Combination therapy significantly increases survival in metastatic prostate cancer

In men with metastatic hormone-sensitive prostate cancer, simultaneous treatment with hormone therapy plus chemotherapy resulted in significantly longer overall survival than hormone therapy alone, according to a study published in the August 20, 2015 issue of The New England Journal of Medicine.

Clinicians traditionally treat metastatic prostate cancer patients with androgen-deprivation therapy (ADT), and wait until the hormone treatment becomes ineffective before initiating chemotherapy.

“[This trial] is the first to identify a strategy that prolongs survival compared with ADT alone in men newly diagnosed with metastatic, hormone-sensitive prostate cancer,” said lead investigator Christopher J. Sweeney, MB, BS, of the Lank Center for Genitourinary Oncology at Dana-Farber Cancer Institute, in Boston, MA.

Dr. Sweeney had shared initial results of the trial in June 2014 at the annual meeting of the American Society of Clinical Oncology (ASCO). Some physicians have reportedly already adopted the new regimen.

In this study, Dr. Sweeney and colleagues randomized 790 patients (median age 63) to either ADT alone or ADT along with 6 cycles of docetaxel chemotherapy treatment. The patients on combination ADT-plus-docetaxel survived for a median of 57.6 months—13.6 months longer than the median 44-month survival for men who received only hormone therapy. Eighty-five prostate cancer deaths occurred in the combination group compared with 114 in the ADT-alone group.

Adding docetaxel benefitted all the subgroups analyzed, the researchers found, but it had the greatest effect in those with a high burden of metastatic disease. In this subgroup, men given combination therapy had a median overall survival that was 17 months longer than those in the ADT-alone group (49 months vs. 32 months).

Men in the combination group also showed improvement in the prostate-specific antigen (PSA) test. More patients in the combination group (28%) had very low PSA levels (less than 0.2 ng per milliliter) at 12 months compared with those in the ADT-alone group (17%).

The authors concluded, “This study showed that docetaxel given at the time ADT was initiated for hormone-sensitive disease resulted in better cancer control than that with ADT alone, with a longer time to the development of castration resistance, a higher rate of decrease of the PSA level to less than 0.2 ng per milliliter at 12 months, a lower number of prostate-cancer deaths, and substantially longer overall survival.”