What is the median survival time for dogs with splenic hemangiosarcoma after splenectomy with and without chemotherapy?

Question

Accepted Answer

Median survival time (MST) for dogs with splenic hemangiosarcoma (HSA) after splenectomy alone is 19–86 days, rising to 117–277 days with adjuvant treatment.2 Splenectomy without chemotherapy yields an MST of 42–86 days across multiple reports.7 The 2026 AAHA Oncology Guidelines summarize this as 1.5–3 months.6 For dogs with incidentally detected, nonruptured splenic masses (a subset with less advanced disease at diagnosis), splenectomy-alone MST was 110 days for those ultimately diagnosed with malignancy, and 132 days specifically for those with HSA, with a 1-year survival rate of 16.7%.3 Adjuvant doxorubicin-based chemotherapy extends MST to 139–179 days in dogs with stage I–II disease.7 The AAHA guidelines cite an MST of approximately 3–6 months with adjuvant chemotherapy.6 In a stage I–II cohort receiving anthracycline-based protocols, MST was 154 days; dogs who received metronomic chemotherapy following anthracyclines achieved an MST of 338 days, and those receiving metronomic chemotherapy alone achieved 225 days — differences that were not statistically significant between groups.13 The overall MST across all adjuvant treatment groups in that cohort was 200 days.13 For stage II disease specifically, splenectomy plus an anthracycline/lomustine alternating protocol produced an MST of 158 days and a 1-year survival rate of 16%. Dogs with a low mitotic score (<11 mitoses/10 hpf) had a significantly longer MST of 292 days and a 1-year survival rate of 42%, compared to 212 days for a mitotic score of 11–20 and 116 days for a score >20.4 For stage III (metastatic) disease, prognosis is substantially worse. Overall MST after splenectomy was 40 days without adjuvant treatment, 58 days with metronomic chemotherapy, and 140 days with maximum-tolerated-dose (MTD) doxorubicin-based chemotherapy — MTD was significantly superior to metronomic chemotherapy (p = 0.023), though at the cost of significantly higher treatment-related adverse events.5 Carboplatin is an alternative