Bonniey & Eileen,

So far I have not heard of diabetes as a post effect of any Cancer itself, except the ones whch may affect pancreas. But there are many things which can contribute to diabetes; like
1) High fructose liquids intake
2) Certain medications which can raise the blood glucose levels,especially taken with in conjunction with other chemo meds.
3) Stress has also been an identified contributing factor to diabetes.
4) Sometimes post cancer treatment due to weakness patients end up adopting a relatively sedentary lifestyle and that can be a contributing factor to diabetes.

I am thinking of all these possibilties just from what I have seen in patients. What I can suggest is instead of regular Blood glucose test, there is a glucose test called HgA1c, which can be a better predictor of someone's predispostion to be a diabetic patient in future,and if that comes out to be positive we can take some proactive measures to keep the glucose levels in check.
Hope it helps.