Differential Study Of Pneumonia Due To Treatment Of Malignancy In The Context Of COVID-19

ObjectiveThis study aims to investigate the clinical and imaging differences between coronavirus disease 2019,radiation pneumonitis,and checkpoint inhibitor-related pneumonia in cancer patients,with the aim of providing a theoretical reference for their differential diagnosis.MethodsData of cancer patients diagnosed with coronavirus disease 2019(COVID-19),radiation pneumonitis(RP),or checkpoint inhibitor-related pneumonia(CIP)in our hospital from July 2019 to May 2022 were collected and grouped according to pneumonia type.The differences in pneumonia grade,clinical symptoms and chest CT imaging were compared.The relationship between RP and the radiotherapy dose zone was also analyzed.Chi-square test or Fisher exact test,Mann-Whitney U test and Kruskal-Wallis H test were used to conduct statistical analysis.Bonferroni correction was performed after multiple comparisons.ResultsA total of 62 patients were included in this study,including 19 patients in the COVID-19 group,30 patients in the RP group,and 13 patients in the CIP group.There was no significant difference in the grade of pneumonia in the first and follow-up visits among the three groups.There were significant differences in fever and fatigue between the COVID-19 and RP groups(P<0.05).In imaging findings,there were significant differences in halo sign,air bronchogram,subpleural line shadow,pleural effusion,nodular and striped ground glass opacity,patchy consolidation,inner zone distribution,single or bilateral lung distribution,whole lung involvement and degree of bilateral lower lung involvement(P<0.05).There were significant differences in fever,expectoration,and fatigue between the COVID-19 and CIP groups(P<0.05).There were significant differences in the imaging findings of centrilobular nodules,halo sign,air bronchogram,subpleural line shadow,fibrosis change,traction bronchiectasis,honeycomb sign,pleural effusion,patchy and striped consolidation,distribution of inner and middle zone and degree of right lung involvement(P<0.05).There were significant differences in symptoms of shortness of breath and chest distress between the RP and CIP groups(P<0.05).In imaging findings,there were significant differences in centrilobular nodules,fibrosis change,traction bronchiectasis,honeycomb sign,nodular and striped ground glass opacity,strip-like consolidation,middle zone distribution,single or bilateral lung distribution,whole lung involvement and degree of involvement in the total lung,left lung,right lung,left upper lung,left lower lung and right lower lung(P<0.05).In the RP group,ground glass opacity was mainly distributed in the high dose area(93.3%,28/30)and the middle dose area(76.7%,23/30),but rarely in the low dose area(20.0%,6/30).The consolidation was mainly in the high dose area(94.7%,18/19),less in the middle dose area(31.6%,6/19),but not in the low dose area.Fibrosis was only found in the high dose area but not in the middle and low dose areas,and the differences were statistically significant(P<0.05).ConclusionThere are differences among COVID-19,RP,and CIP in their clinical symptoms and CT manifestations.COVID-19 usually presents with symptoms of fever and fatigue,and CT scans show ground glass opacities in both lungs and subpleural striped consolidation shadows.The distribution of the inner zone is uncommon,with more severe involvement of the lower lung.Subpleural line shadow is more common,while halo sign,air bronchogram,and pleural effusion are rare.The symptoms of RP are mild,and the distribution of inflammation is related to the dose area.CT scans show striped rather than nodular inflammatory changes involving a single lung with less whole-lung involvement.CIP presents with expectoration,chest tightness,and shortness of breath,and CT scans show nodular ground glass opacity in both lungs.The middle zone of the lung is more commonly affected,with a more severe degree of lung involvement and common centrilobular nodules and fibrosis changes.These characteristics can be used as identification points,combined with medical history or epidemiological characteristics,to provide a reference for clinical diagnosis.