Complete pathologic response to neoadjuvant radiotherapy is predictive of oncological outcome in patients with soft tissue sarcoma.

Unlabelled: We sought to determine if complete pathological necrosis (pathCR) predicts favorable oncological outcome in soft tissue sarcoma (STS) patients receiving pre-operative radiation monotherapy (RT).
Patients and Methods: We evaluated 30 patients with primary STS treated with neoadjuvant RT followed by definitive resection, from 2000 to 2010 at our institution. We defined ≥ 95% tumor necrosis as pathCR.
Results: There were 22 STS of the extremities (73%), 7 of the retroperitoneum (23%), and 1 (4%) of the trunk. The median pathological percentage of tumor necrosis was 35% (range 5-100%) with three tumors (10%) demonstrating pathCR. With a median follow-up of 40 months, the 5-year local recurrence-free survival (LRFS), distant recurrence-free survival (DRFS), and overall survival (OS) for the entire cohort were 100%, 61% ± 11%, and 69% ± 11%, respectively. Among patients with pathCR, 3-year DRFS was 100% compared to 63±11% in patients without pathCR (p=0.28).
Conclusion: Following neoadjuvant RT for STS, pathCR is associated with a clinically but not statistically significant 37% improvement in 3-year DRFS.