JUNEAU, Alaska (AP) — Race officials say veteran musher Lance Mackey has had his 21st place finish in this year’s Iditarod Trail Sled Dog Race vacated because of a failed drug test. Mackey is a four-time Iditarod winner and a cancer survivor who had acknowledged using medical marijuana on the trail before the race began testing mushers in 2010. Thursday’s statement says a urine sample taken at a checkpoint during this year’s race tested positive for methamphetamine. Mackey in a statement released by the race says he is in the process of making arrangements to go to a treatment center.