Compared to neer smokers, current and former smokers had proportionally more squamous cell and small-cell lung cancer, which can be harder to treat than other subtypes.

• 与从未吸烟者相比，目前和原来吸烟者患有较其他类型难于治疗的鳞状上皮细胞和小细胞肺癌的比例较高。