{"entity":{"id":"depth-of-invasion","kind":"term","name":"Depth of invasion (DOI)","aka":["DOI","depth of invasion","tumour depth","tumor depth","invasion depth","depth of stromal invasion","submucosal invasion depth","SM1","SM2","T1a versus T1b","myometrial invasion","deep myometrial invasion","thickness versus depth"],"tldr":"Depth of invasion is how far down a cancer has grown from the surface it started on, measured in millimetres on the pathology slide; in mouth cancer it now sets the T stage and a depth over 4 mm means the neck nodes are treated even when they look clean, and in early stomach cancer it decides whether an endoscopic removal was enough.","summary":"What is measured: the distance from the reconstructed basement membrane of the adjacent normal mucosa to the deepest point of invasion, measured perpendicular to the surface; unlike tumour thickness it excludes the exophytic part. How: microscopy of the resection or biopsy specimen. Thresholds by site: oral cavity (AJCC 8th edition) 5 mm or less, 5 to 10 and over 10 mm move the T stage, and elective neck dissection is recommended above 3 to 4 mm (the D'Cruz trial of elective against therapeutic neck dissection and the Huang meta-analysis); stomach and oesophagus distinguish mucosal from submucosal invasion (SM1 under 500 micrometres against SM2 and deeper) to judge whether endoscopic submucosal dissection was curative (the eCura system); cervix FIGO 2018 stage IA1 is under 3 mm and IA2 3 to 5 mm; endometrial cancer splits at half the myometrial thickness for the ESGO risk groups and adjuvant brachytherapy; cutaneous squamous cell carcinoma over 6 mm or beyond the subcutaneous fat is high risk (Brigham and Women's T2b); Breslow thickness in melanoma is the analogous measure. What a result changes: T stage, elective treatment of the neck, completion surgery after endoscopic resection, adjuvant radiotherapy and sentinel node thresholds. Where it matters: oral, tongue and buccal cancers, early gastric cancer, advanced cutaneous SCC, NSMP endometrial cancer and early cervical cancer.","asOf":"2026-09-17","links":[],"tags":[],"related":["breslow-thickness","lymphovascular-invasion","perineural-invasion","extranodal-extension","sentinel-lymph-node-biopsy","endoscopic-resection","tumour-grade"],"cancers":["oral-cavity-cancer","oral-tongue-cancer","buccal-mucosa-cancer","early-gastric-cancer","advanced-cutaneous-scc","endometrial-nsmp","early-cervical-cancer"],"sections":[],"technologies":[],"targets":[],"drugs":[],"companies":[],"institutions":[],"pathways":[],"terms":[],"trials":[],"people":[],"bottlenecks":[],"keyPapers":[],"journals":[],"dependsOn":[],"notes":[],"category":"Biomarkers"},"route":"/terms/depth-of-invasion/","neighbours":{"term":[{"id":"breslow-thickness","kind":"term","name":"Breslow thickness","route":"/terms/breslow-thickness/"},{"id":"extranodal-extension","kind":"term","name":"Extranodal extension (ENE)","route":"/terms/extranodal-extension/"},{"id":"tumour-grade","kind":"term","name":"Grade","route":"/terms/tumour-grade/"},{"id":"lymphovascular-invasion","kind":"term","name":"Lymphovascular invasion (LVI)","route":"/terms/lymphovascular-invasion/"},{"id":"nsmp","kind":"term","name":"No specific molecular profile (NSMP) endometrial cancer","route":"/terms/nsmp/"},{"id":"perineural-invasion","kind":"term","name":"Perineural invasion (PNI)","route":"/terms/perineural-invasion/"},{"id":"sentinel-lymph-node-biopsy","kind":"term","name":"Sentinel node biopsy","route":"/terms/sentinel-lymph-node-biopsy/"}],"technology":[{"id":"endoscopic-resection","kind":"technology","name":"Endoscopic resection (EMR / ESD)","route":"/technologies/endoscopic-resection/"}],"cancer":[{"id":"advanced-cutaneous-scc","kind":"cancer","name":"Advanced cutaneous squamous cell carcinoma","route":"/cancers/advanced-cutaneous-scc/"},{"id":"buccal-mucosa-cancer","kind":"cancer","name":"Buccal mucosa and gingivobuccal cancer (oral cancer in India)","route":"/cancers/buccal-mucosa-cancer/"},{"id":"early-cervical-cancer","kind":"cancer","name":"Early cervical cancer and fertility-sparing surgery","route":"/cancers/early-cervical-cancer/"},{"id":"early-gastric-cancer","kind":"cancer","name":"Early gastric cancer","route":"/cancers/early-gastric-cancer/"},{"id":"hcc-early","kind":"cancer","name":"Early hepatocellular carcinoma (BCLC 0 and A)","route":"/cancers/hcc-early/"},{"id":"endometrial-nsmp","kind":"cancer","name":"Endometrial cancer with no specific molecular profile","route":"/cancers/endometrial-nsmp/"},{"id":"oral-cavity-cancer","kind":"cancer","name":"Oral cavity cancer (mouth and tongue)","route":"/cancers/oral-cavity-cancer/"},{"id":"oral-tongue-cancer","kind":"cancer","name":"Oral tongue and floor of mouth cancer","route":"/cancers/oral-tongue-cancer/"}]}}