AJCC 9th Edition TNM Staging — Nasopharyngeal Carcinoma – Rodrigo Arrangoiz MS, MD, FACS, FSSO

AJCC 9th Edition TNM Staging — Nasopharyngeal Carcinoma:
- Applies to carcinomas of the nasopharynx:
  - Excludes mucosal melanoma, lymphoma, and sarcoma
- Nasopharyngeal carcinoma is staged separately from all other head and neck mucosal sites
PRIMARY TUMOR (T):
- TX — Primary tumor cannot be assessed
- T0 — No tumor identified, but EBV-positive cervical node involvement
- Tis — Carcinoma in situ
- T1 — Confined to nasopharynx, or extension to oropharynx and / or nasal cavity WITHOUT parapharyngeal involvement
- T2 — Extension to parapharyngeal space, and / or adjacent soft tissue (medial pterygoid, lateral pterygoid, prevertebral muscles)
- T3 — Unequivocal infiltration of bony structures at skull base, cervical vertebra, pterygoid structures, and / or paranasal sinuses
- T4 — Intracranial extension, cranial nerve involvement, hypopharynx, orbit, parotid gland, and / or extensive soft tissue infiltration beyond the anterolateral surface of the lateral pterygoid muscle
REGIONAL LYMPH NODES (N)
- Key landmarks:
  - 6 cm size cutoff; caudal border of the cricoid cartilage
  - N0 — No regional lymph node metastasis
  - N1 — Unilateral cervical node(s) and / or unilateral or bilateral retropharyngeal node(s), ≤ 6 cm, above the caudal border of the cricoid cartilage, without advanced extranodal extension (ENE)
  - N2 — Bilateral cervical node(s), ≤ 6 cm, above the caudal border of the cricoid cartilage, without advanced ENE
  - N3 — Node(s) > 6 cm, and / or extension below the caudal border of the cricoid cartilage, and / or advanced radiologic ENE with involvement of adjacent muscles, skin, and / or neurovascular bundle
DISTANT METASTASIS (M)
- M0 — No distant metastasis
- M1a — ≤ 3 metastatic lesions
- M1b — > 3 metastatic lesions
HISTOLOGIC GRADE
- No grading system is applied to nasopharyngeal carcinoma
STAGE GROUPS
- Stage 0 — Tis, N0, M0
- Stage IA — T1 to T2, N0, M0
- Stage IB — T0 to T2, N1, M0
- Stage II — T0 to T2, N2, M0
- Stage II — T3, N0 to N2, M0
- Stage III — T4, Any N, M0
- Stage III — Any T, N3, M0
- Stage IVA — Any T, Any N, M1a
- Stage IVB — Any T, Any N, M1b
STAGING WORKUP:
- Nasopharyngeal fiberoptic examination
- Biopsy of primary site or FNA of neck node
- MRI with and without contrast from skull base to clavicle (± CT of skull base / neck for bony erosion)
- FDG-PET/CT and / or contrast-enhanced chest CT for distant disease (bone scan if PET/CT not performed)
- Plasma EBV DNA testing:
  - HPV testing may be considered to inform etiology
KEY CHANGES FROM 8TH EDITION:
- Advanced radiologic ENE added as an N3 criterion
- Stage I expanded to T1 to 2 N0 to 1 and subdivided into IA (N0) and IB (N1)
- Former stage III and IVA down-classified to II and III; all M0 disease now falls within stages I to III
- Stage IV reserved exclusively for metastatic disease, subdivided by ≤ 3 cm vs > 3 cm lesions
- T3 now requires unequivocal bone involvement
The stage groups, T/N/M definitions, and workup elements above are taken directly from the NCCN-endorsed AJCC 9th edition tables and the nasopharynx workup algorithm
The summarized changes from the 8th edition reflect the published TNM-9 derivation cohort of 4,914 patients:
- Note that treatment stratification in the NCCN algorithm keys off TNM categories rather than stage groups, so the stage group alone does not determine whether concurrent chemoradiation or induction chemotherapy is indicated
- Plasma EBV DNA, while part of workup, remains outside the anatomic staging system
NCCN Treatment by TNM Category – Nasopharyngeal Carcinoma (v2.2026):
- All recommendations are category 2A unless otherwise indicated
- Recommendations are based on clinical trial data in EBV-associated nasopharyngeal cancer
NON-METASTATIC DISEASE (M0)
- T1, N0, M0:
  - Definitive RT alone
- T2, N0, M0:
  - Definitive RT ± concurrent systemic therapy if high-risk features
- T0 (EBV+) to T2, N1, M0 OR T3, N0, M0:
  - Concurrent systemic therapy / RT
  - Consider induction or adjuvant chemotherapy if high-risk features
- T3, N1 to 3, M0 OR T4, N0 to 3, M0 OR T0 (EBV+)–T2, N2 to 3, M0:
  - Clinical trial (preferred)
  - OR induction chemotherapy followed by concurrent systemic therapy / RT (preferred; category 1)
  - OR concurrent systemic therapy / RT followed by adjuvant chemotherapy
  - OR concurrent systemic therapy / RT alone (category 2B)
- High-risk features:
  - Bulky tumor volume
  - High serum EBV DNA copy number
METASTATIC DISEASE (T1 to 4, N0 to 3, M1):
- Oligometastatic disease:
  - Induction chemotherapy (if PS 0 to 1), followed by one of:
    - RT to primary and regional nodes, and to oligometastases as indicated
    - Cisplatin / RT
    - Maintenance capecitabine
  - OR concurrent cisplatin + RT (if PS 0–1)
  - OR systemic therapy (if PS 0–2)
- Widely metastatic, good performance status (PS 0 to 2):
  - Systemic therapy:
    - If complete or near-complete response:
      - Consider definitive RT to primary and regional nodes (preferred) and to oligometastases as indicated, or continued systemic therapy
- Widely metastatic, poor performance status (PS 3 to 4):
  - Best supportive care
FOLLOW-UP:
- All M0 pathways proceed to post systemic therapy / RT or post-RT neck evaluation, then routine follow-up
- Recurrent or persistent disease is managed per the recurrent / advanced disease algorithm
KEY POINT:
- Treatment assignment keys off TNM category, not AJCC 9th edition stage group:
  - For example, stage II under TNM-9 encompasses both T3N0M0 (chemoradiation) and T3N2M0 (induction chemotherapy followed by chemoradiation):
    - So the stage group alone is insufficient to select therapy
The M0 treatment branches, including the category 1 designation for induction chemotherapy followed by chemoradiation in T3N1 to 3 / T4/N2 to 3 disease and the category 2B designation for concurrent chemoradiation alone in that same group, come directly from the NCCN nasopharynx treatment algorithm
The metastatic branch separates oligometastatic disease — where locoregional RT to the primary and to metastatic sites is incorporated — from widely metastatic disease managed with systemic therapy, with definitive RT considered only after complete or near-complete response
Workup precedes this split, with M0 versus M1 determined by:
- FDG-PET/CT and / or contrast chest CT
References:
- National Comprehensive Cancer Network. NCCN Clinical Practice Guidelines in Oncology: Head and Neck Cancers, Version 2.2026. AJCC TNM Staging System for the Nasopharynx (9th ed., 2021), page ST-3.
- National Comprehensive Cancer Network. NCCN Clinical Practice Guidelines in Oncology: Head and Neck Cancers, Version 2.2026. Staging (nasopharynx excluded from general mucosal head and neck staging systems).
- National Comprehensive Cancer Network. NCCN Clinical Practice Guidelines in Oncology: Head and Neck Cancers, Version 2.2026. Cancer of the Nasopharynx: Workup (NASO-1).
- National Comprehensive Cancer Network. NCCN Clinical Practice Guidelines in Oncology: Head and Neck Cancers, Version 2.2026. Cancer of the Nasopharynx: Treatment of Primary and Neck by Clinical Staging (NASO-2).
- Pan JJ, Mai HQ, Ng WT, et al. Ninth Version of the AJCC and UICC Nasopharyngeal Cancer TNM Staging Classification. JAMA Oncol. 2024.
- Pan JJ, Mai HQ, Ng WT, et al. Ninth Version of the AJCC and UICC Nasopharyngeal Cancer TNM Staging Classification. JAMA Oncol. 2024.
- Pan JJ, Mai HQ, Ng WT, et al. Ninth Version of the AJCC and UICC Nasopharyngeal Cancer TNM Staging Classification. JAMA Oncol. 2024.
- Rai P, Lakhani DA, Agarwal A, Bhatt AA. The 9th Version of the AJCC Staging System for Nasopharyngeal Carcinoma: A Guide for Radiologists. AJR Am J Roentgenol. 2025.
- Du XJ, Wang GY, Zhu XD, et al. Refining the 8th Edition TNM Classification for EBV Related Nasopharyngeal Carcinoma. Cancer Cell. 2024.
- Cao C, Treechairusame T, Wu Y, et al. Staging of Non-Metastatic Nasopharyngeal Carcinoma With PET/CT. Eur Radiol. 2026.
- Lee VH, Kwong DL, Leung TW, et al. The Addition of Pretreatment Plasma Epstein-Barr Virus DNA Into the Eighth Edition of Nasopharyngeal Cancer TNM Stage Classification. Int J Cancer. 2019.
- National Comprehensive Cancer Network. NCCN Clinical Practice Guidelines in Oncology: Head and Neck Cancers, Version 2.2026. Cancer of the Nasopharynx: Treatment of Primary and Neck for T1–4, N0–3, M1 (NASO-3).