In the hunt to understand why some people get certain types of cancer and then have different outcomes, biomedical researchers look at genetic profiles and variables like age, gender, race, and other health conditions. They also factor in geographic location, which may point to socioeconomic or environmental clues.  

A recent study published in the Journal of Neuro-Oncology showed that compared to the rest of the U.S., the Appalachian region has a 5 percent higher incidence of malignant primary brain tumors (PBT) and other central nervous system (CNS) tumors, a higher mortality rate due to these tumors and poorer survival rates. Specific to glioblastoma, a particularly lethal form of brain tumor, the incidence is notably higher in central and northern Appalachia, compared to the rest of the U.S. 

The study compared malignant vs non-malignant brain and CNS tumors and explored several variables including race, ethnicity, age, sub-regions within Appalachia and types of healthcare coverage. Appalachia was selected because it already is known that residents of the region have a higher incidence of other types of cancer as well as behaviors and conditions such as smoking, obesity, diabetes and other cancer-associated behavioral and environmental risk factors. The study is titled Primary brain and other central nervous system tumors in Appalachia: regional differences in incidence, mortality, and survival.

“Examining differences in incidence and survival by place of residence can provide information that is essential to understanding how risk and survival varies in the population,” said Dr. Quinn Ostrom, postdoctoral associate at Baylor College of Medicine. “Some of this variation may relate to access to healthcare, which can affect timing of diagnosis or whether individuals are diagnosed at all. These disparities may also point to unusual environmental or behavioral variables that merit public health investigation.” 

Additional key findings from this study include:

• The Appalachian incidence of malignant PBTs was higher in both males and females and in all age groups compared to U.S. incidence rates. Incidence among males was higher than females, which is similar to sex differences in incidence in the larger U.S. population. 

• Appalachian incidence of non-malignant (or benign) brain and CNS tumors were 3 percent lower than the rest of the U.S., and Appalachian incidence also was lower for two of the most common types of non-malignant brain tumors: meningioma and pituitary tumors.

• Incidence rates within Appalachia varied, with highest incidence of malignant PBTs in the Northern and Central regions. 

• When stratified by race, incidence of malignant PBT was decreased among some populations, notably white non-Hispanics. The higher density of white non-Hispanics in Appalachia may be contributing to the increased overall incidence. 

“Large studies like this can point researchers to unexpected variables that merit further investigation,” said Dr. Barnholtz-Sloan of the Case Western Reserve University School of Medicine who served as a mentor to Ostrom when she was in graduate school at Case Western . “We may want to layer in genetic research, depending on availability of bio-specimens, with a focused look at how cancer-associated behavioral risk factors correlate. Or we may want to explore potential regional environmental factors. These multifaceted lines of inquiry are critical for us to better understand this disease.”