Lung cancer in African-Americans and analysis of estrogen plus progestin use.

Abstract

e18258 Background: The 15-year Women’s Health Initiative (WHI) sponsored by the NIH has provided a robust dataset on health risks for post-menopausal black women (BW), including the impact of hormone therapy (HRT) on cancer risk. Women enrolled in the WHI randomized, placebo-controlled trial and taking HRT demonstrated no increase in lung cancer incidence, but a statistically significant increase in mortality. However, effects of estrogen plus progestin on non-small cell lung cancer (NSCLC) incidence and outcomes has not been extensively examined, especially in African Ancestry (AA) and smoking history. Methods: Study participants were identified who met WHI clinical trial entry criteria. Cox regression models and Kaplan-Meier method plots were utilized. Analyses adjusted for age, BMI, education, smoking status, alcohol use, health status, and physical activity. A secondary analysis was performed on BW based on AA via Affymetrix Human SNP Array. Results: 161, 808 pts were enrolled from October 1993 to December 1998 (after exclusions total analytic cohort = 142,503). 128,682 (90%) were white (WW) and 13,821 (10%) were BW. BW had lower incidence of NSCLC compared to WW (HR 0.68; P < .0001). HRT participants had a 55% increase in incidence of NSCLC (p < .0001). Former alcohol users had highest risk of NSCLC incidence (HR 2.72; p < 0.0001). Age groups (55-59 years; 60-69 years; 70-79 years) were significantly less associated with BW compared to the youngest(50-54 years; P < .0001). HRT participants were more likely BW (OR 1.17; p < .0001). More current smokers were BW compared to WW (OR 1.75; p < .0001). HRT participants had increased risk of death to NSCLC (HR 1.29; p < .001). There was a trend for survival (p = 0.3667) in WW participants compared to BW (32 vs 28.0 months, respectively). BW who had > 80% AA had a decreased incidence NSCLC trend compared to BW with < 80% AA (HR 0.81; p = 0.2806). Conclusions: BW, especially those with high levels of AA had decreased incidence of NSCLC. Those patients who received HRT had higher incidence and death from NSCLC. Further investigations are required to understand the mechanisms that AA and HRT alter risks associated with NSCLC.