False negative in sentinel node frozen section on breast cancer

Abstract

Objective: Evaluate the rate of false-negative sentinel node frozen section on breast cancer and its influencing factors. Method: two hundred and ninety nine patients with breast cancer that underwent lymphoscintigraphy with technetium-99m followed by sentinel node biopsy between March/2005 and February/2009 were evaluated in relation to the following factors: age, tumor size, lymphatic drainage pattern in the lymphoscintigraphy, tumor histologic features (differentiation, type and degree), frozen section diagnosis, and permanent section diagnosis. Results: The false negative rate in the sentinel node frozen section was 4.3% (10 patients). The specificity was 100%, the sensitivity was 87.2%, positive predictive value was 100% and the negative predictive value was 95.7%. None of the variables evaluated were associated with a raise in the false-negative incidence. There was an association between the tumor size and the incidence of axillary metastasis (p=0,00008). Conclusion: The false-negative rate of the sentinel node frozen section was 4.3% and none of the evaluated variables was associated with this event.