Opportunities for molecular epidemiological research on ductal carcinoma in-situ and breast carcinogenesis: interdisciplinary approaches.

Most invasive breast cancers arise from ductal carcinoma in-situ (DCIS), a non-obligate precursor of invasive breast cancer. Given that the natural history of individual DCIS lesions is unpredictable, many women with DCIS receive extensive treatments, which may include surgery, radiation and endocrine therapy, even though many of these lesions may have limited potential to progress to invasion and metastasize. In contrast to valid concerns about overtreatment, the fact that invasive breast cancers outnumber DCIS lesions by more than three-to-one, suggests that many cancer precursors (particularly DCIS, but LCIS also) progress to invasion prior to detection. Thus, DCIS poses a dual problem of overdiagnosis among some women and failure of early detection among others. These concerns are heightened by the multifold increase in rates of DCIS in conjunction with widespread use of mammographic screening and access to outpatient radiologically-guided biopsies. Accordingly, methods are needed to both specifically detect and identify DCIS lesions with potential to progress to invasive cancer and to discover techniques to triage and conservatively manage indolent cases of DCIS.