The sea of uncertainty surrounding ductal carcinoma in situ--the price of screening mammography.

Wouldn't it be easier if we lived in a binary world? Everything would be either black or white, yes or no, 1 or 0. And biopsy results would be either normal or cancer. Unfortunately, in the world of cancer, our efforts to detect the disease early have made this a fantasy. We are increasingly faced with the reality of a big gray zone — a broad spectrum of pathologic fi ndings between normal tissue and invasive cancer. And our nosology refl ects the associated ambiguity — dysplasia, intraepithe-lial neoplasia, hyperplasia with atypia, and even abnormalities of " unknown signifi cance. " The unifying theme for these fi ndings is that they may progress to invasive cancer. Or they may not. Despite the presence of the word " carcinoma, " ductal carcinoma in situ (DCIS) is the poster child for this problem (a senior pathologist involved in developing classifi cation systems confi ded to one of us that he regretted the use of the term carcinoma in DCIS). No one believes that DCIS always progresses to invasive cancer, and no one believes it never does. Although no one is sure what the probability of progression is, studies of DCIS that were missed at biopsy (1 , 2) and the autopsy reservoir (3) suggest that the lifetime risk of progression must be considerably less than 50%. There is an added complexity: DCIS is associated with not just one risk but two. In addition to the specifi c risk that the lesion might progress to invasive cancer, DCIS confers a general risk. It is a marker for an increased chance of developing invasive cancer elsewhere in the ipsi-or contralateral breast. Again, although no one is sure what this probability is, a recent prospective study of a cohort of patients with DCIS who were treated largely by excision alone suggested that the 5-year risk of subsequent invasive breast cancer elsewhere is less than 10% (4). In short, there is a sea of uncertainty surrounding DCIS. Some lesions will progress to cancer, others will not. Some women with DCIS will develop cancer elsewhere in their breasts, whereas others will not. And we're not sure what the chances are. It isn't surprising that among women with DCIS the uncertainty of being in this gray zone leads to anxiety. In this issue of the Journal, Partridge et al. (5) report that many women with DCIS are anxious …