[Cause of failure and false negative result in sentinel lymph node biopsy through vital blue injection in breast carcinoma].

OBJECTIVE

To investigate the cause of sentinel lymph node biopsy failure and false negative result in vital blue injection for breast cancer.

METHODS

Eight-four female breast cancer patients were injected with vital blue to find the sentinel lymph nodes during operation. All patients were treated by the traditional radical or modified radical mastectomy with axillary dissection after sentinel node biopsy. All sentinel nodes, axillary lymph nodes and dissected specimens were submitted separately to pathological examination.

RESULTS

Sentinel node was not identified at the time of operation in 11 patients, giving a failure rate of 13.1%. In 73 patients in whom sentinel nodes were identified, 32 (43.8%) revealed cancer invasion. Postoperative axillary node pathology showed cancer metastasis in all of them. Two patients who showed uninvaded sentinel nodes were demonstrated to have axillary node metastasis. These were the two false negative patients. Therefore, the prediction of axillary metastasis by the sentinel node biopsy showed a sensitivity of 90.4%, a specificity of 100% and a false negative rate of 2.7%.

CONCLUSION

Failure in identifying the sentinel nodes in vital blue injection is related to the degree of mastering the technique and the method of injection. The cause of false negative result is due to an extensive primary tumor and the variation in the position of the sentinel lymph nodes.