Racial Disparities and Socioeconomic Status in Association with Survival in Older Men with Local/Regional Stage Prostate Cancer Xianglin L. Du, M.D., Ph.D. Associate Professor University of Texas School of Public Health at Houston Division of Epidemiology and Center for Health Services Research

Thanks to Coauthors and Collaborators Xianglin L. Du, M.D., Ph.D.* Shenying Fang, MD, MS, Ann L. Coker, PhD, Maureen Sanderson, PhD, Corrine Aragaki, PhD, Janice N. Cormier, MD, MPH, Yan Xing, MD, MS, Beverly J. Gor, EdD, RD, Wenyaw Chan, PhD

Brief Background Racial/Ethnic Disparities in mortality and survival present in the U.S. Higher mortality for prostate cancer in African Americans compared to Caucasians are attributed to: –More aggressive tumors –More advanced stage at diagnosis –Health insurance and access to care –Difference in screening-early detection –Differences in receiving optimal treatments –Socioeconomic status –Healthcare Providers (physicians and hospitals)

Evidence of Racial/Ethnic Disparities in Healthcare Consistent Findings Disparities consistently found across a wide range of disease areas and clinical services Disparities are found even when clinical factors, such as stage of disease presentation, co- morbidities, age, and severity of disease are taken into account Disparities are found across a range of clinical settings, including public and private hospitals, teaching and non-teaching hospitals, etc. Since disparities in health care are associated with poor outcomes – they are not acceptable

Evidence of Racial/Ethnic Disparities in Mortality/Survival not Consistent Findings Numerous studies showed that the outcomes (survival) were similar among different racial/ethnic groups, after controlling for differences in treatment and socio-demographic factors Whereas Other studies showed racial/ethnic disparities still existed even after controlling for socioeconomic factors and for access to equitable care and treatment These inconsistency is also apparent in prostate cancer mortality by race/ethnicity

Objective and Hypothesis Main objective is to determine whether there is racial/ethnic disparity in long-term survival in a large nationwide, population-based cohort of older men who were diagnosed with locoregional stage prostate cancer and who had universal fee-for-services Medicare insurance coverage (both part A and B). We hypothesized that there were no racial/ethnic difference in long-term survival of prostate cancer patents after controlling for differences in patient characteristics (age), tumor characteristics (grade-Gleason score), comorbidity, treatment, and socioeconomic status.

Study Population and Methods Retrospective cohort study of 61,228 men diagnosed with incident (new) local/regional stage prostate cancer at age ≥65 ( and 11 regions) Identified from the NCI’s 11 SEER- Medicare data (covering >14% of the U.S. population). Last follow-up: 12/31/2002 with up to 11 years of FU >98% completeness of case ascertainment (incident cases)

Study Variables Outcomes –All-cause mortality –Prostate cancer-specific mortality –Time to event (in months from date of diagnosis to date of death) Exposures –Race/ethnicity: African American, Caucasian, and Hispanics Other covariates –Demographics (age) –Comorbidity index adjustment (created from Medicare claims) –Locoregional stage, but control for grade and AJCC stage for residual confounding –Treatment (discuss below) –Year of diagnosis (1992 to 1999) –Geographic areas (11 areas) –Socioeconomic factors (discuss below)

Socioeconomic Factors (from 1990 census) Education - percent of adults aged ≥25 who had less than 12 years of education at the zip code level, which was categorized into quartiles. Poverty - percent of persons living below the poverty line at the census tract level Income - median annual household income at the zip code level Composite SES (socioeconomic status) – that summed the normal scores of the above three variables that were equally weighted and categorized the total scores into quartiles

Treatment Primary Treatment: –radical prostatectomy, or –radiation therapy, or –watchful waiting (observational management) –all standard of care (for local stage tumor). Adjuvant therapy: –hormonal therapy and –chemotherapy –efficacy not confirmed in RCTs.

Figure 1. Kaplan-Meier survival curve by 3 ethnic groups

Table 1. Comparison of age among 3 racial/ethnic groups Age (years)CaucasiansAfrican Americans Hispanics n%n%n% Median age (range) 73 (65-103)72 (65-103)71 (65-101) , , , , , , ≥808, Total53, , ,

Table 2. Comparison of tumor grades among 3 racial/ethnic groups Gleason Score CaucasiansAfrican Americans Hispanics n%n%n% 2-47, , , , , u/k2,

Table 3. Comparison of comorbidity among 3 racial/ethnic groups Comorbidity Scores CaucasiansAfrican Americans Hispanics n%n%n% 034, , , , , >=32,

Table 4. Comparison of treatment among 3 racial/ethnic groups Surgery andCaucasiansAfrican AmHispanics Radiationn%n%n% Prostatectomy12, , Radiation20, , Both1, Watchful Waiting 19, , Chemotherapy No44, , Yes9, Hormone No39, , Yes14, ,

Table 5. Comparison of socioeconomic status (SES) among 3 ethnic groups PovertyCaucasiansAfrican AmHispanics (quartiles)n%n%n% 1 st 14, nd 14, rd 13, th 9, Missing Total53, , ,

Table 8. Comparison of socioeconomic status (SES) among 3 ethnic groups Composite SES (quartile) CaucasiansAfrican AmHispanics (high to low)n%n%n% 1 st (High SES) nd rd th (Low SES) Missing Total

Table 9. Observed survival rate* by ethnicity and socioeconomic status Race/ethnicity and SES 3-year survival (%) (cases in ) 5-year survival (%) (cases in ) 10-year survival (%) (cases in ) All-causeDisease- specific All-causeDisease- specific All-causeDisease- specific Ethnic Groups Caucasians African Am Hispanics Composite SES 1 st nd rd th Total *unadjusted

Table 10. Hazard ratio of mortality by socioeconomic status SESHazard ratio (95% CI) of mortality* (high to low)All-cause mortalityCA-specific mortality Model 1Model 2Model 3Model 4 Composite SES 1 st (High SES)1.0 (ref) 2 nd 1.11 ( ) 1.11 ( ) 1.26 ( ) 1.25 ( ) 3 rd 1.22 ( ) 1.22 ( ) 1.24 ( ) 1.22 ( ) 4 th (Low SES) 1.31 ( ) 1.31 ( ) 1.48 ( ) 1.40 ( ) *Models 1 & 3: adjusted for age, comorbidity, AJCC-stage, Gleason score, year of diagnosis, SEER region, and treatment. *Models 2 & 4: adjusted for race/ethnicity, in addition to factors in Models 1 & 3.

Table 12. Hazard ratio of mortality by Poverty SESHazard ratio (95% CI) of mortality* All-cause mortalityCA-specific mortality Model 1Model 2Model 3Model 4 Poverty 1 st nd 1.11 ( ) 1.17 ( ) 1.15 ( ) 3 rd 1.19 ( ) 1.12 ( ) 1.11 ( ) 4 th 1.28 ( )1.28 ( )1.36 ( ) 1.31 ( ) *Models 1 & 3: adjusted for age, comorbidity, AJCC-stage, Gleason score, year of diagnosis, SEER region, and treatment *Models 2 & 4: adjusted for ethnicity, in addition to factors in Models 1 & 3.

Table 17. Hazard ratio of mortality by race/ethnicity Race/Hazard ratio (95% CI) of mortality* ethnicityAll-cause mortalityCA-specific mortality Model 1Model 2Model 3Model 4 Caucasians 1.00 African Am 1.14 ( ) 1.01 ( ) 1.33 ( ) 1.17 ( ) Hispanics 0.85 ( ) 0.78 ( ) 0.84 ( ) 0.78 ( ) * Models 1 & 3 - Adjusted for age, comorbidity, AJCC stage, Gleason score, year of diagnosis, SEER region, and treatment. * Models 2 & 4 - Adjusted for composite SES, in addition to above factors.

Further Analysis Apart from composite SES, the similar results were achieved by controlling for education, poverty, and income. There was no significant interaction between race/ethnicity and socioeconomic status.

Conclusions and public health implications Racial disparity in survival among men with locoregional prostate cancer was largely explained by their socioeconomic status. Lower socioeconomic status appeared to be one of the major barriers to achieving comparable outcomes for men with prostate cancer. Important public health implications if we are to achieve the goals of Healthy People 2010, one of which is to eliminate health disparities.

Strengths Large population-based cohort study, covering all (>98%) incident cases of prostate Ca, pathologically confirmed by the 11 SEER registries. Reliable information on cancer stage, grade, primary therapy (surgery and radiation), and long-term follow-up on vital status. Linked with Medicare claims, providing important data on comorbidity – a strong confounder of survival. Adjuvant chemotherapy and hormonal therapy data can be uniquely identified from Medicare claims. Several measures of SES variables  consistent findings.

Limitations SES at the level of census tract may be imperfect proxy measure for individual SES  ecological fallacy, but studies showed individual and community level SESs in good agreement Local-regional stage  Residual confounding (even after adjusting for AJCC stage and tumor grade etc.) Hispanic ‘Paradox’ – low SES and RFs for mortality but has mortality advantage Lack of info. on providers (physicians and hospitals), on patient/physician preference on the choice of the therapy, and on PSA screening and surveillance Men age 65 or older, and in 11 SEER areas  Generalizability to younger men and other regions or country?

Questions/Comments Thanks for your attention!