Efficacy of internal mammary node dissection in the treatment of breast cancer.

The present study compares clinical and pathological findings and survival data from 410 patients who have undergone extended radical mastectomies in our hospital during the 20 years from 1967 with those derived from 261 who underwent mastectomies without dissections of the internal mammary nodes, in order to determine the value of additional internal mammary node dissection following standard radical mastectomy. Extended radical mastectomy was used in 289 of 361 (80.1%) patients with medial tumors, and in 121 of 310 (39.0%) with lateral tumors. Metastases to the internal mammary nodes were found in 18.5% (76) of all patients, in 20.4% (59) of the patients with medial tumors and in 14.0% (17) of those with lateral tumors. Of the patients with medial tumors, internal mammary node metastases were found in seven of 44 (15.9%) at TNM Stage I, and the rate of metastases rose with advances in stage. Internal mammary node metastases alone, without those to the axillary nodes, were found in 14 patients (4.8%) with medial tumors and in two with lateral tumors. The 10-year survival rate in patients with medial tumors and metastases to the internal mammary nodes only was 67.0%, which was as good as that in patients with metastases to the axillary nodes only. In conclusion, extended radical mastectomy was valuable in the treatment of relatively early medial breast cancer at TNM Stages I and II.