Assessment of Compliance With Monitoring Conducted by a Physician in Person or by a Nurse in Remote Monitoring

This is a multicenter, interventional, randomized study among adult patients recently diagnosed with a rare tumor (\<12 months). The study will aim to compare compliance with the personalized post-treatment surveillance plan, established for each patient according to national guidelines, when the surveillance is conducted in person by a hospital-based physician (control arm) or remotely by a trained nurse (experimental arm).