Changing patterns of gallbladder carcinoma in New Mexico

BACKGROUND. American Indians in the U.S. have a high incidence of gallbladder carcinoma (GBC). Furthermore, American Indians in New Mexico (NM) have the highest incidence rate of GBC in the U.S. The epidemiology of GBC in NM has not been studied in the past 3 decades. METHODS. By using the NM Tumor Registry (NMTR) and the Surveillance, Epidemiology, and End Results (SEER) database, age-specific incidence rates, average annual age-adjusted incidence rates, and incidence rate time trends of GBC were compared among the three major ethnic groups in NM: American Indians, Hispanics, and non-Hispanic whites, for the period 1973-2001. RESULTS. A sharp increase in GBC incidence occurred with advanced age and started earlier in American Indians (at age 55) than Hispanics (at age 60) than non-Hispanic whites (at age 65). GBC occurred more frequently in females than in males in all ethnic groups. In females, the incidence of GBC was the highest in American Indians (14.5 per 100,000) followed by Hispanics (6.8 per 100,000) and non-Hispanic whites (1.4 per 100,000). Similarly in males, American Indians had the highest incidence rate of GBC (7.8 per 100,000), followed by Hispanics (2.0 per 100,000), and non-Hispanic whites (1.0 per 100,000). The time trend analysis revealed that there has been a disproportionate decline in the incidence of GBC in the three ethnic groups, with the greatest drop in American Indians and Hispanics followed by non-Hispanic whites. Despite the decline, American Indians continued to have the highest incidence rate of GBC in NM. CONCLUSION. The incidence of GBC has declined disproportionately in the three major ethnic groups, with the greatest decrease in American Indians and Hispanics followed by non-Hispanic whites.