Hormonal Treatment Improves Ten-Year Survival in High-Risk Prostate Cancer Patients Treated with Radiotherapy

Posted April 16, 2005. Hormonal drugs in addition to radiation therapy in patients with high-risk prostate cancer can improve survival rate, according to a new study published in the April 1, 2005, issue of the International Journal of Radiation Oncology Biology Physics, the official journal of ASTRO, the American Society for Therapeutic Radiology and Oncology.

The study, conducted between 1987 and 1992, enrolled patients with "unfavorable" disease status -- those with palpable primary tumor extending beyond the prostate (clinical Stage T3) or those with regional lymphatic involvement.

Patients who had undergone prostatectomy were eligible if penetration through the prostatic capsule to the margin of resection and/or seminal vesicle involvement was documented by tissue biopsy. The patients were grouped according to tissue differentiation, nodal status, acid phosphatase status, and prior prostatectomy.

In all, 977 patients enrolled were separated into two groups: the adjuvant arm and the observation arm. Those in the adjuvant arm received radiation therapy and Zoladex (goserelin acetate), a drug that suppresses the male hormone testosterone. The drug was to be started during the last week of RT and was to be continued indefinitely or until signs of progression.

The patients in the observation arm received radiation therapy only. Zoladex was given to these men only if they experienced a relapse.

As of July 2003, the median follow-up for all patients was 7.6 years and for surviving patients, 11 years.

At ten years, the overall survival rate was higher for men taking the Zoladex than those not taking it -- 49 percent to 39 percent, respectively.

The local failure rate at ten years for those taking Zoladex arm was 23 percent and higher, 38 percent, for the others; and the ten year rates for cancer spreading to other parts of the body were 24 percent for the patients on Zoladex versus 39 percent for the observation patients.

Finally, the prostate cancer-related death rate was 16 percent for men given Zoladex and 22 percent for those not.

Taking the Zoladex shots appeared to carry greater benefit for men with aggressive disease. The improvement in survival appeared preferentially in patients with a Gleason score of 7-10

"The results of the study firmly establish the role of adjuvant hormonal management in high-risk carcinoma of the prostate treated with definitive radiotherapy,” said Miljenko V. Pilepich, M.D., a radiation oncologist at the University of California, Los Angeles and lead author of the study.