Prognostic value of tumour-related factors associated with canine retroperitoneal hemangiosarcoma in comparison with other anatomic presentations: A retrospective observational study.

Abstract

Dogs with retroperitoneal hemangiosarcoma (HSA) exhibit variable postoperative median survival times (MST). To retrospectively evaluate the prognostic value of selected tumour-related factors, such as tumour size, rupture, invasion into adjacent tissue, involvement of lymph node and distant metastasis, they were analysed in dogs with retroperitoneal HSA. Ten dogs with retroperitoneal HSA managed solely with surgical excision were reviewed and compared with spleen (71) and liver (9) HSA. The Kaplan-Meier method and log-rank analysis were used compare MSTs between factors. Multivariable Cox proportional-hazard analysis was used to compare differences between arising sites. Retroperitoneal HSA showed comparatively longer postoperative MST compared with that of spleen and liver HSA and demonstrated significantly longer MST (p=0.003) for tumours ≥5cm (195 days) than <5cm (70 days). Spleen HSA revealed significantly shorter MSTs in involvement of distant lymph nodes (23 days) and distant metastasis (39 days) than those in negative (83 days, p=0.002 and 110 days, p<0.001, respectively). Liver HSA also revealed significantly shorter MST (16.5 days compared with 98 days, p=0.003) for distant metastasis. Additionally, hazard ratios (HRs) and their forest plot for overall HSA revealed as poor prognostic factors, arising sites (spleen; HR 2.78, p=0.016 and liver; HR 3.62, p=0.019), involvement of distant lymph nodes (HR 2.43, p=0.014), and distant metastasis (HR 2.86, p<0.001), and as better prognostic factor of tumour size ≥5cm (HR 0.53, p=0.037). In combination with overall HSA, retroperitoneal HSA shows comparatively longer postoperative MST compared to spleen and liver HSA, associated with tumour size ≥5cm suggesting better prognostic factor.