Table 3.
Cox Regression Analysis of Association Between Change in CTC Count From Day 0 to 21 and OS Adjusted for Other Clinical Variables
| Variable | HR | 95% CI | P |
|---|---|---|---|
| Model A (all patients) | |||
| Rising CTC count from day 0 to 21* | 2.55 | 1.04 to 6.24 | .041 |
| Falling CTC count from day 0 to 21* | 1.47 | 0.69 to 3.13 | .324 |
| Log2 (day-0 CTC count) | 1.17 | 1.06 to 1.30 | .002 |
| Log2 (baseline PSA) | 0.99 | 0.87 to 1.13 | .915 |
| δ Log2 (PSA from day 0 to 21) | 1.28 | 0.85 to 1.92 | .245 |
| Hemoglobin | 0.77 | 0.65 to 0.91 | .002 |
| Log2 (alkaline phosphatase) | 0.95 | 0.75 to 1.22 | .702 |
| Liver disease | 1.72 | 0.69 to 4.31 | .246 |
| Age | 1.00 | 0.97 to 1.03 | .959 |
| Black race | 0.90 | 0.47 to 1.73 | .761 |
| Performance status | 1.09 | 0.70 to 1.71 | .692 |
| PSA-only progression (v measureable or evaluable disease) | 0.76 | 0.37 to 1.56 | .456 |
| Worst pain ≥ 4 (Brief Pain Inventory score) | 1.47 | 0.90 to 2.38 | .124 |
| Minimal v extensive disease | 0.88 | 0.53 to 1.45 | .609 |
| Model B (subset of patients with unfavorable CTC count at day 0 [≥ five]) | |||
| > 50% fall in CTC count from day 0 to 21*† | 0.53 | 0.27 to 1.06 | .071 |
| Model C (subset of patients with favorable CTC count at day 0 [< five]) | |||
| Rising CTC count from day 0 to 21*† | 6.47 | 1.96 to 21.42 | .002 |
Abbreviations: CTC, circulating tumor cell; HR, hazard ratio; OS, overall survival; PSA, prostate-specific antigen.
*
Association between change in CTC count and OS; all other rows represent other clinical variables for which the association between change in CTC count and OS was adjusted.
†
HR, 95% CI, and P value adjusted for covariates listed in model A.