Can leukemia morph from chronic to acute due to lack of treatment?

Yes it can: The best answer depends on the type of leukemia, but certainly if it is not treated any of them can get worse and go into acute phase. Even with treatment, some leukemias will tend to go into an acute phase. I recommend talking with the primary care physician or oncologist to get individualized answers, as this is almost always a serious, serious problem.

Maybe: This most often comes up as an issue in cll. Be careful there... It is not the observation of the disease that causes the progression to leukemia. In fact, early treatment is the wrong thing to do! most patients are properly observed for years before the disease progresses and needs treatment. Early exposure to chemotherapy causes more harm than good...