Last year, my 23 year old sister was diagnosed with pancreatic cancer and they removed her entire pancreas. Since then, she has not had to have one insulin shot, or taken any sort of blood sugar controlling drugs. She went to a endocrinologist who basically told her that it’s impossible that she does not have diabetes if she does not have a pancreas, but the surgeon removed it! My sister is getting frustrated because doctors keep telling her that what is happening in her body is impossible, and that she will eventually develop diabetes. It seems that if this were the case, it would have happened by now. She tests her blood sugar regularly, and not once since the surgery has it been even the slightest bit high, although on rare occasions it does get a bit low (but not severely so). Have you ever heard of this?

The two most likely explanations are either that the surgeon was not able to remove all of the head of the pancreas for technical reasons or that your sister may have had an additional ectopic pancreas which is now supplying her insulin needs. All of this could be defined, but in the meantime, my inclination would be to be thankful that insulin supplementation is not needed.

DOB
Additional comments from Dr. Stuart Brink:

I do not think that this is physiologically possible either. Without a pancreas, there should be no other source of insulin unless there is some insulin producing tissue elsewhere. Sometimes this is seen in tumors but usually with totally uncontrolled amounts of insulin causing hypoglycemia. This is not what you are describing. Has anyone measured actual insulin levels or hemoglobin A1c levels in her blood? If there was insulin present, the next medical questions would revolve around trying to decide from where the insulin is coming in the body if there is no pancreas.

SB