"Less is More" in the Treatment of Prostate Cancer

By Dr. Ralph Moss
from CancerDecisions.com Newsletter

Top scientists at Dana-Farber Cancer Institute (DFCI) in Boston have made a discovery about the treatment of prostate cancer. Less is more. "Certain prostate cancer patients who receive conformal beam radiation followed by six months of hormone therapy for localized prostate cancer survive longer than those who receive three years of the grueling anti-androgen treatment," they announced.

These latest findings, published in August in the Journal of the American Medical Association, challenge the current 'gold standard' of prostate cancer treatment, which is two months of highly targeted radiation therapy followed by a full three years of hormone suppression therapy. The authors of the Dana-Farber study concede that this combined regimen is associated with "negative side effects significantly impacting quality of life."

While sometimes quality of life is a nebulous concept that tends to get pushed into second place when new treatments are being considered, in this case it has a tangible influence on patients' survival. Androgen suppression therapy (AST) when used for more than one year causes "significant side effects, including bone density loss, impaired memory, anemia, breast enlargement, hot flashes, and impotence in some patients, especially those who are elderly" (DFCI 2004). And this sometimes translates into shorter survival as well.

Welcome News

An endorsement of a more conservative treatment from one of America's top cancer centers is certainly welcome news. It means that those facing treatment for locally advanced prostate cancer may now be spared distressing, and sometimes even life-threatening, side effects.

But it is ironic that here is yet another example of a major 'advance' that consists of sparing patients from the previous excesses of zealous doctors. It reminds me of how the NCI used to claim the demise of the Halsted radical operation for breast cancer as one of its own major achievements—when in fact the NCI had simply given in to the increasingly incontrovertible protests of mavericks in the field.

The Dana-Farber study shows that androgen suppression therapy (AST) coupled with radiation is better than radiation alone.

According to the lead investigator, Anthony D'Amico, MD, PhD, "This is the first study to provide evidence that radiation therapy (in this case, the newer, more precisely targeted 'conformal' radiation) combined with six months of AST provides a survival benefit for those with early-stage prostate cancer."

According to the National Cancer Institute, an earlier meta-analysis (a way of combining data from several previous trials in order to gain greater objectivity) had found "a difference in 5-year overall survival in favor of radiation therapy plus continued androgen suppression compared to radiation therapy alone" (Seidenfeld 2000).

In the Dana Farber study, there was no head-to-head comparison of six months vs. three years of androgen suppression therapy. Instead, what was proven was the superiority of AST + radiation vs. radiation alone. Researchers randomly assigned 206 patients to receive either two months of radiation therapy in conjunction with six months of AST or two months of radiation therapy alone. Patients were studied for an average of four-and-a-half years. Of the patients who were treated with radiation alone, 22 percent died by the end of the study. But among those who also received six months of hormone blockade (AST) 12 percent died. This 10 percent improvement was statistically significant.

"Patients with prostate cancer face a wide variety of decisions regarding their treatment, each with its own distinct benefits and risks," said senior author Philip Kantoff, MD. "Six months of hormone therapy combined with radiation therapy is an effective treatment and provides patients with an important option if they are concerned about hormone therapy-related side effects" (DFCI 2004). And how many patients facing the side effects of long-term hormone ablation wouldn't be concerned?

References:

Dana-Farber Cancer Institute (DFCI). Short course of hormonal therapy improves survival in prostate cancer patients treated with radiation therapy. Press release, August 17, 2004.

Samson DJ, Seidenfeld J, Schmitt B, et al. Systematic review and meta-analysis of monotherapy compared with combined androgen blockade for patients with advanced prostate carcinoma. Cancer. 2002;95:361-76.

Seidenfeld J, Samson DJ, Hasselblad V, et al. Single-therapy androgen suppression in men with advanced prostate cancer: a systematic review and meta-analysis. Ann Intern Med. 2000;13:566-77.

Seidenfeld, J, et al. Relative Effectiveness and Cost-Effectiveness of Methods of Androgen Suppression in the Treatment of Advanced Prostatic Cancer. Evidence Report/Technology Assessment Number 4 Prepared for: Agency for Health Care Policy and Research, AHCPR Pub No. 99-E011. Current as of January 1999.