Prognosis of breast cancer patients after mastectomy and dissection of internal mammary nodes.

The results of the analysis carried out on data on 1119 patients with operable breast cancer treated at the National Cancer Institute of Milan from 1965 to 1979 with enlarged mastectomy are reported. Metastases to internal mammary chain were found to be significantly associated with the maximum diameter of primary (16.1% for tumors less than 2 cm and 24.5% for larger tumors, p = 0.007), the age of the patients (27.6% in patients younger than 40 years, 19.7% in patients between 41-50 years, and 15.6% in patients older than 50 years, p = 0.01). The site of origin of the cancer had no impact on internal mammary node metastases. Patients with positive axillary nodes showed metastases to internal mammary nodes in 29.1% of the cases, while 9.1% of patients with axillary negative nodes had positive retrosternal nodes. Survival was significantly affected by the presence of positive internal mammary nodes: the percentage of 10-year survival varied from 80.4% in patients with axillary and internal mammary negative nodes to 30.0% in patients with both nodal basins involved. Intermediate survival rates (54.6% and 53.0%) were found when one or the other of the nodal stations (axillary and internal mammary) was separately affected. Maximum diameter of the primary significantly affected the survival of each group identified by the status of both axillary and internal mammary nodes. In conclusion, the information on the presence or absence of internal mammary node metastases would be of great importance in formulating the prognosis of breast cancer patients. To obtain this information, a biopsy at the first intercostal space may be reasonable in selected patients (age, maximum diameter, and axillary node involvement being the basis for selection) as long as noninvasive methods of diagnosis are available.