Objective—To determine clinical activity and toxic effects of lomustine when used to treat cats with mast cell tumors (MCTs).
Design—Retrospective case series.
Animals—38 cats with measurable, histologically or cytologically confirmed MCTs treated with lomustine at a dosage ≥ 50 mg/m2.
Procedures—Medical records were reviewed to determine response to treatment and evidence of drug toxicoses. The Kaplan-Meier method was used to estimate remission duration.
Results—26 cats had cutaneous MCTs, 7 had MCTs of the mesenteric lymph nodes, 2 had gastrointestinal tract MCTs, 2 had hepatic MCTs, and 1 had MCTs involving multiple organs. Targeted lomustine dosage was 50 mg/m2 in 22 cats and 60 mg/m2 in 16 cats. Median administered dosage of lomustine was 56 mg/m2 (range, 48 to 65 mg/m2), and median number of doses administered was 2 (range, 1 to 12). Seven cats had a complete response and 12 had a partial response, for an overall response rate of 50%. Median response duration was 168 days (range, 25 to 727 days). The most common toxicoses were neutropenia and thrombocytopenia.
Conclusions and Clinical Relevance—Results suggested that lomustine had activity against MCTs in cats and was well tolerated. Further, findings suggested that treatment with lomustine should be considered for cats with MCTs for which local treatment is not an option.
Objective—To evaluate response rate and duration of
malignant melanomas in dogs treated with carboplatin.
Animals—27 client-owned dogs with spontaneously
occurring measurable malignant melanomas.
Procedure—Records of dogs with melanomas treated
with carboplatin from October 1989 to June 2000
were reviewed. Carboplatin was administered IV at
doses of 300 or 350 mg/m2 of body surface area.
Response to treatment and evidence of drug toxicity
Result—Response to treatment could be evaluated in
25 dogs. Of those, overall response rate was 28%.
One dog had a complete response, 6 (24%) dogs had
a partial response (> 50% reduction in tumor burden).
Median duration of partial response was 165 days.
Eighteen dogs had stable disease (n = 9; 36%) or progressive
disease (9; 36%). Response to treatment
was significantly associated with carboplatin dose on
a milligram per kilogram basis (15.1 mg/kg [6.9 mg/lb]
of body weight vs 12.6 mg/kg [5.7 mg/lb]). Evidence
of gastrointestinal toxicosis could be assessed in 27
dogs. Mean body weight of 5 dogs that developed
gastrointestinal toxicosis was significantly less than
that of 22 dogs without gastrointestinal toxicosis (9.9
kg [21.8 lb] vs 19.3 kg [42.5 lb]).
Conclusions and Clinical Relevance—Carboplatin
had activity against macroscopic spontaneously
occurring malignant melanomas in dogs and should
be considered as an adjunctive treatment for microscopic
local or metastatic tumors. Gastrointestinal
toxicosis was associated with body weight. Because
small dogs are more likely to have adverse gastrointestinal
effects, gastrointestinal protectants should be
considered for these patients. (J Am Vet Med Assoc