Clinical significance of internal mammary lymph node metastasis for breast cancer: Analysis of 337 breast cancer patients.

PURPOSE

Internal mammary nodes (IMNs) is a major pathway of lymphatic drainage for breast cancer, apart from axillary lymph node (ALN). However, owing to lack of a feasible and safe biopsy method, management of IMNs is still controversial in breast surgery.

METHODS

From 2005 to 2009, a total of 337 consecutive breast cancer women patients were recruited. All patients underwent IMNs biopsy through intercostal space or endoscopic lymphatic chain resection. The ER, PR and HER-2 status were retested according to the current ASCO/CAP guidelines. We analyzed the relationship between clinical pathological parameters and IMNs metastasis and investigated the high risk factors and prognostic values of IMNs metastasis in breast cancer.

RESULTS

Among 337 patients, 314 patients underwent intercostal space IMNs biopsy and 23 patients underwent endoscopic lymphatic chain resection. A total of 63 (18.69%) patients were pathologically diagnosed with IMNs metastasis. Among them, 28 (44.44%) patients changed the pathological lymph node staging, and 15 cases (23.81%) changed the postoperative comprehensive treatment program and accepted extended postoperative radiotherapy. Multivariate analysis showed that compared with no ALN involvement, the risk of IMNs metastasis was significantly increased in patients with 1-3 ALN involvement (OR = 42.097, 95% CI = 5.225-339.178; P = 0.0004) and ≥4 ALN involvement (OR = 82.429, 95%CI = 10.134-670.496; P < 0.0001). The risk of IMNs metastasis in HER-2 positive patients was significantly higher than that in negative patients (OR = 5.452, 95% CI = 2.353-12.634; P < 0.0001). However, we did not find IMNs involvement was an independent indicator for both overall survival and disease-free survival.

CONCLUSIONS

Our clinical practice and data indicated that IMNs biopsy through intercostal space and endoscopic lymphatic chain resection are effective and minimally invasive methods to detect the IMNs status, which may be helpful for accurate tumor staging, risk assessment and option of chemotherapy or radiotherapy to improve the patients' survival.