Prognostic Impacts of the Localization and Diameter of Breast Cancer Axillary Micrometastasis

The prognostic importance of breast cancer axillary micrometastases is still controversial. This study aims to investigate the features of the micrometastases on recurrence and survival. Surgically treated breast cancer patients who were detected to harbor axillary micrometastasis were divided into subgroups as sinusoidal and intranodal and 0.2-1 mm and 1-2 mm according to the localization and size of the micrometastases, respectively. The association of micrometastasic features on overall survival (OS) and disease-free survival (DFS) was statistically analyzed. Thirty-three women with a mean age of 58.2 SD13.3 (range: 20-95) years were included. The median follow-up period was 50 (interquartile range: 30-62) months. Sentinel lymph node biopsy was performed in 27 (81.8%) and axillary dissection in 6 (18.2%) patients. The rate of intranodal micrometastasis of 1-2 mm diameter was higher than the other subgroups. Although the patients with a 1-2 mm diameter micrometastasis had an increased risk of distant metastasis development (hazard ratio (HR), 95% CI: 12.3, 1.2-126.0; p=0.035), tumor localization was not found to affect DFS (HR, 95% CI: 5.60, 0.55-57.10; p=0.15). The DFS of the group with a 0.2-1 mm diameter micrometastasis was found to be longer than the group with a micrometastasis of 1-2 mm diameter. Survival analysis revaled that OS was not affected by either the localization or the size of the micrometastases according to the comparisons of the study subgroups. We consider that the size of axillary micrometastasis poses importance during the follow-up of surgically treated breast cancer patients in terms of distant metastasis development.