Lymphatic mapping with tracer administration into the primary breast cancer

There is an ongoing debate over the best tracer injection technique in lymphatic mapping for breast cancer. The technique of low tracer volume administration into the primary breast cancer is presented. The reasons that led to this approach are explained as well as its advantages. Excision of radioactivity that remains at the injection site in the breast cancer prevents the gamma ray scatter that may hamper retrieval of a sentinel node. The intralesional injection technique avoids potential injection of tracer fluid across a lymphatic watershed, it enables identification of extra-axillary sentinel nodes and allows probe-guided excision of non-palpable tumours.