Relation between mammary cancer growth kinetics and the intervals between screenings.

The purpose of this study was to consider the time interval for periodic mammographic screening for breast cancer. One hundred fifteen breast cancers occurring in 10,128 women receiving over 30,000 mammograms over a four year period were reviewed. Tumors were diagnosed at three time intervals: 1) first screening (39/115); 2) annual examination (27/115); and 3) at an examination that occurred less than twelve months from a previous annual examination (10/115). Also, there were tumors that grew to a palpable dimensions and were self-detected between annual examinations (39/115). Our opinion is that screening intervals should be individualized to each patient according to risk factors and suspicious mammographic findings. Further, there is a significant number of breast cancers that grow too fast to be detected effectively by annual mammography. Suspicious mammographic findings did not exist before these cancers reached palpable dimensions. Other risk factors characterizing the hosts who develop these fast growing cancers are yet to be determined.