Sentinel Lymph Node Concept; and Technique of SLN Identification in Breast Cancer Patients Dr S.Gambhir Department of Nuclear Medicine S.G.P.G.I.M.SLucknow These PowerPoint presentations are free to download only for academic purposes, with due acknowledgements to authors and this website.

Axillary Lymph Node Dissection (ALND) in Carcinoma Breast  Axillary clearance for local disease control  Prognosis

Early Carcinoma Breast  Histopathological positivity of axilla on ALND 30% ~40%  60-70% patients of primary carcinoma breast patients are undergoing unnecessary ALND  ALND associated morbidity  ? Adjuvant chemotherapy

Technical Issues in SLN Detection and Imaging  What tracer ?  What injection site ?  Large or small volume.  How many MBq’s ?

Technical Issues in SLN Detection and Imaging What is most appropriate site of injection  Subareolar  Peritumoral  Intratumoral  Subdermal  Subcutaneous

Concept of Single Injection  Lymphatic drainage of breast consists of dermal and parenchymal lymphatics which meet at Subareolar lymphatics which meet at subareolar plexus of Sappey.  This further drain through one or two major lymphatic trunk to axilla.  Position of this lymphatic plexus gives the opportunity of single uniformally consistent subareolar injection of injection of radiopharmaceutical/blue dye into breast lymphatics.  Adjuvant Systemic therapy

Radioactive but non blue lymph node

Invitro demonstration of radioactive but non blue lymph node

Results  Imaging + ve84.8%  Probe +ve 97.3%  Blue dye +ve 91.4%  Concordance between probe and blue dye94.4% probe and blue dye94.4%  SLN histopathology 97.2 % (accuracy) (H.E. matched with axilla nodes) (H.E. matched with axilla nodes)

Technical Issues in SLN Detection and Imaging Which mode of detection is preferable ?  Probe detection and imaging  Probe detection only  Blue dye alone or in combination with probe detection

Best Method of SNB Mapping?

Positive Non-Sentinel Axillary Nodes in Patients with Positive Sentinel Nodes

Technical Issues in SLN Detection and Imaging What pathological evidence is required?  Fine-needle aspiration cytology  Imprint cytology  H.E. Staining alone  Cytokeratin immunohistochemistry

Conclusion  Currently detection of SLN is highly accurate in context of carcinoma breast.  There is rapidly increasing database population.  Training programmers relevant to multidisciplinary teams need to be developed for this methodology.