The EpSSG NRSTS 2005 treatment protocol for desmoid-type fibromatosis in children: an international prospective case series

Background In 2005, the European Pediatric Soft Tissue Sarcoma Study Group (EpSSG) proposed a conservative treatment algorithm—consisting of an initial wait-and-see strategy, non-mutilating surgery, and minimal-morbidity chemotherapy (in the case of tumour progression)—for paediatric patients with desmoid-type fibromatosis. We aimed to investigate the outcomes of this algorithm. Methods In this case series, patients (<25 years) with desmoid-type fibromatosis from 57 centres in eight countries were prospectively registered through a web-based system. Diagnosis was based on histological analysis of the tumour specimen after biopsy or surgery, and we classified patients by tumour site, clinical stage (TNM system), and post-surgical stage (Intergroup Rhabdomyosarcoma Study system). Progression-free survival was defined as the time from diagnosis until disease progression (clinical or radiological progressive disease, relapse, or death from any cause). Findings From Oct 1, 2005, to July 31, 2016, 173 patients (median age 11·4 years [IQR 4·0–14·1], 88 [51%] male patients) were registered. After excluding patients with missing data, 54 (35%) patients had no immediate therapy (wait-and-see strategy), 47 (31%) had immediate surgery, and 53 (34%) had immediate chemotherapy after diagnosis. 5-year progression-free survival was 36·5% (95% CI 27·8–45·2) overall, 26·7% (14·2–41·0) in the wait-and-see group, 41·2% (25·8–55·9) in the surgery group, and 42·8% (27·2–57·6) in the chemotherapy group (overall log-rank p=0·17; wait-and-see vs surgery p=0·12; wait-and-see vs chemotherapy p=0·13). In multivariable analysis, large tumour size (>5 cm) was associated with worse progression-free survival (hazard ratio 2·25, 95% CI 1·34–3·76; p=0·0021). Apart from one patient in the chemotherapy group who died from a secondary tumour (head and neck anaplastic embryonal rhabdomyosarcoma), all patients were alive at the time of analysis. 13 (8%) patients had biopsy only (no further treatment), 65 (42%) had chemotherapy only, 31 (20%) had surgery only, 36 (23%) had both chemotherapy and surgery, and nine (6%) had radiotherapy in addition to other therapies. Interpretation In paediatric patients with desmoid-type fibromatosis, the EpSSG conservative strategy did not compromise outcomes and could be adopted to reduce treatment burden. Funding S Wisnia and la Città della Speranza Foundation.