Sentinel node biopsy in breast cancer: Five years experience from Denmark

Introduction. Danish experience from the first five years with sentinel lymph node biopsy (SLNB) as a routine staging procedure in early breast cancer is reported. Methods. During the period January 1, 2002 to December 31, 2006, 14 923 patients were diagnosed at Danish breast surgical centers certified for the sentinel node method. SLNB was performed in 8 338 patients (55.9%). The fraction increased steadily from 43% in 2002 to 67% in 2006. The median follow-up was 1.7 year (range 0-5.2 years). Results. Patients staged with SLNB were younger, had more often BCS, had smaller tumor size, were more often hormone receptor positive, and had lower grade, than patients staged with lymph node dissection (ALND). Blue dye and radio colloid were used in combination in 82%. Lymphoscintigraphy was performed in 61%, and frozen section was performed in 87%. Originally, peritumoral injection of tracer was most often used, but the recommendations have changed, and in 2006 90% of cases had sub-or periareolar injection of radioactive tracer. In the sentinel nodes 25% had macrometastases, 17% micrometastases only, and 3.2% isolated tumor cells only (ITC). ALND was performed in 2 714 patients, whose lymph node classification by SN was known. In the group of 1563 patients with macrometastases in SN, 45% had non-sentinel node metastases, and in the group of 942 patients with micrometastases only, 23% had more positive nodes. Regional lymph node metastases were found in 15% with ITC in sentinel nodes. Lymph node recurrence among node negative patients was observed more often after staging by SLNB (0.5%) than after ALND (0.2%, p=0.04). Conclusion. Two thirds of breast cancer patients can be safely staged with the sentinel node technique, half of these will need no further axillary surgery. The loco-regional control in node negative patients classified by SLNB is high, but seems not quite comparable to what is seen after ALND.