Close to Half of US New Cancer Diagnoses, Half of Cancer Deaths Preventable

A substantial amount of US cancer diagnoses and deaths are preventable through lifestyle modification, according to a new study in JAMA Oncology, and the authors recommend that primary prevention remain a priority for cancer control.

Mingyang Song, MD, ScD, and Edward Giovannucci, MD, ScD, of Massachusetts General Hospital and Harvard Medical School in Boston, used data from the Nurses’ Health Study and the Health Professionals Follow-up Study to re-examine the contribution of lifestyle factors to cancer occurrence. They calculated cancer incidence and death rates in people with varying lifestyle factors and estimated the risk of cancer these factors carried, as well as the proportion of cancer that might have been prevented if the risk factors were removed. The study was published online May 19, 2016.

Song and Giovannucci divided the study participants into low-risk and high-risk categories based on 4 well-known cancer risk factors: cigarette smoking, alcohol consumption, body mass index (BMI) (as a marker of excess fat), and physical activity. The low-risk group was made up of people who’d never smoked or had smoked for only a few years (< 5 pack-years), those who consumed no or only moderate amounts of alcohol (≤ 1 drink/day for women and ≤ 2 drinks/day for men), those who had a BMI between 18.5 and 27.5, and those who engaged in at least 75 minutes of vigorous aerobic physical activity or at least 150 minutes of moderate-intensity activity per week. Participants who did not meet all of these criteria were classified as high risk.

Cancer incidence and mortality rates were compared between the groups and against the US population to estimate the proportion of cancer that could be prevented in the high-risk group (attributable risk) and the proportion that could be prevented in the US population. The attributable risks varied by type of cancer, from a high of 82% for lung cancer risk in women (78% in men) to lows of 4% for breast cancer, and 21% each for endometrial, ovarian, and fatal prostate cancer. Estimates were even higher in the US population, ranging from a high of 85% for lung cancer risk in women to a low of 15% for breast cancer. The authors estimate that nearly half of all new cancer diagnoses and over half of cancer deaths could be prevented in the United States through lifestyle changes.

Writing in an editorial accompanying the study, Graham A. Colditz, MD, DrPH, and Siobhan Sutcliffe, PhD, conclude that cancer is preventable.

“In fact, most cancer is preventable, with estimates as high as 80% to 90% for smoking-related cancers, such as lung and oropharyngeal cancer, and as high as 60% for other common, lifestyle-related cancers such as colorectal and bladder cancer,” they wrote.

Colditz and Sutcliffe note that the large excess of cancer is not inevitable but rather can be tackled by a broad range of interventions at many levels, from the individual to societal. Our challenge is to act on this knowledge, stop procrastinating, and embrace the opportunity to reduce our collective cancer burden by implementing effective cancer prevention strategies and changing the way we live.