Correlation between extranodal invasion in axillary lymph node metastasis and prognosis of breast cancer patients

Objective: To investigate the significance of extranodal extension of axillary lymph nodes (ALN-ENE) metastases in post-operative primary invasive breast carcinoma of non-specific type.

Methods: Six hundred and thirty-eight invasive breast cancer cases confirmed by postoperative pathological examination were collected from January 2006 to December 2008. The relationship of lymph node metastases and ALN-ENE with other lymph node parameters and patient outcome was analyzed.

Results: Among 638 cases, 263 (41.2%) showed axillary lymph node metastases. ALN-ENE was present in 91 cases (36.4%). The rate of ALN-ENE increased with pT stage and tumor size. Five-year recurrence-free survival rate (RFS) and 5-year overall survival rate (OS) was 86.6% and 91.2% respectively for ALN-ENE positive group, and both were lower than ALN-ENE negative group (P<0.01). One hundred and forty-nine patients with 1 to 3 positive lymph nodes had a 5-year RFS of 91.9%, and 5-year OS of 92.3%, less than ALN-ENE negative group (P<0.01). Univariate analysis showed ALN-ENE positively correlated with lymph node metastasis. Multivariate analysis suggested that ENE was associated with increased recurrence risk and shortened recurrence-free and overall survival, especially in patients with 1 to 3 positive lymph nodes; and it was an independent prognostic factor (P<0.01).

Conclusions: The number of lymph nodes metastases is an important predictor of survival in breast cancer patients. ALN-ENE is an independent risk indicator for recurrence and overall survival. For patients with 1 to 3 metastatic axillary lymph nodes, ALN-ENE could alter the patient's clinical pathologic staging, and therefore it is an independent prognostic factor.