Table 3.
Summary of selected prognostic studies published to date using CellSearch technology.
| Study and cancer type | Breast [Hayes et al. 2006; Cristofanilli et al. 2005, 2004] | Breast [Nole et al. 2008] | Castrate resistant prostate cancer [de Bono et al. 2008] | Castrate resistant prostate cancer [Scher et al. 2009] | Castrate resistant prostate cancer [Olmos et al. 2009] | Castrate resistant prostate cancer [Danila et al. 2007] | Colorectal [Cohen et al. 2009, 2008] | Colorectal [Tol et al. 2010] | Small cell lung cancer [Hou et al. 2009] |
|---|---|---|---|---|---|---|---|---|---|
| No of patients | 177 | 80 | 219 | 156 | 119 | 112 | 413 | 451 | 50 |
| % Positive for CTCs at BL (above cut-off) | 49% (≥5) | 61% (≥5) | 58% (≥5) | 55% (≥5) | 50% (≥5) | 62% (≥5) | 26% (≥3) | 29% (≥3) | 86% (≥1) |
| Line of therapy | Any | 1st, 2nd or 3rd | Any | 1st | Any | Any | 1st, 2nd or 3rd | 1st | 1st |
| CTC prognostic cut-off | 5 | 5 | 5 | no cut-off | 5 | no cut-off | 3 | 3 | no cut-off |
| Median OS according to BL CTC count: | – | – | – | – | – | – | – | – | – |
| <cut-off | 18 m | – | 21.7 m | – | >30 m | – | 20.6 m | 22.0 m | – |
| ≥cut-off | 10.6 m | – | 11.5 m | – | 19.5 m | – | 9.4 m | 13.7 m | – |
| P value | <0.001 | – | <0.0001 | – | <0.0001 | – | <0.0001 | <0.0001 | – |
| Median OS according to BL and FU CTC counts: | – | – | – | – | – | – | – | – | – |
| <cut-off at BL <cut-off at FU | 22.6 m | – | >26 m | – | >30 m | – | 17.7 m | 21.9 m | – |
| ≥ cut-off at BL <cut-off at FU | 19.8 m | – | 21.3 m | – | 21.4 m | – | 11.0 m | 14.5 m | – |
| <cut-off at BL≥cut-off at FU | 10.6 m | – | 9.3 m | – | 11.2 m | – | 10.9 m | 6.3 m | – |
| ≥cut-off at BL ≥cut-off at FU | 4.1 m | – | 6.8 m | – | 9.2 m | – | 3.7 m | 6.3 m | – |
| Timing of FU blood sampling: | Up to 15-20 weeks | – | Up to 13-20 weeks | – | After 1-2 cycles of novel agent in phase 1 setting | – | 3–5 weeks | 1–2 weeks | – |
| Additional comments | CTC values assessed for correlation with radiological response (see Table 4) | Patients with ≥5 CTC at baseline or follow up compared to <5 CTC predicted worse PFS; S not reached | CTC counts predicted OS better than PSA decrement algorithms at all time points | Higher baseline CTCs (as a continuous variable) predicted for worse OS (HR 1.58, p < 0.0001) | Patients with >50 CTC at baseline had poorer OS compared with patients with 5–50 or <5 CTCs (6.3 vs 21.1 vs 30 months, p < 0.001). | Higher baseline CTCs (as a continuous variable) predicted for worse OS. Predictive model improved with inclusion of PSA and albumin levels | CTC values assessed for correlation with radiological response (see Table 4) | CTC values assessed for correlation with radiological response (see Table 4) | Higher baseline CTCs (as a continuous variable) predicted for worse OS (HR 1.1, p = 0.015) |
CTC, circulating tumour cell; HR, hazard ratio; m, months; OS, overall survival; PFS, progression free survival; FU, follow up; BL, baseline.