Long-term androgen suppression superior to short-term in locally advanced prostate cancer

Radiotherapy plus six months of androgen suppression was not superior to radiotherapy plus three years of androgen suppression for the treatment of locally advanced prostate cancer, according to data from the EORTC 22961 trial.

The study included 970 men with locally advanced prostate cancer who received external-beam radiotherapy plus six months of androgen suppression. Patients were randomly assigned to no further treatment (short-term arm, n=483) or 2.5 additional years of treatment (long-term arm, n=487).

A shorter treatment length was tested to try to improve quality of life and comorbidities among men assigned long-term androgen suppression. The primary endpoint was OS. Median follow-up was 6.4 years.

At follow-up, more patients in the short-term group had died from all causes (132 vs. 98), from prostate cancer (47 vs. 28), or from a cardiac event (31 vs. 25) compared with the long-term treatment group.

Five-year overall mortality was greater in the short-term group compared with the long-term group (19.0% vs. 15.2%; HR=1.42; P=.65).

“The two-sided 95.71% CI of 1.09 to 1.85 is a post hoc indication that short-term suppression was inferior, for overall survival, to long-term suppression,” the researchers wrote.

The five-year cumulative rate for prostate-specific mortality was 4.7% in the short-term group and 3.2% in the long-term group; prostate-specific survival curves were significantly different (HR=1.71; 95% CI, 1.14-2.57), according to the researchers.

Fatigue, hot flushes and sexual problems increased after radiotherapy and six months of androgen suppression (P<.001). According to quality of life assessment scales, significant differences favoring the short-term group were observed in terms of insomnia (P=.006), hot flushes (P<.001) and sexual interest and activity (P<.001).

Bolla M. N Engl J Med. 2009;360:2516-2527.

This is an important study that addresses the balance of risk and benefit of adjuvant hormone therapy after radiation in high-risk prostate cancer. Hormone therapy has been proven beneficial in this setting, but the issue is now refining the duration of hormones needed for optimal benefit balanced against the short- and long-term toxicity. This study begins to address this important issue and found that three years of hormones are needed in this setting compared to six months. It doesn't answer whether other durations of hormone therapy shorter than three years would suffice, but it's a well done study that is asking an important question..

– Brian Rini, MD

Staff,
Cleveland Clinic Taussing Cancer Institute