“ Lung cancer is the number one cause of cancer mortality for both men and women ,” Dr . Yang said . “ And more than two-thirds of our lung cancer patients do not have a history of smoking . If we only used smoking history in our lung cancer screening guidelines , we would miss much of the benefit .”
Turning clinical trials into successful screening programs is a complex process . Different populations have different prevalence patterns and risk factors , which affects screening criteria and priorities .
Different countries have distinct health systems and implementation policies . Screening institutions have their own priorities and needs . So do the different providers who order , perform , and interpret CT scans . Barriers can exist at many levels , and it is important to understand the unique barriers in different settings in order to develop a plan to mitigate the challenges .
Pan-Chyr Yang , MD , PhD
“ The devil is in the details ,” Dr . Henschke said . “ To get a whole screening system going takes a lot of coordination . It takes a key person at each institution who really wants to coordinate all the people that are needed to make it work because screening is at the intersection of so many disciplines . You have to have quality assurance for the screening to assure its benefit , and you need to have outreach out to the target population .”
Countries need to identify who is most likely to benefit from screening . Many of the foundational lung cancer screening studies were done in countries where smoking was the primary risk factor . Other populations may have different risk factors .
“ Non-smoking lung cancer is worldwide , particularly in East Asia ,” Dr . Yang said . “ And non-smoking lung cancer is increasing , including in the US and in Europe . We have started looking to find out why .”
Population studies identified specific genetic risk factors for lung cancer , even in patients who never smoked , Dr . Yang said . Passive smoking and chronic lung disease play roles . Environmental exposures , especially air pollution and cooking fumes , increase risk . A family history of lung cancer has emerged as the leading risk factor in people who smoked as well as those who didn ’ t .
Taiwan launched a national low dose CT screening program focused on two groups ; those who smoke , beginning at age 50 , and those who don ’ t with a family history of lung cancer , beginning at age 45 . Most of the lung cancers detected the first year ( 85 %) were stage 0 or stage 1 .
“ Smoking cessation is the most important part of lung cancer prevention ,” Dr . Yang said . “ In countries that have the resources , start screening with heavy smokers . But if more than one-third of your lung cancer prevalence is in patients who never smoked , consider screening based on family history . Your screening program should take into account your own population epidemiology , genetics , and environmental factors , which can be quite different between countries . You cannot just focus on heavy smokers .”
The emphasis on non-tobacco risk factors is not unique to East Asia . As smoking rates decline in the US and elsewhere , people who never smoked are emerging as a growing population at risk for lung cancer .
“ I agree with Dr . Yang that you cannot focus just on heavy smokers ,” Dr . Henschke said .