CHICAGO–For high-risk, localized prostate cancer, adjuvant chemotherapy improved the overall survival from 89% to 93% at 4 years, research presented at the 2015 American Society of Clinical Oncology (ASCO) annual meeting in Chicago, IL, have shown.
“Locally advanced or high-risk localized prostate cancer has a relatively poor prognosis,” Howard M. Sandler, MD, MS, FASTRO, Chair of Radiation Oncology at Cedars-Sinai Medical Center in Hollywood, CA, said. “Standard management often uses radiotherapy and long-term hormonal treatment, but improvement in local and systemic treatment are likely to be beneficial.”
For the study, researchers enrolled 612 patients with high-risk, localized prostate cancer with a median age of 66 years and a median prostate-specific antigen (PSA) of 15.1. Patients were assigned to receive androgen suppression plus radiotherapy with or without adjuvant docetaxel and prednisone.
Results showed that among 563 evaluable patients, the 4 year overall survival rate was 89% (95% CI: 84,92) for the androgen suppression plus radiotherapy arm and 93% (95% CI: 90-96) for the chemotherapy arm (HR: 0.70; 95% CI: 0.51,0.98; P=0.04), with a median follow-up of 6 years.
According to central review, there were 43 deaths in the chemotherapy arm compared with 59 deaths in the arm that did not recieve chemotherapy.
In addition, 6 year disease-free survival rates were 65% and 55% with and without chemotherapy, respectively (HR: 0.76; 95% CI: 0.58, 0.99; P=0.04).
“Adverse events were as expected,” Dr. Sandler said.
One grade 5 possible/probably related adverse event occurred in the no chemotherapy arm compared with two in the chemotherapy arm, while grade 1 to 2 adverse events were more common in the androgren suppression plus radiotherapy arm compared with the chemotherapy arm.
Speaking on the importance of the trial, Dr. Sandler said, “For the first time, [we are seeing] improvement in overall survival with tolerable adjuvant chemotherapy for localized, high-risk, hormone-sensitive prostate cancer. In addition, the cumulative incidence of distant metastases was reduced.”
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“The potential role of docetaxel in hormone-sensitive prostate cancer is consistent with and supported by our data and other studies, such as STAMPEDE and CHAARTED.”
Ultimately, due to the short overall survival assessment, additional follow-up is warranted to evaluate the long-term benefit of chemotherapy compared with the standard of care of long-term active surveillance plus radiotherapy.
- Sandler HM, Hu C, Rosenthal SA, et al. A phase III protocol of androgen suppression (AS) and 3DCRT/IMRT versus AS and 3DCRT/IMRT followed by chemotherapy (CT) with docetaxel and prednisone for localized, high-risk prostate cancer (RTOG 0521). J Clin Oncol. 2015;33:(suppl; abstr LBA5002).