MADISON, Wis. (WKOW/CNN) - She was diagnosed with ovarian cancer not once, but three times. Every time, Stephanie Herfel says her dog Sierra sniffed it out.
The connection between Herfel and her husky Sierra is special, to say the least.
"I don't think I'd be here having this conversation with you [without her,]” Herfel said.
Sierra started acting strangely in 2013, shortly after Herfel found out she had an ovarian cyst.
“She came up and put her nose on my belly, which I dismissed,” Herfel said.
Sierra did it multiple times, but Herfel kept ignoring her.
"She found a different way to communicate with me,” she said.
One day, Herfel found her dog in a back closet, visibly upset.
“[She was] curled in a little ball with her nose under her tail, and her little face was completely wet and her eyebrows were crinched,” Herfel said.
Coupled with persistent abdominal pain, Herfel said that led her to take a leap of faith and go to the doctor. That’s when she found out she had stage three ovarian cancer.
Fortunately, she went into remission after six months of treatment – but several months later, Sierra hid in the closet again.
“I knew in my gut something was wrong,” said Herfel.
The ovarian cancer had returned, this time in her liver.
"Just going through my head, ‘Sierra was telling me, Sierra was telling me,’” she said
Herfel started having conversations about Sierra with her oncologist, Dr. David Kushner.
“I didn’t think she was crazy at all. I said, probably your dog was picking up that you weren’t feeling okay,” said Kushner.
A study by Experimental Biology found a dog’s smell is 10,000 times more accurate than humans' and when they were put to the test to sniff out blood samples of cancer patients, their noses got it right about 97% of the time.
Kushner admitted Sierra’s nose is unique “because of the fact that Sierra will truly focus on the part of the body where there’s a problem, which is really interesting.”
So far, Herfel's ovarian cancer has recurred three times and each time, Sierra hid.
“She’s detecting it so early they can't even see it on a scan yet,” said Kushner.
That’s one reason Herfel says she’s still alive, six years since her first diagnosis.
“I believe she saved my life and she continues to do so. Very grateful for her. I'll start crying,” Herfel said.
As Herfel continues her cancer fight, she had this advice for other loving pet owners: "Pay attention your pet and see if they're communicating with you in a different way, and you might notice some really incredible things."
Since her diagnosis, Herfel has become an advocate, raising awareness about ovarian cancer.
She says the symptoms of this type of cancer can be very vague. They include bloating, difficulty eating, feeling full quickly and trouble with your bladder.