Table 3. Cox proportional hazard regression analysis for the overall survival and lung cancer-specific survival of SCLC patients with SPC being treated as a time-dependent covariate.
| Factors | OS | LCSS | |||||
|---|---|---|---|---|---|---|---|
| HR | 95.0% CI | P | HR | 95.0% CI | P | ||
| Male (versus female) | 1.241 | 1.229–1.253 | 0.000 | 1.212 | 1.200–1.225 | 0.000 | |
| Race (versus White) | |||||||
| Black | 0.987 | 0.973–1.001 | 0.065 | 0.973 | 0.958–0.988 | 0.000 | |
| Others | 0.756 | 0.742–0.769 | 0.000 | 0.744 | 0.729–0.758 | 0.000 | |
| Age (versus ≤60) | |||||||
| 61–70 | 1.098 | 1.084–1.112 | 0.000 | 1.070 | 1.056–1.084 | 0.000 | |
| 71–80 | 1.247 | 1.231–1.263 | 0.000 | 1.179 | 1.163–1.196 | 0.000 | |
| >80 | 1.382 | 1.360–1.404 | 0.000 | 1.289 | 1.276–1.312 | 0.000 | |
| Differentiation (versus well differentiation) | |||||||
| Moderate | 1.344 | 1.310–1.379 | 0.000 | 0.642 | 0.625–0.660 | 0.000 | |
| Poor | 1.572 | 1.533–1.612 | 0.000 | 0.882 | 0.869–0.895 | 0.000 | |
| Undifferentiated | 1.654 | 1.582–1.728 | 0.000 | 1.049 | 1.037–1.062 | 0.000 | |
| Unknown | 1.504 | 1.467–1.542 | 0.000 | 1.101 | 1.057–1.146 | 0.000 | |
| Histology (versus squamous cell carcinoma) | |||||||
| Adenocarcinoma | 0.934 | 0.924–0.944 | 0.000 | 0.903 | 0.884–0.923 | 0.000 | |
| Others | 1.076 | 1.055–1.098 | 0.000 | 0.867 | 0.849–0.885 | 0.000 | |
| T–stage (versus T0) | |||||||
| T1 | 0.759 | 0.707–0.815 | 0.000 | 0.833 | 0.773–0.898 | 0.000 | |
| T2 | 1.103 | 1.029–1.184 | 0.006 | 0.586 | 0.573–0.600 | 0.006 | |
| T3 | 1.416 | 1.318–1.521 | 0.000 | 0.927 | 0.909–0.945 | 0.000 | |
| T4 | 1.485 | 1.385–0.593 | 0.000 | 1.214 | 1.183–1.245 | 0.000 | |
| Tx | 1.181 | 1.100–1.268 | 0.000 | 1.260 | 1.238–1.283 | 0.000 | |
| N–stage (versus N0) | |||||||
| N1 | 1.361 | 1.337–1.386 | 0.000 | 0.701 | 0.685–0.716 | 0.000 | |
| N2 | 1.483 | 1.464–1.502 | 0.000 | 1.008 | 0.982–1.034 | 0.566 | |
| N3 | 1.490 | 1.465–1.516 | 0.000 | 1.093 | 1.070–1.116 | 0.000 | |
| Nx | 1.370 | 1.342–1.399 | 0.000 | 1.093 | 1.067–1.119 | 0.000 | |
| M–stage (versus M0) | |||||||
| M1 | 1.793 | 1.774–1.814 | 0.000 | 0.932 | 0.905–0.960 | 0.000 | |
| Mx | 1.063 | 1.034–1.092 | 0.000 | 1.780 | 1.730–1.831 | 0.000 | |
| Other marriage status (versus married) | 1.096 | 1.085–1.107 | 0.000 | 1.078 | 1.067–1.089 | 0.000 | |
| No radiation or unknown (versus radiation) | 1.135 | 1.123–1.146 | 0.000 | 0.898 | 0.888–0.908 | 0.000 | |
| No chemotherapy or unknown (versus chemotherapy) | 1.910 | 1.890–1.931 | 0.000 | 0.532 | 0.526–0.538 | 0.000 | |
| Surgery (versus no surgery) | |||||||
| Sublobectomy | 0.431 | 0.420–0.442 | 0.000 | 1.217 | 1.139–1.301 | 0.000 | |
| Lobectomy | 0.285 | 0.280–0.290 | 0.000 | 0.491 | 0.457–0.528 | 0.000 | |
| Pneumonectomy | 0.405 | 0.388–0.422 | 0.000 | 0.312 | 0.291–0.334 | 0.000 | |
| Surgery, NOS | 0.464 | 0.420–0.511 | 0.000 | 0.467 | 0.431–0.507 | 0.000 | |
| Unknown | 0.830 | 0.781–0.883 | 0.000 | 0.568 | 0.501–0.644 | 0.000 | |
| SPC* (versus no SPC) | 1.298 | 1.270–1.326 | 0.000 | 1.094 | 1.066–1.123 | 0.000 | |
*, being treated as a time-dependent covariate. NSCLC, non-small cell lung cancer; SPC, second primary cancer; HR, hazard ratio; CI, confidence interval; OS, overall survival; LCSS, lung cancer-specific survival.