The earlier breast cancer is detected, the better the chance of survival. Self-exams once a month are key, even if you have regular mammograms.

Doctors say one of the biggest misconceptions about mammograms is that they catch everything — that if you have a mammogram, you don't have to bother with breast self-exams.

"What they need to understand is that in women who are diagnosed with breast cancer, about 10 percent of those will have a normal mammogram,” explained Dr. Brett Stephens, a radiologist.

Stephens says that number is even higher in younger women. He says he's read more than 150,000 mammograms over the last 20 years.

“Across the board radiologists miss about 10 percent of breast cancers,” he said.

Stephens says this is especially true in younger women who usually have denser breasts. Mammograms are not quite as effective for them.

"This means that women need to do their breast self-exam because about 10 percent or even 15 percent of the time, they're going to be the ones to find their breast cancer,” he said.