The predictive value of initial cytostatic response in primary unresectable rhabdomyosarcoma in children.

The relation between the initial tumour regression produced by chemotherapy and the later event-free survival was studied in a prospective multicentre study on soft-tissue sarcomas in children. The event-free survival rate in patients with complete remission after seven weeks of chemotherapy was 95%; in patients with incomplete tumour reduction of greater than 2/3, 61%; and in patients with tumour reduction of less than 2/3 but greater than 1/3, 31%. Patients with partial remission at week 7, who achieved complete remission by week 16 after additional chemotherapy had an event-free survival rate of 64%. A multivariate analysis suggested that the response per unit of time was an important prognostic factor.