'False positive' mammograms common

Around Christmas-time last year, Ally Svenson received a disturbing phone call concerning her mammogram.

"You know, there was nothing warm and fuzzy about it, you know there is a focal density on your left breast, the radiologist urgently needs to see our films," she said. "I thought that was a really bad sign."

Ally was told the abnormality on her mammogram needed further examination. While she waited, all sorts of frightening scenarios invaded her thoughts.

"You, you carry around for a-week-and-a-half the very distinct possibility that this next year is going to be, you know, full of a battle I didn't want to fight. You can't help but go there," she said.

To Ally's relief, she was cancer-free. But, it turns out her experience is not uncommon.

"Mammograms are very hard to interpret," said Dr. Joann Elmore, a researcher at the University of Washington.

Dr. Elmore confirms this unnerving fact about false positive mammograms.

"The first time a woman goes for a mammogram, she has about a 10 percent chance of a false positive mammogram," she said. "Now what this means is you send 100 women to get a screening mammogram and 10 of them will get a letter that says you need to have more testing."

The more yearly mammograms a woman has, the higher that number goes.

"After 10 years, on her 10th exam she has about a 50 percent chance of having at least one false positive mammogram," she said.

Since it's hard to indentify a single reason for false positives, Dr. Elmore says her research helps calm women -- like Ally -- who get that alarming letter or phone call.

"Somehow we need to do a better job of telling our friends and family, don't worry, that's part of the process and that's a normal part of the process," said Ally.

Dr. Connie Lehman of the Seattle Cancer Care Alliance says one way to lower the risk of getting a false positive is to get a digital mammogram.

The bigger concern among doctors is that more women are skipping the exam. That's the reason behind the make a mammogram promise campaign now through the end of October.