Association between Postoperative Detection of Circulating Tumor Cells and Recurrence in Patients with Prostate Cancer

Purpose: The clinical implications of postoperative detection of circulating tumor cells in prostate cancer are largely unknown. We investigated the association between postoperative circulating tumor cell detection after radical prostatectomy and disease recurrence in prospectively enrolled patients with prostate cancer. Materials and Methods: A total of 203 patients with an undetectable prostate specific antigen who had undergone radical prostatectomy for prostate cancer were prospectively enrolled. Circulating tumor cell sampling was performed at a median of 4.5 months after surgery. The primary end point was biochemical recurrence-free survival. Detection of circulating tumor cells in the blood of patients was performed using a novel approach with a replication-competent adenovirus controlled by prostate specific antigen/prostate specific membrane antigen transcription regulatory elements (Ad5/35E1aPSESE4). Results: Circulating tumor cells were detected in 73 (36.0%) patients with undetectable prostate specific antigen concentrations after surgery. The 3-year biochemical recurrence-free survival rate from the time of surgery was significantly higher in circulating tumor cell-negative than in circulating tumor cell-positive cases (81.6% vs 48.9%, log rank p<0.001). Multivariable analysis showed that postoperative circulating tumor cell detection was independently associated with an increased risk of biochemical recurrence (HR 5.42, 95% CI 3.24-09.06, p<0.001). C-index was increased in combinations of multivariable model and postoperative circulating tumor cell detection compared with the multivariable model alone. Conclusions: Circulating tumor cells in the blood were frequently detected in patients with undetectable prostate specific antigen levels after radical prostatectomy for localized prostate cancer. Furthermore, circulating tumor cell detection was associated with an increased risk of biochemical recurrence, suggesting that circulating tumor cell detection precedes prostate specific antigen rise after surgery in cases of prostate cancer recurrence. Large-scale validation is needed in the future.