Prostate-specific antigen (PSA) bounce following salvage radiotherapy to the prostate bed in a patient with prostate cancer post-prostatectomy.

We present a case of prostate-specific antigen (PSA) bounce in a 76 year old man who underwent salvage radiotherapy to the prostate bed following biochemical relapse 6 years post-radical prostatectomy for a T2N0 Gleason grade 3 + 3 prostate adenocarcinoma; 10 months following completion of salvage radiotherapy for biochemical PSA recurrence of 0.2 μg/L. Following undetectable results (<0.03 μg/L), his PSA rose from 0.04 to 0.3 μg/L with no evidence of prostate cancer recurrence before returning to undetectable levels without medical intervention. This PSA 'bounce phenomenon' is well described following radiotherapy to an intact prostate and has been proposed to be the result of a late fibrotic effect on irradiated prostate tissue. To our knowledge, this is the first case published describing the effect in the post-prostatectomy setting. It highlights the importance of serial PSA monitoring to confirm biochemical relapse before committing the patient to androgen deprivation therapy (with its inherent risks and side effects). © The Japan Society of Clinical Oncology 2020.