Non-specialized centres see relatively few patients with rare cancers like soft tissue sarcoma. This leads to inappropriate diagnostic work-up and treatment resulting in a worse oncological outcome. We believe that modern tailor-made therapy for rare cancers requires not only the multidisciplinary expertise of specialized cancer centres but also, occasionally, the expert knowledge of an international network of specialist centres. Here, we emphasize the importance of national and international networks for the treatment of patients with rare tumours. The importance is placed in perspective using the treatment of sarcoma patients as an example.