Outcome for children with group III rhabdomyosarcoma treated with or without radiotherapy

To analyze the sites of relapse, relapse-free survival, and overall survival in children with Group III rhabdomyosarcoma treated with or without radiotherapy (RT).

The outcomes of 48 children with Group III rhabdomyosarcoma treated between 1980 and 1997 were evaluated. The median overall survival follow-up was 7.3 years. Of the 48 patients, 65% had embryonal histology. Local treatment after induction chemotherapy included complete surgical resection (CSR) alone in 9 (19%), CSR plus RT in 13 (27%), partial resection or rebiopsy plus RT in 10 (21%), and RT alone in 15 patients (31%). One child developed distant disease before completing local therapy.

Of the 48 patients, 12 developed relapse at local (n = 3), regional (n = 4), or distant (n = 5) sites. All 9 patients treated with CSR after induction chemotherapy had embryonal/botryoid histology. Only 1 of these 9 patients developed relapse. No statistically significant difference was found in overall survival (p = 0.95) or relapse-free survival (p = 0.67) between patients treated with or without RT. The Kaplan-Meier estimate of 5-year overall survival and relapse-free survival was 76% +/- 7% and 74% +/- 7%, respectively. Significant predictors of relapse-free survival on univariate analysis included CSR (p = 0.03), nodal positivity (p = 0.001), and embryonal histology (p = 0.0003). On multivariate analysis, embryonal histology was the most significant predictor of relapse-free (p = 0.001) and overall (p = 0.01) survival.

The overall survival for children with Group III rhabdomyosarcoma in this series was favorable. Embryonal/botryoid histology was the most significant predictor of both overall and relapse-free survival. We found that for a selected subgroup of children with embryonal histology, induction chemotherapy followed by complete surgical resection alone may be adequate local therapy.