January 30, 2017Public Health
Cancer is a leading cause of morbidity and mortality in the United States which results in a high economic burden. As a result, a study published in the Journal of the American Medical Association (2017;317(4):388-406), was performed to estimate age-standardized mortality rates by US county from 29 cancers.
For the study, deidentified death records from the National Center for Health Statistics (NCHS) and population counts from the Census Bureau, the NCHS, and the Human Mortality Database from 1980 to 2014 were used. Validated small area estimation models were also used to estimate county-level mortality rates from 29 cancers including: lip and oral cavity; nasopharynx; other pharynx; esophageal; stomach; colon and rectum; liver; gallbladder and biliary; pancreatic; larynx; tracheal, bronchus, and lung; malignant skin melanoma; nonmelanoma skin cancer; breast; cervical; uterine; ovarian; prostate; testicular; kidney; bladder; brain and nervous system; thyroid; mesothelioma; Hodgkin lymphoma; non-Hodgkin lymphoma; multiple myeloma; leukemia; and all other cancers combined.
The main outcome measures were age-standardized cancer mortality rates by county, year, gender, and cancer type. A total of 19,511,910 cancer deaths were recorded in the United States between 1980 and 2014, including 5,656,423 due to tracheal, bronchus, and lung cancer; 2,484,476 due to colon and rectum cancer; 1,573,593 due to breast cancer; 1,077,030 due to prostate cancer; 1,157,878 due to pancreatic cancer; 209,314 due to uterine cancer; 421,628 due to kidney cancer; 487,518 due to liver cancer; 13,927 due to testicular cancer; and 829,396 due to non-Hodgkin lymphoma.
Results showed that cancer mortality decreased by 20.1% between 1980 and 2014, from 240.2 to 192.0 deaths per 100,000 population. However, there were large differences in the mortality rate among counties throughout the period: in 1980, cancer mortality ranged from 130.6/100,000 in Summit County, Colorado, to 386.9/100,000 in North Slope Borough, Alaska, and in 2014 from 70.7 in Summit County, Colorado, to 503.1 in Union County, Florida. For many cancers, there were distinct clusters of counties with especially high mortality. The location of these clusters varied by type of cancer and were spread in different regions of the United States. Clusters of breast cancer were present in the southern belt and along the Mississippi River, while liver cancer was high along the Texas-Mexico border, and clusters of kidney cancer were observed in North and South Dakota and counties in West Virginia, Ohio, Indiana, Louisiana, Oklahoma, Texas, Alaska, and Illinois.
According to the authors, while mortality declined overall in the United States between 1980 and 2014, over this same period, there were important changes in trends, patterns, and differences in cancer mortality among US counties. The authors added that these patterns may inform further research into improving prevention and treatment.