Q: What is the clinical and pathologic stage of a carcinoma in situ (CIS) of the breast where the pathologic criteria has been met – patient underwent a breast lumpectomy.
A: cT blank, cN0, cM0 clinical stage group 0, PTis, pN blank, pM blank pathologic stage group 0
Per AJCC general instructions page 12, carcinoma in situ is an exception to the stage grouping guidelines. By definition, CIS has not involved any structures in the primary organ that would allow tumor cells to spread to regional nodes or distant sites. Therefore, pTis, cN0, cM0 should be reported as both clinical and pathologic stage 0.