Stage migration and therapy modification after thoracoscopic internal mammary lymph node dissection in breast cancer patients

Although internal mammary lymph node (IMN) status is a major prognostic factor in breast cancer, it is not routinely assessed. To evaluate the impact of IMN status on staging and treatment of breast cancer, we enrolled 50 consecutive patients with inner or central tumors who received IMN dissection by video-assisted thoracoscopic surgery (VATS) after breast surgery. Of the 50 patients, 20 (40%) had IMN metastases. Of the 20 patients, 6 (12%) were upstaged from N0 to N2b and 5 (10%), 3 (6%) and 6 patients (12%) were upstaged from N1a, N2a, and N3a, respectively, to N3b. Because of the upstaging, 6 patients (12%) with only IMN metastases received more aggressive adjuvant chemotherapy. Because the whole IMN chain was removed in all patients, radiotherapy on IMN field was not required in our cohort independent of IMN status. In conclusion, VATS IMN dissection might lead to stage migration and therapy modification.