ANCHORAGE, Alaska – Four-time Iditarod champion Susan Butcher, who in 1986 became the race’s second female winner and brought increased national attention to its grueling competition, has died. She was 51.

Butcher, who grew up in Cambridge, Mass., died Saturday in a Seattle hospital of a reoccurrence of leukemia after a recent stem-cell transplant, her doctor said.

She dominated the 1,100-mile sled dog race from Anchorage to Nome in the late 1980s. Her other victories came in 1987, ’88 and ’90, and she finished in the top four through 1993.

“What she did is brought this race to an audience that had never been aware of it before simply because of her personality,” Iditarod spokesman Chas St. George said.

In 1979, Butcher helped drive the first sled-dog team to the 20,320-foot summit of Mount McKinley, the highest peak in North America.

Dr. Jan Abkowitz said that after a stem-cell transplant May 16, Butcher developed graft-versus-host-disease, in which transplanted cells attacked her digestive system.

“Then to our dismay and surprise, about a week ago, when we did a routine bone marrow test, we found that her leukemia had come back,” Abkowitz said.

Butcher received chemotherapy for the leukemia and was moved to intensive care Friday at the University of Washington Medical Center.

“At the time she had the transplant, her leukemia was in remission. She was feeling absolutely fine,” Abkowitz said.

Three years ago, when she was considering a comeback, doctors found Butcher had polycythemia vera, a rare disease that causes the bone marrow to produce excess blood.

Butcher was known as a focused and confident competitor, who loved her dogs, and insisted they remain fit and disciplined.

“Anything she did she’d do with real intensity,” said Joe Runyan, who broke Butcher’s three-year winning streak in 1989. “She was really able to focus on the job and that’s what made her really good at her sport.”

Runyan said the rivalry was always good-natured and that Butcher was more willing than many mushers to share dog-care tips and training methods. During recent Iditarods, she would fly along the trail to chat with old opponents and visit the many friends she had in the Alaska Native villages that serve as checkpoints.

One of the last times Runyan saw Butcher was during this year’s Iditarod in the Yukon River town of Ruby.

“We were talking about who was winning the race,” said Runyan, who was working as a race commentator. “She’s pretty comical, she said, ‘(Winner) Jeff King’s team has left Ruby the best I’ve ever seen, except for when I left Ruby.”‘

Butcher ran her last Iditarod in 1994 when she and husband Davis Monson decided to have children. They have two daughters, Tekla and Chisana.

Butcher planned to compete in a 300-mile race last winter, but was unable to compete after she was diagnosed with leukemia in early December.

“Now my goal is to try and stay alive and fight leukemia,” she told The Associated Press. “No questions asked, that’s what I am going to do.”

During her chemo treatments, Butcher daydreamed about land in the White Mountains she and her husband bought last fall. They planned to build a bigger cabin on the land that comes with 300 miles of groomed trails – perfect for mushing dogs – right out the back door.

“I got the cutest, lovingest group of well-trained females. They are easy to handle and I just enjoy them,” she said. “They will be waiting for me.”