Thyroid cancer is the ninth most common cancer and the single most common endocrine cancer in the U.S., and incidence is rapidly increasing. According to National Cancer Institute (NCI) estimates, there were 60,220 new cases of thyroid cancer in 2013 as well as 534,973 Americans currently living with the disease.
This increase has not come with a concomitant rise in mortality from thyroid cancer, however, leading many researchers to question whether improved detection methods have led to overdiagnosis. With overdiagnosis potentially comes overtreatment, according to a study led by Juan Pablo Brito, MBBS, from the Mayo Clinic Robert D. and Patricia E. Kern Center for the Science of Health Care Delivery, in Rochester, Minn.
Unless the patient belongs to a U.S. racial minority, that is. An estimated 1,850 deaths from thyroid cancer occurred in 2013, of which a disproportionate number were African American. Despite its very high survival rate and that it is twice as common among whites than African Americans, African Americans have a higher mortality rate from thyroid cancer, as several studies show. While many thyroid cancer patients are being overtreated, are African Americans being undertreated, and, if so, what accounts for this outcome disparity?
African Americans and Anaplastic Thyroid Cancer
In 2011, a team of researchers led by Christopher S. Hollenbeak, PhD, and David Goldenberg, MD, of the Penn State College of Medicine, in Hershey, Pa., asked that very question. With 15 years’ worth of data from 25,210 white and 1,692 African American patients from the Surveillance, Epidemiology, and End Results (SEER) registry, they first demonstrated that five-year survival rates differed along racial lines and also examined whence these differences derive. “Our study found a small but significant increase in risk of mortality for African Americans with thyroid cancer. We also found that this increased risk is largely attributable to differences in the type of disease,” Hollenbeak says.
Of the four histologic types of thyroid cancer, papillary (most common [80%–90%] and most treatable), follicular (second most common [15%] but more likely to metastasize), medullary (3%), and anaplastic (most rare [1%–5%] and most aggressive), African Americans were 2.3 times more likely to have anaplastic disease, approximately 80% more likely to have follicular disease, and nearly twice as likely to have tumors measuring at least 4 cm than whites.
“African Americans were more likely to present with anaplastic thyroid cancer, which carries a higher mortality rate,” Hollenbeak says. “So, although the overall rate of thyroid cancer tends to be lower among African Americans, it appears to be slightly more severe. We cannot rule out that the increased mortality is due in part to lack of access to care.”
Because thyroid cancer is typically symptomless, patients without regular healthcare can go undiagnosed for years. That African Americans commonly had larger tumors suggests that those tumors perhaps had persisted longer before diagnosis, giving them time to enlarge. The combination of advancing age plus anaplastic disease with few treatment options results in very poor prognoses.
Gaps in Access to Care
These striking findings launched much-needed investigation into healthcare disparities, such as those summarized in the 2012 Endocrine Society Scientific Statement, “Health disparities in endocrine disorders: biological, clinical, and nonclinical factors.” This literature review looked at race and sex disparities in specific endocrine disorders including thyroid cancer. It sought to determine both what factors might cause these disparities as well as to highlight areas requiring additional investigation. Headed up by Sherita Hill Golden, MD, of the Johns Hopkins University School of Medicine in Baltimore, the team of reviewers found not only additional support for the hypothesis that African Americans have higher death rates from thyroid cancer than do whites, but also that obesity contributes to worse outcomes for women with thyroid cancer. They also found that these disparities exist worldwide, not just in the U.S.
What they did not find was any significant evidence that genes play a role in the difference in outcomes, which, again, suggests, that lack of access to care is possibly the underlying mechanism. “It is important for physicians to be aware of disparities in the treatment of certain thyroid disorders, such as thyroid cancer, so that they can play a role in preventing and narrowing the gap in these disparities,” Golden says. “For example, physicians can help patients with more advanced disease, who are often lowincome minority individuals, to gain access to high-volume surgeons to improve clinical outcomes in disadvantaged groups.”
Indeed, not only is the disease commonly more advanced at presentation among African Americans, but how it is surgically treated can also differ. Katherine Hayes, MD, from Emory University in Atlanta, presented her team’s findings at the 82nd Annual Meeting of the American Thyroid Association (ATA) demonstrating that certain groups (African Americans along with women and older adults) were less likely to have lymph nodes also removed during thyroidectomy and were not treated at high-volume institutions, despite existing ATA guidelines.
Such clinical interventions are key, but nonclinical interventions could also help, Golden’s team says. As has been shown successful with diabetes care, multilevel interventions can make at-risk populations more aware of their risk of thyroid cancer and death from thyroid cancer and can also target weight loss, which could improve disease burden in thyroid cancer as well as other endocrine disorders.
Need for Effective Interventions
Then, in 2013, a retrospective cohort study delved into racial and socioeconomic disparities among 25,945 patients with well-differentiated thyroid cancer from the California Cancer Registry from 1999 to 2008. Of the cohort, 7% were white, 4% were African American, 24% were Hispanic, and 15% were Asian-Pacific Islanders. This study, which was presented at Endo 2013, was led by Avital Harari, MD, from the University of California in Los Angeles, and again showed that African American patients and those with low socioeconomic status (SES) suffer worse outcomes and have lower survival rates than other groups. “Race, social status, wealth, and health insurance coverage make a difference in how advanced thyroid cancer is at presentation,” Harari says.
Low SES patients were 45% more likely to have metastatic cancer and twice as likely if they were poorly insured, uninsured, or on Medicaid. African American patients fared the worst, however, with the lowest survival rates among the minority groups studied. Despite also being more likely to present with remote or advanced disease, Hispanics and Asian-Pacific Islanders demonstrated a possibly genetic survival advantage, although survival rate was still lower than that for privately insured or higher SES patients. “Our work highlights the importance of developing interventions that will lead to equalization of care, better preventative practices, and earlier treatments,” Harari says. “Our group is interested in the underlying predisposing factors leading to the increased incidence and advanced disease in thyroid cancer patients. We have and will continue to investigate how these cancers are presenting across the state [and nation] and what the best intervention will be to allow the greatest impact in cancer prevention.”
What Can Physicians Do?
These three studies each separately reached the same conclusions: Thyroid cancer mortality affects African Americans and low SES groups disproportionately and is therefore primarily a problem of level and quality of care rather than of biology or genetics. Each team also urges the same approach to rectifying these disparities: Address the problem at multiple levels of intervention. Patients should be self-aware about their health, and physicians proactive about their care, Hollenbeak says. “We encourage everyone to be aware of their risk of thyroid cancer and to see their doctor if they find an unusual lump or swelling in their neck. Also, we encourage doctors to perform routine screenings that include an examination of the thyroid.”
Harari’s message to clinicians is one of awareness of external factors: “We hope that [our study] will also make physicians who treat thyroid cancer patients more aware of how aggressive this cancer can be in certain racial and socioeconomic groups.”
Finally, policy makers also play a vital role as part of a multilevel intervention strategy such as that touted by Golden’s team. The “you-get-what-you-pay-for” approach to healthcare has proven lethal for African Americans with thyroid cancer, so a new, more equitable approach must be found. “The policy implications of our findings are serious and call attention to issues of quality of care and access to care for the underprivileged,” Harari says.
With thyroid cancer incidence increasing faster than that of any other cancer in both men and women, according to the NCI, the problem of equal care correspondingly grows. By broadening insurance coverage as well as focusing on prevention, perhaps the Patient Protection and Affordable Care Act will help bring parity to thyroid cancer detection and treatment for Americans, regardless of race or SES.
— Horvath is a freelance writer based in Baltimore. She wrote about the high cost of diabetes treatments in the July 2013 issue
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