Histological necrosis in soft tissue sarcoma following preoperative irradiation.

Forty-eight patients with soft tissue sarcomas that presented adverse features for treatment by limb salvage surgery and postoperative irradiation were treated by preoperative irradiation and surgery using a consistent protocol. Following resection, the extent of histological necrosis in the specimen was scored according to the criteria of Willet et al. Of the 48 cases, 16 (34%) demonstrated Grade 1 response (< 50% necrosis), 15 (31%) Grade 2 (50-80% necrosis), and 17 (35%) Grade 3 (> 80% necrosis). There was a trend toward more extensive necrosis in liposarcoma tumors (53% showing Grade 3 response compared to 26% of other sarcomas). Logistic regression analysis demonstrated a significant relationship between necrosis and tumor size (P < 0.001) with larger tumors having higher grades of necrosis. Tumor grade did not seem to affect the extent of necrosis. In comparison to the previous report of necrosis in soft tissue sarcoma following irradiation, the current analysis revealed a smaller proportion of tumors with Grade 3 necrosis.