Overall Prostate Cancer Survival Rates Improve with Docetaxel plus Standard Care

The standard of care for the treatment of high-risk, localized prostate cancer is combination therapy with radiotherapy and long-term (24 to 36 months) androgen suppression. In a new study published in the Journal of Clinical Oncology, researchers tested the hypothesis that adding adjuvant docetaxel to radiotherapy and long-term androgen suppression would improve overall survival and clinical outcomes for men in that patient population.

Docetaxel, a cytotoxic chemotherapy drug, has improved overall survival in men with castrate-resistant and castrate-sensitive prostate cancers. The drug is well tolerated and may be able to target hormonally resistant cells, complimenting the abilities of androgen suppression to target hormonally sensitive cells. The current study researchers compared standard of care with and without docetaxel-based chemotherapy.

Docetaxel Treatment Arms

The multicenter, phase 3 trial randomly assigned men to one of two treatment arms. Both arms received 8 weeks of androgen suppression followed by radiotherapy with concurrent androgen suppression and then adjuvant androgen suppression for 24 months. Men assigned to the docetaxel arm also received an additional six cycles of docetaxel and prednisone concurrently with androgen suppression beginning 28 days following completion of radiotherapy.

A total of 612 patients were enrolled in the study. Of those, 563 had evaluable results. There were no unexpected toxicity signals during the study period and treatment was well-tolerated in both arms. Overall survival rates at 4 years were 89% in the standard treatment arm and 93% in the standard treatment plus docetaxel-based chemotherapy arm. Six-year rates for disease-free survival were 55% in the standard treatment arm and 65% in the standard treatment plus docetaxel arm.

Positive Results

There were 59 deaths in the standard treatment arm compared with 43 in the standard treatment plus docetaxel arm. In the standard treatment plus docetaxel arm, there were fewer deaths resulting from prostate cancer compared with the standard treatment arm (23 vs. 16 deaths, respectively). The six-year rate of distant metastasis was 24% for the standard treatment arm and 91% for the standard treatment plus docetaxel arm.

Seth A. Rosenthal, MD, FACR, FASTRO, corresponding author of the study, said the results are positive.

“The trial results suggest that the addition of docetaxel chemotherapy to standard treatment with long-term androgen suppression therapy and radiotherapy is a viable treatment option for men with high-risk nonmetastatic prostate cancer,” he said. “Physicians should be considering the discussion of this option with selected patients who are fit for chemotherapy.”