Benefit for Radiotherapy/ Antiandrogen Combination Reinforced by Long-Term Data

Sophie D. Fosså, MD, PhD

Improved outcomes continued to be demonstrated with the addition of radiotherapy to oral antiandrogen therapy in men with locally advanced prostate cancer, according to an updated analysis, conducted after 11 years of observation. The extended analysis of the Scandinavian Prostate Cancer Group’s Study VII (SPCG-7) showed significant improvement in 10- and 15-year prostate cancer-specific mortality rates. The data were presented by lead author Sophie D. Fosså, MD, PhD, at a presscast held ahead of the 2014 Genitourinary (GU) Cancers Symposium.

“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 Fosså, a professor in the Department of Oncology at Oslo University Hospital in Norway. “This combination may be considered as a standard curative treatment option in these patients. It is comparable to prostatectomy,” added Fosså.

In SPCG-7, 875 patients with locally advanced prostate cancer were randomized between 1996 and 2002 to 3 months of total androgen blockade followed by radiotherapy and continuous antiandrogen therapy or hormone treatment alone. The study included patients from Norway, Sweden, and Denmark. In general, the men were aged ≤75 years, had no metastases, had a PSA ≤70 μg/L, and were characterized to be in “good” general health.

Previously reported data from SPCG-7 showed that at 7.6-years’ follow-up, there was a 12% reduction in prostate-cancer specific mortality in the radiotherapy arm versus the control group (Lancet. 2009;373[9660]:301-308).

In the updated data presented at the GU Symposium, the researchers reviewed mortality data from death registries for the Norwegian and Swedish patient populations.

Fosså et al observed that among 439 men receiving hormone therapy alone, 118 died of prostate cancer, compared with 45 out of 436 men who received the combination treatment. For the men who received only hormone therapy, the 10- and 15-year prostate cancer-specific mortality rates were 18.9% and 30.7%, respectively. Among men receiving the combination, the rates were 8.3% and 12.4%. The 10-year overall mortality rate was 35.3% and 26.4% for the control and radiotherapy arms, respectively, with 15-year overall mortality rates reported at 56.7% and 43.4%.

“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,” said Fosså.

Because both hormone therapy and radiotherapy have side effects, including impaired sexual function and minor bowel problems, Fossa recommended assessing each patient’s acceptance of the side effects and priorities when community oncologists discuss treatment options.

Fosså SD, Widmark A, Klepp OH, et al. Ten- and 15-year prostate cancer-specific survival in patients with nonmetastatic high-risk prostate cancer randomized to lifelong hormone treatment alone or combined with radiotherapy (SPCG VII). Presented at: 2014 Genitourinary Cancers Symposium; January 30-February 1, 2014; San Francisco, California. Abstract 4.

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