Hormone therapy not helpful for low-risk patients receiving first-line radiation

A report presented yesterday in Chicago, at the annual meeting of the American Society for Radiation Oncology (ASTRO), suggests that short-term hormone therapy given prior to and during first-line radiation treatment to intermediate-risk prostate cancer patients increases their chance of living longer, compared to those who receive radiation alone. However, the same study also showed that there is no significant benefit for low-risk patients.

RTOG 94-08 enrolled 1,979 low- and intermediate-risk prostate cancer patients between October 1994 to April 2001. All patients had cancer confined to the prostate and a PSA value of ≤ 20 ng/ml. The patients were randomized to receive either complete androgen deprivation therapy (with an LHRH agonist and an antiandrogen) for 2 months prior to and 2 months during radiation treatment or radiation alone as their first-line treatment. In most cases the patients were followed for > 9 years. This timeframe allowed for clear evidence of improved survival benefits of short-term hormone therapy added to what was the standard radiation treatment for prostate cancer at the time of treatment. Slightly higher doses of radiation are currently used to treat patients with localized prostate cancer today because of the advent of newer techniques for radiation delivery, including intensity-modulated radiation therapy (IMRT) and image-guided radiation therapy (IGRT).

The basic results of the trial are that:

  • Short-term hormone therapy prior to and during radiation treatment had a small but significant impact on median survival compared to radiation alone (51 vs. 46 percent).
  • Nearly all of the survival benefit was observed in the intermediate-risk group of patients.
  • Secondary endpoints (progression-free survival, freedom from biochemical failure, and positive 2-year re-biopsy rates) were also better in patients who received short-term hormone therapy and radiation treatment.

Additional information about this trial is available in a report from HealthDay.

One of the study’s principle investigators, Christopher Jones, MD, is quoted in a media release from ASTRO as stating that, “The study provides strong scientific evidence that shows us when to deliver hormone therapy with radiation in patients with localized prostate cancer. Our findings show that men with low-risk disease, which is the vast majority of prostate cancer patients, have little to gain from adding hormone therapy to radiation. However, men with intermediate-risk disease, which is a significant minority of patients, gain a benefit in overall survival from the addition of only 4 months of hormone therapy. Prior to this trial, it was unclear whether or not combining hormone therapy with radiation for medium-risk prostate cancer patients improves survival.”

The use of hormone therapy in combination with radiation as a first-line treatment for prostate cancer has long been a controversial issue. Even a relatively short period of hormone therapy can have significant adverse effects, and so if the clinical benefit is limited, hormone therapy should probably be avoided. The results of this trial appear to give us the first clear evidence that the benefit of short-term hormone therapy before and during radiation is limited to those patients at intermediate (and presumably higher) risk for progressive disease — and even then the benefit is not enormous.

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