More than half of the 26 percent decline in cancer mortality rates in the U.S. since 1991 is due to reductions in tobacco smoking.
On Oct. 10, the Society published our second in a series of articles in CA: A Cancer Journal for Clinicians that collectively will outline our vision for cancer control for the U.S. through 2035. Titled A Blueprint for the Primary Prevention of Cancer: Targeting Established, Modifiable Risk Factors, this second article in the series focuses on existing evidence about established, modifiable risk factors for cancer, the cancer burden in the United States due to each risk factor, and established primary prevention recommendations and interventions to reduce exposure to each risk factor.
The report was led by Susan M. Gapstur, PhD, MPH, our SVP of Behavioral and Epidemiology Research (pictured here).
"A comprehensive cancer control plan designed to support the implementation of evidence-based interventions, including cancer prevention interventions like those we described has enormous potential to substantially reduce the number of individuals diagnosed with and dying from cancer," said Susan. "It is the responsibility of government and industry as well as the public health, medical, and scientific communities to work together to invest in and implement a comprehensive cancer control plan at the national level and support and expand ongoing initiatives at the state and local levels. If we fail to do so, we will slow progress in our national efforts to reduce the burden of cancer."
In specific, the report focuses on several important modifiable risk factors:
- Tobacco: More than half of the 26 percent decline in cancer mortality rates in the U.S. since 1991 is due to reductions in tobacco smoking. Despite this progress, tobacco smoking (active and second-hand smoke) remains the most common cause of cancers diagnosed (19.4 percent) and cancer death (29.6 percent). Moreover, the annual direct health care costs of tobacco in the U.S. are estimated to be $170 billion, and tobacco use results in $156 billion in lost productivity. There is considerable evidence that tobacco control can prevent more cancer deaths than any other primary prevention strategy. The demographic profile of today's smoker has changed over the last half century. Today, tobacco use is more prevalent among persons with lower educational attainment; lower income; within vulnerable populations, such as individuals with mental illness or addiction to other substances; within the Lesbian, Gay, Bisexual, Transgender (LGBT) community; and within certain racial or ethnic groups. Enhanced efforts to reach groups that are more likely to smoke are needed to further reduce the prevalence of tobacco use.
- Obesity and overweight: In the U.S., approximately, 7.8 percent of cancer cases in 2014 were attributed to excess body fatness, second only to cigarette smoking. Its contribution was higher among women (10.9 percent of cases) than among men (4.8 percent of cases). Among women, 60.3 percent of uterine cancer and, among men and women combined, more than 30 percent of gallbladder, liver, and kidney/renal cancers as well as esophageal adenocarcinoma were attributed to excess body fatness. Despite clear evidence that excess body fatness contributes substantially to cancer risk, the full impact of the obesity epidemic on the cancer burden, including the long-term effect of obesity that begins in childhood, is yet to be completely understood.
- Alcohol: Alcohol is the third most-important major modifiable contributor to cancer, associated with 6.4 percent of cancers in women and 4.8 percent of cancers in men in 2014. However, for some cancers, the attributable fraction exceeds 10 percent; among men and women combined, an estimated 40.9 percent of oral cavity/pharynx cancers, 23.2 percent of larynx cancers, 21.6 percent of liver cancers, 21 percent of esophageal cancers, and 12.8 percent of colorectal cancers were attributed to alcohol consumption. Notably, among women, alcohol intake accounted for 16.4 percent of all cases, or 39,060 breast cancers in 2014.
- Diet: The combination of low calcium, fiber, and fruit and vegetable intake and high red and processed meat intake is estimated to cause 4.2 percent of cancers among men and women combined. However, there was considerable variation across specific dietary factors and types of cancer. For example, 5.4 percent of colorectal cancers are associated with high red meat consumption causes, 8.2 percent with high processed meat consumption, and 10.3 percent and 4.9 percent for low dietary fiber and calcium consumption, respectively. Low fruit and vegetable consumption was attributed to 17.6 percent and 17.4 percent of oral cavity/pharynx and larynx cancers, respectively. A lack of clear evidence about the role of early life dietary exposures as well as many other dietary hypotheses means the percentage of cancers attributable to diet may continue to rise beyond current estimates once more is known.
- Physical inactivity: It is estimated that 2.9 percent of all cancer cases in the U.S. in 2014 were attributable to low physical activity, with the contribution greater among women (4.4 percent) than among men (1.5 percent). The cancer with the highest percentage related to low physical activity was uterine cancer (26.7 percent), followed by colorectal cancer (6.3 percent among men and women combined). As additional cancer types are determined to be causally associated with low amounts of physical activity, the total number of cancer cases attributed to low physical activity will continue to rise.
For more information about this chapter and our Blueprint for Cancer Control in the 21st Century, please see the resource list, below. Subsequent Blueprint chapters will focus on screening, treatment, survivorship, and research and will be released in the coming months.