Sentinel node biopsy (SNB) is controversial for in situ breast cancers. We reviewed our experience with in situ and microinvasive carcinomas and surveyed the literature.
Methods: SNB was performed with intraparenchymal administration of vital dye alone or combined with radiocolloid. The SNs were assessed histologically with haematoxylin eosin staining and cytokeratin immunohistochemistry.
Results: Patients with in situ (36) or microinvasive (20) carcinomas underwent SNB: 59 axillary and 1 parasternal, and 39 axillary and 1 parasternal SNs were recovered, respectively. The SNs were positive in 4 patients and 1 patient, respectively: 1 micrometastasis and 3 isolated tumour cells, and 1 micrometastasis in the respective groups. No further axillary nodes were found positive after dissection. Further 21 invasive carcinomas (often with extensive intraductal component) had an in situ carcinoma diagnosis preoperatively: of 39 axillary and 3 parasternal SNs 10 patients had nodal involvement in 13 axillary SNs; 5 patients also had further lymph nodes involved after dissection.
Conclusions: The definitive diagnosis of in situ carcinoma does not warrant SNB. This procedure should be considered if the tumour is to be removed by mastectomy, or if the diagnosis is preoperative and there are associated high-risk factors for the subsequent diagnosis of invasive cancer.