Importance of local treatment in pediatric soft tissue sarcomas with microscopic residual after primary surgery: Results of the Italian Cooperative Study RMS-88

BACKGROUND: The goal of primary excision in soft tissue sarcomas is the complete removal of the tumor by a nonmutilating procedure. However, microscopic residuals may be left after a conservative procedure because of inadequate preoperative assessment or difficulties during the operation. The purpose of this report is to describe the treatment and the outcome in patients, enrolled in the Italian Cooperative Study RMS-88, with microscopic residuals after primary excision (IRS Group IIa). PROCEDURE: Microscopic residuals were evident at histology in 52 of 90 patients who had a macroscopic complete primary excision: 25 rhabdomyosarcomas (RMS) and 27 nonrhabdo-soft tissue sarcomas (NRSTS). Eighteen patients were treated with primary reexcision (PRE) and chemotherapy (CT) using VA or IVA regimens; 27 patients received radiation therapy (RT; 40 Gy) and IVA; 7 children in whom PRE was not feasible and RT could not be administered for age <3 years were treated with CT (IVA) alone. RESULTS: Of the 18 patients who underwent a successful PRE + CT, the local relapses were 3 (16.6%); of 27 cases who had RT + CT there were 4 local relapses (14.8%); 3 local relapses occurred in those 7 patients in whom CT alone was administered (43%). CONCLUSIONS: Microscopic residuals after primary surgery were difficult to manage because of the absence of a measurable target. PRE represented the treatment of choice for children <3 years of age who cannot receive RT and for paratesticular sites. PRE and RT showed similar results in achieving local control in extremity and trunk sites, but they could not always avoid local recurrence. In particular PRE was not effective in tumors larger than 5 cm. If microscopic residuals could not be avoided and PRE was not possible, adequate RT was effective both for RMS and for NRSTS.