CHICAGO, Oct. 9 (Xinhua) -- Lung cancer will continue to be a significant health problem in the United States although smoking-related lung cancer rates are expected to drop dramatically over the next 50 years, the University of Michigan (UM) researchers said.

The researchers utilized four independent models to project lung cancer rates for U.S. men and women aged 30 to 84 from 1964 to 2065. All models projected the impact of changes in smoking prevalence since the 1960s on past and future lung cancer mortality.

They found that the number of annual deaths in those aged 30 to 84 will decrease from 135,000 in 2015 to 50,000 in 2065. But despite those gains, there will be 4.4 million deaths from lung cancer in the United States from 2015 to 2065, and lung cancer will remain a significant health problem in the U.S., with an increasing number and proportion occurring among those who have never smoked.

Under the most optimistic scenario, rates could drop by 81 percent, while under the most pessimistic scenario, rates would fall by 75 percent from 2015 to 2065, the study holds.

The study demonstrates that tobacco control is helping reduce the burden of lung cancer in the U.S. but also that smoking will continue to be an important determinant of lung cancer risk during this century, according to Jihyoun Jeon, first author of the study and a researcher at the School of Public Health at UM.

"Even though lung cancer death rates among never smokers are expected to remain roughly the same in the future, the proportion of never smokers will grow in the U.S. population, which will result in a greater portion of lung cancer deaths to come from never smokers," Jeon said.

The study has been published in the Annals of Internal Medicine.