AJCC 8th edition (2017) — site-selectable; p16-positive oropharynx uses its own framework
T — primary tumour
T1 — ≤ 2 cm, depth of invasion ≤ 5 mm
T2 — ≤ 2 cm with DOI 5–10 mm, or 2–4 cm with DOI ≤ 10 mm
T3 — > 4 cm, or any tumour with DOI > 10 mm
T4a — invades cortical bone, maxillary sinus, or skin of the face; or (tongue) extrinsic muscle
T4b — invades masticator space, pterygoid plates, skull base, or encases the carotid artery
N — regional lymph nodes
N0 — no regional lymph node metastasis
N1 — single ipsilateral node ≤ 3 cm, no extranodal extension (ENE)
N2a — single ipsilateral node > 3 to 6 cm, ENE−
N2b — multiple ipsilateral nodes, all ≤ 6 cm, ENE−
N2c — bilateral or contralateral nodes, all ≤ 6 cm, ENE−
N3a — any node > 6 cm, ENE−
N3b — any node with clinical extranodal extension (ENE+)
Evidence
Original publication
Lydiatt WM, Patel SG, O'Sullivan B, et al. Head and neck cancers — major changes in the AJCC eighth-edition cancer staging manual. Added depth of invasion to oral-cavity T staging, extranodal extension to N staging for most sites, and a separate T/N framework and stage table for p16-positive (HPV-associated) oropharyngeal cancer.
CA: A Cancer Journal for Clinicians, 2017
Guideline
Amin MB, Edge SB, Greene FL, et al., eds. AJCC Cancer Staging Manual, 8th edition. Chicago: Springer; 2017. This tool uses generic per-site T/N options; some sites (e.g. laryngeal subsites, nasopharynx, salivary, skin, mucosal melanoma, thyroid) have additional site-specific rules. Confirm the assigned stage against the manual.
Last reviewed: 2026-09
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