Prostate cancer (PCa) epidemiology and management in the United States have been found to differ across regions. It is well known that there are higher PCa mortality rates among black men compared with white men, although these are statistically significant in only a handful of areas.1 In addition, conservative management for low-risk PCa in the Veterans Affairs (VA) healthcare system is used more frequently in facilities in the Midwest and West than among those in the Northeast.2 Also, radical prostatectomy (RP) for localized PCa is used to a greater extent in the Midwest and High Plains regions and used least in the South Atlantic region.3

To examine race-based regional differences in PCa mortality, Sean A. Fletcher, MD, and colleagues studied 229,771 men (178,204 white, 35,006 black, and 16,561 men of other or unknown race) from 17 geographic registries within the Surveillance, Epidemiology, and End Results (SEER) database from January 1, 2007, to December 31, 2014. Of the 17 registries, the investigators identified 4 in which black men had significantly greater PCa mortality compared with white men: Atlanta, Georgia; Greater Georgia; Louisiana; and New Jersey. Among men with Gleason grade group 1 disease, black men, compared with white men, in Atlanta, Georgia, Greater Georgia, Louisiana, and New Jersey, had a 5.5-, 1.9-, 1.8-, and 2.6-fold increased risk of PCa-specific mortality (PCSM), respectively, in adjusted analyses, Dr Fletcher’s team reported in JAMA Network Open.1 Among men with Gleason grade group 2 through 5 disease in these areas, black men had a 1.9-, 1.3-, 1.3-, and 1.5-fold increased risk of PCSM compared with white men.

“The most striking finding was that there are specific ‘hot spots’ in which racial differences in prostate cancer mortality are most pronounced,” said Dr Fletcher, who conducted the study while at Brigham and Women’s Hospital in Boston but is now at the James Buchanan Brady Urological Institute at The Johns Hopkins Medical Institutions in Baltimore.

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Contributing Factors

Although the study was not designed to determine definitively the underlying causes of the geographic variability in the racial disparity in PCa survival, “we are inclined to attribute a large part of this variability to differences in access to care,” Dr Fletcher told Renal & Urology News. “Prostate cancer, especially of a low-risk nature, requires continual surveillance and communication with the healthcare system to monitor for disease progression. We believe that areas with worse mortality for black men may also have more pronounced disparities in care access and follow-up for minority populations. However, the possibility of men in these areas having higher genetic predisposition to more aggressive disease cannot be definitively ruled out.”

Sean Fletcher, MD
Sean A. Fletcher, MD

Dr Fletcher said his team’s data reinforce work from prior studies showing that racial differences in PCSM are more marked in men initially presenting with low-risk disease, with black men experiencing worse survival compared with white men. “This may be mediated by differences in patterns of management and definitive treatment for men in this risk group,” Dr Fletcher said.

The new findings enable targeted investigation of particular geographic areas to determine what factors (such as access to care, treatment patterns, and disease biology) contribute most to these race-based mortality differences, he said. “More granular qualitative analyses of care processes in these areas may further elucidate the mechanisms of our findings.”

In an accompanying editorial, Willie Underwood III, MD, MSc, MPH, of the Buffalo New York Community Center for Health Equity, commented that the new study “contributes to the literature that nonbiological factors are likely associated with the significant disparity in prostate cancer mortality among black vs white men, thus contributing to the discussion that increased prostate cancer mortality among black men compared with white men is unnecessary and preventable.”4

An earlier study showing regional variation in PCa mortality led investigators to conclude that the variation may be related to differences in access to care. Among white men aged 40 years or older, the age-adjusted death rate (per 100,000 men per year) from PCa ranged from 60.8 in Alaska to 86.4 in Wyoming, according to findings published in Cancer Epidemiology, Biomarkers & Prevention.5 The incidence rate for all PCa stages combined ranged from 294.8 in Arizona to 427.8 in New Jersey. The incidence rate of distant-stage disease ranged from 10.4 in Atlanta to 28.6 in Hawaii.

Among black men aged 40 years or older, the age-adjusted death rates ranged from 129.2 in Rhode Island to 196.7 in North Carolina. The rates for overall incidence ranged from 374 in Hawaii to 692.6 in Michigan; the rates for distant-stage disease ranged from 33.3 in Arizona to 76.9 in West Virginia. Nonmetropolitan areas generally had higher death rates (74.9 vs 71.7) and incidence of late-stage disease (19.3 vs 17.1) and lower prevalence of PSA screening (53% vs 58%) compared with metropolitan areas, the investigators reported.

“Our principal findings are that the geographic variation in prostate cancer death rates is positively associated with incidence of late-stage disease and with residence in nonmetro areas and that the incidence of late-stage disease is inversely associated with the utilization of PSA testing,” the authors wrote. “All of these factors suggest that lower access to medical care may contribute to a higher death rate from prostate cancer in certain regions of the United States.”

Conservative Management

Other studies have revealed substantial differences in how PCa is managed across the nation. In a recent report published in European Urology, Stacy Loeb, MD, of the Manhattan Veterans Affairs Medical Center and New York University, and colleagues described a study of 20,597 men receiving PCa care in the VA healthcare system showing that men receiving care at facilities in the Midwest and West had 23% and 36% increased odds, respectively, of undergoing conservative management such as active surveillance (AS) and watchful waiting compared with those receiving care at Northeast facilities.2

“Even after adjusting for multiple patient and non-patient factors, we observed persistent regional variation in conservative management use among veterans,” Dr Loeb told Renal & Urology News. “It is unclear whether these differences relate to regional differences in patient preferences, availability of other treatment options for prostate cancer, or other factors.”

Initial Treatments Compared

Another study, published in 2019 in Advances in Radiation Oncology, found geographic variation in the use of RP, radiation therapy (RT), and AS among 462,811 men who received treatment for localized PCa during 2010 to 2014.3 Nationwide, as a first-line management strategy, researchers found that approximately 63.5% of patients underwent RP, 31% received RT, and 5% underwent AS. RP, however, was used most commonly in the Midwest (Minnesota, South Dakota, Iowa, and Wisconsin; 75% of cases) and High Plains (Nebraska, Kansas, Missouri, Oklahoma, and Texas; 73.4%) regions, whereas RP was least used in the South Atlantic (Delaware, Maryland, District of Columbia, Virginia, West Virginia, North Carolina, South Carolina, and Georgia; 59%) regions. RT was most commonly used in the South Atlantic (41%) and New England (Maine, Vermont, New Hampshire, Massachusetts, Rhode Island, and Connecticut; 39%) regions. RT was used least in the Midwest (25%) region. AS was used most commonly in the New England (7.3%) and Midwest (6.8%) regions and least used in the High Plains (2.6%) and Mid-South (Kentucky, Tennessee, Arkansas, Louisiana, Mississippi, and Alabama; 2.8%) regions.

Systemic Therapy

Systemic treatment of advanced PCa also varies by region. For example, in a real-world study of 4275 patients using a large national insurer’s claims database, Megan E. V. Caram, MD, of the University of Michigan in Ann Arbor and colleagues, showed that 61.9% of patients in a region that included Alaska, California, Hawaii, Oregon, and Washington received abiraterone as first-line treatment in 2014 compared with only 26.7% in a region comprising Iowa, Kansas, Minnesota, Missouri, Nebraska, North Dakota, and South Dakota. The investigators published their findings in BMC Cancer, where they explained that “geographic variation in treatment patterns may be a result of other factors associated with geography, such as rural/urban differences, patient income, race, and health system factors.”6

References

  1. Fletcher SA, Marchese M, Cole AP, et al. Geographic distribution of racial differences in prostate cancer mortality. JAMA Netw Open. 2020;3:e201839.
  2. Loeb S, Byrne N, Wang B, et al. Exploring variation in the use of conservative management for low-risk prostate cancer in the Veterans Affairs healthcare system. Eur Urol. 2020;77:683-686.
  3. Scherzer ND, DiBiase ZS, Srivastav SK, et al. Regional differences in the treatment of localized prostate cancer: An analysis of surgery and radiation utilization in the United States. Adv Radiat Oncol. 2019;4:331-336.
  4. Underwood W 3rd. Racial regional variations in prostate cancer survival must be viewed in the context of overall racial disparities in prostate cancer. JAMA Netw Open. 2020;3:e201854.
  5. Jemal A, Ward E, Wu X, Martin HJ, McLaughlin CC, Thun MJ. Geographic patterns of prostate cancer mortality and variations in access to medical care in the United States. Cancer Epidemiol Biomarkers Prev. 2005;14:590-595.
  6. Caram MEV, Estes JP, Griggs JJ, Lin P, Mukherjee B. Temporal and geographic variation in the systemic treatment of advanced prostate cancer. BMC Cancer. 2018;18:258.