Radiation to Hilar Lymph Nodes and Throat Pain
Radiation to hilar lymph nodes can cause throat pain, though this is not a typical or primary toxicity of hilar radiation, as the hilar region is anatomically distant from the throat structures. The likelihood and severity depend on the radiation field design, dose to adjacent structures, and individual patient factors.
Anatomic Considerations and Field Design
The hilar lymph nodes are located at the lung roots, adjacent to the main bronchi and pulmonary vessels 1. When these nodes are included in a radiation field:
Historical mantle-field radiotherapy (used in Hodgkin lymphoma) encompassed cervical, supraclavicular, infraclavicular, axillary, mediastinal, subcarinal, and hilar lymph nodes in a single large field 1. This extensive coverage routinely caused throat-related toxicities because the neck and upper esophagus were directly irradiated 1.
Modern involved-node/involved-site radiotherapy uses much smaller, targeted fields 1. When hilar nodes alone are treated with contemporary techniques, the radiation field typically does not directly include throat structures 1.
Mechanisms of Potential Throat Pain
Direct Radiation Effects
If the radiation field extends superiorly to include mediastinal and subcarinal nodes along with hilar nodes, the esophagus may receive significant dose:
Esophageal mucositis develops when the esophagus receives therapeutic doses, causing pain that patients often describe as "throat pain" 2. This is a common toxicity in head and neck radiation but less typical with isolated hilar treatment 3.
Dose-volume relationships matter significantly. A fractional mean dose of ≥1.1 Gy to the esophagus correlates with moderate to severe esophageal pain 3.
Indirect Effects
Referred pain from mediastinal inflammation or esophageal irritation can be perceived in the throat region 4.
Younger patients and females experience more severe throat and esophageal pain during radiation therapy 3.
Clinical Context and Field Extent
The answer depends critically on what else is being irradiated:
Isolated hilar node radiation (as might occur for oligometastatic disease) would be unlikely to cause significant throat pain unless the field extends to include the upper mediastinum and proximal esophagus 5.
Combined mediastinal and hilar radiation (as in lung cancer with N2 disease or lymphoma) has higher probability of throat symptoms if the field includes the upper mediastinum where the esophagus courses 1, 4.
Extended-field techniques that include cervical or supraclavicular nodes along with hilar nodes will definitely cause throat pain through direct irradiation of pharyngeal and upper esophageal structures 1, 6.
Common Pitfalls
Assuming all thoracic radiation causes throat pain: Isolated hilar radiation with modern techniques typically spares the throat 1.
Overlooking field design: The critical factor is whether the radiation portals include the esophagus and pharyngeal structures, not simply whether hilar nodes are treated 6, 7.
Ignoring patient factors: Age and sex significantly modify pain perception during radiation 3.
In summary, isolated hilar lymph node radiation with modern involved-field techniques would not typically cause throat pain unless the treatment field extends superiorly to include mediastinal structures and the esophagus 1, 3.