Removing the entire pancreas in patients with cancer or precancerous cysts in part of the organ does not result in unmanageable diabetes -- as many physicians previously believed, research at Mayo Clinic in Florida has found. The study, published online August 26 in the journal HPB Surgery, evaluates how well patients who had their entire pancreas removed could control their resulting diabetes. The pancreas produces insulin to remove sugar from the blood, so when the organ is gone, insulin must be replaced, usually through an external pump or with injections.

The researchers examined control of insulin over several years in 14 patients whose entire pancreas was removed. They compared their findings with 100 people with type 1 diabetes, and must use insulin replacement. They found both groups had little difficulty controlling their blood sugar, and no complications resulted.

The findings should reassure physicians and surgeons that removing the entire pancreas is reasonably safe and effective, says senior investigator Michael B. Wallace, M.D., chair of the Division of Gastroenterology & Hepatology at Mayo Clinic in Florida.

"What has confounded surgery for pancreatic cancers and precancerous cysts for a long time is the notion that if the entire organ is removed, patients will have great difficulty in controlling the resulting diabetes," Dr. Wallace says. "Most surgeons try to leave as much of the pancreas as possible."

"What we have shown here is that, due to wonderful recent improvements in insulin therapy, patients without a pancreas can control their blood sugar as effectively as type 1 diabetes patients can," he says.

Although this study was small, Dr. Wallace says the findings are mirrored in the experiences of patients treated at Mayo Clinic in Florida with total pancreas removal.

Even though the approach of preserving as much of the pancreas as possible benefits most patients, leaving part of the pancreas in some patients may put them at risk of developing hard-to-detect cancer in the remaining organ, he says.

Similarly, patients who have a potentially precancerous cystic condition known as intraductal papillary mucinous neoplasm in part of the pancreas can develop the same cysts in the part of the pancreas that remains after partial removal, he says. Removing the entire pancreas eliminates the possibility of recurrence in the residual pancreas.

"Most surgeons today make difficult decisions about how much of the pancreas to remove in a patient, but that process may become a little more straightforward now that we have demonstrated patients do well when their entire pancreas is removed," Dr. Wallace says.

The study was funded by Mayo Clinic.