The Value of Combined Large Format Histopathology Technique to Assess the Surgically Removed Breast Tissue following Neoadjuvant Chemotherapy: A Single Institution Study of 40 Cases

Historically, neoadjuvant chemotherapy has been used to treat patients with advanced breast disease in an attempt to convert them into candidates for breast conservation surgery. The ultimate goal of histopathologic examination of the specimens removed after neoadjuvant chemotherapy is the identification of either residual disease or positive identification of the tumor bed. We report a series of 40 patients treated with neoadjuvant chemotherapy and evaluation of the surgical specimens by a combination of standard histopathology and the use of large format histopathology techniques. 1. Introduction The use of preoperative systemic therapy has increased in the last several years. Originally this therapy was used predominantly for patients with locally advanced breast cancer without systemic disease; the purpose was to convert these inoperable patients into candidates for breast conservation surgery [1–3]. However, neoadjuvant chemotherapy has also been extended to patients without locally advanced breast cancer that traditionally were subjected to surgery as the primary treatment modality [4–7]. The definition of pathologic complete response (pCR) was proposed in the NSABP B18 and B27 protocols; it is defined as the complete absence of invasive carcinoma both in the breast and in the axillary lymph nodes. The presence of residual duct carcinoma in situ (DCIS) was acceptable for the definition of pCR in these original studies. This definition has been challenged by others, some of which include small areas of residual tumor [8] or noninvasive disease in the pathologic complete response group [9]. Regardless of the definition used, the role of the pathologist in the evaluation of the resected specimens, whether it is a mastectomy or a partial mastectomy, is the identification of residual viable tumor or documenting the presence of the tumor bed and the absence of residual tumor in cases with pathologic complete response. In order to accomplish this task, the pathologist has to work in close cooperation with the radiologist in order to determine whether there was a residual “mass” or the fiducial clip placed by the radiologist before the start of therapy. A comprehensive review on the evaluation of pathology specimens after neoadjuvant therapy was published by Sneige and Page [10]. They indicate the importance of radiology and the fact that “extensive” sampling is required for complete pathologic evaluation. There are, however, no strict guidelines regarding the volume of tissue recommended for investigation as long as the tumor bed or residual tumor are