Evaluating the effectiveness of adding short-term androgen deprivation therapy with or without pelvic lymph node treatment to prostate bed salvage radiotherapy in patients with resected prostate cancer.

This study evaluated the effectiveness and safety of adding short-term androgen deprivation therapy (ADT) with or without pelvic lymph node radiotherapy (PLNRT) to prostate bed salvage radiotherapy (PBRT) after surgery in patients with prostate cancer (PC). The study found that adding short-term ADT and PLNRT to PBRT significantly improved the survival outcomes without cancer progression in these patients.

Localized prostate cancer (PC) is a form of cancer that has not spread beyond the prostate gland. PC can be treated by surgery, radiotherapy (RT), or hormone therapy. Men with PC usually have high levels of prostate-specific antigen (PSA). PSA is a protein made by the cells of the prostate gland. PSA levels usually go down after successful treatment for PC. Another treatment option is 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.

Up to half of the men who undergo surgery (prostatectomy or complete removal of the prostate gland) as a treatment for PC experience biochemical recurrence (BCR). BCR means an increase of 2 ng/ml from the lowest value of the PSA. In men with a detectable PSA level after surgery, salvage treatments are needed. Salvage PBRT is standard radiation therapy (RT) targeted to the area in which the prostate used to exist before its surgical removal. PBRT results in about 70% of patients being free of cancer progression after 5 years. However, whether adding short-term ADT with or without PLNRT to PBRT after surgery in patients with PC improves the percentage of patients free of cancer progression is still unknown.  

This study involved 1716 patients with persistently detectable or initially undetectable and rising PSA levels after surgery for PC. Patients were randomly assigned into 3 groups. Group 1 included 564 patients who received PBRT alone. Group 2 included 578 patients who received PBRT plus short-term ADT. Group 3 included 574 patients who received PBRT plus short-term ADT plus PLNRT.  The average follow-up time was 8.2 years.

After 5 years, the average survival without cancer progression was 70.9% in group 1, 81.3% in group 2, and 87.4% in group 3. These differences were found statistically significant. 

Short-term (under 3 months) side effects of radiotherapy were more common in group 3 (44%) compared to group 2 (36%) and group 1 (18%). There was a slight increase in the late bone marrow-related side effects in group 3 compared to group 2.

This study concluded that adding short-term ADT and PLNRT to PBRT significantly improved the survival outcomes without cancer progression after surgery in patients with PC.

This study was sponsored by the National Cancer Institute. A longer follow-up period is needed to better evaluate the effectiveness of PLNRT on distant metastasis and survival outcomes.