A new study finds about half of U.S. adult deaths from 12 cancers, including lung, colon and pancreatic cancer, are caused by smoking.
About 346,000 Americans age 35 and older died from 12 cancers in 2011, according to HealthDay.
Almost 168,000 of these deaths were due to tobacco, the American Cancer Society researchers found.
"Despite large declines in smoking in the United States over the last 50 years, smoking still accounts for the majority of lung cancer deaths," said study co-author Rebecca Siegel.
About 80 percent of deaths from cancers of the lungs, bronchi and trachea were due to smoking in 2011, the study concluded.
Three-quarters of deaths due to cancer of the larynx were due to smoking. About half of deaths from cancers of the oral cavity, esophagus and urinary bladder were due to tobacco use, the researchers reported.
Smoking is also the cause of many deaths from cancer of the colon, kidney, liver, pancreas, stomach, cervix and from myeloid leukemia, Siegel said.
The study appears in JAMA Internal Medicine.
Although the U.S. smoking rate dropped from 23 percent in 2000 to 18 percent in 2012, smoking-related cancer deaths will continue to rise over the next several decades, Siegel said. She explained it will take 30 to 40 years for tobacco-related cancer to develop among current smokers.
"If we could reduce smoking, we would have a lot fewer cancers," Siegel said. "While we have made a lot of progress in tobacco control, there is still a lot to do."