Definition of locally recurrent head and neck squamous cell carcinoma: a systematic review and proposal for the Odense–Birmingham definition

Purpose: The objectives of this study were (1) to systematically review current definitions of head and neck squamous cell carcinoma (HNSCC) recurrence and (2) to propose a definition of locally recurrent HNSCC. 

Methods: A systematic literature review was performed according to the ‘Preferred Reporting Items for Systematic Reviews and Meta-Analyses’ statement in Medline, Embase, and Cochrane databases guided by the study question “What is the definition of local recurrence for patients with HN:SCC?”. All retrieved studies were reviewed and qualitatively analyzed. 

Results: The systematic literature search resulted in 3467 publications after removal of duplicates. Forty studies were examined as full text, and a total of five were found suitable for inclusion. All five included studies dealt with definitions of second primary HNSCC and were based on the Warren and Gates Criteria; (1) each of the tumors are malignant, (2) each must be distinct, and (3) the probability of one being a metastasis of the other must be excluded. Each of the included studies added specific anatomical and/or temporal separation measures to the criteria of second primary HNSCC. We propose the definition of locally recurrent HNSCC to be: (1) Same anatomical subsite or adjacent subsite within 3 cm of the primary lesion, (2) time-interval no more than 3 years (from completed treatment of the primary lesion), and (3) same p16-status for oropharyngeal carcinomas. 

Conclusions: No uniform definition of locally recurrent HNSCC currently exists. We propose the Odense–Birmingham definition based on the anatomical subsite combined with a specific measurable distance and a temporal separation of three years.