MIAMI BEACH--Potency status in prostate cancer patients before radiation therapy, not the radiation dose, is the main determinant of potency status afterwards, Adam P. Dicker, MD, said at the 37th Annual Meeting of the American Society for Therapeutic Radiology and Oncology (ASTRO).
The study, from Memorial Sloan-Kettering Cancer Center, showed that prostate cancer patients who have difficulty maintaining an erection before radiation therapy are seven times as likely to be impotent after radiation therapy as patients who are fully potent prior to radiation treatment.
The researchers also found that the risk of impotency was highest in patients who had heart disease and patients who had undergone neoadjuvant hormonal therapy before their radiation treatments.
Dr. Dicker and coworkers looked at the frequency of impotency in 300 men who had been treated with 3D conformal radiation therapy (see related story on page 3 and illustration on page 1). Patients were followed for up to 5 years.
"It has been widely established that prostate cancer patients have essentially the same outcome in terms of survival and a decline in their PSA level whether they are treated with a radical prostatec-tomy or radiation therapy," Dr. Dicker said in an interview.
The Patient's Decision
He noted that "the patient's decision about which treatment he prefers to undergo thus depends on side effects, and the short-term and long-term effects of radiation therapy on potency in these patients had not been systematically assessed before our trial."
The higher doses of radiation used with the 3D conformal technique did not increase the risk of impotency in these patients, Dr. Dicker said. In fact, 84% of patients who were fully potent before therapy, had no previous heart attacks, and had not received hormones remained potent 2 years after radiation therapy.