Value of intraoperative examination of axillary sentinel nodes in carcinoma of the breast.

Background: The value of frozen sections in the intraoperative examination of sentinel nodes (SN) remains controversial. Accurate frozen sections will spare those patients with node metastasis from a second procedure to complete the axillary dissection. We examined our own experience with intraoperative examination of SN.

Study Design: Between January 1, 2006, and December 31, 2006, we performed 236 sentinel lymph node biopsy procedures that were read as "frozen-section-negative." An additional 47 sentinel lymph node biopsy patients were frozen-section-positive for metastatic disease and underwent immediate completion axillary dissection. At least 1 SN was found in all 283 women (100%). The number of patients with false-negative frozen sections was tallied; patient data were reviewed for a number of variables to see which factors might be associated with a false-negative result.

Results: Eleven patients had positive nodes on subsequent examination of the formalin-fixed, hematoxylin and eosin-stained slides; the false-negative rate of intraoperative frozen section was 4.7%. The sensitivity of the negative frozen section was > 95%. The following variables were compared for significance: pathologist, nuclear grade, histologic grade, margins, lymphovascular invasion, tumor type (ductal versus lobular), and estrogen receptor and progesterone receptor values. The only significant variables were lymphovascular invasion (p = 0.019) and presence of in situ ductal carcinoma (p = 0.001).

Conclusions: Our data confirm the value of intraoperative examination of SN: > 95% sensitivity. Presence of in situ ductal carcinoma or lymphovascular invasion makes these tumors more likely than others to have micrometastases to SN overlooked.