Circulating Tumor Cells in Peripheral Blood Samples From Patients With Increased Serum Prostate Specific Antigen: Initial Results in Early Prostate Cancer

TLDR

In metastatic cancers, >5 circulating tumor cells per 22.5 ml are often detected and may predict prognosis, but in localized prostate cancer only 3.1 % of patients and 8 % of controls had ≥3 cells at baseline. The study tested whether circulating tumor cells measured by CellSearch correlate with tumor volume, pathological stage, and Gleason score in localized prostate cancer. Blood samples (30 ml) were collected from 97 men with localized prostate cancer before surgery, on postoperative days 2–3, and at 6 weeks, and from 25 control men with elevated PSA but no tumor; circulating tumor cells were quantified using the CellSearch System. Circulating tumor cells were found in 21 % of cancer patients and 20 % of controls (p = 0.946), showed no correlation with tumor volume, stage, or Gleason score, and largely cleared after surgery, with 18 of 20 baseline‑positive patients becoming negative at 6 weeks.

Abstract

We evaluated the hypothesis that circulating tumor cells as determined using the CellSearch System would correlate with tumor volume, pathological stage and Gleason score in men with localized prostate cancer.Samples of blood (30 ml) were drawn from 97 men with localized prostate cancer before radical prostatectomy, on postoperative days 2 to 3 and at 6 weeks. A control group consisted of 25 men with an increased prostate specific antigen and no tumor detected on extended prostate biopsy. Samples were analyzed for circulating tumor cells using the CellSearch System.Circulating tumor cells were detected in 21% of patients with cancer and 20% of controls (p = 0.946). At 6 weeks after prostatectomy circulating tumor cells were detected in 16% and 11% (p = 0.51) of the men positive and negative for circulating tumor cells at baseline, respectively. Of the 20 patients with cancer who had circulating tumor cells at baseline 18 showed no circulating tumor cells after surgery. Circulating tumor cell values did not correlate with tumor volume, pathological stage or Gleason score. Only 3.1% of the men with cancer and 8% of the control group had 3 or more circulating tumor cells per 22.5 ml blood at baseline.In metastatic breast, prostate and other cancers more than 5 circulating tumor cells are often detected using the CellSearch System, and may correlate with prognosis. However, in the setting of localized prostate cancer the number of detectable circulating tumor cells was low, with findings comparable to those in men who were biopsy negative for cancer. We found no correlation between the number of circulating tumor cells and known prognostic factors in this population.