Predictors of Axillary Lymph Node Metastases in Breast Cancer: Is There a Role for Minimal Axillary Surgery?

Axillary nodal status is one of the most important prognostic factors in breast cancer. In the present study we used it to determine the predictors of axillary lymph node metastases in breast cancer and to determine if there is a group of patients in whom minimal axillary surgery is indicated. This article reports a retrospective study of 953 patients with T1 and T2 invasive breast carcinomas seen in the University Malaya Medical Centre between January 2001 and December 2005, where axillary dissection was done. Of the 953 patients, 283 (29.7%) had breast-conserving surgery, and the rest had mastectomies. In this series, 463 patients (48.6%) were younger than 50 years of age; 365 patients (38.3%) had lymph node involvement. The Malays tend to have more axillary node metastases (45.1%) than the Chinese (36.9%); however, there was no significant relationship between age and race and lymph node involvement. Some 23.9% of grade 1 cancers were node positive, compared to 42.9% of grade 2/3 cancers. Tumor size ranged from 0.2 cm to 5 cm; 55.5% of tumors were T2 (> 2-5 cm). There were only 13 (1.4%) T1a tumors (> 0.1-0.5 cm). Node involvement was documented in 7.7% of T1a tumors, 12.3% of T1b tumors (> 0.5-1 cm), 29.2% of T1c tumors, and 48.2% of T2 tumors. In patients who had no lymphovascular invasion (LVI), 24.4% had axillary node metastases, compared with 52.2% of patients where LVI was reported. On univariate analysis, our study found that tumor diameter > 2 cm, presence of lymphovascular invasion, and higher tumor grade (2 & 3) were factors significantly associated with a higher risk of nodal metastases. On multivariate analysis, however, only lymphovascular invasion and tumor size were independent predictors based on the logistic regression. In T1 tumors, axillary lymph node dissection will overtreat almost 75% of cases; therefore a sentinel lymph node biopsy is justified in these tumors. Sentinel lymph node biopsy has been shown to reduce the complications of formal axillary dissection, such as shoulder stiffness, pain, and lymphedema. In patients with T2 tumors, where almost 45% have lymph node involvement, sentinel node biopsy may not be cost effective.