Prostate Cancer: Start-and-Stop Hormone Therapy Works

On-and-Off Treatment Can Be as Effective as Continuous Treatment for Prostate Cancer

By Salynn Boyles
WebMD Health News

Reviewed by Louise Chang, MD

Sept. 5, 2012 -- "Start and stop" hormone therapy is as effective as continuous therapy in the treatment of some prostate cancer patients, a study shows.

Hormone therapy is also known as androgen deprivation. It is often used to treat prostate cancer if surgery or radiation fails.

The treatment works by blocking the production of the male hormones called androgens, which fuel prostate cancer growth. But there are serious side effects:

In a new study from Canada, researchers compared men who went on and off hormone therapy with men who had continuous treatment. The researchers found the on-and-off treatment can be as effective as continuous treatment with fewer of these troubling side effects.

The study is published in The New England Journal of Medicine.

Rising PSA Led to Treatment

The study included about 1,400 prostate cancer patients whose cancer had not responded as hoped to radiation therapy. The researchers used a blood test called PSA to measure the cancer's response to treatment. Rising PSA levels after treatment can mean the cancer did not respond well to treatment or has recurred.

Roughly half the men in the study were treated with continuous hormone therapy. The other half received the treatment for eight months, followed by observation. These men went back on treatment when PSA levels rose.

Over nearly seven years of follow-up, the average survival time in both groups was around nine years.

A total of 524 men died during this time, but most died from causes other than cancer. Just 18% of deaths in men receiving intermittent hormone therapy and 15% of deaths in the continuous-treatment group were due to the cancer.

Quality of Life Better With Start-and-Stop Treatment

Men who went on and off the hormone treatment reported fewer hot flashes, less loss of libido and erectile dysfunction, and fewer urinary issues. But the researchers say the difference in quality of life was not as profound as might be expected.

There was also no evidence that the start-and-stop treatment schedule prolonged the time in which hormone therapy worked, as the researchers had hoped.

Nevertheless, study researcher Juanita M. Crook, MD, calls the study "practice changing" for prostate cancer patients with rising PSA levels who need more treatment.

She says since many of these men remain on hormone therapy for the rest of their lives, a treatment strategy that can improve quality of life should be embraced.

"Intermittent therapy has been increasingly used over the past few decades, but we never knew if we were risking years of life to achieve a better quality of life," she says. "Now we know that this is not the case."

American Cancer Society Director of Prostate and Colorectal Cancers Durado Brooks, MD, says the findings confirm that on-and-off treatment is as effective as continuous treatment.

But Oliver Sartor, MD, who is medical director of the Tulane Cancer Center in New Orleans, says the study did not address an important unanswered question: "Do men with rising PSAs but no symptoms even need the hormone treatment?"

"The big debate in the field is whether to even treat patients with rising PSAs before there is evidence of [cancer spreading]," he says. "The answer is not clear."

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SOURCES: Crook, J.M. New England Journal of Medicine, Sept. 6, 2012. Juanita M. Crook, MD, British Columbia Cancer Agency, Cancer Centre for the Southern Interior, Kelowna, Canada. Oliver Sartor, MD, department of medicine and urology, Tulane University School of Medicine, New Orleans. Durado Brooks, MD, director of prostate and colorectal cancers, American Cancer Society.

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