Significance of internal mammary lymphoscintigraphy (IML) in clinical staging and prognosis of breast cancer

In breast cancer current clinical stage systems are based on axillary lymphnode status and no recommendations are proposed on internal mammary node staging. Internal mammary lymphoscintigraphy (IML) was demonstrated to be a simple and accurate technique for examining the internal mammary lymphatics. This experience reports the IML results correlated to current clinical staging, to the appearance of bone metastases and to actuarial survival in 334 patients with breast cancer. IML results demonstrated that: a) no quadrant is preserved regarding internal mammary invasion b) internal mammary involvement is faintly related to tumour size c) the appearance of bone metastases is well correlated to both IML and axillary positivity d) actuarial survival is related to internal mammary and axillary node involvement. Contemporary invasion significantly affects the survival rate. These data strongly emphasize the importance of internal mammary node status in clinical staging and completely agree with the clinical classification recently proposed by EGE and CLARK (6). Following this new classification the 'N' stage has to be subdivided in N-A axillary and N-IM internal mammary. Consequently, Stage I has to be considered only when no abnormality was demonstrated in both lymphatic areas.