Do unplanned resections in soft tissue sarcomas of the extremities have an adverse impact on the prognosis? Experience of a Latin-American sarcoma reference center.

Background: Soft tissue sarcomas (STS) are rare, heterogeneous neoplasms often not optimally managed by teams without sarcoma expertise. Between 40 % and 50 % of primary resections for extremity sarcomas occur without prior biopsy, resulting in inadequate excisions, termed "unplanned resections" or "whoops surgery."

Objective: To determine the rate of unplanned resections in extremity STS referred to a high-volume sarcoma center and evaluate their impact on oncological outcomes.

Methods: A retrospective study of 680 extremity STS patients referred between 2005 and 2020. Of these, 239 (35 %) had unplanned resections. We analyzed the impact of unplanned resections on recurrence, disease-free survival (DFS), and overall survival (OS) after re-excision.

Results: Among the 239 patients with unplanned resections, 52 % were male, the median age was 46, and the most common histologies were liposarcoma (24 %) and synovial sarcoma (20 %). The median tumor size was 9 cm. Re-excisions achieved R0 margins of 88.6 %. Recurrence occurred in 26.3 % of cases and progression in 12.9 %, with an overall recurrence or progression rate of 39.2 %. The median DFS was 151 months for R0 resections, compared to 57.1-61.8 months for R1/R2 resections. The median OS was 140 months for R0 resections versus 50.8-52.3 months for R1/R2 resections.

Conclusions: Unplanned resections by non-specialized surgeons significantly reduce DFS and OS. Nonetheless, re-excision with negative margins (R0) provides oncological outcomes comparable to those reported in planned surgeries, emphasizing the importance of timely referral to specialized sarcoma centers.