Like "No, diabetes doesn't cause cancer, cancer can "cause" diabetes. In the example, pancreatic cancer can mean the pancreas can't produce insulin. In that case the person who has it becomes, essentially, an insulin dependent diabetic even though they do not have the autoimmune part of type 1 or any part of type 2. It could also happen from severe trauma. Another form of secondary diabetes is fro long term prednisone. It's a synthetic steroid that will raise your blood sugar in the short term for anyone but long term use, sometimes short term, can basically break you and turn you diabetic. That's a bit of a simplistic explanation, but the end result is diabetic treatment. It's unfortunate because some of the things it works for are worse than diabetes, even though they may not sound like it on paper, so you are kind of left between a rock and a hard place. Risk of diabetes vs extreme allergies that leave you almost unable to breath for example."