Rare cancer patients face lower survival and experience delays in diagnosis and therapeutic mismanagement. Considering the specificities of rare cancers, referral networks have been implemented in France to improve the management and survival of patients. The IGéAS research program aims to assess the networks’ ability to reduce inequalities. Data analysis of the IGéAS cohort (n = 20,590, sarcoma diagnosed between 2011 and 2014) by gathering medical data and geographical index will identify risk factors associated with the belated access to expertise or with no access to expertise. Intermediate results show that referral networks give sarcoma patients access to sarcoma expertise despite the remoteness of some of them. Regional expert centers mostly receive requests from within their area while national referral centers receive requests from the whole country. Delays in the access to expertise may be reduced by making outside practitioners more sensitive to the issues of rare cancers. The perception and involvement of outside practitioners in this device will be assessed using a qualitative survey. All the results are discussed and will contribute to design guidelines to improve early access to expertise and reduce inequalities. Results of the IGéAS research program may contribute to the assessment of referral sarcoma networks and provide some useful lessons to improve cancer care management.