Ethanol Injections Can Ablate Pancreatic Cysts

PHILADELPHIA — Endoscopic injection of ethanol into pancreatic cysts may be an effective alternative to surgery for eliminating premalignant lesions, based on results from a randomized pilot study with 42 patients.

“The big question is whether alcohol injection will prevent development of pancreatic cancer over the long term,” Dr. William R. Brugge said at the annual meeting of the American College of Gastroenterology.

It's also unclear whether patients with newly discovered cysts might fare even better if they're simply monitored annually by CT or MRI to allow early detection of cases in which pancreatic cysts progress to cancer.

The major downside of endoscopic alcohol injection of pancreatic cysts is that some alcohol may enter the pancreas and cause pain. In the study conducted by Dr. Brugge and his associates, two of the patients treated with an alcohol injection developed pancreatitis, although in both cases the inflammation was mild and self-resolving, lasting for about 24 hours, said Dr. Brugge, director of endoscopy at Massachusetts General Hospital, Boston.

The primary advantage of alcohol ablation is that it is minimally invasive, which makes it well suited for older patients, who are the ones most likely to have mucinous cystic lesions in the pancreas. Most patients with pancreatic cysts are currently diagnosed incidentally when they have a CT scan for another reason, such as diverticulitis.

During October 2004 to June 2007, the study enrolled 42 patients with pancreatic cysts; their average age was 69 years. Under endoscopic ultrasound guidance, a biopsy needle was introduced endoscopically to aspirate fluid from the largest cyst in each patient. The average diameter of the target cysts was 19 mm, with a range of 10–40 mm. Analysis of the aspirate identified 35 of the cysts as benign mucinous cysts, four as pancreatic cystic tumors, and three as pseudocysts.

The patients were then randomized to treatment with an injection of either 80% ethanol (25 patients) or saline (17 patients); an average of about 2 cc of fluid was placed into each cyst. Following injection, the fluid was immediately removed from each cyst, and the status of the cyst was assessed using ultrasound. All patients were then offered an immediate second round of cyst lavage, this time exclusively with 80% ethanol, although not all patients agreed to receive a second injection. The study's primary end point was the outcome of the treated cysts as determined by ultrasound imaging or by CT imaging done 3 months after treatment.

Overall, 15 patients received a single injection of saline, and none of these cysts had ablated at follow-up. Twenty-one patients were assessed after a single ethanol lavage, and six of their cysts disappeared (28%). Nineteen patients received two ethanol injections, and in seven cases (37%), the treated cysts were completely ablated by the ethanol treatment, Dr. Brugge reported. The only adverse events linked with ethanol treatment were the two cases of mild, transient pancreatitis.

The effect of the ethanol treatment was further explored by a surgical resection of the cysts from four patients soon after treatment. Three of these patients had been treated with ethanol; in two cases, a pathology assessment showed 50%-75% ablation of the epithelium lining the cyst, and in the second case the pathology examination showed complete epithelial ablation. The specimen obtained from the saline-treated patient showed no ablation.

“The results demonstrate the safety and efficacy of alcohol injection. There is little doubt that this approach is effective for getting rid of pancreatic cysts,” Dr. Brugge said in an interview.

But the long-term effect of treatment on the development of pancreatic cancer is unclear. The next step will be a randomized study with a 5-year follow-up to see if the treatment has a beneficial effect on cancer incidence, he said.

Pancreatic cysts are relatively common in people older than age 65, with a prevalence rate of about 3%. At one time, these cysts were thought to be mostly benign, but more recently, research has determined that many are premalignant and hence require either regular surveillance or ablation, Dr. Brugge said.

“Alcohol injection … is effective for getting rid of pancreatic cysts,” Dr. William R. Brugge said. Massachusetts General Hospital Photography Department

ELSEVIER GLOBAL MEDICAL NEWS