Burns D M
University of California-San Diego School of Medicine, 92108, USA.
Cancer. 2000 Dec 1;89(11 Suppl):2506-9. doi: 10.1002/1097-0142(20001201)89:11+<2506::aid-cncr33>3.3.co;2-#.
Cigarette smoking is the major cause of lung cancer, and most lung cancers have historically occurred among current cigarette smokers or recent quitters. The relative risk of developing lung cancer declines in former smokers to approximately twice that of never smokers after 20 years of cessation, but it remains elevated indefinitely. As an increasing fraction of those who have ever smoked become former smokers, the absolute risk of lung cancer in the population will decline; and an increasing fraction of lung cancer cases will occur among former smokers.
Data from the 12-year follow-up of American Cancer Society Cancer Prevention Study I are used to estimate lung cancer death rates for smokers, never smokers, and former smokers by duration of cessation. These estimates are combined with population-based estimates of smoking status by birth cohort to generate models of lung cancer death rates for current and former smokers.
Modeled estimates of lung cancer death rates suggest that, in the near future, the majority of lung cancer cases will be occurring among former smokers.
Former smokers already have acted on the advice of their physicians to reduce their lung cancer risk; however, they will generate an increasing fraction of the cancers that are seen. Approaches must be developed for these former smokers to alter their risk if lung cancer death rates are going to continue to be affected. Additional primary preventive strategies, including chemoprevention, offer hope to these former smokers, as do secondary preventive efforts, such as screening.
吸烟是肺癌的主要病因，历史上大多数肺癌病例都发生在现吸烟者或近期戒烟者中。戒烟20年后，既往吸烟者患肺癌的相对风险降至从不吸烟者的约两倍，但仍会长期维持在较高水平。随着曾经吸烟的人中越来越多成为既往吸烟者，人群中肺癌的绝对风险将会下降；并且肺癌病例中既往吸烟者所占的比例会越来越高。
利用美国癌症协会癌症预防研究I的12年随访数据，按戒烟时长估算吸烟者、从不吸烟者和既往吸烟者的肺癌死亡率。这些估算值与按出生队列得出的基于人群的吸烟状况估算值相结合，生成现吸烟者和既往吸烟者的肺癌死亡率模型。
肺癌死亡率的模型估算表明，在不久的将来，大多数肺癌病例将发生在既往吸烟者中。
既往吸烟者已经听从医生建议降低了患肺癌风险；然而，他们将在所见的癌症病例中占比越来越高。如果要继续影响肺癌死亡率，必须为这些既往吸烟者制定改变其风险的方法。包括化学预防在内的额外一级预防策略，以及诸如筛查等二级预防措施，都为这些既往吸烟者带来了希望。
