Long-term effect of internal mammary chain treatment. Results of a multivariate analysis of 1195 patients with operable breast cancer and positive axillary nodes

A multivariate analysis on 1195 patients with operable breast cancer and histologically positive axillary nodes treated by mastectomy and complete axillary dissection at the Institut Gustave-Roussy between 1958 and 1978 suggests a beneficial effect of treatment of the internal mammary chain (IMC) on the risks of death and distant metastasis for the patients with medial tumors. For these patients, surgical IMC dissection and post-operative irradiation have similar effects on both the risk of death and of distant metastasis. For the patients with lateral tumors, no beneficial effect of the treatment of the IMC on these two risks was observed. Postoperative irradiation to the IMC, axilla, chest wall and supraclavicular nodes significantly decreases the risk of locoregional recurrences independent of the tumor site and surgical management of the lymph nodes.