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

Abstract

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.

Figure 1

Kaplan Meier curve depicting 5-year local recurrence-free survival, overall survival, and distant recurrence-free survival for the entire cohort of soft tissue sarcoma patients treated with preoperative radiotherapy following by resection with curative intent.

Figure 2

Kaplan Meier curve depicting distant recurrence-free survival grouped by presence or absence of near-complete pathologic necrosis in resected surgical specimen (≥ 95% tumor necrosis). Log-rank test P value is shown.