[Four years of experience with sentinel node biopsy for breast cancer]

The sentinel node (SN) procedure is increasingly being employed in breast surgery to determine the status of the axilla. So far, experience has shown that determination of axillary status is just as accurate as with axillary dissection. Results from 47 months of prospective registration of SN operations are presented here.

From 1 February 2001 to 31 December 2004, SN was performed on 838 patients, constituting 62.6% of the patients treated for primary breast cancer. SNs were detected using two tracers. Primary axillary dissection was performed when no SN was detected. Perioperative investigation of SN was done by frozen section microscopy. If a positive SN was detected, axillary dissection was performed during the same operation. If metastasis was detected only by paraffin microscopy, axillary dissection was performed during a later operation.

SN was detected in 91.2% of the patients. This rate increased significantly during the period. 86 of the patients (25.0%) showing metastasis to SN had false negative results at frozen section microscopy. Of these, 75 had axillary dissection performed at a later operation. In 50 patients (6.0%), an extra-axillary lymph node was removed, changing the staging in 3 cases (0.4%). In 3 cases, a positive axillary lymph node was detected after negative SN within the observation period.

This study showed that we are on a par with international standards for SN procedure. We believe that the degree of the surgeon's experience has a great impact on the rate of detection. We feel that continuous quality control is necessary, so that measures can be taken if and when standards are not fulfilled.