LAS VEGAS — Win or lose Saturday, Miss America contestant Allyn Rose will have conveyed a message about breast cancer prevention using her primary tool as a beauty queen: her body.

The 24-year-old Miss D.C. plans to undergo a double mastectomy after she struts in a bikini and flaunts her roller skating talent. She is removing both breasts as a preventive measure to reduce her chances of developing the disease that killed her mother, grandmother and great aunt.

“My mom would have given up every part of her body to be here for me, to watch me in the pageant,” she said Wednesday between dress rehearsals and preliminary competitions at Planet Hollywood on the Las Vegas Strip. “If there’s something that I can do to be proactive, it might hurt my body, it might hurt my physical beauty, but I’m going to be alive.”

If crowned, the University of Maryland, College Park, politics major could become the first Miss America not endowed with the Barbie silhouette associated with beauty queens.

Rose said it was her father who first broached the subject, during her freshman year of college, two years after the death of her mother

“I said, ‘Dad I’m not going to do that. I like the body I have.’ He got serious and said, ‘Well then you’re going to end up dead like your mom.”’

She has pondered that conversation for the past three years, during which she has worked as a model and won several pageants, including Miss Maryland USA, Miss Sinergy and the Miss District of Columbia competition, which put her in the running for Saturday’s bonanza.

With her angular face, pale blond hair and watchful blue eyes, Rose is unusually reserved. She acknowledged that she comes off as more of an ice queen than a girl next door

“You have to block out everything and I think sometimes that makes me appear a little cold,” she said. “But it’s because I had to be my own mentor, I had to be my own best friend.”

She measures her age by the time of her mother, Judy Rose’s, first diagnosis, at age 27.

“Right now, I’m three years away,” she said.

Judy had one breast removed in her 20s but waited until she was 47 to remove the other one, which Rose’s father had called a ticking time bomb.

“That’s when they found she had a stage-three tumor in her breast,” Rose said. “And that’s why for me, I’m not going to wait.”

She plans to have reconstructive surgery, but said the procedure has complications and there is no guarantee that she will regain her pageant-approved bust.

Preventive surgery is a “very reasonable” choice for someone with Rose’s family history and a genetic predisposition, said Patricia Ganz, Director of Cancer Prevention at the Jonsson Comprehensive Cancer Center in Los Angeles.

“I’ve seen young women have it done, and they have great peace of mind,” she said, adding that the alternative is repeated mammograms and physical exams, which detect but do not prevent cancer from developing.

The number of women opting for preventive mastectomies increased tenfold between 1998 and 2007, as genetic testing and reconstructive surgery options improved, according to a 2010 study published last year in Annals of Surgical Oncology. The procedure is believed to reduce risk by 90 percent.

Art McMaster, CEO of the Miss America Organization, called Rose an “incredible example” of strength and courage.

The Newburg, Md., native said she has received letters from supporters all over the country, including from fellow “previvors” who say they have been inspired to undergo their own preventive surgeries. The Wynn sports book gives her 25-1 odds of winning the Miss America crown, making her a moderate favorite.

But her decision is drawing criticism as well as praise in the staged-managed world of pageants, where contestants regularly go under the knife for a very different reason.

She also receives hate mail from beauty circuit die-hards who write to insist that she continue filling out her bikini.

“You have people who say, ‘Don’t have the surgery. This is mutilating your body. You don’t have cancer.’ They want to pick apart every little thing,” she said. Some have even accused her of faking to make herself a more media-friendly candidate.

This kind of pre-emptive surgery has divided the medical community as well. For someone in her early 20s to have the procedure is “very unusual,” said Todd Tuttle, chief of surgical oncology at the University of Minnesota.

Sandra Swain, medical director of Washington Cancer Institute in Washington, D.C., fears that women who have lost family members to breast cancer could take Rose’s example too literally.

“We’re seen a rise in prophylactic mastectomies and a lot of it is not for a medical reason; it is because of fear and anxiety,” she said.

Rose does not carry the “breast cancer genes” BRCA1 and BRCA2, but she did inherit a rare genetic mutation which might predispose her to the disease.

Her brother, who works for an oncology association, said he sees the irony in a beauty queen choosing to give up her breasts but supports his sister’s choice.

“For me what trumps everything is her living, hopefully to a ripe old age, as opposed to any ancillary things that she might lose from potentially winning Miss America,” said Dane Rose, 31.

Rose initially said that if she won the crown, she would postpone her surgery until after her year as a title-holder. But while shopping for earrings to match her black velvet pageant gown Wednesday, she said she was now considering having the surgery during her reign as a way of inscribing her platform of breast cancer prevention on her body.

“I’ve been thinking how powerful that might be to have a Miss America say, ‘I might be Miss America but I’m still going to have surgery. I’m going to take control of my own life, my own health care,’ “ she said. “So I guess it’s up to what happens on Saturday night.”