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

Objective 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). Study design Multi‐institutional retrospective cohort study. Animals Fifteen dogs with OSA and SSI, and 134 dogs with OSA and no SSI. Methods 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. Results 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. Conclusion SSI did not influence the survival of dogs with appendicular OSA treated with amputation and curative‐intent treatment. Clinical significance 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.

Analysis of outcome in dogs that undergo secondary amputation as an end‐point for managing complications related to limb salvage surgery for treatment of appendicular osteosarcoma

“…1,2,6,16 A recent report found that SSI in dogs that undergo primary amputation for definitive local control of OSA does not carry a similar survival benefit. 17 In the aforementioned study, the SSI risk was 10%, with a similar ratio of superficial and deep infections and all SSI were resolved within 30 days. A possible difference between these two groups of dogs is the chronicity and severity of infection.…”

“…Our finding of prolonged survival with SSI in dogs that undergo limb salvage surgery for appendicular OSA has been consistently reported in the veterinary literature . A recent report found that SSI in dogs that undergo primary amputation for definitive local control of OSA does not carry a similar survival benefit . In the aforementioned study, the SSI risk was 10%, with a similar ratio of superficial and deep infections and all SSI were resolved within 30 days.…”

“…In the dogs that had an SSI in our study population study, only 3% resolved with antibiotic treatment while the remainder were chronic, intractable to treatment, were multi‐drug resistant or lead to secondary amputation. It is possible that the absence of a survival benefit from SSI in the referenced study in canine amputation patients could be the very short duration of SSI and presumed lower severity of infection compared with the limb salvage population studied here. The mechanistic understanding of SSI's influence on prolonged ST in canine OSA patients undergoing limb salvage surgery is still unclear, although investigators have postulated a cytotoxic immunomodulatory effect involving natural killer cells, tumour‐related macrophages and other monocyte populations in the presence of low‐grade, chronic SSI …”

“…In the dogs that had an SSI in our study population study, only 3% resolved with antibiotic treatment while the remainder were chronic, intractable to treatment, were multi-drug resistant or lead to secondary amputation. It is possible that the absence of a survival benefit from SSI in the referenced study 17 populations in the presence of low-grade, chronic SSI. 8,18 Survival differences found here between the amputation and control groups is interesting, and based on the competing risk regression analysis, significant factors influencing this increased survival were moderate and severe SSI.…”

miR‐874‐3p inhibits cell migration through targeting RGS4 in osteosarcoma

“…Before the 1970s, amputation was the main treatment for OS 4 . However, early metastasis may have occurred before amputation such that patients cannot be cured completely 5 . Indeed, the overall therapeutic effects remains poor 6 .…”