Area poverty rate linked to incidence of certain cancers

Incidence of certain cancers in specific neighborhoods varied considerably based on the area’s poverty level, according to study results.

Areas with high poverty had greater rates of Kaposi’s sarcoma and laryngeal, cervical, penile and liver cancers, whereas wealthy areas had higher rates of melanoma, thyroid cancer, nonepithelial skin cancer and testis cancer.

“At first glance, the effects seem to cancel one another out,” researcher Francis P. Boscoe, PhD, of the New York State Cancer Registry, said in a press release. “But the cancers more associated with poverty have lower incidence and higher mortality, and those associated with wealth have higher incidence and lower mortality. When it comes to cancer, the poor are more likely to die of the disease while the affluent are more likely to die with the disease.”

Boscoe and colleagues used the North American Association of Central Cancer Registries to evaluate cancer incidence in 16 states. The geographic areas analyzed accounted for 42% of the US population, and the data included nearly 3 million tumors diagnosed between 2005 and 2009.

Researchers then stratified data according to four residential census tract poverty levels (˂5%, 5% to ˂10%, 10% to ˂20%, and ≥20%).

Results showed no significant associations between poverty levels and cancer rates for all 39 cancer sites combined; however, 32 cancer sites were independently associated with poverty levels.

Fourteen cancer sites were linked to higher poverty. Cancers linked to behavioral risk factors — such as alcohol, tobacco and IV drug use, poor diet and sexual transmission — were associated with higher poverty.

Eighteen cancer sites were associated with low poverty levels. Rates of cancers associated with overdiagnosis — such as prostate, thyroid and skin cancers — were higher in wealthier areas.

Researchers determined males were more sensitive to the associations between cancer rates and poverty, particularly for liver and interhepatic bile duct, lung and bronchus, anus, colon and rectum, oral cavity, pharynx and miscellaneous cancers.

Race-specific incidence rates differed, particularly for lung and prostate cancers, melanoma and Hodgkin’s lymphoma; however, the poverty associations remained for each of these cancer types except Hodgkin’s lymphoma. 

The difference in site-specific risks between the greatest and lowest poverty areas was 2%, “suggesting that the individual site-specific risks effectively canceled one another out,” the researchers wrote. However, high poverty areas had an age-adjusted mortality of 107.7 per 100,000 people, whereas low poverty areas had an age-adjusted mortality of 68.9 per 100,000 people.

Improvements in technology have made it easier to incorporate socioeconomic status into cancer surveillance, Boscoe said.

“Our hope is that our paper will illustrate the value and necessity of doing this routinely in the future,” he said.

Disclosure: The study was funded in part by the CDC. The researchers report no relevant financial disclosures.