Indocyanine Green as a practical and viable alternative to blue dye or lymphoscintigraphy in sentinel node mapping

Background and Purpose: Dual tracer sentinel node biopsy (SNB) with lymphoscintigraphy and blue dye is considered the gold standard but logistical requirements, radioactivity and blue staining can be troublesome. Indocyanine green (ICG) has been described as an alternative in breast and melanoma sentinel node identification with benefits over current dyes. This study is a prospective review hypothesising that ICG is as safe and effective at locating sentinel nodes in breast cancer as patent blue or lymphoscintigraphy. Method: 35 breast cancer patients were consented for SNB using both blue dye and ICG (Verdye) by a single surgeon with data collected over 15 months. ICG and patent blue were injected in the anaesthetised patient, once usual pre-operative checklists and preparation completed. SNB was performed first to avoid contamination of the axilla with dye from the breast resection. ICG was detected using the Stryker Handheld SPYPHI camera, sentinel nodes were defined as those being blue, ICG positive or clinically enlarged. Results: Of the 35 patients localised with ICG and blue dye, 33 had nodes identified, with 100% concordance. 2 patients did not have blue, ICG positive or palpable nodes, one of these was re-do axillary surgery. The mean number of nodes retrieved was 2.3 and 3 patients had positive nodes on histopathology. Conclusion: This prospective audit has shown that ICG is non-inferior to blue dye and lymphoscintigraphy in identifying sentinel nodes including in re-do surgery, multifocal and neoadjuvant settings. ICG is superior in the ease of booking patients, improved flow through the pre-operative setting while having no impact on theatre utilisation time over injection of blue dye alone. ICG is more comfortable for the patient compared to lymphoscintigraphy as it is injected post-induction. It does not cause skin staining or have associated radiation for either patient or staff and it is cost effective. The main limitation of ICG is that it contains iodine and therefore should not be used in patients with iodine or shellfish allergies but this information is generally available on history unlike blue dye allergy which can be severe and is completely unpredictable. Overall ICG is a practical, safe and cost-effective alternative to lymphoscintigraphy or blue dye in sentinel node mapping.Tabled 1Number of total patients35Mean age65 yearsPost neoadjuvant chemotherapy3(8.6%)Multifocal cancer3(8.6%)Re-do breast surgery4(11.4%)Cases where at least one node identified33(94.2%)Cases where no nodes were identified3(8.6%)Nodes identified by both dyes33(100%)Nodes identified by only 1 dye0Cases dye injected together(mean time to surgery 13 minutes)28Cases dye injected separately(mean time to surgery 18.9 minutes)7Mean massage time2.9 minutes Open table in a new tab