Men who receive pelvic radiotherapy to treat a primary cancer have a significantly lower risk of developing prostate cancer as a second cancer, according to a study of more than 550,000 men published in the April issue of Cancer Epidemiology.
With patients receiving pelvic radiotherapy being the only major exception, long-term secondary cancer risk was comparable between the Dutch male population and male cancer survivors, according to lead author Dr. Dieuwertje E.G. Kok of the division of human nutrition at Wageningen University, the Netherlands, and co-authors. After the first year, patients who had received pelvic radiotherapy were half as likely as both groups of men to develop prostate cancer.
Seeking to evaluate the risk of prostate cancer as a second cancer in a population-based setting, the researchers used the Netherlands Cancer Registry to identify 9,243 out of 551,553 men diagnosed with a primary cancer between 1989 and 2008 who subsequently developed prostate cancer. Overall, cancer survivors, regardless of whether they had pelvic radiotherapy treatment or not, showed a 30% increased risk in the first 12 months following treatment compared with the general Dutch population (Cancer Epidemiology, April 2013, Vol.37:2, pp. 140-145).
Men who received pelvic radiotherapy were being treated for sigmoid colon, rectum, anus and anal canal, penis, testis, renal pelvis, ureter, and urinary tract tumors. The authors suggested one of the reasons for the reduced risk was that early prostate tumors were suppressed by the irradiation exposure. Another hypothesis was radiotherapy initially increases, but in the long-term lowers, prostate specific antigen (PSA) production.
