(RxWiki News) While treatments for prostate cancer can be very effective, they can also cause erectile dysfunction. Now, genetic markers may help identify which patients are more likely to get Erectile Dysfunction (ED).
While surgery, brachytherapy (radioactive seeds implanted near the tumor) and external beam radiation therapy have been proven to often eliminate prostate cancer, erectile dysfunction is often a side effect.
Recent research has identified genetic markers that are seen in prostate cancer patients who have undergone radiation treatment and later experienced ED.
Scientists believe this discovery could lead to the development of new therapies with fewer side effects.
"Check with a doctor about ED treatments."
Harry Ostrer, MD, Professor of Pathology and Genetics at Albert Einstein College of Medicine and Director of Genetic and Genomic Testing at Montefiore Medical Center in New York City, acted as co-principal investigator of the study, along with Barry Rosenstein, PhD, Professor of Radiation Oncology, at Mount Sinai School of Medicine in New York City.
The authors noted that erectile dysfunction following external beam radiation for prostate cancer strikes 65 to 85 percent of patients, according to the National Cancer Institute. The Prostate Cancer Foundation estimates that 25 to 50 percent of patients receiving seed therapy get ED.
“The risk of developing erectile dysfunction after radiation treatment is highly variable, suggesting there may be a genetic component to determining that risk,” said Professor Rosenstein.
“Our study confirms that specific markers make certain patients more susceptible to this side effect.”
Patients in this study received one of three treatments: brachytherapy, brachytherapy plus external beam radiation or external beam radiation alone. Doctors followed the patients over a course of about four years to measure if and how these therapies effected sexual function.
Researchers looked at two groups of prostate cancer patients who received radiation treatment. In the first group of men, 132 developed erectile dysfunction and 103 did not. In the second group, 128 patients developed erectile dysfunction after and 102 did not.
From the study, scientists identified 12 biomarkers called single nucleotide polymorphisms (SNPs) associated with higher risks of erectile dysfunction following radiotherapy.
According to the U.S. National Library of Medicine, SNPs (pronounced “snips”) are the most common type of genetic variation among people. Each SNP represents a difference in a single DNA building block, called a nucleotide.
The researchers concluded that these SNPs affect genes that make a patient more sensitive to developing erectile dysfunction when exposed to radiation during therapy. With more knowledge of this genetic change, scientists expect to develop better treatments.
“Prostate cancer screening and treatment are undergoing major shifts,” said Dr. Ostrer.
“This is part of our ongoing effort to identify men at highest risk for disease, identify the aggressive tumors that would be responsive to therapy, and to improve quality of life for men with prostate cancers who might benefit from active surveillance, rather than therapy.”
The authors said a larger study would be needed to definitively determine which SNPs are best to identify men at risk of getting erectile dysfunction after radiation treatment.
The study was published in the October issue of the International Journal of Radiation Oncology• Biology• Physics, the official scientific journal of the American Society for Radiation Oncology. The study was supported by the American Cancer Society, United States Department of Defense and the National Institutes of Health.