Circulating tumor cells in patients undergoing androgen deprivation therapy with versus without cryosurgery for metastatic prostate cancer: a retrospective analysis

BACKGROUND: The study aimed to assess the value of circulating tumor cells (CTCs) as a prognostic and treatment response marker in patients undergoing androgen deprivation therapy (ADT) plus cryosurgery vs. ADT alone for metastatic prostate cancer (mPCA). METHODS: This retrospective analysis included 43 patients with mPCA: 23 receiving ADT alone (control) and 20 receiving additional cryosurgery (cryosurgery group). CTCs and progression-free survival (PFS) were compared between the two groups. Cox proportional hazards regression was conducted to identify variables associated with PFS. RESULTS: Median PFS was 35 months (IQR, 33‑37) in the cryosurgery group vs. 30 months (IQR, 27‑32) in the control (p < 0.001). CTCs count was significantly lower in the cryosurgery group at both 3 months (z = 2.170, p = 0.030) and 12 months (z = 2.481; p = 0.013). In comparison to the baseline, the number of CTCs at both 3 and 12 months was lower in the cryosurgery group (p = 0.004 and p < 0.001, respectively), but not in the ADT alone group. In multivariate Cox regression, shorter PFS was associated with baseline PSA ≧100 ng/ml (HR 6.584, 95% CI, 5.309‑8.166), biopsy Gleason score ≧ 8 (HR 2.064, 95% CI, 1.608‑2.650), clinic T stage>T2b (HR 5.021, 95% CI, 3.925‑6.421), number of bone metastases>3 (HR 3.421, 95% CI, 2.786‑4.202), positive CTCs at 3 months post-treatment (HR 6.833, 95% CI, 5.176‑9.022), positive CTCs 1 year post-treatment (HR 6.051, 95% CI, 4.347‑8.424). Prostate cryosurgery was associated with longer PFS (HR 0.062, 95% CI, 0.048‑.080). CONCLUSIONS: CTC was a prognostic and treatment response marker for mPCA. ADT plus cryosurgery could reduce CTCs and prolong PFS vs. ADT alone in mPCA patients with low metastatic volume.