{"entity":{"id":"sentinel-node-mapping","kind":"indication","name":"Sentinel lymph node mapping in breast cancer and melanoma","aka":[],"tldr":"Before removing lymph nodes to check whether a breast cancer or melanoma has spread, surgeons inject a small radioactive tracer that flows to the very first node the tumour would reach, so only that node needs to come out to find the answer.","summary":"Sentinel lymph node biopsy replaced routine full axillary or regional lymph node dissection for clinically node-negative breast cancer and melanoma, because the sentinel node - the first node draining the tumour site - accurately predicts the status of the rest of the nodal basin, and removing it alone causes far less lymphoedema and morbidity. Lymphoscintigraphy maps that node before surgery: a radiocolloid (Tc-99m sulfur colloid, albumin colloid, or antimony trisulphide colloid depending on jurisdiction) or the receptor-targeted agent Tc-99m tilmanocept is injected around the tumour or biopsy site, and a gamma camera images its lymphatic drainage over the following one to twenty-four hours.\n\nThe joint EANM/SNMMI practice guidelines for breast cancer and for melanoma specify injection technique (peritumoral, subdermal, periareolar or intradermal depending on the setting), imaging timing (early dynamic imaging immediately after injection to see the draining lymphatic channel, then delayed static images at 1-4 hours and sometimes up to 18-24 hours), and processing including SPECT/CT for anatomically complex drainage such as head and neck melanoma or extra-axillary breast drainage. Tc-99m tilmanocept, approved by the FDA in 2013, targets the mannose-binding CD206 receptor on macrophages within lymph nodes rather than relying on particle size for retention, giving more reliable single-node localisation with less second-echelon node uptake than traditional colloids.\n\nIn the operating theatre, a handheld gamma probe locates the radioactive node(s) intraoperatively, often combined with blue dye or, increasingly, a fluorescent tracer, for direct visual confirmation; the dual technique (radiotracer plus dye) achieves the highest sentinel node identification rates. The procedure has a low radiation burden to both patient and staff and no significant contraindications beyond pregnancy precautions and rare tracer hypersensitivity.","asOf":"2026-09-22","links":[{"label":"EANM and SNMMI practice guideline for lymphoscintigraphy and sentinel node localization in breast cancer","url":"https://snmmi.org/common/Uploaded%20files/Web/Clinical%20Practice/Procedure%20Standards/2013/Final%20Breast%20Sentinel%20Node%20Guideline.pdf"},{"label":"EANM practice guidelines for lymphoscintigraphy and sentinel lymph node biopsy in melanoma","url":"https://snmmi.org/common/Uploaded%20files/Web/Clinical%20Practice/Procedure%20Standards/2015/2015_EANM_PracticeGL_Lymphoscintigraphy.pdf"},{"label":"SNMMI technologist guideline: lymphoscintigraphy, breast and melanoma","url":"https://tech.snmjournals.org/content/48/4/315"}],"tags":["surgery","SPECT","breast","melanoma"],"related":["tc-99m"],"indications":[],"sections":[],"technologies":[],"targets":[],"drugs":["tilmanocept-tc99m"],"companies":[],"institutions":[],"pathways":[],"terms":["sentinel-lymph-node-biopsy"],"trials":[],"people":[],"bottlenecks":[],"keyPapers":[],"journals":[],"dependsOn":[],"notes":[],"group":"surgery","burden":"Sentinel lymph node biopsy is now standard practice for the large majority of clinically node-negative breast cancers and invasive melanomas thicker than 1 mm worldwide, replacing routine axillary or regional lymphadenectomy in these settings.","subtypes":[],"biomarkers":[],"standardOfCare":[{"setting":"Clinically node-negative early breast cancer, primary surgery","approach":"Preoperative lymphoscintigraphy with Tc-99m sulfur colloid, albumin colloid or Tc-99m tilmanocept, followed by intraoperative gamma-probe-guided sentinel node biopsy, often combined with blue dye.","refs":[]},{"setting":"Clinically localised invasive melanoma with Breslow thickness above 1 mm","approach":"Lymphoscintigraphy after intradermal peritumoral injection, imaged with dynamic and delayed static views (and SPECT/CT for complex sites such as head and neck), then intraoperative sentinel node biopsy combined with wide local excision.","refs":[]}],"stateOfArt":["The EANM/SNMMI practice guideline for lymphoscintigraphy and sentinel node localisation in breast cancer, and the EANM practice guideline for lymphoscintigraphy and sentinel lymph node biopsy in melanoma (SNMMI-endorsed), define current injection, imaging and reporting standards.","Tc-99m tilmanocept (Lymphoseek) offers CD206 receptor-mediated retention rather than passive particle trapping, giving consistent single-node uptake across breast cancer, melanoma and oral cavity squamous cell carcinoma with a recommended dose of about 18.5-74 MBq depending on same-day or next-day surgery.","SPECT/CT is now recommended whenever planar lymphoscintigraphy is positive in an anatomically ambiguous drainage basin, improving anatomical localisation for the surgeon."],"history":[],"pipeline":[],"openProblems":["Variability in radiocolloid particle size and availability between countries (for example antimony trisulphide colloid in Canada and Australia versus sulfur colloid in the US) means protocols are not fully standardised worldwide.","False-negative sentinel node results still occur, particularly with aberrant or multiple drainage basins, and long-term outcome data are needed as fluorescence-only mapping (without radiotracer) is trialled as a lower-cost alternative in some centres."]},"route":"/indications/sentinel-node-mapping/","neighbours":{"isotope":[{"id":"tc-99m","kind":"isotope","name":"Technetium-99m","route":"/isotopes/tc-99m/"}],"drug":[{"id":"tilmanocept-tc99m","kind":"drug","name":"Technetium-99m tilmanocept","route":"/drugs/tilmanocept-tc99m/"}],"term":[{"id":"sentinel-lymph-node-biopsy","kind":"term","name":"Sentinel node biopsy","route":"/terms/sentinel-lymph-node-biopsy/"}]}}