Effect of surgical site infection on survival after limb amputation in the curative-intent treatment of canine appendicular osteosarcoma: a Veterinary Society of Surgical Oncology retrospective study.

Abstract

To determine the influence of surgical site infection (SSI) on the median disease-free interval (DFI) and median survival time (MST) in dogs after amputation in the curative-intent treatment of appendicular osteosarcoma (OSA). Multi-institutional retrospective cohort study. Fifteen dogs with OSA and SSI, and 134 dogs with OSA and no SSI. Medical records were reviewed, and dogs were included if the following criteria were met: histologic confirmation of OSA, no evidence of metastasis, ≥1 chemotherapy treatment, and available follow-up data. We used the definition of SSI from the Centers for Disease Control and Prevention. Kaplan-Meier estimates of median DFI and MST for the SSI and non-SSI groups were compared by log-rank test. Univariate and multivariate Cox proportional hazard regression analysis was evaluated for associations with DFI and survival. The median DFI and MST of all OSA dogs were 236 days (95% CI, 181-283) and 283 days (95% CI 237-355), respectively. The median DFI of dogs with SSI (292 days) did not differ from that of dogs without SSI (224 days, P = .156). The MST of dogs with SSI (292 days) did not differ from that of dogs without SSI (280 days, P = .417). Failure to complete chemotherapy was associated with decreased DFI and survival (P < .001). Adjustments for chemotherapy completion found no effect of SSI on survival. SSI did not influence the survival of dogs with appendicular OSA treated with amputation and curative-intent treatment. The extended survival associated with SSI after limb-spare surgery for OSA does not appear to be present after amputation. Interactions between the canine immune system and OSA warrant additional study.