Background: Guidelines for the learning period of sentinel lymph node biopsy in breast cancer do not address important details such as the false negative rate way of calculation and the number of patients with positive axilla that should be included among the cases of this period. The aim of this study was to identify refinement points which should be included in the guidelines.
Methods: We studied 138 breast cancer cases of the sentinel lymph node biopsy learning period of three surgeons. The sentinel node was identified using isosulfan blue or technetium sulfur colloid or both. All patients underwent complementary axillary dissection.
Results: All three surgeons (A, B, C) fulfilled the guidelines' false negative rate criteria of 5, 0 and 5%, respectively, after 20 cases. However, only six, 10 and 10 cases with positive axilla, respectively, were included and the false negative rates using only these cases were 17, 0 and 10%, respectively.
Conclusions: Current guidelines may lead surgeons to inappropriate conclusions about their ability to perform sentinel lymph node biopsy with an acceptable false negative rate. The learning period should include as many cases with positive axilla as possible and the false negative rate should be calculated only on those patients.