The gallbladder is a small sac-like organ that forms part of the biliary tract. Bile, produced in the liver, flows into the gallbladder, where it is stored and concentrated until released into the small intestine. Approximately 90–95 per cent of gallbladder cancers are adenocarcinomas, while only a small proportion are squamous cell carcinomas.
Incidence and survival rates
Gallbladder cancer is the twentieth most common cancer worldwide and the seventeenth most common cause of death from cancer. Although rates of gallbladder cancer are generally declining, survival rates are low; about 178,100 new cases were diagnosed around the world in 2012, but the number of deaths from the disease was relatively high by comparison at 142,800.
One of the reasons for the low survival rates is that gallbladder cancer symptoms do not generally manifest in the early stages of the disease, which means that the cancer is often advanced by the time it is diagnosed.
Gallbladder cancer is more common in women than men – about 57 per cent of cases occur in women – and the highest rates are seen in eastern Asia, which accounts for 45 per cent of all cases worldwide.
Lifestyle factors and gallbladder cancer risk
In this report from our Continuous Update Project (CUP) – the world’s largest source of scientific research on cancer prevention and survivorship through diet, nutrition and physical activity – we analyse global research on how certain lifestyle factors affect the risk of developing gallbladder cancer. This webpage forms part of the World Cancer Research Fund/American Institute for Cancer Research Third Expert Report Diet, Nutrition, Physical Activity and Cancer: a Global Perspective.
Findings on gallbladder cancer
There is strong evidence that:
- being overweight or obese increases the risk of gallbladder cancer
Other causes of gallbladder cancer
Other causes, with the exception of gallstones, have not been established.
The pathogenesis of gallbladder cancer is not well understood, partly because it is often diagnosed at a late stage. Having gallstones increases the risk of this cancer. Inflammation associated with gallstones decreases the speed at which bile empties from the gallbladder; gallstones may also have a direct effect by blocking the transit of bile or by causing direct mechanical irritation to the surrounding mucosal surface. Other factors may also be involved, and many toxins, whether they come from diet, smoke inhalation or other environmental sources (and their metabolic products), are excreted and concentrated in the bile.
Link between body fat and gallbladder cancer
The precise way in which body fatness, obesity, or energy balance specifically influence the risk of gallbladder cancer needs more research.
Obesity is a known cause of gallstone formation and having gallstones increases the risk of gallbladder cancer.
Other more general factors may be involved. Body fatness increases the levels of hormones circulating in the body – such as insulin and insulin-like growth factors – creating an environment that may encourage the development or progression of cancer in a variety of organs.
Body fat also stimulates a general inflammatory response, which may contribute to the development of several cancers.
Full references and a summary of the mechanisms underpinning all the findings can be found in the gallbladder cancer report.
How the research was conducted
The global scientific research on diet, nutrition, physical activity and the risk of gallbladder cancer was systematically gathered and analysed, and then independently assessed by a panel of leading international scientists in order to draw conclusions about which of these factors increase or decrease the risk of developing gallbladder cancer.
This webpage is a summary.
For much more, download the full chapter.