Ultrasensitive prostate specific antigen and its role after radical prostatectomy: a systematic review.

Abstract

PURPOSE: Prostate specific antigen is an important tool to monitor patients with prostate cancer after radical prostatectomy. Ultrasensitive prostate specific antigen assays are increasingly used with a lower limit of detection as low as 0.001 ng/ml. We systematically reviewed currently available ultrasensitive prostate specific antigen technologies and the role of this method in monitoring patients after radical prostatectomy.

MATERIALS AND METHODS: We searched the relevant literature using the MEDLINE® database. For various study objectives the series eligible for review provided serial ultrasensitive prostate specific antigen (lower detection limit less than 0.1 ng/ml) data on men after radical prostatectomy as well as comparative data on standard prostate specific antigen (lower detection limit 0.1 ng/ml or greater).

RESULTS: Ultrasensitive prostate specific antigen could potentially detect prostate cancer recurrence years earlier than standard prostate specific antigen assays. The specificity of detectable ultrasensitive prostate specific antigen is low. Ultrasensitive prostate specific antigen kinetics may improve the positive predictive value for detecting cancer recurrence. However, the usefulness of prostate specific antigen doubling time at the ultrasensitive level remains controversial. Undetectable nadir ultrasensitive prostate specific antigen after radical prostatectomy confers a low risk of disease recurrence while a detectable nadir above 0.01 ng/ml requires additional measurement and consideration of other risk factors to determine management and avoid overtreatment. This monitoring method may spare patients with high risk disease adjuvant radiation therapy and enable more selective early salvage radiation. Currently no data demonstrate improved survival after early salvage therapy prompted by ultrasensitive prostate specific antigen surveillance.

CONCLUSIONS: Ultrasensitive prostate specific antigen is useful in the early diagnosis of cancer recurrence after radical prostatectomy but specificity is poor. To date there is a lack of evidence that earlier detection of recurrence translates into prolonged time to metastasis. Integrating ultrasensitive prostate specific antigen with other clinicopathological factors can help determine optimal adjuvant and salvage therapy.