"Women who undergo mammograms every two years instead of every year have fewer falsepositive results but the tradeoff is a slightly higher risk of being diagnosed with latestage breast cancer new research finds. After  years biennial mammograms reduced the risk of falsepositives by about onethird and over a lifetime that would accumulate said Rebecca Hubbard lead author of a study published in the Oct.  issue of Annals of Internal Medicine and funded by the U.S. National Cancer Institute.  But the increase in breast cancer diagnoses wasnt statistically significant she said. And breast cancer stage was only analyzed in women who actually developed cancer.  On the other hand among roughly  women screened between  and  and followed for a decade more than half who received annual mammograms were called back at least once because of a falsepositive result and  to  percent were recommended to get a biopsy.  Fewer women  about  percent  who had biennial screening were called back because of a falsepositive while . percent were referred for a biopsy.  Having a previous mammogram for comparison purposes sliced the rate of falsepositives in half.  For the study researchers used data from NCIs Breast Cancer Surveillance Consortium. Women undergoing onceyearly mammograms need to be prepared for possible call backs and being prepared may reduce the anxiety around such an event the authors stated.  This is the latest volley in an ongoing debate about when to start mammography screening in women.  In  the U.S. Preventative Services Task Force USPSTF a governmentsponsored organization startled the world by recommending that women start mammograms at age  instead of  and then only once every two years rather than once a year.  The move released an outcry in the medical community leading to this and other studies to try to determine the best timing for mammograms the only screening tool shown to reduce deaths from breast cancer.  The new study gives a nod in the direction of the UPSTF recommendations but practitioners arent necessarily ready to let go of the longstanding onceayear recommendation.  Hubbard an assistant investigator with Group Health Research Institute in Seattle Wash. said she definitely wouldnt make a specific recommendation for individual women. I feel its really an individual choice where a woman needs to think about her own risk tolerance and also their own breast cancer risk. This gives women more information as to what the risks and benefits of mammography are added Dr. Stephanie Bernik chief of surgical oncology at Lenox Hill Hospital in New York City. Its a personal choice as to whether or not you absolutely have to screen at . As breast surgeons were still going to advocate that mammograms start at . A second study in the same journal issue looked at more than  U.S. women screened from  to  and found that newer digital mammography and older film mammography were similarly accurate in finding cancer in women ages  through .  But in premenopausal women in their s who tend to have denser breast tissue digital mammography performed better. Again though the risk of falsepositives was higher than with film mammography.  There was a tradeoff here as well said Hubbard who was also an author of this study. In general in women aged  to  the two modalities performed pretty equivalently but in younger women the sensitivity of digital mammography was a little bit better so it found more cancers but there was also a bigger decrease in specificity resulting in more falsepositives. More information  The U.S. National Cancer Institute has more on mammography http"