Although relatively rare, gallbladder cancer is a very invasive form of cancer. Signs and symptoms are similar to those of gallstones, and they usually appear only after the cancer has spread. Early gallbladder cancer is often only discovered when the gallbladder is removed to treat gallstones. The exact cause of gallbladder cancer isn’t clear, but people with gallstones are four to five times more likely to have gallbladder cancer than are people without stones. Removing the gallbladder and possibly some surrounding tissue may cure cancers that are found early.