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Overall US cancer deaths falling, but vary greatly by county

Cancer mortality in the United States decreased by more than 20% from 1980 to 2014, according to a study conducted by researchers from University of Washington and published in JAMA.

However, mortality rates tended to vary greatly by county, with greater mortality rates observed in 160 U.S. counties.

Christopher J.L. Murray

Further, despite the overall decrease in mortality rates, the study revealed sharp increases in liver cancer death rates.

“When looking at mortality rates at the county level, we discovered dramatic differences in mortality rates between different types of cancers and by geographic region,” Christopher J.L. Murray, MD, study researcher from the Institute for Health Metrics and Evaluation (IHME) at University of Washington, told HemOnc Today. “Certain regions saw great progress in reducing cancer deaths, and others fell behind, raising questions about access to care, prevention efforts and treatment.”

Behind heart disease, cancer is the leading cause of death both globally and in the United States. Most previous reports on geographic differences in cancer mortality in the United States focused on variation by state. However, Murray and colleagues evaluated data at the county level “because public health programs and policies are mainly designed and implemented at the local level.”

Using death records from the National Center for Health Statistics and population counts from the Census Bureau, the NCHS and the Human Mortality Database, researchers estimated mortality rates for 29 different cancers throughout the country.

Murray and colleagues found that overall rate of death from cancer decreased by 20.1% from 1980 to 2014, from 240.2 deaths per 100,000 people in 1980 (95% uncertainty interval [UI], 235.8-244.1) to 192 deaths per 100,000 in 2014 (95% UI, 188.6-197.7).

Disparities ‘unacceptable’

In 1980, the U.S. county with the lowest cancer mortality rate was Summit County, Colorado (130.6, 95% UI, 114.7-146.0), and the highest rate of cancer mortality was in North Slope Borough, Alaska (386.9, 95% UI, 330.5-450.7). In 2014, Summit County, Colorado again had the lowest cancer mortality rate in the country (70.7, 95% UI, 63.2-79.0), whereas Union County, Florida recorded the highest (503.1, 95% UI, 464.9-545.4).

Researchers reported that in 2014 there were clusters of high cancer mortality rates in several areas of Kentucky, West Virginia, Alabama, North Dakota, South Dakota, Texas and western Alaska, as well as along the Mississippi River. The lowest cancer death rates were reported in Utah and Colorado.

“Such significant disparities among U.S. counties in regards to cancer deaths are unacceptable,” Murray said. “Every person should have access to early screenings for cancer, as well as adequate treatment. For cancers with high survival rates, such as testicular cancer and Hodgkin lymphoma, wide differences in mortality rates in the United States should raise a red flag.

“It is essential that state and local health officials, as well as other health policy decision-makers and cancer care advocates, take note of and act on this important evidence to save more lives in their communities,” Murray added.

More than 19.5 million people in the United States died of cancer between 1980 and 2014. Of those, an estimated 5.6 million died of lung, bronchus or tracheal cancer; 2.5 million of colon or rectal cancer; 1.6 million of breast cancer; 1.2 million of pancreatic cancer; 1.1 million of prostate cancer; 829,000 of non-Hodgkin lymphoma; 487,000 of liver cancer; 422,000 of kidney cancer; 209,000 of uterine cancer; and 14,000 of testicular cancer. An additional 5.6 million cancer deaths were attributed to other cancer types.

The greatest decreases in cancer mortality from 1980 to 2014 were observed for testicular cancer (36.8% decrease); colon and rectal cancers (35.5%); breast cancer (32.7%); prostate cancer (21.7%); tracheal, bronchus and lung cancers (21%); and uterine cancer (16.1%). There was a slight decrease in deaths of pancreatic cancer (1.8%). Mortality rates remained virtually unchanged in kidney cancer and NHL.

Increase in liver cancer deaths

Conversely, there was a significant 87.6% rise in liver cancer mortality rates from 1980 (3.6; 95% UI, 3.5-3.8) to 2014 (6.8; 95% UI, 6.6-7.1). Almost all U.S. counties (3,069) showed significant increases in liver cancer death rates, with the highest rates observed in California, Oregon, Washington and Texas, along with Native American populations in South Dakota, New Mexico and Alaska.

“Liver cancer mortality increased in nearly every county, and clusters of counties with large increases were found,” Murray said. “Although alcohol is a well-known risk factor for liver cancer, the counties with high or increasing death rates differ from those known for high rates of alcohol consumption, warranting further investigation on the root causes of this cancer.”

Lung cancer in the South

Deaths from lung, bronchus and tracheal cancers declined steadily from 1980 to 2014, with the West, Northeast and Florida showing the greatest improvement. However, deaths rose in the South and Appalachian regions, along with the Midwest, with the greatest increase reported in Owsley County, Kentucky (99.7%; 95% UI, 73.7-130.8). The highest mortality rates from lung, bronchus and tracheal cancers were observed in Kentucky and West Virginia.

“Lung cancer kills more people in the United States than any other cancer, but death rates are more than 20 times higher in some parts of the country than others,” Murray said. “Fewer Americans smoke today than in previous decades, but parts of the South and many rural areas still show high rates of this deadly habit. It is not surprising that these same areas show high rates of lung cancer, especially within states like Kentucky, Tennessee, Alabama, Missouri, Arkansas, Mississippi and rural Alaska.”

Most U.S. counties had significant declines in breast cancer mortality, with Summit County, Colorado (55.3%) and Nassau County, New York (54.9%) showing the strongest improvement. Clusters of high rates of breast cancer remained in the southern belt and along the Mississippi River.

Behavioral risks

Murray said his team’s study did not examine the association or causation of environmental factors that may drive cancer mortality.

“However, in the Global Burden of Disease study, a collaborative study coordinated by IHME, we found that in the United States, behavioral risks account for approximately 38% of the total cancer burden, with environmental risk accounting for approximately 1%,” Murray said.

“There are several likely explanations for high or increasing rates of cancer mortality in particular regions of the United States, but these factors warrant further investigation. Known cancer risk factors — smoking, diet and obesity, among others — combined with poor prevention programs may increase cancer cases. Unequal access to and quality of care are likely contributors to cancer mortality disparities, and the resulting lack of early detection for some cancers and lack of specialized treatment can be deadly.”

The data provide valuable information on what geographical regions require interventions to improve cancer outcomes, Stephanie B. Wheeler, MD, PhD, and Ethan Basch, MD, MSc, both of University of North Carolina Chapel Hill, wrote in an invited commentary.

“It is difficult to ignore that many of the regions with the worst cancer outcomes correspond to areas of greatest electoral support for the incoming presidential administration, raising hopes that future policies developed by the incoming administration will provide resources for public health interventions for this constituency,” they wrote. “These are precisely the regions and people with the greatest potential for better cancer outcomes through primary prevention, screening/early detection, and timely treatment. Shifting the socioeconomic landscape in these regions may not be possible in the short term, so at a minimum, to be successful, physicians, politicians, and patients must acknowledge that it is important to ensure that cancer prevention and control strategies are of low cost or no cost, convenient in terms of hours and location, understandable, compelling, and part of normative behavior.”

Because the barriers to screening, prevention and treatment vary from county to county, interventions to improve outcomes in counties with high mortality rates should be individualized, they added.

“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 wrote. – by Chuck Gormley

For more information:

Christopher J.L. Murray, MD, DPhil, can be reached at cjlm@uw.edu.

Disclosure: Murray reports no relevant financial disclosures.