Table 2.

Commonly-utilized acute pneumonitis grading criteria.

Scale	Grade 1	Grade 2	Grade 3	Grade 4	Grade 5
RTOG	Mild symptoms of dry cough or dyspnea on exertion	Persistent cough requiring narcotic, antitussive agents/dyspnea with minimal effort but not at rest	Severe cough unresponsive to narcotic antitussive agent or dyspnea at rest/clinical or radiological evidence of acute pneumonitis/intermittent oxygen or steroids may be required	Severe respiratory insufficiency/continuous oxygen or assisted ventilation	Death
CTCAE	Asymptomatic; clinical or diagnostic observations only; intervention not indicated	Symptomatic; medical intervention indicated; limiting instrumental ADL	Severe symptoms; limiting self-care ADL; oxygen indicated	Life-threatening respiratory compromise; urgent intervention indicated (e.g., tracheotomy or intubation)	Death

Abbreviations: RTOG, Radiation Therapy Oncology Group; CTCAE, Common Toxicity Criteria for Adverse Events (Version 4.0); ADL, activities of daily living.