Table 3.

Commonly-utilized pulmonary fibrosis grading criteria.

Scale	Grade 1	Grade 2	Grade 3	Grade 4	Grade 5
RTOG	Asymptomatic or mild symptoms (dry cough); slight radiographic appearances	Moderate symptomatic fibrosis or pneumonitis (severe cough); low grade fever; patchy radiographic appearances	Severe symptomatic fibrosis or pneumonitis; dense radiographic changes	Severe respiratory insufficiency/continuous oxygen/assisted ventilation	Death
CTCAE	Mild hypoxemia; radiologic pulmonary fibrosis	Moderate hypoxemia; evidence of pulmonary hypertension; radiographic pulmonary fibrosis 25–50%	Severe hypoxemia; evidence of right-sided heart failure; radiographic pulmonary fibrosis >50–75%	Life-threatening consequences (e.g., hemodynamic/pulmonary complications); intubation with ventilatory support indicated; radiographic pulmonary fibrosis >75% with severe honeycombing	Death

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