Optimized sentinel node scintigraphy in breast cancer.

INTRODUCTION: Axillary lymph node dissection (ALND) represents an important staging procedure in the surgical treatment of breast cancer. However, it may result necessary in tumors of little dimensions because of low percentage of metastatic axillary lymph node (ALN). If a non invasive technique predicted the status of ALN, ALND procedures could be avoided. We carried out this study i) to establish the best technique to perform the lymphoscintigraphy for detecting the sentinel node in breast cancer and ii) to determine whether a clear sentinel node reliably predicts a disease free axilla.

METHODS: 215 patients were submitted to the lymphoscintigraphy before surgery. Three different colloidal radiotracers with particle size ranging between < 50 and 1000 nm were injected sudermically or peritumorally. Early and late images were recorded in anterior and oblique projections and the SN was marked on the skin and biopsied using a gamma detection probe (GDP) during surgery.

RESULTS: The SN was identified in 210/215 cases (97.6%). The SN accurately predicted axillary ALN status in 204/210 (97.1%) patients in whom a sentinel node was identified and in all the cases (45 patients) with tumor < 1.5 cm in diameter. In 38/101 cases with metastatic axillary nodes (37.7%) the only positive node was the SN.

CONCLUSIONS: Lymphoscintigraphy can easily locate the SN in breast cancer. SN detection resulted easier when large size microcolloids were used. Subdermally administration appeared the best way of injection for palpable lesions. Breast cancer patients without clinical involvement of the axilla should undergo SN biopsy routinely and this may allow sparing complete axillary dissection when the SN is free of disease.