanoma development. For oral melanoma, dogs were subclassified into two groups: loco-regional control and gross disease. All patients in the digital and cutaneous groups had achieved loco-regional control with surgery. Comparisons between survival data for each group at each anatomical site were then made. Within the loco-regional control groups survival time was compared between those treated with and without chemotherapy post surgery. For the oral melanoma patients with gross disease survival was compared between those treated with chemotherapy and palliative therapy. The toxicity of carboplatin chemotherapy was evaluated overall. RESULTS: The overall median survival times for patients with oral, digital and cutaneous melanoma were 389, 1,350 days and not reached (with a median follow-up of 776 days) respectively. Median survival time was defined as "not reached" when less than 50% of the subjects died of the disease at the end of the follow-up period, or at the time they were lost to follow-up. The addition of chemotherapy to surgery did not confer a survival benefit in the loco-regional control setting when assessing survival for each anatomical site. For oral melanoma patients with gross disease there was no difference between survival of patients treated with chemotherapy and palliative intent therapy. There was however an improvement in survival in the three dogs that responded to chemotherapy (978 days; p=0.039) compared to the eight non-responders (147 days). On univariate and multivariate analysis, anatomic location was the only variable that was significantly related to survival (p=0.0002 and p=0.009, respectively). CONCLUSIONS: The addition of chemotherapy to local treatments for canine melanoma at oral, digital and cutaneous sites did not lead to a significant increase in survival times. Carboplatin was well tolerated and appeared to have activity against oral melanoma in a subset of patients with gross disease that responded to treatment. CLINICAL RELEVANCE: Carboplatin with piroxicam could be considered for patients with gross disease when more traditional therapies, such as surgery or radiation therapy, are declined or are not available. In the loco-regional control setting, prospective randomised blinded studies with matched control groups are required to determine if chemotherapy has a role in the treatment of these types of cancer.

CCNU (lomustine) toxicity in dogs: a retrospective study (2002-07).

OBJECTIVE: To describe the incidence of haematological, renal, hepatic and gastrointestinal toxicities in tumour-bearing dogs receiving 1-(2-chloroethyl)-3-cyclohexyl-1-nitrosourea (CCNU). DESIGN: The medical records of 206 dogs that were treated with CCNU at the Melbourne Veterinary Specialist Centre between February 2002 and December 2007 were retrospectively evaluated. RESULTS: Of the 206 dogs treated with CCNU, 185 met the inclusion criteria for at least one class of toxicity. CCNU was used most commonly in the treatment of lymphoma, mast cell tumour, brain tumour, histiocytic tumours and epitheliotropic lymphoma. Throughout treatment, 56.9% of dogs experienced neutropenia, 34.2% experienced anaemia and 14.2% experienced thrombocytopenia. Gastrointestinal toxicosis was detected in 37.8% of dogs, the most common sign of which was vomiting (24.3%). Potential renal toxicity and elevated alanine transaminase (ALT) concentration were reported in 12.2% and 48.8% of dogs, respectively. The incidence of hepatic failure was 1.2%. CONCLUSIONS: CCNU-associated toxicity in dogs is common, but is usually not life threatening.