Actually, he claims to be cancer free at this point:
http://www.theithacajournal.com/article/20120118/NEWS01/201180366/Hinchey-retire-from-Congress-end-2012?odyssey=tab|topnews|text|FRONTPAGE
He’s still suffering from it. Cancer free or not he’s probably suffering from the treatment. He also probably has realized his life could be over sooner than he wants and finishing out his days in Congress isn’t on his bucket list.