A study was performed to distinguish between genetic vs socioeconomic factors or artifacts inherent in retrospective studies to discover explanations for the apparent shorter survival of blacks than whites with lung and colon cancer.
Detailed biological and socioeconomic data were collected prospectively from a large cohort of patients with advanced lung and colon cancer who had not previously received chemotherapy and who consented to be entered in the clinical trial. Twelve medical centers within the Department of Veterans Affairs hospital system (Veterans Affairs Cooperative Study 188) entered patients between May 1981 and May 1986. These patients were evaluated and treated in a uniform manner within this hospital system and followed up to death. Outcome measures included time to tumor progression, tumor response, and survival.
A total of 719 patients were entered in the study, 704 of whom were either black or white men. Blacks were found to have a significantly lower socioeconomic status than whites as measured by marital and educational status, occupation, income, housing, and number of individuals residing in household. Blacks had a significantly lower frequency of prior tumor resection and a significantly increased frequency of mediastinal lymph node involvement and of metastasis than whites. Trends existed toward a shorter time interval from original diagnosis to entry and a lower frequency of prior radiation therapy among blacks in comparison with whites at the time of entry to the study. However, no differences in intensity of treatment or follow-up, time to progression, response to treatment, or overall survival (measured from entry to the study to death) were observed for blacks vs whites.
Lung and colon cancer are not necessarily more aggressive diseases in blacks than in whites. Based on a comparison of these data with those reported from other practice settings, we postulate that lung and colon cancer outcomes may be similar among black and white patients who receive equal access to comparable medical care in spite of socioeconomic differences. Findings suggest that future studies might focus profitably on racial factors that may exist at the time of patient entry to the health care system.(Arch Intern Med. 1993;153:1681-1688)