Hugh Lokey travels 497 miles each time he comes to MD Anderson for thyroid cancer treatment. Then it's 497 miles back home to Broken Arrow, Okla. He's been making the trip for five years, sometimes twice a month.   "It's been tremendously worth it," says Hugh, a 70-year-old Marine Corps veteran who's benefited from, and perhaps even survived because of, lenvatinib. This new thyroid cancer drug was tested here and approved...