Men with localized prostate cancer are equally unlikely to relapse during the eight years after treatment whether treated with either external-beam radiation or surgery, new research confirms.

"Surgical removal of the prostate and external beam radiotherapy have equal eight-year, biochemical free relapse rates in men with localized prostate cancer," said study author, Patrick A. Kupelian, MD, at the Cleveland Clinic.

But radiotherapy is only equally effective if modern techniques and adequate doses are used, said an editorial published with Kupelian's report in the Journal of Clinical Oncology (Vol. 20, No. 16: 3376-3385).

Kupelian agreed, saying that low-dose, external beam radiotherapy should no longer be used.

A recent study showed that when men talk to doctors about treatment for their newly diagnosed prostate cancer, urologists tend to recommend surgery and radiotherapists tend to recommend radiation therapy, leaving some men uncertain which is best, the researchers said.

Both specialists have reason to believe the treatment they offer has been shown to be superior because some studies support the advantages of one therapy, while others suggest an advantage for the other, said Kupelian.

To make things even more complicated, both radiotherapy and surgery have been improved in recent years, with new techniques in both fields capable of producing better results with fewer side effects, but making comparisons over time more difficult.

To clarify any treatment differences, Kupelian and colleagues looked at follow-up data on 1,682 men treated for early stage prostate cancer with either radical prostatectomy or radiotherapy between 1987 and 1993.

At first glance, surgery looked like a better choice, with 72% of the men not relapsing in eight years, compared to 70% of radiotherapy patients.

But a closer look showed that many of the radiotherapy patients had been treated with doses lower than those usually used now.

When relapse among surgery patients was compared to relapse among those treated with radiation doses at or above 72 Gy — the doses typically used in modern radiotherapy — both treatments were equally effective.

Rather than treatment method, it was easier to predict relapse based on whether a patient had a high PSA level before treatment, a high or low Gleason score, how large the tumor was, and if treated by radiation, how high the radiation dose was.

Earlier comparisons suggesting that surgery gave better results than radiotherapy compared "antiquated radiotherapy" to "modern surgery," said the editorial by two doctors at Memorial Sloan-Kettering Cancer Center in New York. Such comparisons should no longer be used, they said.

"This study reinforces the need for men to be truly informed about their treatment options before making treatment decisions," said Durado Brooks, MD, MPH, director of prostate and colorectal cancer control for the American Cancer Society.

Men should talk with both a surgeon, a radiation oncologist, and perhaps previously treated patients, then make a decision based on their tolerance for risk of specific side effects, said Brooks.

Historically, surgery patients have had more problems with sexual and urinary functions, and radiation patients more difficulty with bowel problems, but that can vary by doctor and by treatment center, noted Brooks.

Large cancer centers may use state-of-the-art radiation treatment with tightly focused high doses, while other centers may not, Brooks said.

And some surgeons may be better trained to leave unharmed the nerves important to sexual and urinary function, he added.

Brachytherapy and cryotherapy haven't been studied as much as other methods so a man considering those options should ask about relapse rates several years after treatment, said Brooks.

"The consequences of his decision will be with him for quite some time, so a man should invest the time and effort necessary to fully understand the likely outcome for him of each treatment option before deciding," said Brooks.