Background: External beam radiation has been commonly employed for the management of localized prostate cancer, which is the most frequent cancer type in men in Norway. Recent developments in conformal radiation therapy permit higher doses to be delivered to the target volume and may thus lead to improved tumor control. Unfortunately, improved tumor control may be accompanied by increasing adverse effects as late gastrointestinal, genitourinal and erectile dysfunction. It is therefore important to have detailed knowledge about how these adverse effects are influenced by the dose level and the irradiated volume of healthy tissue in order to understand how to minimalize them in radiation therapy. Purpose: To present an up-to-date review of the research literature concerning late toxicities and the dosimetric factors.
Methods: Non-systematic searches of the PubMed/Medline database.
Results: This review summarizes the literature on adverse effects related to radiation therapy. The review presents dosimetric factors in relation to the adverse effects. There is very strong agreement in suggesting dose-volume constraints in the “high dose” region (65-80 Gy). In particular, it has been demonstrated that keeping the volume that receives >70 Gy below 25% and keeping the volume of the rectum that receives <75 Gy below a few percent are predictive of a very low incidence of late toxicity. Quantitative data on bladder and sexual organs are scarce but are rapidly emerging; however, for these organs, further investigations on larger groups of patients are necessary.