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M.V. Brock



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    MO11 - Screening and Epidemiology (ID 131)

    • Event: WCLC 2013
    • Type: Mini Oral Abstract Session
    • Track: Imaging, Staging & Screening
    • Presentations: 1
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      MO11.06 - Minority Status as a Strong Predictor of Health Disparities: A Global Perspective (ID 3296)

      16:15 - 17:45  |  Author(s): M.V. Brock

      • Abstract
      • Presentation
      • Slides

      Background
      The existence of healthcare disparities by race and ethnicity is well documented, often attributed to a lack of economic and educational parity among groups, and manifested by unequal healthcare access and delivery. Inexplicably however, in many countries the wealthiest and most educated populations have the worst health outcomes. We hypothesize that minority status within a country rather than race, ethnicity, socioeconomics or educational level is more closely associated with poor health outcomes globally and functions independently of other variables.

      Methods
      Minority and majority populations in 34 countries/territories were evaluated for smoking prevalence and age-adjusted lung cancer incidence rates. A global, systematic review of over 1000 sources of epidemiological data was performed using rigorous screening criteria including only national data in original form (national cancer registry, census, or health surveys), from an official government agency, or from peer-reviewed publications. Relative risks (RR) of smoking and lung cancer were computed for all minority groups with the majority population as the referent null. Relative wealth based on median per capita income and relative schooling based on educational attainment were also calculated. Minority groups were only included if so defined by both the Minority Rights Group International and the CIA World Fact Book.

      Results
      Data were collected from approximately 60% of the global population including all six WHO world regions and every populated continent. The RR of smoking for at least one minority group was greater than that of the referent majority in every country or territory analyzed. The RR of lung cancer for at least one minority group was greater than that of the referent majority in all but three countries/territories. These results were remarkably consistent and durable with RR ≥ 1.0 for smoking prevalence and lung cancer incidence in nearly all countries despite minority status being defined differently in many nations whether by race, ethnicity, religion, language, indigenous affiliation, or immigrant status. These results were further corroborated by age-specific lung cancer incidence for selected countries/territories. Racial and socioeconomic status differentials were insufficient explanations for these observations. In the U.S., for example, blacks are generally less wealthy and educated than whites and have higher smoking prevalence and lung cancer incidence rates. However, in neighboring Bermuda and distant South Africa where blacks are the majority, whites have both higher smoking prevalence and lung cancer incidence rates despite being far wealthier and educated. This relationship of increased smoking and lung cancer rates in wealthier, more educated minorities is replicated in nine of the 34 countries in this study.

      Conclusion
      Our results show an empirical relationship between minority status and both increased smoking prevalence and lung cancer incidence rates in minority populations globally. This suggests that minority status may be a potent, behavioral driver leading to elevated health risks in minority populations around the world. Moreover, minority status seems to be independent of traditional socioeconomic variables, and alone may be a powerful predictor of disparate health outcomes in many diverse nations, distinctive societies, and unique cultures on a global scale.

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    P1.20 - Poster Session 1 - Early Detection and Screening (ID 172)

    • Event: WCLC 2013
    • Type: Poster Session
    • Track: Imaging, Staging & Screening
    • Presentations: 1
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      P1.20-010 - A Prospective Study of Annual CT Screening for Lung Cancer in HIV Smokers (ID 3367)

      09:30 - 16:30  |  Author(s): M.V. Brock

      • Abstract

      Background
      Of all the non-AIDS associated malignancies, lung cancer is the most deadly because of its advanced stage of presentation. Within the HIV population, the incidence of non-small cell lung cancer (NSCLC) is estimated to be 2-4 times that of the general population. Despite this growing burden of NSCLC in HIV-infected smokers, no data exist regarding early detection of lung cancer in this population since screening trials, such as the U.S. National Lung Cancer Screening Trial, excluded HIV-infected participants. Preliminary data have highlighted the ineffectiveness of chest x-rays in diagnosing lung cancer early, and waiting for HIV-positive individuals to develop symptoms is misguided. These facts provide a compelling argument for the use of helical CT as a screening tool for lung cancer in HIV-infected patients.

      Methods
      From 2006-2013, a prospective feasibility study was conducted to determine the prevalent and incident CT detection rates in HIV-infected smokers of lung cancer. The secondary objective was to determine if CT screening could change the stage distribution of HIV lung cancer to that of an early stage disease. Annual CT screening was conducted for lung cancer in current or former smokers over age 25 years old with ≥20 pack-years history and a confirmed HIV diagnosis. To determine markers of lung cancer risk, we also analyzed from trial participants, clinical data, sera, and CT scans using quantitative, densitometry imaging as an estimate of emphysema, and compared these variables to similar parameters from 130 HIV patients at our institution with known lung cancer.

      Results
      Of the 224 individuals enrolled, 72% were males, 90% African-Americans, 9.5% Caucasian, and 0.5% Hispanic. The median age was 48 years and the median number of smoking pack-years was 34. No prevalent lung cancers were detected by CT screening and only lung cancer was found on incident screening. There were no interim diagnoses of lung or extrapulmonary cancers. Eighteen deaths occurred but none were cancer-related. Of 29 nodules detected at baseline screening, fifteen were further imaged, five biopsied, but none progressed to cancer at study end. Emphysema was commonly observed and its heterogeneity across the entire lung as measured by CT densitometry was significantly higher in HIV subjects with lung cancer than in those without (p≤0.01). On multivariate regression, increased age, higher smoking pack-years, low CD4 nadir, and increased heterogeneity of emphysema on quantitative CT imaging were all significantly associated with lung cancer in HIV individuals.

      Conclusion
      This pilot feasibility study is the world’s first reported annual lung cancer CT screening trial in HIV-positive smokers. During 4 years of CT screening of 224 HIV subjects with a median age of 48 years, only one incident lung cancer was found. This suggests that until the median age of the worldwide HIV population increases, the ability of annual CT screening to detect lung cancers in HIV-infected smokers will be low. Immunologic and radiographic differences that exist between HIV patients with and without lung cancer may serve as biomarkers of lung cancer risk.