Background: A significant number of patients who are initially diagnosed with pure DCIS will harbor missed or occult invasive disease at their definitive surgery. To provide more accurate staging information and to avoid a second operation, some investigators believe that SLN mapping should be performed in DCIS patients. The role of SLN biopsy after neoadjuvant chemotherapy in patients with advanced breast cancer is controversial.
Methods: A review of the literature was performed to determine the role of SLN biopsy in patients with DCIS or advanced breast cancer receiving neoadjuvant chemotherapy. The success rate of SLN biopsy after neoadjuvant chemotherapy was investigated as well as the percentage of positive SLNs in patients with DCIS.
Results: Two consecutive studies revealed metastatic disease to the regional lymph nodes in up to 13% of DCIS patients. In addition, 10% of DCIS patients were upstaged to infiltrating ductal carcinoma at their definitive therapy. The ability of the SLN to predict the status of the remaining non-SLNs after neoadjuvant chemotherapy is unknown. False-negative rates range from 0% to 33%. The success rate for SLN identification for the combined series varies from 84% to 97%.
Conclusions: SLN biopsy is a minimally invasive technique that can be used to evaluate the regional nodal status of DCIS patients. Performing a SLN biopsy during the initial surgical procedure may avoid a second operation in some DCIS patients who are diagnosed with invasive disease at their definitive operation. The success rate of sentinel node identification does not seem to be altered after neoadjuvant therapy. However, the ability of the SLN to predict the pathologic status of the adjacent non-SLNs remains unknown. Therefore, until further prospective randomized trials are conducted, it cannot be assumed that all the regional nodes have the same biologic response to chemotherapy as the SLN.