Had the late Susan Butcher reached Nome that much faster in 1989 during her dominating reign atop the Iditarod Trail Sled Dog Race, she would have ended up with an eye-popping five consecutive titles.

But Joe Runyan, then of Nenana, turned a five-minute lead out of White Mountain, 77 miles from the finish, into victory. As a result, Butcher, who won again in 1990, shares the record of three straight with Doug Swingley of Montana and Lance Mackey of Fairbanks, who will begin his bid for a record fourth in a row on March 6 when the 38th Iditarod gets under way on Fourth Avenue in Anchorage.

The consecutive-victories mark is among Iditarod's most hallowed records.

Rick Swenson's record of five Iditarod championships, Martin Buser's speed record of 8 days, 22 hours, 46 minutes, and Libby Riddles first victory by a woman may be the only bigger ones.

How difficult is ringing up a four-peat?

Mackey has seemed invincible at the end of this decade, just as Swingley was a decade ago and Butcher was during the late 1980s.

But anything can happen in a 1,000-mile race, including mishaps beyond the control of even the most prepared mushers. A look back at Butcher's 1989 race makes that clear.

At the time, Runyan was a 41-year-old on his fifth Iditarod and a musher seldom mentioned as someone who could dethrone Butcher.

But two huge factors tipped the race in his favor.

• Runyan boosted what was then the norm of four hours running followed by four hours rest to a six-and-six schedule.

• A intestinal virus ran though Butcher's dogs, sapping the team of its speed while making the power of Runyan's team more crucial.

"Athletically, Susan's was the best team in the race, but (the dogs) just didn't have anything left in the tank after the virus," said her husband Dave Monson, who followed the race. "Susan was spending most of her time doctoring her dogs. The virus lasted all the way to Nome. The dogs were eating and then not eating. Or if they were eating, they were blowing it out.

"When she got to Nome, Susan said she considered it her dogs' and especially (famous leader) Granite's greatest race."

Runyan knew how good they were.

"I was having nervous breakdowns the last hour," Runyan said at the time. "I didn't know where she was. I knew she would be right on my tail. I saw her headlamp."

But he never saw it from behind.

FRONT STREET MARRIAGE

Swingley's three-peat stretched from 1999-01, then came to a crashing halt in 2002 when Martin Buser ran the fastest Iditarod in history and Swingley finished more than four days behind him in 40th place.

Early in the race, Swingley announced he wasn't racing competitively, and at the finish line he wed longtime companion Melanie Shirilla as several dozen friends, relatives, mushers and visitors looked on amid a thick snowfall on Front Street. Several sled dogs stood by as canine bridesmaids and groomsmen, according to KNOM radio in Nome.

CHINKS IN ARMOR

As Mackey chases the record this year, he may not seem quite as invincible as he has over the past three seasons. Here's why:

• Competition. Mackey's unprecedented double of winning the Yukon Quest and Iditarod back to back -- first accomplished in 2007 and repeated the following year -- seems a little less superhuman these days. Canadian musher Sebastian Schnuelle nearly accomplished the same feat last year, winning the Quest and finishing second to Mackey in the Iditarod. Schnuelle is back, as are four mushers with 14 championships among them -- Jeff King of Denali Park (4), Martin Buser of Big Lake (4), Rick Swenson of Two Rivers (5) and Mitch Seavey of Sterling (1). There are also four other mushers who've finished second at least once but never won -- DeeDee Jonrowe and Linwood Fiedler of Willow, Sonny Lindner of Fairbanks and Paul Gebhardt of Kasilof. John Baker of Kotzebue, who captured the Kuskokwim 300 in January, is atop another group of up-and-comers who may be ready to grab the top spot,

• Performance. Mackey's early season has been lackluster -- third in the Kuskokwim 300 and sixth in the Tustumena 200 after a victory in the men's division of the Gin-Gin 200 in December.

• Distractions. In addition to running his own dogs, Mackey has trained Jamaican musher Newton Marshall for the Iditarod. In fact, Mackey handler Braxton Peterson, son Cain Carter and Marshall are all training and racing out of Mackey's Comeback Kennel, north of Fairbanks. That's a lot of detail to track daily.

But, as usual, Mackey is upbeat. After the Kusko, he blamed himself for a wrong turn and praised his dogs.

"I have a real nice young group, and I feel that this is going to be a damn tough team to beat in the Iditarod again. This is a warm-up. I wanted to see what they were made of, and they far exceeded my expectation."

"At this time," he told the Iditarod's Web site last year, "we have a Dream Team."

YOUNG STUDS

Others may think they have one, too. But no musher has even approached Mackey's consistent excellence over the last three years.

While Mackey was compiling his three-peat, only two other mushers could find their way into the top-5 more than once between 2007-09; King and Buser both turned in two top-five finishes. But both are aging. King, already the oldest musher to ever win, is 54 now. Buser is 52.

Where is the young talent that years ago was supposed to nudge the graying veterans out of the game?

As always, this Iditarod boasts some fresh young talent, but cracking the top-five is never easy.

• Seavey's son Dallas, 22, finished sixth last year, moving up a remarkable 35 places from his previous race. The fact that Dallas is a superb athlete, a junior national wrestling champion who spent a year training at the U.S. Olympic Training Center, makes him even more intriguing.

• Jessie Royer, 33, of Fairbanks, was eighth last year, just as she was in 2005. Like Dallas Seavey, her decades of work on a Montana cattle ranch built her fitness.

• Warren Pelfrey, 34, of British Columbia, was 19th last year, another step up the finishers' list. Three years ago, he was 60th.

• Zack Steer, 36, owner of the Sheep Mountain Lodge, finished third in 2007, and this year he's embracing the Mackey model by doubling up with the Quest in February and the Iditarod in March.

Suffice it to say, few sports this side of shuffleboard consider a 36-year-old young.

MACKEY AILMENTS

The fact that Mackey isn't even 40 might be enough to convince hordes of would-be mushers to take up chess or another sport. But the defending champion has already beaten, or beaten back, many ailments -- cancer, surgery to rid his right arm of a staph infection, the lack of cartilage in both knees that leave bone rubbing bone.

Cancer, of course, was his biggest challenge.

The piercing headaches Mackey experienced after the end of his rookie Iditarod run in 2001 were due to a squamous cell carcinoma growing rapidly in his neck. Within weeks, he was on the operating table. To save Mackey's life, Dr. William Fell had to cut out neck muscle, lymph nodes, the internal jugular vein and several nerves.

Afterward, Mackey endured 12 weeks of post-surgery radiation to try to zap whatever cancer cells might have been left. The radiation ate away at his jawbone. As a result, he had to have 10 teeth pulled. When the skin over the jawbone refused to heal, Mackey had to sit through 16 weeks of hyperbaric oxygen treatment to help build red blood cells and regrow tissue.

He healed eventually but was left with permanent handicaps. Because most of his saliva glands came out with the cancer surgery, he has to constantly drink water to keep his throat moist. Because of nerve damage from surgery, he has limited mobility in his right arm.

The radiation treatments left his body weakened against the cold. He has to take extra precautions to keep his hands and feet warm. He admits it is frustrating to see other mushers quickly and efficiently changing dog booties barehanded in zero-degree temperatures while his work is slowed by the need to stuff his freezing fingers back into his beaver mitts to grab finger-warming chemical heat packs.

"I'm a medical nightmare," he allowed in January.

And racing a couple thousand miles each winter across some of the roughest terrain on Earth in temperatures that can plunge beneath minus-50 is seldom the prescription for body pain.

But celebrating under the burled arch in Nome can make it vanish.

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Reach reporter Mike Campbell at mcampbell@adn.com or 257-4329.

On the Web ADN.COM/IDITAROD: Follow the race from Anchorage to Nome with daily updates, photo galleries and minute-by-minute race coverage with updated standings on our leaderboard and trail map.

CEREMONIAL START: 10 a.m. March 6 on Fourth Avenue

RACE RESTART: 2 p.m. March 7 on Willow Lake

As of Feb. 12, 71 mushers remained in the field for the 2010 Iditarod Trail Sled Dog Race. Bib numbers have not been selected yet. Rookies are indicated by an (R).

Alaska mushers

1) Sue Allen, Wasilla

2) Ken Anderson, Fairbanks

3) John Baker, Kotzebue

4) Kristy Berington, Kasilof (R)

5) Martin Buser, Big Lake

6) Emil Churchin, Anchorage (R)

7) Judy Currier, Fairbanks

8) Dave DeCaro, Denali Park (R)

9) Zoya DeNure, Gakona

10) Jane Faulkner, Soldotna (R)

11) Linwood Fiedler, Willow

12) Kathleen Frederick, Willow (R)

13) Paul Gebhardt, Kasilof

14) Sven Haltmann, Fairbanks

15) Matt Hayashida, Willow

16) Karin Hendrickson, Chugiak

17) Quinn Iten, Kotzebue (R)

18) William “Middie” Johnson, Unalakleet (R)

19) DeeDee Jonrowe, Willow

20) Dan Kaduce, Chatanika (R)

21) Peter Kaiser, Bethel (R)

22) Jeff King, Denali

23) Jim Lanier, Chugiak

24) Thomas Lesatz, Two Rivers

25) Sonny Lindner, Two Rivers

26) Bruce Linton, Kasilof

27) Lance Mackey, Fairbanks

28) Allen Moore, Two Rivers

29) Hugh Neff, Tok

30) Robert Nelson, Kotzebue

31) Ryan Redington, Wasilla

32) Ray Redington Jr, Wasilla

33) Colleen Robertia, Kasilof (R)

34) Tamara Rose, Fairbanks (R)

35) Jessie Royer, Fairbanks

36) Justin Savidis, Willow (R)

37) Mitch Seavey, Seward

38) Dallas Seavey, Seward

39) Cim Smyth, Big Lake

40) Ramey Smyth, Willow

41) Gerald Sousa, Talkeetna

42) Zack Steer, Sheep Mountain

43) Michael Suprenant, Chugiak

44) Rick Swenson, Two Rivers

45) Michael Williams Jr., Akiak (R)

46) Aliy Zirkle, Two Rivers

Lower 48 mushers

1) Lachlan Clarke, Buena Vista, Colo.

2) William Pinkham, Glenwood Springs, Colo.

3) Tom Thurston, Oak Creek, Colo.

4) Trent Herbst, Ketchum, Idaho

5) Pat Moon, Chicago, Illinois (R)

6) Blake Freking, Finland, Minn.

7) Chris Adkins, Sand Coulee, Mont. (R)

8) Jason Barron, Lincoln, Montana

9) Celeste Davis, Deer Lodge, Mont. (R)

10) Cindy Gallea, Seeley Lake, Mont.

11) Kirk Barnum, Seeley Lake, Mont.

12) Scott White, Woodinville, Wash. (R)

13) Billy Snodgrass, DuBois, Wyoming

Canadian mushers

1) Ross Adam, Grande Prairie, Alberta

2) Karen Ramstead, Perryvale, Alberta

3) Warren Palfrey, Quesnel, British Columbia

4) Hank Debruin, Haliburton, Ontario (R)

5) Hans Gatt, Whitehorse, Yukon

6) Michelle Phillips, Tagish, Yukon (R)

7) Sebastian Schnuelle, Whitehorse, Yukon

8) Gerry Willomitzer, Whitehorse, Yukon

International mushers

1) Sam Deltour, Sint-Kruis, Belgium

2) Newton Marshall, Jamaica (R)

3) Wattie McDonald, Scotland (R)

4) John Stewart, Scotland (R)