Background. Disparities have been observed in both the incidences of lung and esophageal cancers and the survival of those patients. Our goals were to determine if race was associated with stage of cancer at diagnosis, and to identify predictors of advanced-stage lung and esophageal cancers.
Methods. All cases of lung and esophageal cancer between 1991 and 1995 in the Savannah River Region Information System cancer registry were studied. Data were analyzed using logistic regression to identify independent predictors of advanced disease at the time of diagnosis.
Results. Among lung cancer patients, histology and distance to nearest hospital predicted diagnosis at an advanced stage. Residence in an area with a high proportion of Medicaid recipients was a predictor of advanced stage in esophageal cancer patients.
Conclusions. In this predominantly rural area, decreased utilization of health services was evident among older, poor, black, rural cancer patients. Further investigation involving prospective data collection from cancer patients is warranted.
Lung cancer is the second most frequent malignancy and the leading cause of cancer-related deaths in both men and women. It was estimated that there would be 169,500 new cases of lung cancer and 157,400 lung cancer deaths in the United States in 2001. The burden of lung cancer is greater in the black than in the white population of the United States. The Surveillance, Epidemiology, and End Results (SEER) program reported that the age-adjusted incidence of lung cancer was 56.3 per 100,000 among whites and 72.4 per 100,000 among blacks in 1998. The 5-year relative survival for lung cancer between 1992 and 1997 was 14.8% among whites and 11.7% among blacks. Cancer of the esophagus is less common than lung cancer but imposes an especially high burden on the black population. It was estimated that there would be 13,200 new cases of esophageal cancer in the United States in 2001, and 12,500 esophageal cancer deaths. According to SEER, the age-adjusted incidence of esophageal cancer in 1998 was 3.6 per 100,000 among whites and 7.5 per 100,000 among blacks. The 5-year survival for esophageal cancer patients between 1992 and 1997 was 15.1% among whites and 9.0% among blacks.
The two overarching goals of the US Healthy People 2010 program are to increase the quality and years of healthy life, and to eliminate health disparities. The Healthy People 2010 goal for cancer is to reduce the number of new cases, as well as the disability and death it causes. The overall target is a 21% reduction in cancer deaths, focusing on the more prevalent and preventable cancers. The specific objective for lung cancer is a 22% reduction in deaths; no specific targets are included in Healthy People 2010 for esophageal cancer. The overall goals of the National Cancer Institute (NCI) Strategic Plan to Reduce Health Disparities are to understand the causes of health disparities and to develop effective interventions to eliminate them; the objectives are to conduct cancer control and population research to elucidate the causes of cancer-related health disparities, and to define and monitor them. Our study addresses these national priorities.
The Savannah River Regional Health Information System (SRRHIS) is a population-based cancer registry jointly developed by the Medical University of South Carolina in Charleston, and Emory University in Atlanta, Georgia. All incident cancer cases in the 22 counties surrounding the Savannah River (10 counties in South Carolina, 12 in Georgia) occurring from 1991 through 1995 were identified. The SRRHIS documented racial disparities in the incidence of lung and esophageal cancer. The incidence of lung cancer is higher in young black men than in white men, but is lower in black women than in white women. The incidence of esophageal cancer is higher in black men than in white men and higher in black women than in white women. Thus, racial disparities reported nationally are also present in this predominantly rural region with a high proportion of African Americans.
For patients with lung or esophageal cancer, the stage of cancer at diagnosis and treatment received are the major determinants of outcome. Stage of cancer at diagnosis varies by the age, sex, and race of the patient, and by the histology of the cancer. In addition, personal illness behavior and health-system factors may influence access to health care, and could be related to the stage of cancer at diagnosis.
Access to care has been defined by the Institute of Medicine as "the timely receipt of personal health care services to achieve the best possible outcome." Reduced access to care is believed to be associated with reduced use of health services, more severe illness, and worse health outcomes. In this study, we adapted a conceptual framework for the investigation of access to health care and used data from the SRRHIS cancer registry and the US census to identify factors that may be associated with advanced stage of cancer at diagnosis. We hypothesized that socioeconomic factors (education, marital status, military service), geographic factors (distance to nearest hospital, number of primary care physicians), and health system factors (health insurance) are associated with having advanced-stage lung cancer or esophageal cancer at the time of diagnosis.