Evaluation of Neoadjuvant Therapy and Histopathologic Response in Primary, High-Grade Retroperitoneal Sarcomas Using the Sarcoma Nomogram

BACKGROUND: 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. METHODS: 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 >= 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. RESULTS: 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 >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). CONCLUSIONS: 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. Cancer 2010;116:3883-91. (C) 2010 American Cancer Society