Original Research

Disparities in prostate cancer survival in Appalachian Kentucky: a population-based study

AUTHORS

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Zin W Myint1
MD, Hematology/Oncology Fellow

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Richard O’Neal2
MD, Hematology/Oncology Fellow

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Quan Chen3
DrPH, Statistician

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Bin Huang4
DrPH, Associate Professor

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Robin Vanderpool5
DrPH, Associate Professor

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Peng Wang6
MD, Ph.D, Assistant Professor *

AFFILIATIONS

1, 2, 6 Department of Internal Medicine, Division of Medical Oncology, University of Kentucky Medical Center, Lexington, Kentucky, USA

3, 4, 5 Biostatistics Shared Resource Facility, Markey Cancer Center, Lexington, Kentucky; and Department of Biostatistics, College of Public Health, Lexington, Kentucky, USA

ACCEPTED: 13 February 2019


early abstract:

Background: Prostate cancer is the most common male cancer in the United States. When comparing the incidence and mortality rates of prostate cancer, the Surveillance Epidemiology and End Results (SEER) data from 2005-2014 shows that Appalachian Kentucky had a lower incidence (113/100,000 vs 137/100,000) but a higher mortality rate (23.8% vs. 21.8%) when compared to non-Appalachian Kentucky. The aim of this study is to further characterize the survival disparities of prostate cancer between Appalachian and non-Appalachian Kentucky.

Methods: All stages of prostate cancer patients diagnosed between 2007-2011 were collected through the Kentucky Cancer Registry (KCR). Baseline characteristics and survival outcomes were compared between Appalachian Kentucky and non-Appalachian Kentucky, using Pearson Chi-square and Cox regression analyses in this population-based analysis.

Results: Of 12,871 patients studied, 3,482 (26.8%) were from Appalachian Kentucky whereas 8,489 (73.2%) were from non-Appalachian Kentucky. Caucasians predominated in both groups. Most Appalachian Kentucky patients were between 65-74 years of age. Appalachian Kentucky patients had a higher Gleason score, higher prostate specific antigen, more aggressive histologic grade, more distant disease, higher comorbidity score, lower education, and higher poverty compared to patients from non-Appalachian Kentucky. There was a 5-year survival difference between Appalachian Kentucky and non-Appalachian Kentucky in unadjusted analysis (p<0.001) that disappeared after adjusting with Cox regression analysis (p=0.4). However, worsened survival was still seen with higher Gleason score, higher PSA, distant stage disease, higher Charlson comorbidity index, and very low high school education (p<0.001).

Conclusions: In this population-based analysis, this study shows a significant difference in prostate cancer survival between Appalachian and non-Appalachian Kentucky. The difference was not related to geographic location, but rather to high comorbidity score, high poverty rate, and low education. Additional research is needed to understand the health care restraints for Appalachian Kentucky.