Late effects of radiation therapy.

Tissue complications of radiation therapy depend on the interplay of therapy, patient and tumor factors. Acute local effects result from parenchymal cell hypoplasia. Chronic damage is caused by both injury to parenchymal cells and to the underlying vasculature. No body tissue or system is immune to damage from radiation therapy, but many effects are dose-dependent. Many of the toxicities can currently be avoided by the optimal use of this important cancer therapy.