Docetaxel add-on improves outcomes in high-risk localized prostate cancer
medwireNews: Adding docetaxel chemotherapy to standard long-term androgen suppression plus radiotherapy significantly improves survival in patients with high-risk nonmetastatic prostate cancer, show data from the NRG Oncology RTOG 0521 study.
The results of the phase III trial indicate that “docetaxel [chemotherapy] may be an option to be discussed with selected men with high-risk prostate cancer,” Seth Rosenthal (Sutter Medical Group and Sutter Cancer Centers, Sacramento, California, USA) and co-authors write in the Journal of Clinical Oncology.
During a median 5.7 years of follow-up there were 43 deaths (16 from prostate cancer) among the 282 patients who received 8 weeks of androgen suppression, followed by radiotherapy with concurrent androgen suppression and then adjuvant androgen suppression for 24 months plus six cycles of concurrent docetaxel and prednisone beginning 28 days after radiotherapy completion.
By comparison, there were 59 deaths (23 from prostate cancer) among the 281 patients who received androgen suppression plus radiotherapy only.
Across both groups, the median prostate-specific antigen (PSA) level at baseline was 15.1 ng/mL, more than half (53%) had a Gleason score 9 to 10, and 27% had cT3 to cT4 disease.
The researchers report that the 4-year overall survival rate was significantly higher in the docetaxel group than in the no docetaxel group at 93% versus 89%, which gave a significant hazard ratio (HR) of 0.69 in favour of chemotherapy.
The 6-year rates of distant metastasis (9.1 vs 14.0%) and disease-free survival (65.4 vs 54.9%) were also significantly higher in the patients who received chemotherapy compared with those who did not, and resulted in HRs of 0.60 and 0.76, respectively.
Conversely, there was no significant difference between the two groups in the 5-year PSA failure-free rates, at 78.5% versus 75.1%.
Discussing their findings, Rosenthal et al point out that a number of other studies – GETUG-12, SPCG-13, and SPCG-12 – observed little benefit among patients who received docetaxel. They suggest that this disparity “may stem from differences in patient populations among the studies.”
Indeed, they point out that “[t]he RTOG 0521 cohort included patients with more aggressive disease; 84% of patients in RTOG 0521 had a Gleason score 8 to 10 disease, whereas a majority of patients in GETUG-12, SPCG-13, and SPCG-12 had a Gleason score less than or equal to 7 disease.”
“These differences underscore the need to select high-risk patients with the most aggressive disease when considering treatment with adjuvant docetaxel,” the researchers remark.
They add: “Improved methods of risk stratification, including the emerging use of molecular profiling, may help to better identify patients who will benefit from intensification of treatment with [chemotherapy] in the future.”
By Laura Cowen
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