Limited prognostic value of preoperative circulating tumor cells for early biochemical recurrence in patients with localized prostate cancer

- 17 of 152 patients with localized prostate cancer after radical prostatectomy harbored CTCs.
- CTCs had no significant correlations with PSA, pT Stage, or Gleason scores.
- There was no significant difference in BCR-free survival between CTC+vs. CTC- patients.

IntroductionThe presence of circulating tumor cells (CTCs) is an established marker for prognosis in men with castration-resistant prostate cancer. A cutoff of ≥5 CTCs/7.5 ml blood in the CellSearch Epithelial Cell Test has been shown to stratify prognostic groups and predict outcome of abiraterone treatment. In contrast, the value of CTC detection in men with localized prostrate cancer before radical prostatectomy (RP) is unknown.Materials and methodsA total of 152 patients treated with RP between 06/2009 and 09/2009 were included. Peripheral venous blood drawn the day before RP was evaluated for CTCs by the CellSearch system. The detection of CTCs was correlated with prostate-specific antigen (PSA) and the histopathological outcome of the RP specimen. A cutoff of 0 vs. ≥1 CTC/7.5 ml blood was defined as the threshold for positive vs. negative CTC status.ResultsMedian age was 62 years and median PSA was 6.7 ng/dl. Staging revealed 62.5% pT2, 26.3% pT3a, and 11.2% pT3b tumors, and high-grade disease (≥Gleason 4+3) was determined in 25.6% of patients. CTCs were detected in 17 patients (11%) with a median CTC count/7.5 ml of 1 (range: 1-clusters with>100 epithelial cells) without significant correlations to PSA levels, pT stage, or Gleason scores. Postoperative pT stage was a significant predictor of biochemical recurrence (BCR) in univariable logistic regression models and as a composite measure together with positive CTC counts (P<0.0001). CTC positivity alone tended to have a higher hazard ratio for BCR, but this was not statistically significant (P = 0.1). After a median follow-up of 48 months, there was no significant difference in BCR-free survival between patients with or without CTCs (P = 0.7).ConclusionUsing the CellSearch system, we infrequently detected CTCs in patients with localized tumors before RP. The detection of CTCs did not correlate significantly with PSA, disease characteristics, or the development of BCR. However, larger cohorts with extended follow-up are needed to validate our findings.