Survival time of dogs with splenic hemangiosarcoma treated by splenectomy with or without adjuvant chemotherapy: 208 cases (2001–2012)

Abstract

Objective—To determine survival time for dogs with splenic hemangiosarcoma treatedwith splenectomy alone, identify potential prognostic factors, and evaluate the efficacy ofadjuvant chemotherapy.Design—Retrospective case series.Animals—208 dogs.Procedures—Medical records were reviewed, long-term follow-up information was obtained,and survival data were analyzed statistically.Results—154 dogs were treated with surgery alone, and 54 were treated with surgeryand chemotherapy. Twenty-eight dogs received conventional chemotherapy, 13 receivedcyclophosphamide-based metronomic chemotherapy, and 13 received both conventionaland metronomic chemotherapy. Median survival time of dogs treated with splenectomyalone was 1.6 months. Clinical stage was the only prognostic factor significantly associatedwith survival time. When the entire follow-up period was considered, there was no significantdifference in survival time between dogs treated with surgery alone and dogs treatedwith surgery and chemotherapy. However, during the first 4 months of follow-up, afteradjusting for the effects of clinical stage, survival time was significantly prolonged amongdogs receiving any type of chemotherapy (hazard ratio, 0.6) and among dogs receiving bothconventional and metronomic chemotherapy (hazard ratio, 0.4).Conclusions and Clinical Relevance—Clinical stage was strongly associated with prognosisfor dogs with splenic hemangiosarcoma. Chemotherapy was effective in prolonging survivaltime during the early portion of the follow-up period. Combinations of doxorubicin-basedconventional protocols and cyclophosphamide-based metronomic protocols appeared to bemore effective than either type of chemotherapy alone, but prolongations in survival timeresulting from current protocols were modest.