A retrospective analysis has (again, somewhat predictably) shown that adding long-term androgen deprivation therapy (ADT) to dose-escalated radiation therapy improves outcomes of men initially diagnosed with high-risk prostate cancer.
The study by Feng et al. looked at data from men with high-risk prostate cancer who were treated with dose-escalated external beam radiation therapy (EBRT), with a minimum total dose of 75 Gy, with or without ADT. All patients met National Comprehensive Cancer Network criteria for high-risk disease (clinical stage ≥ T3a and/or Gleason score 8 to 10 and/or PSA > 20 ng/ml).
Unfortunately, the abstract of the paper by Feng et al. does not provide information on the total numbers of patients included in their analysis, but we would expect that it was > 200 patients in total. With that reservation, here are the key findings of their study:
- Average (median) follow-up time was 64 months.
- Among men treated with radiation therapy but no adjuvant, long-term ADT
- Metastasis was evident in 35 percent of patients at 60 months.
- Prostate cancer-specific mortality (PCSM) occurred in 11 percent of patients at 60 months.
- Among men treated with radiation therapy plus adjuvant, long-term ADT
- Metastasis was evident in 13 percent of patients at 60 months.
- Prostate cancer-specific mortality (PCSM) occurred in 6 percent of patients at 60 months.
- Compared to men who received no adjuvant, long-term ADT
- The hazard ratio (HR) for metastasis at 60 months among men receiving adjuvant, long-term ADT was 0.34.
- HR for PCSM at 60 months among men receiving adjuvant, long-term ADT was 0.41.
- On multivariate analysis,
- Gleason score was the single, strongest, negative prognostic factor.
- Among men with Gleason scores of 8 to 10 there was a time-on-ADT-dependent improvement in
- Time to biochemical failure
- Time to evident metastasis
- Time to prostate cancer-specific death
- Overall survival
- Long-term ADT improved patients’
- Metastasis-free survival (P = 0.002)
- PCSM (P= 0.034)
- Overall survival (P= 0.001)
Feng et al. conclude that,
For men with high-risk prostate cancer treated with dose-escalated EBRT, this retrospective study suggests that the combination of [long-term ADT] and [radiation therapy] provided a significant improvement in clinical outcome, which was especially true for those with Gleason scores of 8 to 10.