Pneumonitis in older lung cancer patients after radiotherapy (POLCAR): A prospective study to develop a scoring instrument that helps identify radiation pneumonitis in elderly patients with lung cancer

Abstract

Background: Pneumonitis caused by radiotherapy for lung cancer may be missed, since it often occurs only several months later. In a previous trial including patients of any age, a symptom-based scoring system was tested to facilitate the correct diagnosis of radiation pneumonitis. Since elderly lung cancer patients have a greater risk of developing this complication, a separate scoring system particularly for this age group appears reasonable. This trial investigates such a specific tool for elderly patients irradiated for lung cancer. Methods: Patients with lung cancer patients aged ≥65 years will be included in this prospective multi-center trial and complete paper-based questionnaires (symptom-based scoring system). Patients indicate and rate symptoms potentially caused by pneumonitis, namely cough, dyspnea, and fever, once a week during and up to 24 weeks following their radiotherapy course. If symptomatic (grade ≥2) pneumonitis is confirmed by corresponding diagnostic procedures, patients receive prednisolone whenever possible. The total score of the symptom-based scoring system, which ranges between 0 and 9 points, is correlated to pneumonitis (yes or no). The discriminative power of the scoring system is evaluated by calculating the area under the receiver operating characteristic curve (AUC). Optimality is defined as a cut-off score with sensitivity ≥90% and specificity ≥80%. In addition, the Youden index (sensitivity + specificity – 1) will be applied. Fifty-nine patients (18 with and 41 without pneumonitis) are required in the full analysis set. Assuming that 5% of the patients will not qualify for this set, 62 patients should be enrolled. In addition, patient satisfaction with the scoring system is evaluated. If the dissatisfaction rate is >20%, the score needs modifications; if the dissatisfaction rate is >40%, the scoring system is considered not useful. Discussion: If the optimal cut-off score facilitates the diagnosis of radiation pneumonitis and its discrimination from other lung diseases in elderly patients with lung cancer, it will contribute to the development of a mobile application for identification of radiation pneumonitis, which can be used by the patients at home. Trial registration: clinicaltrials.gov (NCT06480734; URL: https://clinicaltrials.gov/show/NCT06480734); protocol version 1.2, registered on 27th of June, 2024.