Therapeutic advances in recent years have significantly improved the prognosis for patients with nasopharyngeal carcinoma, resulting in a need to update the staging system for this disease. To address this, investigators from the American Joint Committee on Cancer (AJCC) and the Union for International Cancer Control (UICC) collaborated to evaluate and update the tumor-node-metastasis (TNM) system for nasopharyngeal carcinoma staging classification. An article in JAMA Oncology published in October 2024 summarized the evaluation and the recommended updates to the staging system. The AJCC and UICC working group first conducted a comprehensive systematic review of publications and a multicenter validation study, and then invited an author to provide external validation of findings that concurred in both studies. Proposed changes were reviewed by the AJCC and UICC International Panel and suggestions that attained strong consensus were recommended. The recommendations were then evaluated by the AJCC Evidence-Based Medicine Committee and given final endorsement.
Expected to be launched early in 2025, the ninth version of the AJCC and UICC TNM staging system for nasopharyngeal carcinoma features a few key updates
- Advanced extranodal extension was added as a criterion for N3
- M1 was subdivided into M1a and M1b
- Stage I expanded to include T1-2N0-1 subgroups
- Stage III and stage IVA were revised to stage II and stage III, confining stage IV to patients with metastatic disease
- Stage IV was subdivided into IVA and IVB and used exclusively for patients with distant metastases
No changes were proposed for the T category classification. In an invited commentary, Dr Sweet Ping Ng and Dr Darrion Mitchell noted that while only computed tomography and magnetic resonance imaging (MRI) were used for staging in this analysis, other imaging modalities such as positron emission tomography or MRI liver may upstage a patient’s disease. They also mentioned that there are different definitions of extranodal extension (ENE) for other tumor types and advised clinicians and researchers to pay careful attention to ensure the correct one is used for accurate staging and documentation at multidisciplinary care consults and/or clinical trials.
High level
The new nasopharyngeal carcinoma staging classification offers a framework for researchers in the design of future clinical trials and for cancer registries for epidemiologic studies. Looking ahead, growing evidence suggests potential incorporation of Epstein-Barr virus DNA load for both prognostication and treatment response, which may impact future TNM staging for nasopharyngeal carcinoma.
Ground level
For clinicians, the new nasopharyngeal carcinoma staging classification provides a structure for treatment decision-making, as well as personalized risk stratification. The inclusion of ENE as a radiologic prognostic biomarker reflects the advancement in imaging and is expected to improve prognostication.