Table 1.
Summary of pros and cons for various applications of CTC enumeration in prostate cancer (PC) management.
| Application | Pros | Cons |
|---|---|---|
| Prognostic factor in metastatic PC | Some evidence suggests that ≥5 CTC per 7.5 mL might be an unfavorable prognostic factor [18] | Only approximately 25% of patients with metastatic PC have ≥5 CTC per 7.5 mL [47,48] Some patients without CTC have a worse prognosis [49] Unclear whether the CTC number should be considered as a binary or continuous variable [49] |
| Marker of treatment response in metastatic PC | Multiple clinical trials demonstrated that the CTC number (≥5 vs. <5 per 7.5 mL) correlates with survival after treatment [57,58,59,60,61,62,63] Inclusion of the CTC number as a response marker improved the discrimination and calibration of survival models [56] |
None |
| Surrogate survival endpoint in metastatic PC | CTC number (≥5 vs. <5 per 7.5 mL) was confirmed as an accurate surrogate survival endpoint in multiple clinical trials [64,65,66,67,68,69,70] | None |
| Marker in the monitoring of PC outcomes | In some small studies, a higher CTC number correlated with worse survival and faster progression [72,73,74] | Not enough data from large studies confirming prognostic value of the CTC number No data justifying a change of treatment regimen in patients with without the CTC response/increase in the CTC number The cut-off value of ≥5 CTC per 7.5 does not seem to be applicable to clinical setting [18] Unclear whether a single change in CTC number is clinically relevant [71] |
| Prognostic factor in localized PC | Theoretically suitable for the identification of patients with occult disseminated disease | CTC rarely found in patients with localized PC [75,76,77] CTC number does not seem to correlate with other clinicopathological parameters [75,76,77,78,79] Discrepancies in the CTC numbers obtained with various methods negatively affect cost-effectiveness of this parameter [81,82,83,84] |
| Source of the genetic material of PC | CTC mirror accurately genetic status of cancer cells found in biopsy specimens [89] Genetic status of CRC was shown to be a predictor of prostate cancer aggressiveness [103] and therapeutic responses [90,91,92,93,94,95,96,97,98,99,100,101,102] |
Not enough evidence confirming superiority of this method over conventional biopsy |