More people are surviving cancer than ever before as cancer death rates continue to decrease, yet incidence of several cancers related to obesity are on the rise, finds the the latest national report on cancer.
The Annual Report to the Nation on the Status of Cancer, 1975-2014, overall has positive news showing cancer death rates are decreasing, due in large part to early detection and treatment. During the period 2010-2014, which has the most available data. mortality decreased for 11 of the 16 most common types of cancer in men and for 13 of the 18 most common types of cancer in women, including lung, colorectal, female breast, and prostate cancers. Several but not all cancer types showed a significant improvement over time for both early- and late-stage disease, and varied significantly by race/ethnicity and state.
The report was published in the Journal of the National Cancer Institute (JNCI) and includes a special section on cancer survival.
Survival rates increasing
Compared to cases diagnosed in 1975-1977, five-year survival for cancers diagnosed in 2006-2012 increased significantly for all but two types of cancer: cervix and uterus. Cancers with the lowest five-year relative survival for cases diagnosed during this time period were pancreas, liver, lung, and esophageal; those with the highest were prostate, thyroid, melanoma, and female breast.
Increasing survival over time reflects progress in treatment and these must be interpreted in a broader context due to biases related to screening and early detection the report notes. For example, cancer screening may lengthen time of survival by moving back the time of diagnosis without altering the date of mortality. Screening may also lead to overdiagnosis by finding cancers that never would have been clinically detected during that person’s lifetime.
Survival varied substantially by race/ethnicity and state. In general, survival for common cancers, such as breast and colorectal, tended to be lowest in select Southern and Midwestern states and highest in Northeastern states.
Incidence for many cancers
Yet while more women are surviving breast cancers, this remains the most common cancer among US women of all racial and ethnic groups and rates of this cancer are increasing. For breast cancer incidence there was an increase of 0.4% per year over the past five years.
Overall for women, incidence rates from 2009 to 2013 remained the same for all cancers. Of note is the increasing rates for 9 of the 18 most common cancers. Liver cancer among women increased by 3.8 percent per year over the past five years, replacing thyroid cancer as the most rapidly increasing cancer among women.
Among men, rates of new cancers developing decreased by 2.3% per year.
Incidence rates may also reflect changes in detection. For example, prostate cancer incidence rates decreased after the US Preventive Services Task Force recommended against routine PSA testing among men age 75 years or older (2008) and in men age 50 years or older (2011).
Obesity is likely fueling some of the increases in incidence, such as the continued increase in liver cancer rates. This is also likely due to the high prevalence of chronic hepatitis C virus infection, the authors write. Obesity also may have contributed in part to the increases in endometrial, pancreas, and kidney cancer incidence rates.
This report found that tobacco-related cancers have low survival rates, which underscores the importance of continuing to do what we know works to significantly reduce tobacco use,” said Lisa C. Richardson, M.D., M.P.H., director of CDC’s Division of Cancer Prevention and Control, in a news release. “In addition, every state in the nation has an adult obesity prevalence of 20 percent or more. With obesity as a risk factor for cancer, we need to continue to support communities and families in prevention approaches that can help reverse the nation’s obesity epidemic.”
The report was supported by the American Cancer Society (ACS), the Centers for Disease Control and Prevention (CDC), the National Cancer Institute (NCI), and the North American Association of Central Cancer Registries.
AICR research has found that excess body fat is a cause of 11 cancers, including post-menopausal breast and colorectal.
Joan Lappe, Patrice Watson, Dianne Travers-Gustafson, Robert Recker, Cedric Garland, Edward Gorham, Keith Baggerly, Sharon L. McDonnell. Effect of Vitamin D and Calcium Supplementation on Cancer Incidence in Older Women. JAMA, 2017; 317 (12): 1234