It'd also be interesting if they keep that he got cancer before from wearing the Kryptonite ring. Its hard to tell what post-Crisis stuff is in and out with Lex. For example I'm assuming all the clone stuff is out, and if so he obviously never lost his hand, but they could still keep the illness and he was just simply cured. The history would add an extra layer to Lex's anger over trying to do good and getting sick. The first time, its almost like karma intervened with his nefarious deeds of trying to kill Superman. He gets cancer from the ring he would use to keep Superman away and plot against him. Years later he turns a new leaf and spends a year trying to be a hero, fighting for the same things Superman fights for and even aiding him. And he gets cancer again. Talk about a thought that would piss off a trying-to-reform-sociopath.
The threat of the loss of intellect in the disease is also a great observation, steph. I'm leaning toward this now.