Twelve genetic markers associated with development of erectile dysfunction (ED) have been found in prostate cancer patients treated with radiation—a discovery that researchers hope will help led to development of therapies without the side effects produced by current treatments.
A research team led by Mount Sinai School of Medicine and Albert Einstein College of Medicine of Yeshiva University carried out the first large scale Genome-Wide Association Study (GWAS) to identify single nucleotide polymorphisms (SNPs) associated with susceptibility to ED following radiotherapy for prostate cancer.
The study consisted of two parts: Discover the candidate genetic markers of side-effect risk, then confirm which of those markers are replicated in a second group of patients. Patients in the study cohort were given brachytherapy, brachytherapy plus external beam radiation, or external beam radiation alone. They were followed for an average of nearly four years to determine their level of sexual function after treatment.
In the first group of prostate cancer patients—132 men who developed ED after radiotherapy and 103 men similarly treated who did not develop the disorder—researchers found genetic markers associated with ED. In the second part of the study, which examined 128 patients who developed ED after radiotherapy and 102 who did not, researchers confirmed that 12 SNPs were associated with ED.
The 12 SNPs were located near genes appearing to be related to erectile function rather than related to radiation response. The researchers concluded that these SNPs may affect genes that sensitize a patient to developing ED when exposed to radiation during therapy.
"If validated further, these SNPs could provide the basis for a blood test that would enable radiation oncologists to predict more accurately which men are most likely to develop erectile dysfunction after prostate cancer radiation therapy," Harry Ostrer, M.D., professor of pathology and genetics at Einstein, and a member of the research team, said in a statement.
Researchers are also evaluating the impact of radiation treatment on urinary complications and inflammation of the rectum or proctitis.
Results from the study were published today in advance of the October 1, 2012 print issue in the International Journal of Radiation Oncology• Biology• Physics, the official scientific journal of the American Society for Radiation Oncology.