Advice to local doctors from the chief radiologist at one of the nation’s leading medical schools: Mammography remains the most effective and affordable tool for detecting breast cancer and, for women with average risk of developing the disease, annual screening should begin at age 40.

That’s contrary to advice from the U.S. Preventive Services Task Force, which two years ago took the controversial stand that women with no family history of the disease do not need to begin screening for breast cancer until age 50 and then should be tested every two years until age 74. It said there was insufficient evidence to show any benefit to continued testing after that age.

But Bonnie Joe, head of breast imaging at the University of California, San Francisco, said 70 to 80 percent of breast cancer diagnoses are in women with no family history or identifiable risk of the disease. Joe also said benefits of screening earlier and more often outweigh the "harms" — radiation exposure, pain caused by compression, testing anxiety, false results and over diagnosis — that the task force said led to its recommendations.

Joe said a typical mammography screening is equivalent to two months exposure to normal background radiation and is estimated to increase the lifetime risk of breast cancer from 1.3 to 1.7 cases in 100,000 women at age 40.

"So it’s small, bottom line," Joe said. Also, "screening anxiety is not equal to death from breast cancer," she added.

Joe spoke Saturday at the 2012 Cowan Cancer Symposium at LDS Hospital, which this year focused on aspects of diagnosing and treating breast cancer. Sponsored by Intermountain Healthcare, the symposium provides continuing education for physicians. Breast cancer is the second leading cause of cancer death among women nationally, affecting one in eight during their lifetime. In Utah, it is the top cancer-related cause of death among women.

Joe reviewed the use of mammography, magnetic resonance imaging (MRI) and ultrasound to detect breast cancer. The effectiveness of mammography has long been established, she said. An organized mammography screening program in seven Swedish countries, covering 33 percent of the population, found breast cancer deaths were reduced 44 percent among women screened. A 2010 Swedish study, comparing counties in which screenings started at either age 40 or age 50, found a 29 percent decrease in breast cancer deaths among women ages 40 to 49.

She also cited a 2011 journal article that estimated 100,000 lives would be saved if all women currently ages 30 to 39 began annual screenings at age 40 — something the American Cancer Society continues to recommend.

Before age 40, only certain groups of women at high risk of developing breast cancer should receive routine mammogram screenings, Joe said.

If mammography is used with MRI, Joe said, the ability to detect the disease is even greater, especially among women at higher risk of breast cancer. According to one analysis, eight additional cancers were detected among 463 high-risk women who had an MRI following a mammogram.

The American Cancer Society recommends combined mammogram and MRI screenings for women with a family history, genetic tendency and certain other factors.

At UCSF, staff stagger mammogram and MRI screenings, alternating between the two every six months for high-risk patients, Joe said.

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