Different injection sites of radionuclide for sentinel lymph node detection in breast cancer: single institution experience

OBJECTIVE
The sentinel node is defined as the first lymph node in a regional basin that receives lymph flow from the primary tumor. There is still a controversy over deep versus superficial injection administration in the breast.

STUDY DESIGN
From June 2006 to June 2008, 133 patients with biopsy proven breast carcinoma and clinically negative axilla have been treated with conservative surgery and a study of their axillary sentinel lymph nodes (SLN) has been conducted.

RESULTS
The median number of SLN detected was significantly higher in the periareolarly injected (PA) group (2.43) than in the intratumorally injected (IT) group (1.92) (p=0.008). The incidence of positive SLN in the PA group was not significantly different from the incidence observed in the IT group (p=0.22).

CONCLUSION
Both techniques seem to reliably identify the true SLN in the axilla. Although intradermal as compared with intratumoral injection has numerous advantages, including ease of injection, shorter time between injection and sentinel node identification, and increased radiotracer nodal uptake, nevertheless, intradermal injection allows almost exclusive identification of axillary nodes, and only on rare occasions, of non-axillary nodes.

We therefore think that intratumoral injection must be preferred to intradermal when possible to identify the node that is the first draining step of the tumoral tissue.