Late sequelae of radiotherapy in adults.

Around 3-5 million cancer patients receive radiotherapy worldwide every year. Improved cure rates have led to physicians being confronted with a range of late radiation sequelae, broadly of two types-late effects on normal tissues (LENT) and radiation-induced second malignancies (RISM). These late changes affect the function and quality of life of cancer survivors, increase with increasing radiation dose and show a relationship with time. Overall risks for LENT and RISM are 5-10% and 2-10%, respectively, and the potential benefits of radiotherapy outweigh these risks.