The challenge of scoring radiation-induced lung toxicity

The increasing use of curative radiation treatment in lung cancer mandates accurate assessment of late lung toxicity. The Radiation Therapy Oncology Group/European Organization for Research and Treatment of Cancer (RTOG/EORTC) scoring schema combines clinical symptoms and radiological changes and may be confusing. Some have used a scoring scale modified from the National Cancer Institute Common Toxicity Criteria (NCI-CTC) version 2 scale based on symptoms only. Clinical data using these two different scales have been compared as if they give similar results. The present study compared the outcomes using the two scales in the same group of patients.

The medical records and imaging of patients with non-small cell lung cancer who received definitive radiotherapy were reviewed. Eligible patients had a minimum follow-up of 12 months with no clinical signs of local relapse. Radiation-induced lung toxicity was scored using the RTOG/EORTC and the NCI-CTC scales.

In total, 50 patients were analysed. All patients developed radiographic abnormalities after curative radiotherapy. Grade 0, 1, 2 and 3 toxicity was 0, 28, 49 and 23%, respectively, according to the RTOG/EORTC scale and 86, 7, 7 and 0%, respectively, according to the NCI-CTC scale, showing that the inclusion of radiographic abnormalities changes and significantly upgrades the toxicity scores.

After curative radiotherapy, all patients presented some radiographic abnormality. There was no correlation with lung symptoms. The assessment of radiation-induced lung toxicity differs depending on the scoring system used. Comparison of reports that use different scoring scales should be made with caution. A scale based on symptoms only, such as the NCI-CTC scale, may be more appropriate to evaluate long-term toxicity after curative radiotherapy for lung cancer.