A fresh look at the causes of cancer has come up with some surprising numbers. While smoking is still by far the biggest cause of cancer and cancer deaths, obesity, poor diet and drinking too much alcohol cause an increasing number of cancer cases and deaths. Overall, modifiable risk factors — things people can change — cause 42 percent of cancer cases and 45 percent of deaths, the American Cancer Society found. NBC News “We are identifying what an individual can do to live a more healthy life,” said Dr. Otis Brawley, Chief Medical and Scientific Officer for the American Cancer Society said in an interview. Cancer is the second leading cause of death in the United States. In 2017, the American Cancer Society estimates, cancer will be diagnosed in 1.7 million Americans and will kill more than 600,000. But more people are surviving cancer. In 1975, 49 percent of people diagnosed with cancer were still alive five years later. By 2012 it was 69 percent. For decades, experts have routinely said that a third of all cancers were caused by smoking. “A bunch of us got to thinking sometime about October of last year. You know in 1981 when we said a third of all cancer deaths were due to tobacco, those guys knew that 10 cancers were linked to tobacco and one additional might be,” Brawley said. It’s now known that 17 cancer types are linked to smoking, that obesity raises cancer risk and that fewer people smoke. And now, three-fourths of Americans are overweight or obese. So a team re-ran the numbers. What they found surprised them. It’s still true that 45 percent of cancer deaths are due to things people can change — mostly smoking, but also, increasingly, obesity and drinking alcohol. “Cigarette smoking was associated with far more cancer cases and deaths than any other single risk factor, accounting for nearly 20 percent of all cancer cases and 30 percent of all cancer deaths, followed by excess body weight,” the team wrote in a report released Tuesday. And drinking too much alcohol causes 5.6 of cancer causes and 4 percent of deaths, they found. “One of the things that came through that surprised me was alcohol,” Brawley said. Drinking too much can cause liver cancer