Advertisement

Duration of Androgen Deprivation Therapy Influences Outcomes for Patients Receiving Radiation Therapy Following Radical Prostatectomy

      Purpose/Objective(s)

      Concurrent/adjuvant androgen deprivation therapy (ADT) is known to improve survival for patients receiving radiation therapy (RT) as a primary treatment for localized prostate cancer. The optimal duration of ADT with RT varies by prostate cancer risk stratification. Short-term (4-6 months) concurrent ADT is considered for those with intermediate-risk disease, and long-term (2-3 years) ADT is recommended for those with high-risk disease. Less in known regarding the optimal duration of ADT in patients who receive either adjuvant or salvage RT (ART or SRT) for a rising prostate-specific antigen (PSA) following radical prostatectomy (RP). We sought to assess if the duration of ADT use influences clinical outcomes for patients receiving RT post-RP.

      Materials/Methods

      Six hundred eighty patients who received ART or SRT at a single institution post-RP were retrospectively reviewed in an IRB approved analysis. We assessed the impact of ADT duration on biochemical failure (BF), distant metastasis (DM), prostate cancer-specific mortality (PCSM), and overall mortality (OM) using Kaplan-Meier and Cox Proportional Hazards models.

      Results

      One hundred forty-four patients (17%) received concurrent/adjuvant ADT with post-RP RT. One hundred thirteen patients received SRT and 31 received ART. No difference existed between the mean duration of ADT in SRT and ART (p = 0.6). Median follow-up post-RT was 57.4 months. Median ADT duration was 12 months (interquartile range [IQR] 6.0-23.7). Patients receiving ADT were dichotomized using median ADT duration. Patients who received <12 months of ADT were at an increased risk for BF (hazard ratio [HR]: 2.3, p = 0.003) and DM (HR: 2.5, p = 0.03) as compared to patients receiving >12 months of ADT. 5-year rates of DM were 6% and 23% for those receiving >12 months, and <12 months of ADT, respectively. On multivariate analysis, when controlling for pre-RT PSA, Gleason score, seminal vesicle invasion, extracapsular extension, presence of positive surgical margins, and the use of ART vs SRT, each month of ADT was associated with a 1.1-fold decrease in risk of BF (p = 0.01), DM (p = 0.01), PCSM (p = 0.04), and OM (p = 0.04). Thus, patients who received 6 months of ADT had a 1.8 fold decrease in risk of BF, DM, PCSM, and OM, whereas patients who received 24 months of ADT had a 9.8-fold decrease in risk of BF, DM, PCSM, and OM.

      Conclusions

      For patients receiving concurrent/adjuvant ADT with post-RP RT, the duration of ADT impacts clinical outcomes. Each month of ADT was associated with a statistically significant decrease in BF, DM, PCSM, and OM. Our findings suggest that for patients receiving concurrent/adjuvant ADT with post-RP RT, an extended course of ADT may be preferable. This is consistent with the hypothesis that patients experience BF after post-RP RT because of subclinical metastatic relapse rather than failure of RT to eradicate pelvic disease.

      Comments

      Commenting Guidelines

      To submit a comment for a journal article, please use the space above and note the following:

      • We will review submitted comments as soon as possible, striving for within two business days.
      • This forum is intended for constructive dialogue. Comments that are commercial or promotional in nature, pertain to specific medical cases, are not relevant to the article for which they have been submitted, or are otherwise inappropriate will not be posted.
      • We require that commenters identify themselves with names and affiliations.
      • Comments must be in compliance with our Terms & Conditions.
      • Comments are not peer-reviewed.