Unplanned excision of soft tissue sarcoma: does it impact the accuracy of intra-operative pathologic assessment at time of re-excision?

Purpose: An “unplanned excision” refers to soft tissue sarcomas excised without planning imaging studies and a diagnostic biopsy, resulting in the presence of residual disease and usually necessitating a re-excision procedure. We aimed to assess the impact of previous unplanned excisions on the intra-operative pathologic assessment at the time of re-excision, in terms of need to perform repeat assessments and the accuracy to predict margin status of the final pathologic specimen. Methods: Data was collected for all patients with extremity soft tissue sarcoma who had undergone wide local excision limb salvage surgery or amputation between 2012 and 2017. Intra-operative pathologic assessment with frozen sections was performed in all cases and was classified as negative, negative but close (< 1 mm), and positive. Results: A total of 173 patients with extremity soft tissue sarcoma were included, 54 in the unplanned excision group and 119 in the planned excision group. The accuracy of intra-operative pathologic assessment to predict the margin status on final pathology was similar between groups (87% unplanned vs. 90.7% planned excisions). However, the need for repeat intra-operative pathologic assessment and subsequent resection due to microscopically positive margins was found to be higher within the unplanned excision group ((p = 0.04), OR = 3.2 (95% CI: 1.1–9.1, p = 0.048)). Conclusions: Intra-operative pathologic assessment of resection margins had a similar accuracy in planned and unplanned excisions; however, unplanned excisions showed a higher risk of re-resection during the same surgical setting.