Impact of internal mammary lymph node drainage identified by preoperative lymphoscintigraphy on outcomes in patients with stage I to III breast cancer

BACKGROUND: Involvement of internal mammary (IM) lymph nodes is associated with a poor prognosis for patients with breast cancer. This study examined the effect of drainage to IM nodes identified by lymphoscintigraphy on oncologic outcomes. METHODS: A prospectively maintained breast cancer patient database at the University of Texas MD Anderson Cancer Center was used to identify patients with stage I to III breast cancer who underwent preoperative lymphoscintigraphy with peritumoral injection of colloid and intraoperative lymphatic mapping from 1996 to 2005. Medical records were reviewed of 1772 patients who had drainage to any lymph node basin on lymphoscintigraphy but who did not undergo IM nodal biopsy. Patients with IM drainage, with or without axillary drainage, were compared with patients without IM drainage. Local‐regional recurrence, distant disease‐free survival (DDFS), and overall survival were evaluated. RESULTS: We identified IM drainage in 334 patients (18.8%). Patients with IM drainage were significantly younger, less likely to have upper outer quadrant tumors, and more likely to have smaller and medial tumors than patients without IM drainage. Rates of IM irradiation did not differ between the 2 groups. The median follow‐up time was 7.4 years. On multivariate analysis, IM drainage was significantly associated with a worse DDFS (hazard ratio, 1.6; 95% confidence interval, 1.03‐2.6; P = .04) but not local‐regional recurrence or overall survival. CONCLUSIONS: IM drainage on preoperative lymphoscintigraphy was found to be significantly associated with worse DDFS. Further study is needed to determine the role of lymphoscintigraphy in the personalization of breast cancer staging and therapy. Cancer 2012. © 2012 American Cancer Society. This study examined whether internal mammary lymph node drainage observed on preoperative lymphoscintigraphy affected outcomes in breast cancer patients. On multivariate analysis, internal mammary drainage was significantly associated with worse distant disease‐free survival.