Intraoperative examination of sentinel nodes in breast cancer: is the glass half full or half empty?

Background: Intraoperative identification of positive sentinel lymph nodes in patients with breast cancer may avoid a return to the operating room.

Methods: In a group of 402 consecutive patients with primary breast cancer who underwent sentinel lymph node biopsy, an intraoperative examination (IE) was obtained in 236 cases either by frozen section (FS; n = 68) or by touch preparation cytology (TP; n = 168).

Results: IE had an accuracy of 89% (209 of 236), but it identified only 52 of 77 positive cases (sensitivity, 68%). There were 25 false-negative cases (13.7%), of which 7 were macrometastases and 18 by micrometastases (P < .001). Six macrometastases were missed by TP and one by FS (P = .9). There were two false-positive cases (3.7%). Overall, 48 (20%) of 236 patients avoided a delayed return to the operating room for a completion lymphadenectomy because of IE findings. This occurred in 10% of patients with tumors <1 cm in diameter, in 20% of those with tumors between 1 and 2 cm, and in 34% of those with tumors >2 cm in diameter (P = .05). The cost savings for the Italian Health System amounted to 198,040 (US$223,794) in these patients.

Conclusions: IE has acceptable sensitivity for lymph node macrometastases, but it is a weak tool for diagnosing micrometastases. FS and TP are roughly equivalent. IE allows management changes, because approximately 20% of all patients are expected to undergo synchronous axillary dissection, and it is particularly helpful in T2 patients. This may allow substantial cost savings for the health-care system.