Brachytherapy for localized rhabdomyosarcoma: results from the European paediatric soft tissue sarcoma study group RMS2005 trial

Background Brachytherapy (BT) is an alternative radiotherapy modality for carefully selected patients with rhabdomyosarcoma (RMS). The results of the use of BT in the European paediatric Soft tissue sarcoma Study Group (EpSSG) RMS2005 trial were analysed. Methods All consecutive patients with RMS registered and treated in the E p SSG RMS2005 trial whose local therapy involved BT were included. Endpoints were 5-year event-free survival (EFS) and overall survival (OS). Additionally, a pattern of relapse analysis was performed. Results One hundred and eighteen patients received BT and had full available data. Median age at diagnosis was 2.6 years (range 68 days – 17.2 years). With a median follow-up of 9.2 years (range 39.8 – 188.2 months), 19 patients developed an event, either local (n=14, where n=8 in field), regional (n=2), metastatic (n=1) or second malignancy (n=2). The 5-year EFS and OS were 84% and 97%, respectively. No statistically significant differences were found based on IRS group, BT type (interstitial vs. intracavitary vs. both), dose rate (high- vs. pulsed- vs. low-), nor applied physical dose (≤ 40Gy vs. ≥ 40Gy). A lower 5-year EFS for orbit cases was noted (60%), but the 5-year OS (100%) was good. Conclusions The outcome of patients with RMS treated with BT in the EpSSG RMS2005 trial is excellent. Our results support the continuation of use of BT in suitable RMS cases. Careful selection of patients and treatment delivery by experienced teams are mandatory.