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Is It Time to Retire the Term of “In Situ Carcinoma” and Use the Term of “Borderline Breast Disease?”

The article published in July 19, 2010 issue in the New York Times about a few patients who have undergone cancer therapy for over diagnosis of ductal carcinoma in situ (DCIS) brought international attention to this entity. The story of each patient was real and the message was powerful. The patients spoke about a serious issue that has had a major impact on their lives both emotionally and psychologically. Their stories brought to public attention an issue that has been known to the medical community for a long time. And yet we have no solutions to offer to resolve this issue. Several position papers from different societies were issued only to restore the trust of the public and to minimize the associated anxiety. Meanwhile discussions are taking place among the key opinion leaders and several organizations in an effort to explore some possibilities for future direction. The discipline of pathology is no different from other specialties in medicine in regard to differences in opinion and diversity in the pattern of practice. As in any other profession, mistakes are inevitable and often heavy prices are paid to compensate for the consequences. However, errors provide an opportunity for improvement. This is best reflected by the following statement made by Dr. John Azzopardi, an expert in Breast Pathology. ‘‘One relies on one’s experience. But ‘‘experience’’ can be merely the repetition of the same error often enough... One must be willing, even anxious, to learn from one’s error. This requires a degree of humility, a readiness to listen to the arguments of others, including those of one’s juniors, and the inclination to re-examine cases in which a mistaken diagnosis has been made and to analyse the reasons for the original mistake.’’ Distinction between atypical ductal hyperplasia (ADH) and low grade DCIS remains a diagnostic challenge in the everyday practice of breast pathology. Reported studies including a highly cited article by Dr. Rosai in 1991 continue to highlight the significant inter-observer variability even among experienced breast pathologists. This issue is compounded by the increasing number of tissue sampling by core needle biopsy as a consequence of screening mammography. The small sample size of core needle biopsies and tissue fragmentation contributes to the complexity of an accurate diagnosis of DCIS. It is important to recognize that assessment of core needle biopsy is different from circumstances under which the various diagnostic criteria were originally defined by reviewing multiple histologic sections obtained from surgical excisions. The real challenge is how to minimize the occurrence of over-diagnosis of DCIS and how to balance the scope of therapy based on the biology and the extent of this disease. Ductal carcinoma in situ is a heterogenous disease characterized by neoplastic proliferation of epithelial cells within a breast duct with no ability to metastasize. DCIS is considered a precursor lesion with a variable rate of progression into invasive breast cancer. Based on nuclear grade, presence or absence of necrosis and the pattern of morphologic features, DCIS is stratified into different grades and types. High nuclear grade lesions are associated with rapid growth and early progression to an invasive cancer and are easier to diagnose. In contrast, low nuclear grade lesions remain indolent and even when they progress to invasive cancer the tumor is frequently low grade and well differentiated. Low grade DCIS and high grade DCIS represent two genetically distinct entities that lead to different forms of invasive cancer. Low grade DCIS share similar morphologic and biologic features with ADH, which raises the question of whether these two lesions represent different spectrums of the same entity. Up to now, suggested terminologies of mammary intraepithelial neoplasia (MIN) by Dr. Rosai and ductal intraepithelial neoplasia (DIN) by Dr. Tavassoli have not been fully embraced by the pathology DOI: 10.1111/j.1524-4741.2010.01014.x