Nationwide incidence of sarcomas and connective tissue tumors of intermediate malignancy over four years using an expert pathology review network

Abstract Background Since 2010, NETSARC and RREPS collected and reviewed prospectively all cases of sarcomas and tumors of intermediate malignancy (TIM) nationwide. Methods The nationwide incidence of sarcoma or TIM (2013-2016), confirmed by expert pathologists using WHO classification are presented. Yearly variations and correlation with published clinical trials was analyzed. Results 139 histological subtypes are reported among the 25172 patients with sarcomas (n=18710, 64%) or TIM (n=6460, 36%), respectively n=5838, n=6153, n=6654, and n=6527 yearly from 2013 to 2016. Over these 4 years, the yearly incidence of sarcomas and TIM was therefore 79.7, 24.9 and 95.1/10 6 /year, above that previously reported. GIST, liposarcoma, leiomyosarcomas, undifferentiated sarcomas represented 13%, 13%, 11% and 11% of tumors. Only GIST, as a single entity had a yearly incidence above 10/million/year. There were respectively 30, 63 and 66 different histological subtypes of sarcomas or TIM with an incidence ranging from 10 to 1/10 6 , 1-0.1/10 6 , or < 0.1/10 6 /year respectively. The 2 later “incidence groups” included 21% of the patients. The incidence of 8 histotypes varied significantly over this 4 years. Patients with tumors with an incidence above 1/10 6 per year have significantly higher numbers of dedicated published phase III and phase II clinical trials (p<10 −6 ). Conclusions This nationwide registry of sarcoma patients with histology reviewed by sarcoma experts shows that the incidence of sarcoma and TIM is higher than reported, and that tumors with an incidence<10 6 /year have a much lower access to clinical trials.