An updated analysis of clinical trial data from the Scandinavian Prostate Cancer Group’s Study VII showed that adding radiotherapy to oral anti-androgen therapy, a type of hormone therapy, more than halved the 10- and 15-year prostate cancer-specific mortality rates for men with locally advanced prostate cancer, compared to anti-androgen therapy alone.

“When this study started in 1996, the standard treatment was hormone therapy alone, but this trial continues to show that adding radiotherapy substantially boosts long-term survival,” said lead author Sophie Dorothea Fosså, MD, a professor in the department of oncology at Oslo University Hospital in Norway.

“This combination more than doubles the 10-year survival rate and confirms that this approach should be a standard option for men with this type of prostate cancer who are expected to live at least another 10 years.”

After almost eight years of observation, results published in 2009 showed a 12 percent reduction in prostate cancer-specific mortality in patients with locally-advanced prostate cancer who initially received one injection of testosterone-removing hormone treatment that lasts for three months followed by two months of radiotherapy and continuous pill-based hormone therapy, compared with those who received hormone therapy alone.

Locally-advanced prostate cancer is defined as cancer that has grown through the prostate capsule that covers most of the organ. When this study began, this type of prostate cancer was considered inoperable, and surgery is still not often used because it may be difficult to remove all of the cancer.

Radiotherapy can be directed at tissue beyond the prostate and is able to kill cancer cells outside the capsule.

In this updated analysis, after 11 years of observation, researchers reviewed mortality data from Norwegian and Swedish death registries. Among the 439 men receiving hormone therapy alone, 118 died of prostate cancer, compared with 45 out of 436 men receiving the combination treatment. For the men receiving hormone therapy alone, the 10- and 15-year prostate cancer-specific mortality rates were 18.9 percent and 30.7 percent, respectively. For those receiving the combination, these rates were 8.3 percent and 12.4 percent.

Both hormone therapy and radiotherapy cause side effects, such as impaired sexual function and minor bowel problems. Dr. Fosså added that it is important to assess each patient’s acceptance of the side effects and priorities when discussing treatment options so patients are comfortable with their expected post-treatment quality of life.

Source: ASCO