Evaluating the effectiveness and optimal duration of additional androgen deprivation therapy after radiotherapy in locally advanced prostate cancer

This study investigated the outcomes and effectiveness of administering additional (adjuvant) androgen deprivation therapy (A-ADT) for long-term after radiotherapy (RT) in high-risk or very high-risk locally advanced prostate cancer (LAPC). The study found that the addition of A-ADT longer than 1 year after RT showed good treatment outcomes in these patients.

Locally advanced prostate cancer (LAPC) is a form of cancer that has spread to the tissues outside the prostate gland but not yet spread to lymph nodes or other distant organs. Men with LAPC usually have high levels of prostate-specific antigen (PSA). PSA is a protein made by the cells of the prostate gland. It can be treated using radiotherapy (RT) or hormone therapy such as androgen deprivation therapy (ADT). ADT reduces the production of androgens (male sex hormones such as testosterone). Reducing these androgens prevents cancer cell growth. When ADT is administered during or after RT it is called adjuvant ADT (A-ADT).

Several studies have shown the effectiveness of A-ADT administered with RT for the treatment of LAPC. Also, administering A-ADT over a longer period of time could improve outcomes in high-risk LAPC patients treated with RT. However, the optimal duration of A-ADT is unknown for high-risk or very high-risk LAPC after treatment with RT.

This study involved 197 men with high-risk or very high-risk LAPC who were previously treated with RT. Patients also received A-ADT during and after RT. The average duration of A-ADT was 36 months. The average follow-up period was 72 months. PSA levels in the blood were measured to check for recurrence. If, after treatment, the PSA levels increased by 2 ng/ml from the lowest value it was considered as evidence of recurrence or biochemical failure (BCF).

The overall survival rate at 5 years was 89.1%. The cancer-specific survival (CSS; percentage of patients who have not died from prostate cancer) rate was 99.5% after 5 years. 96.9% of patients were alive without cancer spreading far from the prostate after 5 years. 91.1% of patients were alive after 5 years without BCF. 

The duration of A-ADT significantly affected BCFFS. The patients who received A-ADT for 1 year or longer had better survival without BCF than those who received A-ADT for less than 1 year or those who did not receive A-ADT. 

The most common side effects were frequent need to urinate, discomfort while urinating, anal pain, and diarrhea.

This study concluded that the addition of A-ADT for longer than 1 year to RT demonstrated good treatment outcomes in patients with LAPC.

The study looked back in time for medical records. Information about patients might have been missing. This could affect the results.