Early Identification of Pneumonitis in Patients Irradiated for Lung Cancer—Final Results of the PARALUC Trial

SIMPLE SUMMARY: Pneumonitis is a serious complication following radiotherapy for lung cancer. Since it generally occurs weeks or even months following treatment, it is often not attributed to the previous irradiation and may be missed. The PARALUC trial was performed to help develop a mobile application (app) that allows early diagnosis and treatment of radiation pneumonitis. The primary goal was the identification of the optimal cut-off of a pneumonitis score (presence or absence of pneumonitis). Based on the severity of related symptoms, scoring points ranged between 0 and 9. The highest sensitivity was achieved with 0–4 points, followed by 5 points, and the highest specificity with 5–6 points. The highest Youden-index (optimal cut-off) was found for 5 points. Moreover, pneumonitis was significantly associated with an increase of ≥3 points from baseline. Patient satisfaction with this scoring tool was very high. Five points were the optimal cut-off to differentiate between pneumonitis and other pulmonary morbidities. The score provided high diagnostic accuracy and patient satisfaction. ABSTRACT: Radiotherapy of lung cancer may cause pneumonitis that generally occurs weeks or months following therapy and can be missed. This prospective trial aimed to pave the way for a mobile application (app) allowing early diagnosis of pneumonitis. The primary goal was the identification of the optimal cut-off of a score to detect pneumonitis of grade ≥2 after radiotherapy for lung cancer. Based on the severity of symptoms (cough, dyspnea, fever), scoring points were 0–9. Receiver operating characteristic (ROC)-curves were used to describe the sensitivity and specificity. The area under the ROC-curve (AUC) was calculated to judge the accuracy of the score, Youden-index was employed to define the optimal cut-off. Until trial termination, 57 of 98 patients were included. Eight of 42 patients evaluable for the primary endpoint (presence or absence of radiation pneumonitis) experienced pneumonitis. AUC was 0.987 (0.961–1.000). The highest sensitivity was achieved with 0–4 points (100%), followed by 5 points (87.5%), highest specificity with 5–6 points (100%). The highest Youden-index was found for 5 points (87.5%). The rate of patient satisfaction with the symptom-based scoring system was 93.5%. A cut-off of 5 points was identified as optimal to differentiate between pneumonitis and no pneumonitis. Moreover, pneumonitis was significantly associated with an increase of ≥3 points from baseline (p < 0.0001). The scoring system provided excellent accuracy and high patient satisfaction. Important foundations for the development of a mobile application were laid.