When Gene Jones was diagnosed with stage IV colon cancer in 1993, cryoablation was such a new therapy that MD Anderson was still waiting on delivery of the equipment from the manufacturer.

But a clinical trial here enabled Gene to become one of the very first patients to benefit from this now well-established surgery, which treats cancer by freezing it. And today, the 81-year-old farmer is still out baling hay and lifting 50-pound...