Experts say cancer rates are dropping, but it’s not all good news. More and more Americans are living lifestyles that put them at elevated risk for various kinds of cancer.
Over the decade covered by the study, starting 1999, overall cancer incidence in the United States has declined by a significant amount, particularly among men. The death rate for adult cancer patients has also gone way down across all demographic groups. The effect was most marked or the period after 2004.
However, certain cancers are getting worse, and researchers say it’s because many Americans are living unhealthy lives. Obesity and inactivity can mean bad news for cancer survivors and worsen prognoses for patients.
“In the U.S., two in three adults are overweight or obese, and fewer than half get enough physical activity. Between children and youth, one in three is overweight or obese, and fewer than one in four high school students get recommended levels of physical activity,” said American Cancer Society head John R. Seffrin in a statement.
“For people who do not smoke, excess weight and lack of sufficient physical activity may be among the most important risk factors for cancer.”
In particular, six kinds of cancer—esophageal, colorectal, kidney, pancreatic, endometrial, and postmenopausal breast cancer—were linked with obesity and lack of physical activity. Even among these six, results were somewhat inconsistent, however.
For childhood cancers the news was somewhat grimmer. Children showed a slight rise in cancer cases over the study period, though mortality went down as much as in adults.
Despite the general decline, rates of melanoma and of pancreatic, kidney, thyroid, and liver cancer increased during the period. Breast cancer declined over the decade but rose slightly after 2004.