Investigating Patient-Reported Outcomes as a Tool for Assessing Risk of Developing Radiation Pneumonitis After Thoracic Radiation in Patients With Non-Small Cell Lung Cancer

Abstract

Patient reported outcomes (PRO) show promise in predicting which patients are at risk for worst outcomes after chemoradiation (CRT) and may be used to improve symptom management. We investigate if patient-reported symptoms collected during thoracic radiation (TRT) may help identify patients at risk of developing radiation pneumonitis (RP) post-TRT.Between 2016 to 2020, patients with stage III NSCLC treated with definitive-intent TRT at our institution were identified. Patients completed a 10-item symptom-report questionnaire using the PRO Common Terminology Criteria for Adverse Events (PRO-CTCAE v.1.0) weekly during RT and at follow-up. Physicians graded lung-specific symptoms and side-effects using CTCAE v4.0 at the same time-points. RP was defined as radiographic inflammation of the lung within the radiation field attributable to TRT, and excluding other causes. Patient and treatment characteristics were recorded. Descriptive statistics and univariate competing risks analysis were performed to describe and identify variables associated with development of RP.Of 131 patients identified: median age was 66 years, 53% were male, and 45.8% patients had co-morbid lung disease. Patients received a median of 63 Gy (Interquartile range (IQR): 60-63 Gy) with chemotherapy (88%). The median mean-lung-dose (MLD) was 14.5 Gy (IQR: 12-17 Gy) and the median lung V20 was 20% (IQR: 20%-30%). After TRT, 61 patients received immunotherapy. In the entire cohort, twenty-four patients (18%) developed any grade RP, of which n = 21 were grade ≥2. The median time to diagnosis of RP after TRT was 3.0 months. Factors associated with the development of RP included: age (HR 1.06, P = 0.0004) and MLD (P = 0.0005). In terms of PROs associated with development of RP: patient reported severe pain was significantly associated (HR 3.4, P = 0.01), while moderate anxiety (HR 2.3, P = 0.06), and cough (HR 4.53, P = 0.06) were non-significantly associated with RP. Physician assessed grade 2 dyspnea where medical intervention was needed was associated with RP (HR 3.43, P = 0.02).Patient symptom reports during treatment may be associated with the risk development of RP. Larger studies of prospectively collected PROs during TRT are needed to further explore these potential associations with RP.