About one-third of the 565,650 cancer deaths expected to occur in the United States this year can be attributed to lifestyle factors, like overweight and obesity, poor nutrition, and physical inactivity, and another 170,000 deaths will be caused by tobacco use alone, the report shows. The numbers magnify a trend seen last year: progress in curbing the number of deaths attributed to these causes appears to be slowing, if not stalling.

"Earlier this year, we reported that death rates from cancer in the United States have dropped by 18.4 percent among men and 10.5 percent among women since mortality rates began to decline in the early 1990s, translating into more than half a million cancer deaths avoided in the United States," said Otis W. Brawley, MD, national chief medical officer of the American Cancer Society. "If we want these gains to continue, we need comprehensive, systematic efforts to reduce tobacco use, to address the epidemic levels of obesity in this country, and to make sure all Americans have access to and receive established cancer screening tests."

The report, Cancer Prevention and Early Detection Facts and Figures 2008 (CPED), provides an overview of current statistics on controllable cancer risk factors and outlines ways for improving cancer prevention and early detection efforts at the local, state, and national level. It has been published annually since 1992.

Smoking rates steady

Thirty percent of cancer deaths are linked to tobacco use, yet as of 2006, 23.9% of men and 18.0% of women still smoked, numbers that have hovered around the same mark for the last 2 years. As of 2005, 23% of high school students smoked--a rate that has leveled off after declining from 1997 to 2003. Cigar smoking has been rising since 1993; use of smokeless tobacco products, such as snuff, has remained constant since 2000. According to the report, some possible explanations for this steady tobacco use include increases in marketing efforts by tobacco companies, declines in funding for state tobacco control programs, and the proliferation of cigarette price discounts.

Smoking rates are particularly high among certain populations (Alaska Natives and American Indians have the highest prevalence rates) and in lower income and education brackets (adults without a high school diploma are about 3 times more likely to be current smokers than those with a college degree).

Currently, 25 states have a state excise tax less than $1.00 per pack of cigarettes. Six of the 10 states with the lowest excise tax (less than $1.00 per pack) are among the 10 states with the highest lung cancer rates in men (Kentucky, Mississippi, Tennessee, Louisiana, South Carolina, and Missouri). Although 43 states and the District of Columbia have increased their cigarette taxes since 2000, only 23 states have laws requiring that a portion of their excise taxes be used for health, cancer control, or tobacco control programs.

Good news comes from Maine, Washington, and New York, states whose tobacco control programs brought declines in smoking rates of 15-25% among adults and 40-65% among youth. More needs to be done at the federal, state, and local levels to enact smoke-free legislation, promote cessation messages and interventions, and further regulate the tobacco industry, the report says.

A big problem

Overweight and obesity contribute to 14%-20% of all cancer deaths. The report shows 34% of men and 36.4% of women met the criteria for obesity in 2005-2006; overweight prevalence among US adolescents aged 12 to 19 more than tripled in the past 20 years, from 5% to 17.1%. Poor nutrition and physical inactivity are largely to blame.

To reduce cancer risk, the American Cancer Society recommends Americans maintain a healthy weight throughout life, adopt a physically active lifestyle (30 minutes of moderate physical activity 5 days a week is recommended for adults; 60 minutes for children and adolescents), and eat a healthy diet, with an emphasis on plant sources. In 2005, only 24.3% of adults reported eating the recommended 5 or more servings of fruit and vegetables a day, and in 2006, 23.9% of adults reported no leisure-time physical activity. Among US youth, only 35.8% were physically active for at least 60 minutes 5 days a week in 2005, and only 1 in 5 (20.1%) US high school students ate vegetables and fruits 5 or more times per day.

The report outlines several measures for improving these dismal statistics, including increasing K-12 physical education requirements; limiting the marketing of high-sugar, high-fat foods in schools; encouraging more restaurants to post nutrition information; supporting community development that provides sidewalks, bike lanes, and green space; and increasing funding and resources for collaborative nutrition and physical activity plans to combat the obesity problem.

For more information on this topic, see Nutrition and Physical Activity Guidelines for the Prevention of Cancer.

In addition to modifying your diet and increasing your activity level, the report also includes information on another way to reduce cancer risk: wearing sunscreen or limiting sun exposure. Skin cancer is the most common of all cancer types, but it can be prevented by reducing UV exposure (see Skin Cancer Prevention and Early Detection). In a national 2005 survey of adults, just 28.3% reported always or often using sunscreen when outside for an hour or more on a sunny day, and 43.4% reported seeking shade.

Screening numbers still lagging

The American Cancer Society recommends annual mammograms for women starting at age 40 and colorectal cancer screening tests for men and women beginning at age 50, as well as other tests. (See the American Cancer Society Guidelines for the Early Detection of Cancer.) But many Americans aren't availing themselves of those exams.

After increasing for more than a decade, mammography rates have stabilized or even declined slightly since 2000. In one national survey, only 51.2% of women aged 40 and older reported having a mammogram within the past year; the percentages were lowest among immigrant women and those without health insurance.

Between 2000 and 2005, the number of US adults aged 50 and older who got colorectal cancer screening tests increased from 42.5% to 46.8%, due in part to expanded coverage by Medicare and private health insurance. However, prevalence varied considerably by population. Hispanics, immigrants who have been in the US for less than 10 years, and the uninsured were least likely to get screened.

For more information on reducing your cancer risk, see Tobacco and Cancer, Nutrition and Physical Activity Guidelines for the Prevention of Cancer, and the American Cancer Society Guidelines for the Early Detection of Cancer.