Gallbladder cancer is the most common biliary tract cancer. The highest incidence rates occur in Chile, which also has the highest mortality rates. This lethal gastrointestinal cancer has a predilection among adult women and older subjects of both sexes, and also among populations throughout central and Eastern Europe and certain racial groups, such as Native American Indians. Unfortunately, prospects are poor for preventing this form of cancer.
Gallbladder cancer is a rare cancer that was first described more than 2 centuries ago. Individuals with gallbladder cancer usually have no symptoms or signs and deteriorate quickly with the development of metastatic disease. Unfortunately, this gastrointestinal cancer continues to have a poor prognosis because of late diagnosis and few effective treatment options. Gallbladder cancer is an unusual gastrointestinal cancer in that it is much more common among older women than men. The incidence of gallbladder cancer also shows wide geographic and ethnic variations. Understanding the epidemiology of gallbladder cancer has and will continue to provide valuable insights into determining causes and risk factors for gallbladder cancer.
Descriptive epidemiology
Incidence
In describing the incidence of gallbladder cancer, two sources of data have been used. First, the Cancer Incidence in Five Continents, Volume IX (CI5) presents incidence data from populations worldwide. The reference period for this volume was defined as 1998 to 2002. In addition, data was obtained from the Surveillance, Epidemiology, and End Results (SEER) Program of the National Cancer Institute (NCI), which is a leading source of information on cancer incidence and survival in the United States. SEER currently collects and publishes cancer incidence and survival data from population-based cancer registries covering approximately 26% of the United States population. SEER coverage includes 23% of African Americans, 40% of Hispanics, 42% of American Indians and Alaska Natives, 53% of Asians, and 70% of Hawaiian/Pacific Islanders.
World
Using data from the CI5 database, the world standardized incidence rates for gallbladder cancer for men ( Fig. 1 ) and women ( Fig. 2 ) was determined. Chile (Valdivia) was found to have the highest incidence of gall bladder cancer among men and women: 12.3 and 27.3 per 100,000 population, respectively (ASW, age-standardized to the world population). Among the top 10 locations around the world, men seem to have very little geographic variation, with regions in Korea and Japan making up most of these. Most of the top 50 locations for gallbladder cancer have an incidence of approximately 3.0 to 4.0 per 100,000. Geographic locations for women however, shows more variation for gallbladder cancer, with regions in India, Peru, Korea, Japan, Columbia, and the United States among the top 10 locations. Among women, incidences of gallbladder cancer among the top 50 locations around the world are higher than those for men, with most between 4.0 and 6.0. The highest incidence rates among women are twice those of men, but incidence rates decline sharply for women and show a steady decline among men.
United States
According to the CI5 data, the highest incidence of gallbladder cancer in the United States occurs among Korean men in Los Angeles and American Indian women in New Mexico (ASW, 5.9 and 7.1, respectively). Among men, American Indians are next in terms of incidence (3.8), with Hawaiians (3.2) in Hawaii, Japanese (2.6) in Los Angeles, and African Americans (2.5) in Connecticut constituting the top five United States locations.
Among the top five United States locations with the highest incidence of gallbladder cancer for women, Hispanic Whites (3.9) from Los Angeles were second, followed by Koreans (3.6) in Los Angeles, Hispanic Whites (3.5) from California, and Hispanic Whites from San Francisco (3.3) . The high incidence of gallbladder cancer among non-White ethnic groups suggests that either genetic or environment factors are responsible for these high rates.
Data from the United States ( Figs. 3–6 ) show changes in incidence over time for women (1992–2006), with Asian/Pacific Islanders showing a gradual decline in gallbladder cancer incidence from 2.7 in 1992 to 0.7 in 2006 (see Fig. 3 ). Hispanics also showed a decreased incidence from 4.5 in 1992 to 2.5 in 2006 (see Fig. 4 ). African Americans showed no real change in incidence over this 15-year period (see Fig. 5 ), which is similar to non-Hispanic White women, who show a very slight decrease during this timeframe (see Fig. 6 ).
