Your gallbladder is a small sac-like organ about 3 inches long and 1 inch wide that lives underneath your liver. Its job is to store bile, which is a fluid made by your liver. After being stored in your gallbladder, bile is released into your small intestine to help digest food.

Gallbladder cancer is rare. According to the American Cancer Society (ACS):

  • Just over 12,000 people in the United States will receive a diagnosis in 2019.
  • It’s almost always adenocarcinoma, which is a type of cancer that starts in glandular cells in the lining of your organs.

Doctors don’t know exactly what causes gallbladder cancer. They do know that, like all cancer, an error, known as a mutation, in a person’s DNA causes uncontrolled rapid growth of cells.

As the number of cells quickly increases, a mass, or tumor, forms. If not treated, these cells eventually spread into nearby tissue and to distant parts of the body.

There are risk factors that increase the odds for gallbladder cancer. Most of them are related to long-term gallbladder inflammation.

Having these risk factors doesn’t mean you’ll get cancer. It just means your chances of getting it may be higher than someone without the risk.

Risk factors

Gallstones are little chunks of hardened material that form in your gallbladder when your bile contains too much cholesterol or bilirubin — a pigment formed when red blood cells break down.

When gallstones block the passageway — called bile ducts — out of the gallbladder or in your liver, your gallbladder becomes inflamed. This is called cholecystitis, and it can be an acute or long-term, chronic problem.

Chronic inflammation from cholecystitis is the biggest risk factor for gallbladder cancer. According to the American Society of Clinical Oncology (ASCO), gallstones are found in 75 to 90 percent of people with gallbladder cancer.

But it’s important to remember that gallstones are extremely common and having them doesn’t mean you’ll get cancer. According to ASCO, over 99 percent of people with gallstones never get gallbladder cancer.

Some other factors associated with the risk of gallbladder cancer are:

  • Porcelain gallbladder. This is when your gallbladder looks white, like porcelain, because its walls are calcified. This can occur after chronic cholecystitis, and it’s associated with inflammation.
  • Gallbladder polyps. Only about 5 percent of these small growths in your gallbladder are cancerous.
  • Sex. According to the ACS, women get gallbladder cancer up to four times more often than men.
  • Age. Gallbladder cancer typically affects people over 65. On average, people are 72 when they find out they have it.
  • Ethnic group. In the United States, Latin Americans, Native Americans, and Mexicans have the highest risk of gallbladder cancer.
  • Bile duct problems. Conditions in the bile ducts that block the flow of bile can cause it to back up into the gallbladder. This causes inflammation, which increases the risk of gallbladder cancer.
  • Primary sclerosing cholangitis. Scarring that forms due to inflammation of the bile ducts increases your risk of bile duct and gallbladder cancer.
  • Typhoid. Salmonella bacteria causes typhoid. People with chronic, long-term infections with or without symptoms have a higher risk of gallbladder cancer.
  • Family members with gallbladder cancer. Your risk goes up slightly if there’s a history of it in your family.

Noticeable symptoms of gallbladder cancer typically don’t appear until the disease is very advanced. That’s why, usually, it’s already spread to nearby organs and lymph nodes or traveled to other parts of your body when it’s found.

When they do occur, signs and symptoms may include:

  • abdominal pain, usually in the upper right portion of your abdomen
  • jaundice, which is yellowing of your skin and the whites of your eyes due to high levels of bilirubin from obstruction of your bile ducts
  • lumpy abdomen, which occurs when your gallbladder enlarges due to blocked bile ducts or the cancer spreads to your liver and lumps are created in your upper right abdomen
  • nausea and vomiting
  • weight loss
  • fever
  • abdominal bloating
  • dark urine

Occasionally, gallbladder cancer is found by coincidence in a gallbladder that was removed for cholecystitis or another reason. But usually, your doctor will run diagnostic tests because you had symptoms appear.

Tests that might be used to diagnose, stage, and plan treatment for gallbladder cancer include:

  • Blood tests. Liver function tests show how well your liver, gallbladder, and bile ducts are working and give clues about what’s causing your symptoms.
  • Ultrasound. Images of your gallbladder and liver are created from sound waves. It’s a simple, easy-to-perform test that’s usually done before others.
  • CT scan. The images show your gallbladder and surrounding organs.
  • MRI scan. The images show greater detail than other tests.
  • Percutaneous transhepatic cholangiography (PTC). This is an X-ray taken after dye is injected that shows blockages in your bile ducts or liver.
  • Endoscopic retrograde cholangiopancreatography (ERCP). In this test, a lighted tube with a camera, known as an endoscope, is inserted through your mouth and advanced to your small intestine. Dye is then injected through a small tube placed in your bile duct and an X-ray is taken to look for blocked bile ducts.
  • Biopsy. A small piece of the tumor is removed and looked at under a microscope to confirm a cancer diagnosis.

Cancer staging tells you if and where the cancer has spread outside of your gallbladder. It’s used by doctors to decide on the best treatment strategy and determine the outcome.

Gallbladder cancer is staged using the American Joint Committee on Cancer TNM staging system. The scale goes from 0 to 4 based on how far the cancer has grown into the gallbladder wall and how far it’s spread.

Stage 0 means the abnormal cells haven’t spread from where they first formed — called carcinoma in situ. Larger tumors that spread to nearby organs and any tumor that’s spread, or metastasized, to distant parts of your body are stage 4.

More information about cancer spread is given by TNM:

  • T (tumor): indicates how far the cancer has grown into the gallbladder wall
  • N (nodes): indicates spread to lymph nodes close to your gallbladder
  • M (metastasis): indicates spread to distant parts of the body

Surgery can potentially cure gallbladder cancer, but all of the cancer must be removed. This is only an option when the cancer’s found early, before it’s spread to nearby organs and other parts of the body.

Unfortunately, statistics from the ACS show only about 1 in 5 people get a diagnosis before the cancer has spread.

Chemotherapy and radiation are often used to make sure all the cancer is gone after surgery. It’s also used to treat gallbladder cancer that can’t be removed. It can’t cure the cancer but can prolong life and treat symptoms.

When gallbladder cancer is advanced, surgery can still be done to relieve symptoms. This is called palliative care. Other types of palliative care may include:

  • pain medication
  • nausea medication
  • oxygen
  • placing a tube, or stent, in the bile duct to keep it open so it can drain

Palliative care is also used when surgery can’t be done because a person isn’t healthy enough.

The outlook for gallbladder cancer depends on the stage. Early-stage cancer has a much better outlook than advanced-stage cancer.

The five-year survival rate refers to the percentage of people with a condition that are alive five years after diagnosis. On average, the five-year survival rate for all stages of gallbladder cancer is 19 percent.

According to ASCO, the five-year survival rate for gallbladder cancer by stage is:

  • 80 percent for carcinoma in situ (stage 0)
  • 50 percent for cancer confined to the gallbladder (stage 1)
  • 8 percent for cancer that’s spread to the lymph nodes (stage 3)
  • less than 4 percent for cancer that has metastasized (stage 4)

Because most of the risk factors, such as age and ethnicity, can’t be changed, gallbladder cancer can’t be prevented. However, having a healthy lifestyle may help lower your risk. Some tips for a healthy lifestyle may include:

  • Maintaining a healthy weight. This is a big part of a healthy lifestyle and one of the main ways to lower your risk of getting many kinds of cancer, including gallbladder cancer.
  • Eating a healthy diet. Eating fruits and vegetables can help boost your immune system and help protect you from getting sick. Eating whole grains instead of refined grains and limiting processed foods can also help you stay healthy.
  • Exercising. The benefits of moderate exercise include reaching and maintaining a healthy weight and strengthening your immune system.