Mortality rates from cancer in the United States have declined substantially during the past 3 decades, but there is still substantial regional variation in cancer-specific mortality rates across many counties, new research shows.
"Most previous reports on geographic differences in cancer mortality have focused on variation by state, with less information available at the county level," lead author Ali Mokdad, PhD, Institute for Health Metrics and Evaluation, the University of Washington, in Seattle, and colleagues report.
"And we found that cancer mortality decreased by a relative 20.1% between 1980 and 2014; however, there were substantial differences among counties through the period [and] for many cancers, there were distinct clusters of counties in different regions with especially high mortality," investigators add.
The study was published online January 24 in JAMA.
Investigators used death records from the National Center for Health Statistics (NCHS) along with population counts from the Census Bureau, the NCHS, and the Human Mortality Database to tabulate cancer deaths and population by county, among other variables.
"From 1980 to 2014, 19,511,910 cancer deaths were recorded in the United States," the authors report. Mortality rates dropped from 240.2 deaths per 100,000 population in 1980 to 192.0 per 100,000 population in 2014.
In 1980, the lowest cancer-related mortality rate, at 130.6 deaths per 100,000 population, was in Summit County, Colorado. The highest cancer-specific mortality rate was 386.9 per 100,000 population in North Slope Borough, Alaska.
In 2014, cancer-related death rates were again lowest in Summit County, Colorado. They were highest in Union County, Florida, where cancer-related death rates soared to 503.1 per 100,000 population.
Furthermore, "there were statistically significant increases in cancer mortality between 1980 and 2014 in 160 counties," Dr Mokdad and colleagues write, "with the highest rates of increase observed in Kentucky and scattered across regions of the South."
Cancer-Specific Mortality Rates
The cancer types with most deaths (a total of 5.7 million persons died between 1980 and 2014 from tracheal, bronchial, and lung cancer) showed a decline in mortality by 21% during the same period. The biggest increase from these site-specific cancers was documented in the South, the Appalachian region, and the Midwest. The biggest increase occurred in Owsley County, Kentucky, where it were it went up almost 100% between 1980 and 2014.
"Mortality from colon and rectum cancer declined by 35.5% [between 1980 and 2014]," the investigators write. Significant declines in colorectal cancer death rates were documented in most counties during the study period. In 2014, the highest death rate from colorectal cancer was again recorded in Union County, Florida, at 58.4 per 100,000, compared to the lowest rate of 8.1 per 100,000, again seen in Summit County, Colorado.
Clusters of high rates of colorectal cancer deaths were also documented along the Mississippi River in Missouri, Arkansas, and Louisiana, although such clusters were not limited to these regions alone, the investigators note.
Across the nation, mortality rates from breast cancer dropped by almost one third between 1980 and 2014, and they dropped significantly in most counties as well. The largest reductions in breast cancer–specific mortality were again recorded among women in Summit County, Colorado, as well as in women living in Nassau County, New York. Breast cancer mortality rates remained high in the southern belt and along the Mississippi River.
As for prostate cancer, mortality rates declined by 21.7% during the study period, from 13.0 to 10.2 per 100,000, although much more significant declines in prostate cancer death rates were documented in the Aleutians East Borough and the Aleutians West Census Area, Alaska.
Overall, mortality from prostate cancer varied from a low of 64.1 deaths per 100,000 in Madison County, Mississippi, to 10.0 deaths per 100,000 in Summit County, Colorado.
Less Common Cancers
Changes in mortality rates for a number of less common cancers ranged from minimal to major during the 3 decades analyzed. For example, the death rate from pancreatic cancer was only 1.8% lower in 2014 than it was in 1980.
On the other hand, an increase in pancreatic cancer–specific deaths was documented across the United States, with clusters of larger increases in Kentucky, Kansas, and northeastern Pennsylvania, although mortality rates decreased in southern Texas, California, and the Dakotas.
"Uterine cancer mortality declined in the United States by 16.1%," the investigators continue, but the decline in uterine cancer deaths was "not steady," they add. For example, increases in clusters of uterine cancer deaths were seen with northern Maine, Iowa, Texas, the Carolinas, Virginia, and West Virginia.
In contrast, larger decreases in uterine cancer–related morality were seen in many counties in California and Arkansas, among others.
Deaths from kidney cancer remained "essentially unchanged from 1980 to 2014," although some counties, including those in the Northeast and southern Florida, recorded "considerable" declines in kidney cancer death rates.
Bucking the general trend of a decline in mortality from cancer across the United States were mortality rates from liver cancer, which increased by more than 87% from 1980 to 2014. Almost all counties reported significant increases in mortality rates from liver cancer, Dr Mokdad and colleagues report.
The largest decreases in cancer-related mortality rates were from testicular cancer, which dropped by almost 37% from 1980 to 2014. At study endpoint, mortality from testicular cancer accounted for only to 0.1 deaths per 100,000 across the nation. Again, however, declines in death rates from testicular cancer varied substantially across counties, from as much as a 72% decline in some counties to increases of almost 40% in others during the study period.
Mortality rates from non-Hodgkin lymphoma remained "essentially unchanged" between 1980 and 2014, although rates increased in clusters of counties in some regions and declined in others.
Possible Explanations
The investigators point out that high cancer mortality rates in certain counties and regions could reflect a combination of a high risk-factor profile of its residents and inadequate prevention and screening programs.
Alternatively, cancer mortality rates in these high-cluster counties might reflect inadequate or lack of screening for preventable cancers, poor awareness of cancer and its symptoms among its citizens, and poor access or a lack of access to healthcare.
It could be that for persons diagnosed with cancer in areas where mortality rates are high, the treatments are not optimal.
Accompanying Editorial
In an accompanying editorial, Stephanie Wheeler, PhD, MPH, University of North Carolina at Chapel Hill, and Ethan Basch, MD, Lineberger Comprehensive Cancer Center, University of North Caroline at Chapel Hill, write that the value of the data provided by Dr Mokdad and colleagues lies in their ability to support both scientific and public health initiatives in counties where they are most needed.
"Colorectal, lung, breast, and prostate cancers collectively account for a substantial proportion of life years lost within all cancers and are among the most preventable and treatable," Dr Wheeler and Dr Basch observe.
Much research has been directed toward strategies to prevent and treat these malignancies, they acknowledge, but "there has been limited work to understand how to effectively implement those strategies in real-world settings."
Currently, at least some of the $1.8 billion earmarked for the Cancer Moonshot program during the next 7 years will be directed toward implementation science.
The editorialists suggest that cancer-related mortality data go a long way toward identifying cancers such as pancreatic cancer, for which little progress has been made over time. To this end, the National Cancer Institute has been directed to issue funds through the Recalcitrant Cancer Act of 2012 to increase research into rare, lethal diseases, the editorialists point out.
The analysis provided by Dr Mokdad and colleagues also allows authorities at the county level to identify "hot spots" where cancer patients do not benefit from treatment as much as they might. Special efforts are needed in these counties to ensure that public health interventions and supportive policies improve outcomes for people with cancer, Dr Wheeler and Dr Basch suggest.
Some steps are already making a difference in cancer management in a number of the hot spots identified by the current analysis. "For example, in rural Appalachian counties, use of lay health advisors and patient navigators has improved mammography rates," the editorialists point out.
The same approach has also reduced time to definitive diagnosis for patients undergoing breast, cervical, and colorectal cancer screening as well as PAP testing, especially among high-risk women, they add.
Linguistically appropriate strategies have also been introduced in a number of regions where there are growing communities of Spanish-speaking citizens, who tend to be at higher risk for colorectal cancer mortality than others.
In addition, peer support initiatives targeting African American neighborhoods in Alabama have increased rates of screening mammography, and human papillomavirus DNA testing performed at home offers another novel way to reach women living in the Mississippi Delta, where mortality rates from cervical cancer are high.
"The reality is that barriers to cancer prevention and control are not one size fits all in communities with higher cancer mortality," Dr Wheeler and Dr Basch conclude.
"Therefore, policies and interventions targeting those regions cannot be one size fits all," they add.
"[Rather,] effective strategies in these regions must be tailored to address specific barriers to care, respond to local community needs and expectations, and attend to local community resource capacity constraints, cultural norms, and leadership, governance, and social network structures," they state.
The study was funded by the Robert Wood Johnson Foundation, the National Institute on Aging, and John W. Stanton and Theresa E. Gillespie. The study authors and Dr Basch have disclosed no relevant financial relationships. Dr Wheeler has received receiving research funding from Pfizer.
JAMA. Published online January 24, 2017. Full text, Editorial
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Cite this: Cancer Death Rates Down, but Big Variation Across US - Medscape - Jan 25, 2017.
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