Background: Classifying ductal carcinoma in situ (DCIS) remains problematical for interpretation of specified histological features and field selection where morphology is heterogeneous. Emphasis is placed on the role of intraductal proliferative lesions as risk factors of variable magnitude in subsequent development of invasive breast carcinoma. The present study is designed to investigate the relative contribution of diagnostic and treatment paradigms on the lack of consistency in the analysis of these lesions.
Materials and methods: A cohort of in situ lesions of the breast was reviewed according to ductal intraepithelial neoplasia (DIN) classification adopted by the World Health Organization (WHO). In this retrospective study 458 patients with DIN diagnosed by core needle biopsy had undergone conservative or radical surgical treatment and SLNB in cases of DIN1C-DIN3.
Results: Breast conservative surgery was the definitive treatment in 80% of cases. All the SLNs sampled showed 1.2 % (4/336) positivity of metastatic or micrometastatic nodal involvement by H&E stain while the IHC assessment for cytokeratin showed 4.5% (15/336) positivity.
Conclusions: The widely recognised variation in the growth pattern of DCIS makes difficult to identify uniform indications for clinical procedure. Although the incidence of metastases in patient with initial diagnosis of DIN is considered to be low, SLNB remains an attractive option to guarantee oncological safety. In patients at high risk occult invasion does occur and without lymphatic analysis, undertreatment is possible.
KEY WORDS: breast cancer, ductal carcinoma in situ, sentinel node biopsy, underestimation.