Mark Klein, MD
Kishan et al conducted a meta-analysis to evaluate the relative effects of the addition of androgen deprivation therapy (ADT) to radiation therapy (RT) on metastasis-free survival (MFS) in patients with localized prostate cancer in the following three settings: 1) RT alone versus RT plus adjuvant ADT, 2) extension of ADT duration in the neoadjuvant setting before RT, and 3) extension of adjuvant ADT duration. MFS was increased in the adjuvant ADT setting, and prolongation of ADT duration was associated with a higher MFS than shorter duration. However, extension of neoadjuvant ADT was not associated with a higher MFS compared to a shorter duration. The meta-analysis further supports a longer versus shorter ADT duration, but it does not support a longer neoadjuvant ADT duration.
To determine the effects of salvage RT on outcomes in the setting of biochemical relapse, Tilki et al conducted a retrospective cohort analysis of a multi-institutional database of patients with biochemical recurrence after radical prostatectomy (RP). MFS at 15 years post-RP was 84.3% in the RT group and 76.9% in the non-RT group, while overall survival (OS), also at 15 years post-RP, was 85.3% in the RT group versus 74.4% in the non-RT group (both analyses were statistically significant). While supportive of salvage RT, there was no data on prostate-specific antigen (PSA) doubling times, nor was it possible to control for imaging modality. It is possible that newer prostate-specific membrane antigen (PSMA)-based positron emission tomography imaging may affect MFS in studies such as these.
Prostatectomy (with or without lymph node dissection), external beam RT (EBRT) with ADT, or EBRT with brachytherapy (BT) with or without ADT are options in unfavorable intermediate-risk prostate cancer. The optimal use of BT in localized prostate cancer is somewhat uncertain, especially across the risk spectrum. Andruska et al conducted an analysis of the National Cancer Database (NCDB) to evaluate whether EBRT plus BT with or without ADT results in an improvement in overall survival (OS) compared with BT with or without ADT. OS was higher for the EBRT plus BT groups; however, when the ADT + EBRT + BT group was compared with EBRT + BT without ADT group, the improvement in OS was not statistically significant. Overall, the analysis favored EBRT + BT over BT alone, further supporting current guidelines.