Table 2. Univariate analysis to determine factors associated overall survival (OS) of patients who underwent re-challenge chemotherapy with gemcitabine plus carboplatin (rGC).

Variate	HR	95% CI	P
Sex	1.5	0.6 to 3.8	0.412
Smoking history	0.4	0.1 to 2.0	0.253
Pathologic subtype	0.8	0.4 to 1.7	0.586
RR for first-line chemotherapy	0.8	0.4 to 1.5	0.454
Interval between first-line and second-line chemotherapy	0.9	0.9 to 1.0	0.018
>6 months	0.6	0.2 to 1.9	0.441
>12 months	0.5	0.2 to 1.3	0.052
>15 months	0.1	0.0 to 0.6	0.007
PS at rGC	2.7	1.3 to 5.7	0.006
Stage at rGC	0.8	0.1 to 7.7	0.881
Third-line chemotherapy	0.8	0.3 to 2.0	0.591
RR for rGC chemotherapy	1.9	0.2 to 5.2	0.199

RR, response rate; PS, performance status; HR, hazard ratio; CI, confidence interval.