Internal mammary lymphoscintigraphy: current status in the treatment of breast cancer

In the management of breast carcinomas, the internal mammary lymphoscintigraphy represents a simple, nontraumatic and reproducible technique to visualize and investigate the internal mammary nodes. As suggested by the total absence of visualization of nodes on the operated side in all or in the two upper intercostal spaces, internal mammary chain invasion concerns 30% of the population. This frequency increases with the clinical staging of the tumor, its size, and the extent of the disease in the axilla. It is higher for tumors of inner rather than of outer quadrants. When internal mammary lymphoscintigrams are compared in frontal view to the limits of the usual irradiation fields, parasternal nodes outside these limits or in borderline position are observed in 15 to 34% of the population according to the X-ray technique used. Furthermore, 40% of the tangential irradiation fields does not give an adequate irradiation dose to the internal mammary nodes. In one case out of four, IMLSc allows the reduction of useless heart- and lung-irradiated volumes. Internal mammary node invasion as demonstrated by lymphoscintigraphy has been demonstrated to have a prognostic value as the anatomopathological axillary node status, concerning both survival and disease evolution rates. IMLSc, when compared to the other possible investigation techniques of these nodes (X-ray computed tomography, echography or surgery, etc.), represents at the present time the investigation method of choice with the widest implications (diagnostic, therapeutic, and prognostic).