Accuracy of sentinel lymph node biopsy for the assessment of axillary status in patients with early (T1) breast carcinoma.

OBJECTIVE

To determine the accuracy of SLN biopsy for the assessment of axillary status, and prognostic markers leading to lymphatic metastasis in patients with early (T1) breast cancer.

DESIGN

Cross-sectional study.

PLACE AND DURATION OF STUDY

Department of Surgery, Teaching and Research Hospital. Between January 2000 and August 2004.

PATIENTS AND METHODS

SLN mapping by blue dye method was performed on 39 patients with T1 breast carcinoma. SLNs, level 1 and 2 axillary nodes were dissected and excised. The size, pathologic features of the primary tumor, SLNs and other axillary nodes, and hormone receptors were evaluated by histopathologic examination. The rate of SLNs and non-SLNs involvement, and demographic, clinical and pathologic risk factors leading to nodal metastasis were established. The diagnostic accuracy of SLN for axillary status was calculated.

RESULTS

SLNs were identified in 37 (95%) patients. The axilla had metastasis in 11 (28%) patients. Malignant cells involved SLNs in 8 patients. Non-SLNs had metastasis in 3 patients without SLN involvement. The sensitivity, specificity and accuracy of SLN biopsy for predicting axillary status was calculated as 73%, 100% and 92% respectively. Four of 5 patients with non-SLN metastasis were pre-menopausal (p=0.03), and hormone receptor negative (p=0.04). All 5 patients had T1c tumors (p=0.14) and lymphovascular invasion (p=0.0004).

CONCLUSION

SLN biopsy with high diagnostic accuracy may prevent unnecessary dissection of the axilla in the majority of patients with early (T1) breast carcinoma. Some risk factors as pre-menopausal status, absence of hormone receptors, and presence of lymphovascular invasion must be taken into account as important determinant of non-SLNs metastasis.