Head and neck adult-type soft tissues sarcomas: survival analysis and comparison between the last two editions of the TNM staging system

Purpose: Head and neck soft tissues sarcomas (HNSTS) are a heterogeneous group of rare tumours. The 8th edition of the TNM staging system (8TNM) considered these lesions separately for the first time. The aim of this study is to assess its effectiveness and identify the most significant prognostic factors for HNSTS. Methods: A retrospective survival analysis on 101 HNSTS operated between 1995 and 2015 at the National Cancer Institute of Milan was carried out. The variables considered were pathological stage (according to both the 7TNM and 8TNM), site, histotype, depth, grading, surgical radicality, (neo)adjuvant radiotherapy and/or chemotherapy. Results: According to the 7TNM, the T category distribution was 35 T1a, 23 T1b, 11 T2a, and 32 T2b. Applying the 8TNM, the distribution changed to 19 T1, 18 T2, 35 T3, and 29 T4. Five-year overall and disease-specific survivals were 74.3 and 76.2%, respectively. Univariate analysis demonstrated an increased hazard ratio (HR) for deep lesions invading adjacent structures, high-grade, surgery with close/microscopically positive margins, and chemotherapy. Multivariate analysis confirmed an increased HR for deep location and size > 5 cm, G2–G3 tumours, and marginal surgery. No significant difference was found among T categories of the 8TNM. Conclusion: The present study underlines the negative prognostic impact of depth, size > 5 cm, high grade, and marginal treatment for HNSTS. Our results did not allow to validate the 8TNM staging system since, apparently, it was not associated with meaningful prognostic stratification. Further studies with wider multicentric cohorts should, however, be performed to obtain more powerful statistical data.