Risk Factors for Radiation Pneumonitis and a Prognostic Instrument for Very Elderly Patients With Lung Cancer

Elderly and very elderly patients with lung cancer have a comparably high risk of radiation pneumonitis (RP). Risk scores may help to identify these patients. We have developed a risk score for very elderly patients. Nine characteristics were retrospectively investigated in 21 patients aged ≥80 years for associations with symptomatic RP. Characteristics achieving significance or showing a trend were incorporated in the score, which was compared to a previous tool without age limit. The incidence of RP was 33.3% and significantly associated with mean lung dose (MLD) >20 Gy. Trends were found for MLD >13 Gy and cardiovascular disease. Based on these characteristics, three risk groups were formed (2-5, 7-9, and 12 points). RP rates were 0.0%, 44.4%, and 100.0%. Positive (PPV) and negative (NPV) predictive values were both 100.0%. When using the previous score, PPV and NPV were 71.4% and 100%. Given the limitations of this study, the newly developed age-specific risk score appears to be a valuable tool for identifying very elderly lung cancer patients at high or low risk of radiation pneumonitis, and may offer improved predictive performance over previously established models.