If people in the U.S. adopted a healthy lifestyle—not smoking, drinking in moderation, maintaining a healthy body weight and exercising regularly—half of all cancer deaths and close to half of all cancer diagnoses could potentially be prevented, according to a new study from Harvard T.H. Chan School of Public Health.

The study’s emphasis on prevention contrasts with findings from a 2015 study, widely reported in the media, that suggested that most cancers are due to random cell mutations and therefore not preventable.

Using data from participants in two large ongoing studies, the researchers looked for associations between a healthy lifestyle—not smoking, drinking no more than one drink a day for women or two for men, maintaining a body mass index between 18.5 and 27.5, and doing aerobic exercise each week of at least 75 vigorous-intensity minutes or 150 moderate-intensity minutes—and cancer incidence and death.

They found that healthy behaviors could have a large effect on preventing certain cancers—particularly lung cancer, colon cancer, pancreatic cancer, and kidney cancer.

Extrapolating the findings to the U.S. population at large, they estimated that, for women, 41% of cancer cases and 59% of cancer deaths were potentially preventable. Among men, they estimated that 63% of cancer cases and 67% of deaths were preventable.

“We should not ignore the knowledge we already learned over the past decade, or the past 100 years,” said lead author Mingyang Song, research fellow in the Department of Nutrition, in a May 19, 2016 Washington Post article. “We should use this knowledge…to improve the current cancer prevention effort.”

Senior author of the study was Edward Giovannucci, professor of nutrition and epidemiology at Harvard Chan School.

The study was published in JAMA Oncology. An accompanying editorial, co-authored by Harvard Chan School adjunct professor of epidemiology Graham Colditz, noted that, “As a society, we need to avoid procrastination induced by thoughts that chance drives all cancer risk or that new medical discoveries are needed to make major gains against cancer, and instead we must embrace the opportunity to reduce our collective cancer toll by implementing effective prevention strategies and changing the way we live.”

Read the Washington Post article: Scientists have determined how we can prevent half of all cancer deaths

Learn more

Greater focus needed on cancer prevention (Harvard Chan School news)

Most cancers not just ‘bad luck’ (Harvard Chan School news)