Sen. Edward M. Kennedy lived 15 months with an incurable brain tumor, a little longer than usual for a patient in his late 70s. Perhaps equally important is that Kennedy lived those months well—able to work almost to the end, to sail the choppy New England waters he adored, to help elect a president he supported, and even to give him a dog. Time is important to any cancer patient. Quality of life, not just how much life they can squeeze out, is increasingly the focus for people with a terminal illness, cancer specialists say.