Intermittent Hormone Therapy Less Effective Than Continuous Therapy for Some Men With Advanced Prostate Cancer

ASCO Annual Meeting
June 3, 2012

A long-term study comparing two common hormone therapy schedules showed that intermittent (short breaks in treatment) hormone therapy is less effective than continuous (no breaks in treatment) hormone therapy for men with hormone-sensitive prostate cancer with minimal disease spread (cancer that has not spread beyond the spine, pelvis, and lymph nodes). Hormone-sensitive prostate cancer is cancer that uses male sex hormones called androgens, such as testosterone, to grow and spread. Hormone therapy, also called androgen ablation or androgen-deprivation therapy, lowers levels of androgens in the body to help keep the cancer from growing or spreading. Eventually, metastatic prostate cancer (cancer that has spread) develops a resistance to hormone therapy, meaning the treatment stops working to control the cancer's growth.

Hormone therapy causes side effects that can affect a man's quality of life, such as impotence, loss of sexual desire, hot flashes, and weight gain. Because of early research on hormone therapy, doctors thought intermittent hormone therapy could decrease these side effects and delay the cancer from developing a resistance to treatment. This study shows that this may not be the case for some men with prostate cancer.

The 1,500 men who participated in this study received either intermittent hormone therapy or continuous hormone therapy after their prostate-specific antigen (PSA) levels fell to 4 nanograms (ng)/milliliter (ml) or lower after seven months of continuous hormone therapy. A decreasing PSA level is a sign that the treatment is working to control the cancer's growth. Because intermittent therapy includes breaks in treatment, the men receiving intermittent hormone therapy received about half as much hormone therapy as the men receiving continuous hormone therapy.

In this study, the men with minimal disease spread who received continuous hormone therapy lived about two years longer than those receiving intermittent hormone therapy (7 years compared with 5 years). Men with prostate cancer that had spread more widely throughout the body lived about the same amount of time whether they had intermittent or continuous hormone therapy.

What this means for patients

"Some doctors recommend intermittent hormone therapy to men with metastatic prostate cancer, believing it will reduce their risk of side effects without compromising their outcome, but these findings show a clear downside to this approach for certain men," said lead author Maha Hussain, MD, Professor of Medicine and Urology at the University of Michigan Comprehensive Cancer Center in Ann Arbor. "The findings clearly show that intermittent hormone therapy is not safe for all patients with metastatic prostate cancer." Intermittent hormone therapy may still be used for men with prostate cancer that has spread more widely or for men with prostate cancer that has not spread. It's important to talk with your doctor about the recommended schedule of hormone therapy for your specific prostate cancer.

Questions to Ask Your Doctor

  • What stage of prostate cancer do I have? What does this mean?
  • What are my treatment options?
  • Will hormone therapy be a part of treatment?
  • What type of treatment schedule do you recommend? Why?
  • What are the side effects of treatment? How can they be managed?

For More Information

Guide to Prostate Cancer

What to Know: ASCO's Guideline on Hormone Therapy for Advanced Prostate Cancer

Hormone Deprivation Symptoms: Men

When the First Treatment Doesn't Work

After Treatment for Prostate Cancer: Managing Side Effects