Nasopharynx

Head & NeckNasopharynxNPCChemoradiationSkull baseMRI
Overview

Nasopharyngeal carcinoma is treated with radiotherapy, usually with chemotherapy, because the site is not easily reached surgically. The target sits at the skull base, surrounded by the brainstem, optic structures, temporal lobes and inner ears, so this is the subsite where the brain and eye organs in the constraint table matter most.

How It Differs

Setup, dose levels and organ limits follow Head & Neck Planning Essentials. What is specific to the nasopharynx:

  • Chemoradiation is the standard for T2 and higher tumors with any nodal stage, with concurrent cisplatin; carboplatin is a reasonable alternative for patients who cannot have cisplatin. Radiotherapy alone may be considered for low-risk T2 N0 disease, and early-stage disease has its own schedules. Selected patients receive induction chemotherapy first, then chemoradiation.
  • Schedule. Commonly 70 Gy in 35 fractions with an SIB, but the lower levels differ from other subsites: 60 and 50 Gy rather than 63 and 56 Gy. Alternatives in 33–35 fractions are also published.
  • The target reaches the skull base. Which skull-base structures are included depends on T stage, so MRI fused to the planning CT is essential.
  • Two current guidelines differ. A 2025 multi-society guideline and a 2024 international guideline disagree on some margins and on which volumes include which structures — check which one your protocol follows.
  • Brain and eye organs decide the plan. The brainstem, optic chiasm, temporal lobes and cochleae sit right against the target, and nasopharynx-specific guidance ranks which of them may take priority over target coverage.

Target Delineation

What goes into the nasopharynx CTVs under the 2025 guideline. Expansions come only from your protocol.

Primary CTVs — Nasopharynx and skull base

Definition

The high-dose CTV is the gross primary, with little or no expansion. The low-dose CTV includes the whole nasopharynx — even for well-lateralized tumors — and high-risk structures such as the posterior nasal cavity, the pterygopalatine fossa, part or all of the clivus and sphenoid sinus, the parapharyngeal space and the skull-base foramina. The cavernous sinus and the whole clivus are added only for T3–T4 tumors with skull-base invasion.

Why it matters

Nasopharynx cancer spreads upward through the skull-base foramina and along nerves, so the elective primary volume follows those pathways and changes with T stage.

Contouring resources

Organ contouring guides →

Relevant protocols

Nodal CTVs — Retropharyngeal and upper neck

Definition

Levels II, III and Va on both sides; levels IV and Vb on the side of involved nodes; retropharyngeal nodes; level Ib only in specific situations, such as involved level Ib nodes or large level II nodes.

Why it matters

Nasopharynx cancer spreads to the retropharyngeal and upper neck nodes first. Leaving out the lower neck on an uninvolved side reduces dose to the larynx, esophagus and thyroid region.

Contouring resources

Organ contouring guides →

Relevant protocols

Organs at Risk

Uses the shared head and neck constraint table, which includes nasopharynx-specific rows. What changes here:

  • Brainstem, spinal cord and optic chiasm/nerves — serial organs right against the target, ranked among the highest planning priorities in nasopharynx guidance.
  • Temporal lobes and pituitary — the table gives separate limits for nasopharynx cancer, depending on T stage for the temporal lobes.
  • Cochleae — close to the target and sensitized by cisplatin.
  • Lenses — low limits; matter when the target extends into the nasal cavity or orbit.
  • Parotids — the upper-neck and retropharyngeal targets sit close to the deep lobes.

Protocols & Literature

Consensus guidelineUnder Review

An international expert guideline that ranks targets and organs at risk for nasopharyngeal carcinoma planning and gives ideal and acceptable dose criteria, including D0.03 cc near-maximum doses. A correction was published later in 2019. Citation checked against Crossref; content not yet reviewed by DoseLab.

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Clinical protocolUnder Review

NRG Oncology's page for RTOG 0615, a phase 2 trial of concurrent chemoradiotherapy with IMRT (or 3D-CRT) plus bevacizumab for locally or regionally advanced nasopharyngeal cancer. The protocol document lists planning goals for head and neck organs. The larynx and cochlea values in DoseLab's head and neck table are credited to it in the compiling protocol; DoseLab could not extract readable text from the protocol copy it found, so these values have not yet been checked against the protocol itself.

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Clinical resourceSource Verified

Endorsed eviQ protocol for definitive chemoradiation of nasopharyngeal carcinoma (T2 or higher, any N). It summarizes the 2025 primary and nodal target delineation guidelines and notes where the 2024 international guideline differs. Separate eviQ protocols cover early-stage disease and chemoradiation after induction chemotherapy.

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All head & neck literature →