Does giving radiotherapy to metastatic sites and the prostate tumor improve the outcomes of patients with prostate cancer and few metastases?

This study aims to evaluate if giving radiotherapy to both the areas the tumor has spread (metastases), along with the prostate tumor, will improve the survival of patients with prostate cancer (PC) and few metastases (oligometastatic disease). This study suggested that this treatment could benefit patients with PC and few metastases.

Oligometastatic PC (O-PC) means that small amounts of the prostate tumor have spread to 3-5 other areas of the body. There is no current standard treatment for O-PC. Radiotherapy (RT) is commonly used as a treatment for prostate cancer. It is usually given to the prostate gland. However, the safety and effectiveness of aiming RT at both the prostate tumor and the metastases in patients with O-PC remain under investigation.

This study included 37 patients with O-PC. All patients had fewer than 5 metastases. 36 patients received hormonal treatment before RT and 1 patient received chemotherapy before RT. Patients were given daily RT for 5 weeks to the prostate and at the site of metastases. The effectiveness of the treatment was evaluated through prostate-specific antigen (PSA) blood levels. PSA is a protein made by the prostate gland. High levels are associated with PC. Decreased PSA levels after therapy are associated with treatment effectiveness. Patients were followed up for an average of 55.5 months.

The average overall survival was 68.8 months. At 2 years, 96.9% of the patients were alive. At 5 years, 65.4% of patients were alive. The average time patients survived with low PSA levels (1 ng/ml or lower) was 76 months. 

The number of metastasis did not impact the overall survival of patients. Patients who had their PSA levels decrease below 1 ng/ml after 1 month of treatment had longer survival without relapse (66.2 months) than those whose PSA levels were still high after treatment (25.7 months). PSA levels higher than 10 ng/ml at diagnosis were associated with lower survival without relapse (38.1 months) compared to those with PSA levels lower than 10 ng/ml at diagnosis (66.2 months).

48.6% of patients had short-term side effects. Most of these side effects were mild and involved side effects to the genital and urinary tract.

This study concluded that patients with O-PC could benefit from radiotherapy to the prostate tumor and metastases sites. 

This study had a small number of patients. Also, this study did not include a placebo or control group to compare outcomes. Further studies are needed.