Determinants of axillary recurrence after axillary lymph node dissection for invasive breast cancer

Aim This study was undertaken to gain insight into the risk factors for axillary recurrence among patients with invasive breast cancer who underwent breast-conserving treatment or mastectomy and axillary lymph node dissection. Methods In a matched case–control design, 59 patients with axillary recurrence and 295 randomly selected control patients without axillary recurrence were compared. Matching factors included age, year of incidence of the primary tumour and postsurgical axillary nodal status. Results For patients with negative axillary lymph nodes, those with a tumour in the medial part of the breast had a 73% (95% CI: 4–92%) lower risk of axillary recurrence compared to those with a tumour in the lateral part of the breast. For the patients with positive axillary lymph nodes the risk of axillary recurrence was 65% (95% CI: 16–86%) lower for those who had received axillary irradiation compared to those without axillary irradiation. Within the age group <50 years, the risk or axillary recurrence was 82% lower (95% CI: 45–94%) for patients with more than six lymph nodes found in the axillary specimen compared to those with six or less than six lymph nodes. Conclusions Although based on a small number of patients, this study indicates that axillary irradiation is effective in reducing the risk of axillary recurrence for patients with positive lymph nodes. This favourable effect only applies to the subgroup with extranodal extension or nodal involvement in the apex of the axilla, as these were the only patients receiving axillary radiation during the study period.