Background: In patients with breast cancer, sentinel nodes (SNs) are detected outside the axilla in 1-2% of cases after superficial injection of radiocolloid in the breast. We investigated whether deep injection of tracer visualized internal mammary chain lymph (IMC) nodes more often, and assessed the impact of IMC status on disease staging.
Methods: A total of 400 patients were enrolled in this trial. The study group included 200 patients with T1-T2 N0 breast cancer in an inner quadrant. Radio tracer was injected superficially in 100 (group A), and deeply under the tumor in the others (group B). If an IMC took up tracer in group B patients it was biopsied. An additional 200 patients with outer quadrant lesions were also studied lymphoscintigraphically following superficial (100 patients) or deep (100 patients) injection, but IMC nodes were not biopsied as this would have required an additional surgical excision.
Results: An SN was visualized in the IMC in 65.6% of inner quadrant patients after deep injection and in 2.1% after superficial injection. In outer quadrant patients, deep injection visualized an SN in the IMC in 10% of cases. The IMC SN was located mainly in the 2nd and 3rd intercostal spaces. Radioguided IMC biopsy was performed in 62 patients. Node removal proved simple and risks insignificant. Stage migration occurred in 8% of cases.
Conclusions: Deep injection allows SN localization in the IMC in 65% of inner quadrant breast lesions. Biopsy of the axillary plus IMC resulted in stage migration in 8% of patients. It is unclear whether this additional information can lead to better survival.