Gallbladder cancer is the 6th most common digestive cancer in the United States. American Cancer Society statistics estimate 6,000 new cases in 2009. Although the incidence rate is fairly low in the U.S. the death rate is high, because most new cases are not found until the cancer has spread beyond the gallbladder. Only 20% of gallbladder cancers are found in the early stages (before metastasis). This cancer is more common in females and usually occurs at age 60 or older. Obesity is also a risk factor because obese individuals are more likely to have gallstones. Native and Mexican Americans also have higher gallbladder cancer rates than other American ethnic groups. Chronic inflammation of the gallbladder and large gallstones are thought to increase cancer risk. Researchers now believe that inflammation and gallstones may cause the gallbladder to drain more slowly. This exposes the gallbladder to more bile and can irritate the gallbladder lining. It also increases the amount of time the cells are exposed to carcinogens which may be in the bile. All of these factors can result in malignant changes to the gallbladder cells.
Symptoms of gallbladder cancer can include upper right quadrant pain and tenderness (worse after eating a fatty meal), nausea, vomiting, weight loss and jaundice. These symptoms may also be seen in people with gallstones so having these symptoms is more likely to be gallstones than cancer. Lab tests may show an elevated serum bilirubin as well as cancer markers in more advanced stages.
The following imaging studies may be used for diagnosis: Ultrasound, ERCP, CT (with oral/IV contrast), and MRI. Ultrasound is usually the first modality used because of low cost. Treatment is based on the staging on the disease but is usually surgical, followed by chemotherapy and radiation therapy. Unfortunately, only 20 - 25% of gallbladder cancers are found early enough to be treated by surgery only. 5 year survival rates for stage 2 – 5 gallbladder cancers are low, from 2% to 7%. 5 year survival rates for cancer that has not spread beyond the gallbladder range from 29% to 81%.
This contrast CT image shows invasion of the liver (arrow) and a malignant gallbladder mass and gallstone (arrowhead).
American Cancer Society Detailed Guide: Gallbladder Cancer. Accessed February 8, 2010 at http://www.cancer.org/docroot/CRI/CRI_2_3x.asp?rnav=cridg&dt=68
MayoClinic.com. Gallbladder Cancer. Accessed February 8, 2010 at http://www.mayoclinic.com/health/gallbladder-cancer/ds00425
Image: RadioGraphics September 2008 vol. 28 no. 5 1307-1323. Accessed February 8, 2010 at http://radiographics.rsna.org/content/28/5/1307/F13.large.jpg
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