[Contribution] Why ursodeoxycholic acid may help prevent gallstones after gastric cancer surgery

It is well established through numerous studies that patients who undergo gastric cancer surgery are more likely to develop gallstones than the general population. For this reason, some hospitals prescribe ursodeoxycholic acid for a certain period after surgery. However, practices vary among institutions, and the optimal duration of treatment has not yet been clearly established.

Why, then, do gallstones occur more frequently after gastric cancer surgery?

Professor Song Kyo-young

The gallbladder stores bile produced by the liver and releases it into the duodenum in response to food intake. Following gastric cancer surgery, however, gallbladder motility often declines and bile flow may be altered, creating favorable conditions for gallstone formation. One of the most common reasons is vagus nerve transection.

During gastrectomy, cutting the vagus nerve -- which runs along the esophagus -- is often necessary to achieve complete lymph node dissection. The problem is that some branches of the vagus nerve help regulate gallbladder contraction. When these branches are severed, gallbladder movement becomes sluggish, bile stagnates, and the risk of gallstone formation increases.

Reduced food intake and rapid postoperative weight loss are also important contributing factors. After surgery, patients often eat less and may experience rapid weight loss, which can disrupt bile composition and promote gallstone formation. The method used to reconstruct the digestive tract after gastrectomy can also affect outcomes. In Roux-en-Y reconstruction, for example, food bypasses the duodenum, reducing gallbladder stimulation and potentially worsening bile stasis.

In addition, prolonged fasting or poor nutritional status immediately after surgery may further impair gallbladder function. As a result, studies have reported gallstone incidence rates ranging from about 5 percent to 25 percent after gastric cancer surgery -- significantly higher than in the general population.

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There is also a period during which gallstones are most likely to develop. Current evidence suggests that the highest incidence occurs within the first one to three years after gastric cancer surgery. Patients at particularly high risk include those who have undergone total gastrectomy, those reconstructed with the Roux-en-Y method, and individuals who experience rapid postoperative weight loss. Elderly patients, men, patients with diabetes, and those who receive adjuvant chemotherapy may also face an elevated risk.

So, can ursodeoxycholic acid help these patients?

Ursodeoxycholic acid improves bile flow and helps inhibit the formation of cholesterol gallstones. It is also widely used to prevent gallstones in patients undergoing bariatric surgery or experiencing rapid weight loss. Clinical studies conducted in Korea, including research involving Seoul St. Mary's Hospital and several other centers, have reported lower rates of gallstone formation among gastric cancer patients who received ursodeoxycholic acid.

Patients who received ursodeoxycholic acid developed gallstones less frequently than those who did not, with the preventive effect being particularly evident during the first year after surgery. However, there is still no international consensus regarding which patients should receive the medication, what dosage should be used, or how long treatment should continue. In current clinical practice, the drug is often prescribed for six months to one year after surgery, particularly for patients considered at high risk.

If gallstones develop after gastric cancer surgery, does every patient require another operation?

The answer is no. In many cases, gallstones are discovered incidentally on CT scans or ultrasound examinations and cause no symptoms or inflammation. Such patients are generally managed through observation and follow-up.

However, if gallstones progress to symptomatic cholecystitis, surgery may become necessary. Symptoms may include right upper abdominal pain, fever, and jaundice. Once diagnosed, cholecystectomy -- the surgical removal of the gallbladder -- is usually recommended. In patients who have previously undergone gastric cancer surgery, severe intra-abdominal adhesions may make laparoscopic cholecystectomy technically challenging, sometimes requiring an open surgical approach.

Some studies have suggested performing prophylactic cholecystectomy at the time of gastric cancer surgery because of the increased risk of gallstones and the greater technical difficulty of later gallbladder surgery due to postoperative adhesions. Nevertheless, prophylactic gallbladder removal is not routinely recommended for most patients today.

There are, however, special circumstances in which simultaneous cholecystectomy may be considered during gastric cancer surgery. These include patients with pre-existing gallstones, gallbladder polyps or other gallbladder diseases, and patients expected to undergo reconstructive procedures that may make future endoscopic access particularly difficult.

In summary, gastric cancer surgery is associated with an increased risk of gallstone formation, particularly during the first few years after the procedure. Several studies have shown that ursodeoxycholic acid may help reduce that risk, leading some hospitals to prescribe the medication for a period after surgery, especially in high-risk patients.

Most gallstones that develop after surgery remain asymptomatic and can be monitored without intervention. However, patients who develop cholecystitis may require gallbladder removal. These considerations underscore the importance of regular follow-up after gastric cancer surgery.