Racial Disparities in Risk Group at Presentation and Access to Treatment for Prostate, Lung, Colorectal and Ovarian Cancer: Insights from the PLCO Cancer Screening Trial
Over two decades ago, the NIH sought to identify and address disparities in healthcare with respect to race, ethnicity, sex, and gender; the mandate included an imperative to “ensure that women and members of minorities and their subpopulations are included in all human subject research.”(3) Racial disparities in trends in cancer epidemiology, treatment patterns, and outcomes are readily apparent and play significant but complex roles on care and outcomes that patients experience. Significant work has been conducted on the disparities experienced by patients with prostate, lung, colorectal, and ovarian cancer. For example, Black men are more likely to be diagnosed with prostate cancer and are more likely to die from low-grade prostate cancer.(1) Treatment at minority-serving hospitals was associated with lower odds of receiving definitive therapy and longer time to definitive therapy for localized intermediate and high-risk prostate cancer.
Many of these studies have compared African Americans and White Americans, and they have identified key disparities that will hopefully affect policy and individual physicians’ treatment practices. However, much less is known about disparities experienced by Asian American patients. What is known is that these differences also exist – but their magnitude and characteristics are far less clear. The goals of our series of studies are to identify cancer disparities faced by an increasingly large fraction of Americans (i.e., Asian Americans) and to assess their implications on outcomes (in particular, cancer-specific survival).
Although screening rates and quality of care has improved across prostate, lung, colorectal, and ovarian cancer in the United States over the past two decades, various sub-groups of Asian Americans remain at higher risk for developing high-risk disease associated with increased mortality than White Americans.(4) Through comprehensive examination of the PLCO Cancer Screening Trial, we expect to identify disparities in factors such as educational attainment, financial status, insurance status, and presence of co-morbidities, paired with secondary disparities in follow-through after a positive screening test and adherence to treatment, between Asian Americans and other populations across all cancers. By building an evidence-based disparities model supported from data in the PLCO Cancer Screening Trial, we hope to provide insight into areas for policymakers and public health officials to focus on with regards to Asian American cancer care.
- We hypothesize that, even controlling for socioeconomic status, educational attainment, and baseline health status, there will be significant differences in cancer outcomes between Asian Americans and White Americans.
- We further hypothesize that poor adherence to treatment following screening tests across prostate, lung, colorectal, and ovarian cancers will be associated with worse outcomes among Asian Americans, partially explained by known sociodemographic disparities.
Using the Prostate, Lung, Colorectal and Ovarian (PLCO) Cancer Screening Trial and combining data across the screening, incidence, and mortality datasets for all four cancers, we will conduct the following analyses:
- Simple incidence and mortality data, reporting what fraction of each population (stratified by race) receives and adheres to treatment following screening
- Multivariate logistic regression analysis to assess the contributions of the following data on mortality and duration of time between positive screening results and treatment: race, family income, self-reported health status, co-morbities, educational attainment, geographic US region, sex, and smoking status
- Interaction term analysis to assess for effect modification – for example, we will test for interaction terms between race and gender, gender and educational attainment, etc.
- Kaplan-Meier curves, Log rank tests, and Cox proportional hazard regression modeling to build a comprehensive statistical model relating co-variates of interest with clinical outcomes
References:
1. Rebbeck TR. Prostate cancer disparities by race and ethnicity: From nucleotide to neighborhood. Cold Spring Harb Perspect Med. 2018;
2. Mahal BA, Ziehr DR, Aizer AA, Hyatt AS, Sammon JD, Schmid M, et al. Getting back to equal: The influence of insurance status on racial disparities in the treatment of African American men with high-risk prostate cancer. Urol Oncol Semin Orig Investig. 2014;32(8):1285–91.
3. National Institutes of Health. NIH Guidelines on The Inclusion of Women and Minorities as Subjects in Clinical Research. Fed Regist. 1994;59:14508–13.
4. McCracken M, Olsen M, Chen MS, Jemal A, Thun M, Cokkinides V, et al. Cancer Incidence, Mortality, and Associated Risk Factors Among Asian Americans of Chinese, Filipino, Vietnamese, Korean, and Japanese Ethnicities. CA Cancer J Clin. 2007;57(4):190–205.
Bhav Jain (Massachusetts Institute of Technology)
Paul L. Nguyen, MD (Department of Radiation Oncology, Dana-Farber Cancer Institute/Brigham and Women’s Hospital, Boston, MA)
Vinayak Muralidhar, MD, MSc (Department of Radiation Oncology, Dana-Farber Cancer Institute/Brigham and Women’s Hospital, Boston, MA)
Brandon A. Mahal, MD (University of Miami/Sylvester Comprehensive Cancer Center, Miami, FL)