Analysis on the incidence and risk factors of pneumonia in patients with lung cancer receiving thoracic radiotherapy and immunotherapy / 国际肿瘤学杂志

ABSTRACT

Objective:To analyze the incidence, risk factors and occurrence time of radiation pneumonia (RP) and immune checkpoint inhibitor-related pneumonia (CIP) in patients with lung cancer and lung metastatic cancer who received both thoracic radiotherapy and immunotherapy.Methods:The clinicopathological data of 137 patients with lung cancer and lung metastatic cancer receiving thoracic radiotherapy and at least one cycle of immunotherapy from January 2019 to January 2022 in Renmin Hospital of Wuhan University were retrospectively analyzed. The occurrence of RP and CIP was determined according to the clinical symptoms and thin-slice chest CT. The risk factors of symptomatic RP were evaluated by univariate and multivariate analyses of clinical data and treatment plan. The relationship between the occurrence time of symptomatic RP and the sequence of thoracic radiotherapy and immunotherapy was compared.Results:In the 137 patients with lung cancer and lung metastatic cancer who received both thoracic radiotherapy and immunotherapy, symptomatic RP was observed in 42 patients (30.7%) , including grade 2 RP in 33 patients (24.1%) , grade 3 RP in 6 patients (4.4%) , grade 4 RP in 1 patient (0.7%) , and grade 5 RP in 2 patients (1.5%) . The incidence of symptomatic RP was 40.0% (28/70) in patients who received thoracic radiation concurrent with immunotherapy and 20.9% (14/67) in non-synchronous patients, and the incidence of severe RP was 10.0% (7/70) and 3.0% (2/67) respectively. CIP was observed in 11 (8.0%) of 137 patients, including grade 2 CIP in 4 patients (2.9%) , grade 3 CIP in 6 patients (4.4%) , grade 5 CIP in 1 patient (0.7%) . There were 54.5% (6/11) of CIP patients with prior or concurrent symptomatic RP. Univariate analysis showed that smoking history ( χ2=9.85, P=0.002) , chronic obstructive pulmonary disease (COPD) history ( χ2=31.34, P<0.001) , thoracic radiotherapy concurrent with immunotherapy ( χ2=5.88, P=0.015) , total radiotherapy dose ( χ2=8.57, P=0.003) were associated with symptomatic RP. Multivariate logistic regression analysis showed that COPD history ( OR=9.96, 95% CI 3.40-29.14, P<0.001) , thoracic radiotherapy concurrent with immunotherapy ( OR=2.84, 95% CI 1.15-7.00, P=0.024) , and total radiotherapy dose ≥60 Gy ( OR=4.76, 95% CI 1.68-13.50, P=0.003) were independent risk factors for symptomatic RP. RP occurred earlier in patients who received immunotherapy before thoracic radiotherapy [68.5 d (47.0 d, 101.8 d) ] than in patients who received immunotherapy after thoracic radiotherapy [117.5 d (79.0 d, 166.3 d) ], with a statistically significant difference ( Z=2.54, P=0.010) . Conclusion:The incidence of symptomatic RP is high in patients who receive both thoracic radiotherapy and immunotherapy. The history of COPD, thoracic radiotherapy concurrent with immunotherapy, and the total radiotherapy dose ≥60 Gy are independent influencing factors of symptomatic RP in patients with thoracic radiotherapy combined with immunotherapy. Symptomatic RP occurs earlier in patients who receive immunotherapy before thoracic radiotherapy than in patients who receive immunotherapy after thoracic radiotherapy.