Aim: Ductal carcinoma in situ (DCIS) refers to the preinvasive stage of breast carcinoma and should not give axillary metastases. Its diagnosis, however, is subject to sampling errors. The role of sentinel lymph node biopsy (SLNB) in management of DCIS or DCISM (with microinvasion) remains unclear. The purpose of this study was to review our experience with SLNB in DCIS and DCISM.
Methods: A review of 51 patients with a diagnosis of DCIS (n=45) or DCISM (n=6), who underwent SLNB and a definitive breast operation between January 1999 and December 2006, was performed.
Results: In 10 patients (19.6%) definitive histology revealed an invasive carcinoma. SLN (micro)metastases were detected in 5 out of 51 patients, of whom 2 had a preoperative diagnosis of grade III DCIS and 3 of DCISM. Three patients (75%) had micrometastases (< 2 mm) only. In 2 patients, histopathology demonstrated a macrometastasis (> 2 mm). All 5 patients underwent axillary dissection. No additional positive axillary lymph nodes were found.
Conclusions: In case of a preoperative diagnosis of grade III DCIS or a grade II DCIS with comedo necrosis and DCIS with microinvasion, an SLNB procedure has to be considered because in almost 20% of the patients an invasive carcinoma is found after surgery. In this case the SLNB procedure becomes less reliable after a lumpectomy or ablation has been performed. SLN (micro)metastases were detected in nearly 10% of the patients. The prognostic significance of individual tumour cells remains unclear.