Evaluation of neoadjuvant therapy and histopathologic response in primary, high‐grade retroperitoneal sarcomas using the sarcoma nomogram

Abstract

Patients with primary high-grade retroperitoneal soft tissue sarcomas have a 5-year disease-specific survival (DSS) of <40%. The impact of neoadjuvant therapy on histopathologic response and DSS are unknown. From 1987 to 2007, 55 patients with primary high-grade retroperitoneal sarcoma received neoadjuvant therapy. All patients underwent surgical resection, and response was assessed histopathologically. Patients with >or=95% pathologic necrosis were classified as responders. Clinicopathologic variables were analyzed for association with DSS. Observed DSS was then compared with the Memorial Sloan-Kettering Cancer Center Sarcoma Nomogram predicted DSS. The median tumor size was 15 cm, and the median follow-up time for survivors was 68 months. The 5-year DSS for all 55 patients was 47% and did not significantly differ from the 37% predicted by the sarcoma nomogram for such patients (P=.44). Fourteen (25%) of the patients had >or=95% pathologic necrosis and were defined as responders; 41 (75%) were nonresponders. The 5-year DSS for responders was 83%. This was significantly better than the 5-year DSS of 34% for nonresponders (P=.002) and the 39% predicted by the sarcoma nomogram for responders (P=.018). The 34% 5-year DSS for nonresponders did not significantly differ from the 35% predicted by the sarcoma nomogram (P=.51). Neoadjuvant therapy was not associated with an overall improvement in DSS in patients with primary high-grade retroperitoneal sarcoma compared with the sarcoma nomogram prediction. Histopathologic response to neoadjuvant therapy was associated with a significantly improved DSS compared with nonresponders and with the sarcoma nomogram prediction for such patients.