Risk of second malignancies after prostate irradiation?

Several recent SEER- (Surveillance, Epidemiology and End Results-) analyses gave rise to a highly controversial discussion in how far radiotherapy for prostate cancer is associated with an increased risk of secondary neoplasms.

In order to enable a rational discussion, the available literature was reviewed covering all publications from the mid 80s to January 2007.

The reported numbers of secondary cancer (bladder, rectum, lung cancer and sarcoma) after irradiation were found to be increased in some publications. However, after age adjustment and correction for follow-up duration no clear increase was detectable.

Up to now, all available data are highly heterogeneous. Thus, a low risk for secondary cancer cannot be ruled out completely. Nevertheless, it seems very unlikely that there is a relevant risk for secondary cancer since the largest of the published series did not document an increased risk for any secondary cancer.

Only very large prospective studies which are designed to minimize the influence of possible confounders will be able to address the real risk of prostate irradiation-related cancer induction. The available data are clearly not valid and helpful for guiding any treatment decision.