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.