Staging of T2 and T3 nasopharyngeal carcinoma: Proposed modifications for improving the current AJCC staging system

• Published in: Cancer medicine (Malden, MA) Vol. 9; no. 20; pp. 7572 - 7579
• Main Authors: Cui, Chunyan, Li, Haojiang, Ma, Huali, Dong, Annan, Xie, Fei, Liang, Shaobo, Li, Li, Zhou, Jian, Xie, Chuanbo, Yan, Yue, Liu, Lizhi
• Format: Journal Article
• Language: English
• Published: United States John Wiley & Sons, Inc 01.10.2020; John Wiley and Sons Inc; Wiley
• Subjects: Adult; Aged; AJCC stage system; Biopsy; Cancer therapies; Clinical Cancer Research; Combined Modality Therapy; Disease Management; Female; Humans; Lymphatic system; Magnetic Resonance Imaging; Male; Medical prognosis; Middle Aged; MRI imaging; Nasopharyngeal carcinoma; Nasopharyngeal Carcinoma - diagnosis; Nasopharyngeal Carcinoma - mortality; Nasopharyngeal Carcinoma - therapy; Nasopharyngeal Neoplasms - diagnosis; Nasopharyngeal Neoplasms - mortality; Nasopharyngeal Neoplasms - therapy; Neoplasm Invasiveness; Neoplasm Staging - methods; Neoplasm Staging - standards; Original Research; Patients; Prognosis; Proportional Hazards Models; Regression analysis; Reproducibility of Results; Sinuses; Skull; Soft tissues; Survival; Survival analysis; T staging; Throat cancer; Treatment Outcome; Vertebrae; AJCC stage system; nasopharyngeal carcinoma; MRI imaging; survival analysis; T staging
• ISSN: 2045-7634; 2045-7634
• DOI: 10.1002/cam4.3328

Objectives We aimed to reconstitute T2 and T3 stage classification in nasopharyngeal carcinoma (NPC) cases and verify its utility in clinical settings. Materials and Methods We enrolled 792 NPC patients. Cox proportional hazards model was used to compare the effect sizes (hazard ratio [HR]) of the cranial structure invasion on survival and select the structures for up‐staging or downstaging T2 and T3 NPC. The samples were reclassified and the survival curves for T2 and T3 stages were analyzed. The proposed new staging system was validated on an external sample (n = 433). Results Thirteen cranial structures were examined. American Joint Committee on Cancer (AJCC) T3 stage patients with the invasion of the base of the sphenoid (HR = 2.58, 95% CI = 1.16‐5.77) or base of the pterygoid (HR = 2.00, 95% CI = 0.84‐4.77) had significantly lower hazard ratios than T2 stage patients with the invasion of soft tissues in the bilateral parapharyngeal space (HR = 5.26, 95% CI = 2.02‐13.68) and single/bilateral carotid sheath (HR = 7.78, 95% CI = 3.06‐19.76). T3 stage with the invasion of the above‐mentioned bones was reclassified as T2, and T2 stage with the invasion of the above‐mentioned soft‐tissue structures was reclassified as T3. Survival analysis showed a significant difference between the reclassified T2 and T3 stages (P < 0.001). The results were replicated in the validation samples. Conclusion The proposed staging system for defining T2 and T3 stage NPC appears to be superior to the AJCC 8th edition. It could improve prognosis and optimize the treatment selection. Hazard ratio was lower for AJCC T3 with bone than AJCC T2 with soft tissue invasion ·The 5‐year OS and PFS were higher for re‐classified T2 than T3 stage NPC patients·Modified staging system for T2 and T3 NPC may result in better management.