Aggressive local therapy combined with systemic chemotherapy provides long-term control in grade II stage 2 canine mast cell tumour: 21 cases (1999-2012)^*

This retrospective case series evaluates the outcome of 21 dogs with grade II stage 2 mast cell tumour (MCT) treated with adequate local therapy and adjuvant systemic chemotherapy (prednisone, vinblastine and CCNU). The median survival for all dogs was 1359days (range, 188-2340). Median disease-free interval was 2120days (149-2325days). Dogs treated with surgery and chemotherapy had shorter survival (median, 1103days; 188-2010days) than those that underwent surgery, radiation therapy and chemotherapy as part of their treatment (median, 2056days; 300-2340days). Two patients had local recurrence in the radiation field and four patients had de novo MCT. Distant metastasis was not observed in any dogs. The results of this study suggest that, in the presence of loco-regional lymph node metastasis in grade II MCT, the use of prednisone, vinblastine and CCNU after adequate local-regional therapy can provide a median survival in excess of 40months.