(Ivanhoe Newswire) --The National Cancer Institute says that women over the age of 40 should get a mammogram every one to two years.  The U.S. Preventive Services Task Force issued guidelines in 2009 that said biennial mammography, rather than every one to two years, should be performed for women ages 50 to 74.  Now, a recent study compared the benefits (like early detection) and risks (like false-positives) of the frequency of screening mammography to age, breast density, and postmenopausal use of hormone therapy (HT).

 

Researchers at the University of California, San Francisco, found that women ages 50 to 74 years who had biennial screenings have a similar risk of advanced-stage disease and a lower risk of false-positive results than those who get them annually.

 

The study analyzed data collected from January 1994 to December 2008 from mammography facilities in community practice that participate in the Breast Cancer Surveillance Consortium (BCSC) mammography registries.  Data was collected from 11,474 women with breast cancer and 922,624 without breast cancer.

 

Results showed that biennial vs. annual mammography for women ages 50 to 74 was not associated with an increased risk of advanced-stage or large-size tumors regardless of a woman’s breast density or HT use.  The results also found that women between ages 40 and 49 with extremely dense breasts, biennial mammography vs. annual was associated with an increased risk of advanced-stage cancer and large tumors.  

 

Researchers also found that cumulative probability of a false-positive mammography result was high among women undergoing annual mammography with really dense breasts who were either between the ages of 40 and 49 (65.5%) or who used estrogen plus progestogen (65.8%) was lower than women ages 50 to 74 who underwent biennial or triennial mammography with scattered fibro-glandular densities or fatty breasts.  

 

The study suggests that women between 50 and 74, despite breast density or HT use, can undergo biennial rather than annual mammography because biennial screening does not increase the risk of presenting with advanced disease, but does reduce the risk of a false-positive result and biopsy recommendation. 

 

Women aged 40 to 49 years with really dense breasts should get an annual screening to decrease their risk of advanced-stage disease, but they should be informed that it could lead to a high cumulative probability of a false-positive mammography result because of the additional screening examinations.

 

SOURCE:  JAMA, March 2013

 

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