Estimating the Risk of Radiation Pneumonitis in Elderly Patients With Lung Cancer

Pneumonitis is a potential complication following radiotherapy of lung cancer, particularly in elderly patients. We developed a risk score for this age group. Thirteen factors were investigated in 124 elderly lung cancer patients. Factors significantly associated with symptomatic radiation pneumonitis (RP) or showing a trend were used for the score, which was compared to an existing tool created in patients of any age. RP was significantly associated with mean lung dose (MLD). Trends were found for autoimmune disease and cardiovascular disease. Based on these three factors, four risk groups were designed (6-7, 8-9, 11-12, and 14 points). RP rates were 0.0% (0/25), 19.1% (9/47), 51.1% (24/47), and 80.0% (4/5). Positive (PPV) and negative (NPV) predictive values were 80.0% and 100.0%. When using the existing tool based on MLD and autoimmune disease, PPV and NPV were the same. The new score was highly accurate but not superior to the existing tool. The existing tool appears preferable, since it requires only two variables.