mammograms before 50 in healthy women=useless?

50 000 plus healthy woman were split into 2 groups. One group had yearly mammograms and breast exams for 5 years while the other group had breast exams/mammograms if the doctor thought it prudent. The numbers of invasive (cancer that had spread into surrounding areas) and in situ (cancer that had not spread) cancers were similar in both groups. These results suggest that mammograms and regular breast examinations do not reduce breast cancer deaths. The power of the study could not detect if ther differences were less than 20%. Annals 2002 137: 305-312-http://www.annals.org/cgi/content/full/137/5_Part_1/I-28?maxtoshow=&HITS=10&hits=10&RESULTFORMAT=&fulltext=mammograms&searchid=1&FIRSTINDEX=0&resourcetype=HWCIT