Predictive factors of symptomatic radiation pneumonitis induced by durvalumab following concurrent chemoradiotherapy in locally advanced non-small cell lung cancer

Abstract

Background

Concurrent chemoradiotherapy (CCRT) followed by durvalumab is the standard of care for unresectable locally advanced non-small cell cancer (LA-NSCLC). However, a major concern about the administration of durvalumab after CCRT is whether the incidence of symptomatic radiation pneumonitis (RP) increases. In the present analysis, we report the initial results of CCRT followed by durvalumab in patients with LA-NSCLC in a real-world setting with a focus on predictive factors for symptomatic RP.

Methods

Patients who were pathologically diagnosed with NSCLC and initiated treatment with CCRT followed by durvalumab between July 2018 and December 2019 were eligible for this study. Patients were included if they completed the planned CRT course and were administered at least one course of durvalumab. We retrospectively investigated the preliminary survival outcome and incidence and predictive factors for symptomatic RP.

Results

Of the 67 patients who were scheduled to receive CCRT, 63 completed the entire CCRT course. Of these patients, 56 proceeded to consolidation with durvalumab. The median time to eternal discontinuation of durvalumab was 9.7 months. The cumulative proportions of patients who exhibited symptomatic RP were 30, 40 and 44% at 3, 6 and 12 months, respectively. In multivariate analyses, the pulmonary fibrosis score and lung V40 were significant predictive factors for symptomatic RP (p < 0.001, HR: 7.83, 95% CI: 3.38-18.13, and p = 0.034, HR: 3.17, 95% CI: 1.09-9.19, respectively).

Conclusions

The pulmonary fibrosis sore and lung V40 are significant predictive factors for symptomatic RP. We should be cautious about the administration of durvalumab for patients with subclinical pulmonary fibrosis. To the best of our knowledge, this is one of the first reports showing the predictive value of high dose volumes to the lung in patients with LA-NSCLC who receive CCRT followed by durvalumab.

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Tables

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