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