Correlation Between Breast Tumour Size and Level of Axillary Lymph Node Involvement

Axillary lymph node dissection (ALND) is important for prognosis but does carry certain morbidities, particularly arm lymphoedema. Our aim was to determine whether tumour size correlates with level of axillary lymph node involvement in order to minimize ALND for small tumours. Data were collected prospectively. Patients undergoing breast cancer surgery between May and December 2002 underwent preoperative breast ultrasound to measure the size of the primary tumour. Standard ALND was performed for all patients and levels of lymph nodes were sent separately to determine extent of involvement. Of the 203 cases studied, 91 (44.8%) had T1 tumours (< 2 cm). The incidence of level II lymph nodes in T1 tumours was 4.4% (4/91 patients). The greater the T stage, the higher the incidence of level I and II involvement (4.4% in T1, 7.1% in T2 and 36.5% in T3 tumours). No node-positive patients had isolated level II lymph node involvement. Ultrasound-determined tumour size correlated well with final histological size (p < 0.0005). Based on size, 95.6% (87/91) of patients with T1 tumours did not have level II lymph node metastases, so for these patients, level I axillary dissection is adequate.