DCIS and sentinel lymph node biopsy

This article provides evidence-based guidelines for the appropriate management of the sentinel lymph node (SLN) in patients with ductal carcinoma in situ (DCIS). Invasive cancer can often be intimately associated with DCIS. With minimally invasive core biopsy techniques, 20% of preoperatively diagnosed DCIS will be upstaged to invasive cancer on final pathology. The clinician must consider a patient’s chances of having an invasive malignancy concealed in an area of DCIS. Palpable tumor and large mammographic DCIS size >5 cm are the most consistent predictors of underlying invasive cancer and metastasis to SLNs. DCIS with microinvasion (DCISM) parallels DCIS with respect to risk for identification of nodal metastases. However, identification of isolated tumor cells (ITCs) or micrometastases in the SLN may lead to overtreatment. When local excision is performed for DCIS, SLN biopsy is possible as a subsequent procedure if invasion is identified on final pathology. Several meta-analyses have reported SLN positivity rates for pure DCIS between 3 and 4%. In patients with pure DCIS, lymph node status failed to predict inferior outcomes and hence should not change subsequent management. Therefore, local control should be the goal for treatment of DCIS and systemic treatment targeted to the biology of any invasive component.