Figure 1

Comparison of cumulative survival rate of different smoking index groups. Figure 1 shows a comparison of cumulative survival rate in different smoking index groups. Cumulative survival rate decreased with increasing smoking index. Although differences between group1 (smoking index<350) and group2 (350<smoking index<569), group2 and group3 (569<smoking index<749) were not significant, there were significant differences between the other two groups (P < 0.05).