Novel Location-Grading-Node-Metastasis Staging System in Patients With Head and Neck Soft Tissue Sarcoma

ImportanceUnlike other head and neck cancers, head and neck soft tissue sarcoma (HN-STS) is staged similarly to sarcomas in the trunk and extremities. The current American Joint Committee on Cancer (AJCC) staging system has limitations that hinder accurate prognosis prediction for HN-STS.ObjectiveWe aimed to develop a novel location-grading-node-metastasis (LGNM) staging system based on the primary tumor location to more accurately stratify prognosis for HN-STS.DesignA retrospective case series from 1990 to 2021.Setting/ParticipantsThis study included 471 patients diagnosed with HN-STS at Sun Yat-sen University Cancer Center between 1990 and 2021.Main outcome measuresIn the primary analysis, we obtained the overall survival (OS) rate. Secondary measures included area under the receiver operating characteristic curve, Harrell's C, Somers' D, Gönen and Heller's K, O'Quigley's ρ2k, Royston's R², the Bayesian information criterion for concordance, and variation in patient outcomes.ResultsThe eighth edition of AJCC T classification for tumor size inadequately conveys prognosis information. In contrast, the primary tumor location and local invasion are prognostic factors for HN-STS and categorized into 4 stages: L1 (low risk: scalp, face, supraclavicular, ear), L2 (intermediate risk: neck, paravertebral, pharynx, tonsil, eye, orbit), L3 (high risk: cavity, lip, palate, buccal mucosa, salivary gland, maxilla, mandible), and L4 (any location with local invasion). The new LGNM staging system effectively distributed patients into stages I to IV, with statistically-significant survival differences among these stages. Five-year OS rates were 96.9% for stage I, 78.4% for stage II, 37.1% for stage III, and 7.1% for stage IV (P < .001). Additionally, the LGNM staging system demonstrated superior predictive ability and concordance compared with the seventh and eighth editions of AJCC staging systems.Conclusions/RelevanceThe LGNM staging system shows better homogeneity and discriminatory power than the AJCC system, improving risk stratification and prognosis prediction in HN-STS.