Clinical relevance of intra-operative sentinel lymph node examination in breast cancer management

KM Leung, KW Chan, GPS Yeoh, JKC Chan, PSY Cheung
Diagnostix Pathology Laboratories Ltd, Canossa Hospital, 1 Old Peak Road, Hong Kong

OBJECTIVES. To determine the sensitivity, accuracy, and clinical relevance of intra-operative examination of sentinel lymph nodes in breast cancer management.

DESIGN. Retrospective study.

SETTING. Private anatomical pathology practice.

PARTICIPANTS. Three hundred breast cancer patients who underwent axillary sentinel lymph node biopsies for intra-operative assessment between January 2004 and March 2006.

MAIN OUTCOME MEASURES. Correct identification of metastatic carcinoma in sentinel lymph nodes during intra-operative examination, sparing patient a second surgery.

RESULTS. The intra-operative diagnosis of sentinel lymph node biopsies from 300 consecutive patients were compared with the final pathological diagnoses. The final pathology results showed metastatic carcinoma in 74 patients, of whom 63 (85%) were correctly diagnosed during frozen section examination. There was no false-positive case (positive predictive value 100%). The sensitivity for detecting macro- and micro-metastases were 95% and 50%, respectively (P<0.01). The sensitivity for detecting metastases in T1 and T2/ above tumours were 72% and 90%, respectively (P<0.05).

CONCLUSIONS. Intra-operative examination is a reliable and sensitive method for the detection of sentinel lymph node metastasis. Eighty-five percent of the patients with metastatic disease were correctly diagnosed and spared a second operation for axillary dissection. The disadvantage of missing a positive lymph node is by far outweighed by the advantage of a single stage operation in case of a positive diagnosis. The benefit of intra-operative examination was slightly less in patients with smaller tumours.

Hong Kong Med J 2007;13:8-11

Key words: Axilla; Breast neoplasms; Frozen sections; Lymph node excision