But, as CBS News Correspondent Elizabeth Kaledin reports, when it comes to her health, she often wishes she could turn back time. In 1994, she was diagnosed with breast cancer and made a full recovery; a stroke of luck since six other women in her family, including her mother and sister, also had breast cancer.
"Everyone has died," she says. "I'm the only one left."
Because of the family history, Marrs' oncologist Jay Brooks recommended she take a genetic test to see if she carried the abnormal genes known to cause breast cancer. The presence of the genes can forecast future health problems.
"If you have the gene you have a 50 percent lifetime risk of developing ovarian cancer," says Brooks.
But at the time, genetic testing was new and a little scary. And it was expensive.
"The cost was $3,000, and I thought, 'I have three kids in private school,'" she says.
So Marrs never got tested, and in late 2000 she developed ovarian cancer.
Doctors say the genetic test for breast cancer is a widely available but underutilized tool. Most insurance companies will cover the costs today. It involves a simple finger prick to draw blood and some lab work. But many women don't know it exists.
Doctors like Brooks use the results to make crucial health care decisions.
"If we diagnosed Randi with this gene, we would have recommended that she have her ovaries and uterus removed and would have most likely prevented her from having ovarian cancer," says Brooks.
The test is most useful for women with breast cancer in their 30s or 40s or for those who have relatives who've been diagnosed young.
One of Marrs' daughters Jamie opted to get tested, and was relieved to find out that she does not carry the gene.
It's one bit of good news for Marrs, who is now undergoing more chemotherapy in a fight for her life. She's optimistic but regrets not having taken the test.
"I went through a lot of anguish about that and now, gosh, I wish I would have, I wish I would have," she says.
From here, she'd rather look forward than back, telling her story to other women who think genetic testing is something to fear.