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

Summary

In 2005, the European Pediatric Soft Tissue Sarcoma Study Group (EpSSG) proposed a conservative treatment algorithmÑconsisting of an initial wait-and-see strategy, non-mutilating surgery, and minimal-morbidity chemotherapy (in the case of tumour progression)Ñfor paediatric patients with desmoid-type fibromatosis. We aimed to investigate the outcomes of this algorithm. 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). From Oct 1, 2005, to July 31, 2016, 173 patients (median age 11.4 years [IQR 4.0Ð14.1], 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 27.8Ð45.2) overall, 26.7% (14.2Ð41.0) in the wait-and-see group, 41.2% (25.8Ð55.9) in the surgery group, and 42.8% (27.2Ð57.6) 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 1.34Ð3.76; 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. In paediatric patients with desmoid-type fibromatosis, the EpSSG conservative strategy did not compromise outcomes and could be adopted to reduce treatment burden.