Overall Cancer Incidence and Death Rates Fall Significantly in the United States
November 25, 2008 —The incidence and death rates for all cancers combined have decreased significantly for both men and women in the United States, according to an annual report from the nation's leading cancer organizations. The findings are published online November 25 in the Journal of the National Cancer Institute.
The Annual Report to the Nation on the Status of Cancer is a combined effort of the American Cancer Society, the Centers for Disease Control and Prevention (CDC), the National Cancer Institute (NCI), and the North American Association of Central Cancer Registries. Data in the report run through 2005.
Cancer death rates have been dropping since the publication of the first report 10 years ago. However, the latest report is the first time that there is also a simultaneous decline in cancer incidence for both men and women.
The overall decreases are driven by declines in both incidence and death rates for the 3 most common cancers in men (lung, colorectal, and prostate) and for 2 of the 3 leading cancers in women (breast and colorectal), along with a leveling off of women's lung cancer death rates.
The drop in rates is encouraging but needs interpretation, suggested Otis W. Brawley, MD, chief medical officer of the American Cancer Society.
"The drop in incidence seen in this year's annual report is something we've been waiting to see for a long time," he said in a statement. "However, we have to be somewhat cautious about how we interpret it, because changes in incidence can be caused not only by reductions in risk factors for cancer, but also by changes in screening practices."
One of the coauthors of the report said that a continued decline in overall cancer incidence and death rates is not guaranteed. "We could lose these gains if we don't continue to pay attention to screening, prevention, and treatment," said Christine Eheman, PhD, chief of the cancer surveillance branch of the CDC, in an interview with Medscape Oncology.
When asked about potential federal budget restraints on cancer efforts in the near future, Dr. Eheman said: "We will be undaunted and move forward with our partners," such as state governments.
The generally positive report sounded an alarm about lung cancer in women in certain areas of the country. "Large state and regional differences in lung cancer trends among women underscore the need to maintain and strengthen many state tobacco-control programs," write the authors.
Report Details: Death Rates
Rates for all cancers combined decreased 0.8% per year from 1999 through 2005. The rates decreased 1.8% per year from 2001 through 2005 for men and 0.6% per year from 1998 through 2005 for women.
From 1996 through 2005, death rates for all cancers combined decreased for all racial and ethnic populations, except for American Indian/Alaska Native men and women, for whom rates were stable.
The decrease in death rates has been sharper for men, who have higher rates than women. Death rates declined for 10 of the top 15 causes of cancer death among both men and women. However, death rates for some individual cancers are increasing, including esophageal cancer for men, pancreatic cancer for women, and liver cancer for both men and women. Overall cancer death rates were highest for African Americans and lowest for Asian American/Pacific Islanders.
Report Details: Incidence Rates
Among men, incidence rates dropped for cancers of the lung, colon/rectum, oral cavity, and stomach. Prostate cancer incidence rates decreased by 4.4% per year from 2001 through 2005, after increasing by 2.1% per year from 1995 to 2001. In contrast, incidence rates increased for cancers of the liver, kidney, and esophagus, as well as for melanoma (2003–2005), non-Hodgkin's lymphoma, and myeloma. Incidence rates were stable for cancers of the bladder,pancreas, and brain/nervous system, and for leukemia.
For women, incidence rates dropped for cancers of the breast, colon/rectum, uterus, ovary, cervix, and oral cavity, but increased for cancers of the lung, thyroid, pancreas, brain/nervous system, bladder, and kidney, as well as for leukemia, non-Hodgkin's lymphoma, and melanoma.
Incidence rates are less likely to trend as predictably as death rates, suggested Barry A. Miller, DrPH, an epidemiologist in the Division of Cancer Control and Population Sciences at the NCI. "Incidence rates for new diagnoses of cancer can change more quickly from year to year than what we see with death rates. The reason for this is that changes in incidence can result not only from changes in risk factors, but also from changes in screening practices," he told Medscape Oncology.
A recent example of changes in incidence resulting from a change in risk factors is the "sharp declines in breast cancer incidence in 2002–2003 following the reduced use of hormone-replacement therapy," says the report.
The report also describes recent changes in incidence rates due to changes in screening practices, including for colorectal cancer. "The accelerated decline in the colorectal cancer incidence rate since 1998 may be associated with increased use of colorectal cancer screening, which prevents cancer through removal of precancerous adenomatous polyps," says the report. Between 2000 and 2005, the percentage of adults 50 years and older who reported having had a colonoscopy increased from 20% to 39%, say the authors.
Women and Smoking
The report provides a historic view of the reason men's death rates for lung cancer have decreased and women's have only leveled off. "These temporal differences reflect the later uptake of cigarette smoking among women, who began smoking predominantly during and after World War II, compared with men, who began cigarette smoking in the early 20th century."
However, the report highlights the importance of regional variation in smoking. "Less attention has been paid to the prominent state and regional variations in the trends in lung cancer and tobacco use in men and women, particularly as these relate to various indices of state tobacco-control activity," write the authors.
California is a great example of the way states can have varied lung cancer death rates. California was the first state in the United States to have a comprehensive statewide tobacco-control program and has made the greatest progress in reducing tobacco use. According to the report, the average percentage decrease in the lung cancer death rate among men in California from 1996 through 2005 (2.8% per year) is more than twice that of many states in the Midwest and South.
Notably, geographic variations are outstanding among women, for whom the lung cancer death rate increased from 1996 through 2005 in 13 states and decreased in only 3. California was the only state with decreasing lung cancer incidence and death rates in women.
The report cites a number of reasons that the incidence and death rates related to lung cancer have not decreased nationally for women. They include the facts that incidence and death rates are increasing for groups 70 years and older, and that smoking cessation rates are historically lower in women than in men, especially at older ages.
The researchers have disclosed no relevant financial relationships.
J Natl Cancer Inst. 2008;100:1672-1694.