The risks to healthy tissues from the use of existing and emerging techniques for radiation therapy.

As radical radiotherapy treatments become more effective, more and more cancer patients are becoming cured of their disease and surviving for decades. Damage to exposed healthy tissues that becomes manifest in the medium-to-long-term is becoming a more significant factor in the choice of individual treatment plans and treatment modality. However, currently there are no reliable objective methods for predicting in an individual patient the occurrence of normal tissue complications, or second cancers caused by radiation. This is especially needed as new competing techniques and modalities become available, such as IMRT, protons, carbon ions, etc., all advancing the ability to focus the radiation dose on the target while sparing normal tissue. ALLEGRO is a Euratom-funded project that is currently investigating the current state of knowledge, and attempting to define the priority research areas. Preliminary considerations of the problems to be solved and research priorities are presented.