By Leigh Martinez

UC DAVIS (CBS13) — For the first time in 12 years, the American Cancer Society has updated its guidelines for mammograms.

The organization says women should wait until 45 to start getting the yearly exam. This new recommendation is based on a study out of UC Davis that finds annual mammograms should be based on a woman’s menopausal status, not their age.

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The American Cancer Society asked UC Davis researchers to find a group of women that could safely benefit from not getting a mammogram every year. Researchers say they found one—women who already went through menopause.

“Women screening every other year were diagnosed with similar tumor characteristics than women screening annually. This suggests post-menopausal women can be safely screen every other year,” said Diane Miglioretti.

The research suggests post-menopausal women experience slowed breast cancer growth, but Albie Aware, a Sacramento breast-cancer patient advocacy group, does not agree with the research and says telling women not to get tested annually is dangerous.

“Because we don’t precisely have one reason that women get breast cancer. There is no other test except a mammogram for women to detect breast cancer,” Cindy Love said.

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The American Cancer Society also changed its recommendations for screenings, raised to age 45, but UC Davis researchers say pre-menopausal women are at higher risk for developing breast cancer and they recommend annual exams.”

“Pre-menopausal women have more circulating hormones, which might affect tumor biology and might make the tumors grow faster,” Miglioretti said.

“For us, our caseload, the women are younger and younger all the time,” Love said. “We are actually testing someone who is 14 years-old this week.”

She says the new guidelines add a new anxiety to women’s health and fears the change could cost lives.

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“Had they missed that one year, they would’ve gone from a survival rate of 80 to 100 now down to 20 percent,” she said. “It makes a huge difference.”