Studying non-Hodgkin's lymphoma in two Oklahoma counties: a call for centralized cancer data management

Anecdotal evidence for an increased incidence of non-Hodgkin's lymphoma (NHL) had been informally discussed within several clinical practices in north central Oklahoma. This study was conducted to determine the incidence rates of NHL in Garfield and Kingfisher counties and to evaluate whether these counties represented unique cancer clusters. Data were collected from medical records and tumor registries in 22 area hospitals between 1990-1994. The annual incidence rate per 100,000 persons for Garfield county was 15.51 (95% CI: 10.9-20.1), and for Kingfisher county, 24.22 (95% CI: 12.4-36.1). Both of these rates are increased from the national incidence rate of 13.7 cases of NHL per 100,000 persons, suggesting a significant clinical impact. However, a statistical significance was not detected given the conservative methodology and the small populations involved. The difficulties of performing community-based research, the need for epidemiological studies to reduce clinical experience bias, and the need for centralized cancer data management are discussed.