Aug. 13There's a mystery behind one of the most common cancers among men in America, and Dr. Tracy Layne is trying to solve it.
Layne, a postdoctoral fellow at the National Cancer Institute, has spent the last several years researching cancer of the prostate, a walnut-sized gland that serves an integral role in the male reproductive system. Prostate is a common cancer diagnosis for American men second only in frequency to non-melanoma skin cancer but incidence rates are significantly higher for black men, who are more likely to die of the disease than any other racial or ethnic group. Why? Unfortunately, Layne said, nobody knows for sure.
"There are lots of unknowns overall for prostate cancer, but particularly for black men, who have close to two times the chance of developing it and more than two times the chance of dying from the disease," Layne said. "There are some leads, but there's no concrete evidence as to why that is. So, what we're hoping to do is to characterize some of the factors that may be associated with the development of prostate cancer in this population."
In other, more detailed words which Layne patiently explains she and some fellow researchers are studying metabolites in the blood of black men in an effort to identify potential risk factors for prostate cancer. Metabolites are the molecules formed in the process of human metabolism, classified into eight groups including amino acids, carbohydrates and peptides. The blood she's examining comes from two previous studies that followed a group of men over time to see which developed prostate cancer and which did not. By re-analyzing the blood of the patients who participated, Layne and her peers are hoping to identify the biochemical characteristics of prostate cancer in African-American men that could contribute to their increased risk for the disease.
"Because, let's say you find that a particular amino acid increases the risk of disease," Layne said. "So, you're measuring it years before a patient develops disease and you're seeing that it's associated with the disease years later. That particular amino acid could potentially be used as a screening tool to identify men who could subsequently develop the cancer. It could be used as an indicator of risk, it could be used as an indicator of progression following treatment potentially far in the future."
To help accomplish this, Layne was given an inaugural William G. Coleman Jr., Ph.D., Minority Health and Health Disparities Research Innovation Award, a grant bestowed by the National Institutes of Health. Specifically, the grant was offered by the National Institute on Minority Health and Health Disparities (NIMHD), which works to address the frequent health imbalances seen among minority populations.
There's a reason that health disparities have their own specific institute at one of the largest biomedical research centers in the world. Nationwide, minorities have higher rates not just of prostate cancer but of many other conditions, including diabetes, high blood pressure and strokes. Black patients in particular have a higher risk of developing or dying from many other types of cancer, including colorectal, lung and cervical.
That includes in Frederick County, where cancer incidence for black residents increased by 15 percent from 2008 to 2013. According to the most recent available data from 2013, the cancer incidence rate now stands at 454.8 per 100,000 population for black county residents, compared to 445.2 for whites. And while cancer mortality rates are higher for white residents 145.9 per 100,000 versus 133.2 they've also seen a steady decrease for the past five years. Blacks, on the other hand, saw a 10 percent increase from 2012 to 2013.
"It is a point of concern whenever we see anything like that," said Rissah Watkins, the director of planning, assessment and communication for the Frederick County Health Department. "But there has been an overall decrease in all cancer mortality over the past several years, so that's important to keep in mind. We do look at changes from year to year, but it's most important to keep a larger picture and see in general where we're going."
Watkins along with co-worker Beth Mowrey, the department's program administrator for preventive health work on a local level to increase health access for minority populations and encourage early prevention. The Health Department offers free screenings for breast, colorectal and cervical cancers, as well as providing education on lung cancer and a tobacco cessation program.
To try and increase awareness among vulnerable populations, the department has tried grassroots efforts, including door-to-door canvassing and leaving program information at minority-owned businesses. But minority health disparities still present a challenge, especially as scientists continue to debate their underlying cause, Watkins said.
"That's one of the big questions researchers are still looking at," she said. "Why some people react differently. It's something that's not just unique to Frederick, but that we've seen throughout Maryland and throughout the country."
Though a variety of factors play into the development of cancers, some researchers including Layne continue to investigate potential genetic causes. Layne has also explored whether lower rates of circulating vitamin D in black men could contribute to higher rates of prostate cancer, and there's evidence that the prevalence of the disease in black patients could be due to genetic or cultural, rather than socioeconomic, factors.
Two studies from the NIH, for example, linked census data from San Francisco, Oakland, Detroit and Atlanta with data from the Surveillance, Epidemiology, and End Results program at NCI. Ultimately, they found no real link between educational, income or employment levels and prostate cancer risk in black men, and no correlation between higher risks and having health insurance.
Another study from researchers with the Southwest Oncology Group looked at the medical records for prostate cancer patients in clinical trials and found that African-American patients were still 21 percent more likely to die from the disease than white patients, even while receiving identical treatment and follow-up care.
"In other research, too, that has looked within populations with a similar source of care like the veteran population or Medicare population you're still seeing these differences by race," Layne said. "So there are still a lot of unanswered questions."
But for cancer overall, many experts continue to emphasize social determinants the environments where people are born, live and work as a greater component of health disparities than genetic causes. The Maryland Comprehensive Cancer Control Plan for 2016-2020 even states that, "Recent evidence suggests that social determinants of health play a far more pivotal role contributing towards health disparities than biological factors."
Angela Spencer, a local health advocate, cited lower screening rates as just one reason why the African-American community may have higher incidence rates for cancer. In her work with the Faith Striders of Frederick, an educational nonprofit that promotes cancer awareness in area churches, Spencer has noticed a lack of preventive testing among many black parishioners including women who have never received a mammogram.
"That's why the only reason I can think of is that people are not going out and getting screened," she said. "These numbers could change if people would go to the doctor and get checked."
But if social determinants do play a key role in overall cancer development, they could also contribute to the disparities. According to 2015 Census Bureau data, roughly 16 percent of African-American residents in Frederick County live below the poverty line, compared to 5 percent of adults. And nationwide, African-Americans are overrepresented among extremely low-income housing renters, according to the National Low Income Housing Coalition.
Ultimately, the way to decrease health disparities in Frederick County might be to decrease living disparities, both Watkins and Mowrey said. The Health Department has worked with other local agencies to implement systemic changes, including a partnership with the Housing Authority of Frederick to establish a smoke-free policy in Section 8 housing.
Solving long-standing health problems can be hard to achieve without cooperation from the entire community, Mowrey said.
"Because if you're thinking, 'How can the health department lower lung cancer rates?'" you might not necessarily think "Let's go to the housing people and get that passed," Watkins said. "That's an unconventional approach."
Follow Kate Masters on Twitter: @kamamasters.
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