Extranodal extension (ENE) is defined as "the extension of a nodal metastasis through the lymph node capsule into adjacent tissue" and is a prognostic factor for most head and neck tumors. This data item pertains to clinical staging extension.

Extranodal Extension Head and Neck Clinical is a Registry Data Collection Variable in AJCC. It was previously collected as Head and Neck SSF# 8 (Common SSF).

Item #	Length	Source of Standard	Year Implemented	Version Implemented	Year Retired	Version Retired
3831	1	NAACCR	2018	18

0	Regional lymph nodes involved, ENE not present/not identified during diagnostic workup
1	Regional lymph nodes involved, ENE present/identified during diagnostic workup, based on physical exam WITH or WITHOUT imaging
2	Regional lymph nodes involved, ENE present/identified during diagnostic workup, based on microscopic confirmation
4	Regional lymph nodes involved, ENE present/identified, unknown how identified
7	No lymph node involvement during diagnostic workup (cN0)
8	Not applicable: Information not collected for this case (If this information is required by your standard setter, use of code 8 may result in an edit error)
9	Not documented in medical record ENE not assessed during diagnostic workup, or unknown if assessed Clinical assessment of lymph nodes not done, or unknown if done

Each Site-Specific Data Item (SSDI) applies only to selected primary sites, histologies, and years of diagnosis. Depending on applicability and standard-setter requirements, SSDIs may be left blank.