The value of prostate-specific antigen monitoring during salvage radiotherapy: a retrospective study and systematic review with meta-analysis

Use of salvage radiotherapy (SRT) after cancer surgery has a low disease control rate. Low prostate-specific antigen (PSA) levels in the blood pre-SRT seem to be the best predictor of success. Our study used PSA monitoring during and after treatment to investigate if PSA levels during SRT can give further information about its chances of success. In a retrospective cohort of 78 patients submitted to salvage radiotherapy (SRT) for biochemical relapse after cancer surgery, we assess PSA values at start of the treatment, 1 week before the end of treatment, and every 3 months for at least 2 years. Post-treatment PSA in our series and the systematic review of the literature aimed to investigate the prognostic value of PSA variation for biochemical disease-free survival. The results suggest that a decline in PSA levels after at least 45 Gy of radiation therapy dosage or a decrease of at least 0.2 ng/mL compared with the start value may be a favorable prognostic factors for biochemical disease-free survival. These results need confirmation using prospective data before being applied to clinical practice and could help physician to choose the correct therapeutic strategy.