ABSTRACT
Interval cancers are an inevitable consequence of mammographic screening. In some cases they occur because the cancer has been missed or misinterpreted by the fi lm reader(s). In many cases, however, the cancer is not visible on the screening mammograms even in retrospect, either because it was present but not distinguishable from normal breast tissue or because it had not yet developed. Either way, women with interval cancers represent an interesting and important group in which screening has failed to confer a benefi t.
