Breast Cancer and Internal Mammary Sentinel Nodes: A Meta-Analysis

Background: The management of internal mammary (IM) nodes in breastcancer lacks a well-defined consensus. Lymphoscintigraphy identifies up to onethirdof breast cancer patients with extra-axillary drainage, which is mainly locatedin the IMchain.Our aimin thismeta-analysis is to identify the lymphoscintigraphytechnique variables that effect IMnode identification.Methods: An internet database was utilized to review articles concerningsentinel nodes and breast cancer from ۱۹۹۳ through the end of ۲۰۱۱; ۷۴ articlesmet our inclusion criteria. The total number of patients included was ۲۲۹۵۹. Wegrouped the citations by injection location and injection material. We thenanalyzed the rate of identification of IM nodes according to these groupings andtheir subsets.Results: The overall IM identification rate using the random effect model was۹%. The injection location had the most significant impact on IM identificationrate; the deeper injections were associated with the highest rate of identification.Variation in IM identification was associated with the particle size of injectionmaterial; the smaller particle size group had a higher rate of identification.Increased dose of the tracer was also associated with increased identification rate.Conclusions: The use of smaller particle size tracers and a deeper injectionlocation achieve the highest IM identification rate. The dose of the tracer alsoincreased theidentification rate. These observations can help in the selection ofpatients for IM sentinel node biopsy, which can affect their prognosis andtreatment management.

Keywords:

Breast cancer , lymphoscintigraphy , extra-axillary nodes , internal mammary nodes