Clinical aspects of sentinel node biopsy

Sentinel lymph node (SLN) biopsy requires validation by a backup axillary dissection in a defined series of cases before becoming standard practice, to establish individual and institutional success rates and the frequency of false negative results. At least 90% success in finding the SLN with no more than 5-10% false negative results is a reasonable goal for surgeons and institutions learning the technique. A combination of isotope and dye to map the SLN is probably superior to either method used alone, yet a wide variety of technical variations in the procedure have produced a striking similarity of results. Most breast cancer patients are suitable for SLN biopsy, and the large majority reported to date has had clinical stage T1-2N0 invasive breast cancers. SLN biopsy will play a growing role in patients having prophylactic mastectomy, and in those with 'high-risk' duct carcinoma in situ, microinvasive cancers, T3 disease, and neoadjuvant chemotherapy. SLN biopsy for the first time makes enhanced pathologic analysis of lymph nodes logistically feasible, at once allowing greater staging accuracy and less morbidity than standard methods. Retrospective data suggest that micrometastases identified in this way are prognostically significant, and prospective clinical trials now accruing promise a definitive answer to this issue

Additional tracer injection to improve the technical success rate of lymphoscintigraphy for sentinel node biopsy in breast cancer

BACKGROUND: Sentinel node (SN) biopsy has become the standard of care in the treatment of breast cancer. The aim of this study is to determine the value of additional tracer injection to increase the technical success rate of the SN procedure and to identify factors that influence the ability to visualize hotspots. METHODS: From February 1997 to August 2007, 1,208 clinically node-negative breast cancer patients underwent lymphatic mapping for SN biopsy. The technique involved the injection of 370 MBq (10 mCi) Tc-99 m-nanocolloid peritumorally. In case of insufficient or absent visualization of hotspots 37 MBq (1 mCi) of additional tracer was given intracutaneously above the tumor. RESULTS: In 93 patients (7.7%) visualization of hotspots on initial lymphoscintigraphy was insufficient (41 patients) or absent (52 patients). The first 14 patients did not receive additional tracer injection. In five patients, additional tracer did not result in successful lymphoscintigraphy, which is correlated with massive nodal tumor infiltration. In 33 patients with negative initial lymphoscintigraphy, additional tracer injection resulted in secondary SN visualization. In 41 patients with faint hotspots on initial lymphoscintigraphy, additional tracer injection, by increasing nodal uptake, simplified accurate SN biopsy. Decreased radiotracer uptake in this group was associated with older age and high body mass index (BMI). CONCLUSIONS: Additional tracer injection following initial scan failure increases the success rate of lymphoscintigraphy during lymphatic mapping in breast cancer, without compromising accuracy. If additional tracer injection does not result in secondary SN visualization, gross nodal tumor involvement is often present and axillary lymph node dissection (ALND) is mandatory