Predictive factors of histological response to primary chemotherapy in Ewing's sarcoma

Clinicopathologic variables associated with a good histological response to primary chemotherapy in Ewing's sarcoma are identified. The histological r esponse to preoperative chemotherapy in 243 cases of Ewing's sarcoma treate d with neoadjuvant chemotherapy was analyzed in relation to different clini copathological features (sex and age of the patients. tumor size, serum lac tate dehydrogenase (LDH) levels, tumor site) and to the type and schedule o f anticancer drugs delivered preoperatively according to three consecutive chemotherapy regimens. A higher rate of good responses was achieved with th e use of ifosfamide and dactinomycin in addition to a conventional three-dr ug VAC regimen, suggesting that these drugs should be included from the beg inning in neoadjuvant regimens for the treatment of Ewing's sarcoma. The an alysis of event-free survival in 158 patients with a 4-year minimum follow- up confirmed that histological response to preoperative chemotherapy is a r eliable predictor of outcome in Ewing's sarcoma.