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

Abstract

Objective 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. Methods 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. ResultsThe 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. Conclusion These results need confirmation using prospective data before being applied to clinical practice and could help physician to choose the correct therapeutic strategy.

Study of prostate-specific antigen levels during salvage radiotherapy after prostate cancer surgery

“…The results of our study examining patients with a decline in PSA levels during salvage RT were consistent with those of previously reported studies, showing that a decrease of 0.2 or more in PSA levels during irradiation affects BR [ 20 ]. However, our results contradicted those of previous studies showing BR to be affected by decreases in PSA levels after radiation doses reached and exceeded 45 Gy [ 5 , 12 , 13 , 20 ]. In fact, our results revealed no evidence of BR in patients in whom PSA levels declined relatively early after the initiation of RT.…”

“…Despite salvage RT being a widely adopted strategy, our literature search yielded only 9 articles [ 5 – 13 ] and one review [ 20 ] on changes in PSA levels during RT. All but one of these articles showed that such changes might be a factor impacting biochemical or clinical recurrence [ 5 – 8 , 10 – 13 ], while the other article described changes in PSA levels as not being a factor associated with recurrence [ 9 ].…”

Predictive value of Prostate Specific Antigen variations in the last week of salvage radiotherapy for biochemical recurrence of prostate cancer after surgery: A practical approach

“…Some authors have reported that PSA changes measured during SRT can be used to predict treatment outcome. 24,[36][37][38][39] Our results shown that the combined analysis of the PSA_start In the PSA_start -diffPSA plane (Figure 1), the diffPSA_ threshold line (Equation 2 F I G U R E 2 In the PSA_start-diffPSA plane, the diffPSA_threshold line ideally splits patients with post-SRTBF (above the line) from patients without post-SRTBF (below the line): the location of a patient in the PSA plane identifies the probability of evolution of his biochemical state…”

“…Some authors have reported that PSA changes measured during SRT can be used to predict treatment outcome 24,36‐39 …”

“…A previous study 24 highlighted that in the salvage setting, a decline in PSA value after at least 45 Gy of SRT dose or a PSA decrease of at least 0.2 ng/mL, compared to the treatment start value, results in a positive prognostic factors for BDFS.…”