Sentinel node biopsy for breast cancer larger than 3 cm in diameter

Background: Sentinel node biopsy (SNB) is a standard staging procedure in early breast cancer. Its suitability for larger tumours has been questioned. This study evaluated the reliability of SNB in women with invasive breast cancer larger than 3 cm in diameter who were clinically axillary node negative. Methods: Some 109 women with a turnout larger than 3 cm on pathological analysis were identified from the Swedish prospective SNB database. They were included if a completion axillary clearance was planned, regardless of SNB results. Results: The sentinel node detection rate was 103 (94.5 per cent) of 109. The overall false-negative rate was eight (13 per cent) of 64. Although a preoperative diagnosis of multifocal turnout was an exclusion criterion, 16 such cases were revealed on postoperative pathological examination. The false-negative rate in this subgroup was higher than that in women with a unifocal tumour (four (31 per cent) of 13 versus four (8 per cent) of 51; P = 0.012). No other significant predictors of a false-negative sentinel node biopsy were identified. Conclusion: SNB is feasible in patients with unifocal breast tumours larger than 3 cm. When large tumour size coincides with multifocality, however, the false-negative rate seems to be increased and a completion axillary clearance should be considered even if the SNB is negative.