The diameter of metastasis in positive sentinel lymph node biopsy affects axillary tumor load in early breast cancer.

INTRODUCTION: Omission of axillary lymph node dissection (ALND) after positive sentinel lymph biopsy (SLNB) has become a standard procedure for breast cancer patients with one or two metastatic lymph nodes. Here the aim was model development for selection for ALND.

MATERIAL AND METHODS: We analyzed 323 positive SLNB breast cancer patients, who afterwards underwent ALND. In 126 (39%), there were positive additional axillary lymph nodes. Specimens of resected lymph nodes were scanned and the volumes of tumors (expressed as diameter in mm) were calculated. The maximal diameter of metastasis in the sentinel lymph nodes (SLNDmax ) and axillary lymph nodes (ALNDsum ) indicated tumor load in the resected lymph nodes. ALNDsum higher or equal to 5 mm was defined as high and present in 62 patients (21%).

RESULTS: Risk factors for high ALNDsum were primary tumor diameter (P = 0.0092), histopathological type (P = 0.0173), number of positive SLNs (P = 0.0012), type of metastasis (P = 0.0025), molecular type (P = 0.0037), SLNDmax (P = 0.0001), and Her-2 status (P = 0.0093). Independent variables for high ALNDsum were SLNDmax (P < 0.0001), number of positive SLNs (P = 0.0237) and primary tumor diameter (P = 0.0296).

CONCLUSIONS: Twenty-one percent patients with positive SLNB are at risk of high ALNDsum . SLNDmax is the strong predictive factor for high ALNDsum after positive ALND.