Michael J Thun; Lindsay M Hannan; Lucile L Adams-Campbell; Paolo Boffetta; Julie E Buring; Diane Feskanich; W. Dana Flanders; Sun Ha Jee; Kota Katanoda; Laurence N Kolonel; I-Min Lee; Tomomi Marugame; Julie R Palmer; Elio Riboli; Tomotaka Sobue; Erika Avila-Tang; Lynne R Wilkens; Jon M Samet

“ Like all cancers, lung cancer occurs when cells begin to divide uncontrollably because of changes in their genes. The main trigger for these changes in lung cancer is exposure to the chemicals in cigarette smoke—either directly through smoking cigarettes or indirectly through exposure to secondhand smoke. Eighty-five to 90% of lung cancer deaths are caused by exposure to cigarette smoke and, on average, current smokers are 15 times more likely to die from lung cancer than lifelong nonsmokers (never smokers) . ”

“ Furthermore, a person's cumulative lifetime risk of developing lung cancer is related to how much they smoke, to how many years they are a smoker, and—if they give up smoking—to the age at which they stop smoking. ”

“ The general population or ecological data on women cover a 70-y time span and represent the total population—not a selected subgroup—of a diverse range of countries or regions. The pooled cohort data, which provide individual level information on smoking behavior and disease endpoints, yield more stable and statistically precise estimates of age-, sex-, and race-specific incidence and death rates than have been available from individual studies. ”

“ The researchers' detailed statistical analyses reveal, for example, that lung cancer death rates in African Americans and in Asians living in Korea and Japan (but not among Asians living in the US) are higher than those in people of the European continental ancestry group. They also show that men have higher death rates from lung cancer than women irrespective of racial group, but that women aged 40–59 years have a slightly higher incidence of lung cancer than men of a similar age. ”

“ For example, the death rate among men of European descent who reported never smoking exceeded the general population death rate for melanoma beginning at age 50 y, from cancer of the brain and other nervous system at ages 65+ y, from cancers of the kidney and liver at ages 70+ y, and from cancer of the esophagus at ages 80+ y. ”

“ Diagnostic errors are especially problematic when comparing lung cancer rates across different time periods or countries at different stages of economic development. Missed diagnoses almost certainly contribute to the low recorded rates of lung cancer in Africa and parts of India during the 1980s, and to the lower incidence and death rates recorded in the oldest age groups. ”

“ Men and women of European descent who smoked actively had lung cancer death rates that were 21.9 and 13.7 times higher, respectively, than the rates of never-smokers, when the rates were standardized to all ages 40+ y. ”

“ It is reassuring that the pooled incidence and death rates for women age 40–69 y in the cohort studies are similar to those in the general population of countries with a similar level of economic development. ”

“ A challenge in interpreting temporal trends in cancer incidence and death rates is to distinguish actual changes in disease occurrence from artifacts due to changes in disease detection or classification. Technological advances such as bronchoscopy, percutaneous thin needle biopsy, and imaging technologies make it possible to biopsy pulmonary masses without open chest surgery [55] . ”

“ These technologies particularly affect the rates in older patients, increasing the likelihood that primary lung cancers will be detected, and decreasing the chances that pulmonary metastases will be misdiagnosed as lung cancer. ”

“ We first used the likelihood ratio test in generalized linear models (SAS GENMOD) [30] to determine whether controlling for “study” improved the fit of the model, within each sex and race combination. ”

“ Black Women's Health Study;CI: confidence interval;CPS-I: Cancer Prevention Study;CPS-II: Cancer Prevention Study II;CPS-II Nutrition: Cancer Prevention Study II Nutrition Cohort;HPFS: Health Professionals' Follow-up Study;HR: hazard ratio;KCPS: Korean Cancer Prevention Study;MEC: Multiethnic Cohort;NHS: Nurses' Health Study;RR: rate ratio;SEER: Surveillance Epidemiology and End Results;WHS: Women's Health StudyAuthor contributions. ”