The death rate from all cancers combined in the United States has dropped by 25% over the past 2.5 decades, although cancer incidence and mortality rates are typically higher in men and racial disparities still exist, a Cancer Statistics 2017 report indicates.
However, liver cancer continues to increase in the United States, as has been reported previously by Medscape Medical News.
"Cancer death rates peaked in the United States in 1991 and they've gone down 1 to 2% every year ever since," Otis Brawley, MD, chief medical officer, American Cancer Society, Atlanta, Georgia, said in a prepared audio clip for the press.
"That actually equates to 2.1 million cancer deaths that did not happen over that time period and the drop is the result of a steady reduction in smoking as well as advances in early detection and treatment," he added.
The report was published online January 4 in CA: A Cancer Journal for Clinicians.
Rebecca Siegel, MPH, strategic director, American Cancer Society, and colleagues used incidence data from the Surveillance, Epidemiology, and End Results Program; the National Program of Cancer Registries; and the North American Association of Central Cancer Registries to project the number of new cancer diagnoses that will be made across the country in 2017.
At the same time, they used mortality statistics from the National Center for Health Statistics to project cancer-related mortality rates over the same year.
Researchers estimated that the number of new invasive cancers that will be diagnosed across the United States in 2017 will total 1,688,780, which works out to over 4600 new cancer diagnoses a day.
"An estimated 600,920 Americans will die from cancer in 2017," researchers add, "corresponding to about 1,650 deaths per day."
For women, cancers most likely to cause death will include those of the lung and bronchus as well as breast and colorectal cancer.
For men, the most common cause of cancer death will again include cancer of the lung, bronchus, and colorectum as well as prostate cancer.
Indeed, "these 4 cancers account for 46% of all cancer deaths, with more than one-quarter (26%) due to lung cancer," investigators observe.
Lung Cancer Incidence
Interestingly, the incidence of lung cancer will continue to drop almost twice as fast in men as it will in women, reflecting the fact that women started smoking later and at an older age than men. Women have also been slower to quit.
Breast cancer in turn is expected to figure in approximately 30% of all new cancer diagnoses in women in 2017, researchers point out.
"In contrast, incidence patterns for colorectal cancer are very similar in men and women, with rates declining by 3% per year from 2004 through 2013," the investigators state
The recent rapid declines in the incidence of colorectal cancer are thought to be due to an increase in people being screened for colorectal cancer and the simultaneous removal of precancerous polyps, if present. In fact, colonoscopy use among adults 50 years of age and older has increased from 21% in the year 2000 to 60% in 2015.
In contrast, incidence rates of colorectal cancer have increased by about 2% a year between 1993 and 2013 in those younger than age 50 years, an age group for whom screening is not routinely recommended.
Liver Cancer Continues to Increase
Liver cancer is also increasing by about 3% a year in women and 4% a year in men. As Dr Brawley observed, there is a lot more hepatitis C in men than women.
"As a result, we have a lot more liver cancer," he observed. "Men also have more alcohol consumption," Dr Brawley added. "And alcohol unfortunately is a driver of cancer as well."
In fact, overall incidence rates of invasive cancer are about 20% higher in men than in women, and mortality rates are approximately 40% higher in men. These higher rates are at least in part due to higher rates of liver cancer in men, which is a highly fatal malignancy. Men are also more likely to develop cancer of the esophagus, larynx, and bladder, all of which are also associated with high mortality rates.
The incidence of melanoma is also about 60% higher in men than in women, even though incidence rates of melanoma appear to be slowing overall.
As for thyroid cancer, the incidence appears to have stabilized in recent years following guideline recommended to take a more conservative approach to its diagnosis, as researchers point out.
"For a long time, we've looked at black/white differences [in cancer rates], and the good news is that black/white differences are going down for both men as well as women over the last few years," Dr Brawley observed.
This is due in part to better access to care among blacks made possible by the Affordable Care Act, he added.
For example, "over the past 3 decades, the 5-year relative survival rate for all cancers combined has increased 20 percentage points among whites and 24 percentage points among blacks," as study authors point out.
Nevertheless, cancer-related mortality was still 15% higher in blacks than in whites in 2014. In 1990, the racial disparity between cancer death rates in black men and white men was as large as 47%.
"[T]hat gap had narrowed to 21% in 2014...[and] racial disparity has declined similarly in women, from a peak of 20% in 1998 to 13% in 2014," the study authors write.
Poor Survival for Lung and Pancreatic Cancers
Not all is good news on the cancer front. The 5-year relative survival rate for lung cancer continues to be poor at only 18%, and it's even worse, at 8%, for pancreatic cancer. These poor survival odds reflect the fact that at least 50% of patients with lung and pancreatic cancer are diagnosed at a very late stage and only a handful of patients with either malignancy can be expected to survive out to 5 years.
Geographic gaps in cancer incidence also persist, largely due to smoking. For example, lung cancer rates are highest in Kentucky, where smoking rates remain high, and lowest in Utah, where smoking rates remain low.
Rates of cancer in children and adolescents also appear to have stabilized over recent years. In fact, relative survival rates at 5 years for all cancers combined in both children and adolescents have improved to over 80% between 2006 and 2012, although survival rates vary greatly by cancer type and age at diagnosis, as researchers point out.
Need to Improve on Prevention
"The continuing drops in the cancer death rate are a powerful sign of the potential we have to reduce cancer's deadly toll," Dr Brawley said in a statement, adding that if there was one thing that he could focus on he would try to increase efforts to prevent cancer across the United States.
"One of the things that we've not done really well in the United States is actually work to prevent cancer," he said.
"So much of our focus has been on screening for it and treating cancer, we've not done that as well as we should have, but we certainly have not done the aspect of prevention as well as we should have. I really wish that we could have a greater emphasis on coaching people on diet and exercise and a greater emphasis on coaching people regarding not smoking or, if they are smoking, how to stop smoking," he added.
CA Cancer J Clin. Published online January 5, 2017.
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