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Inter‐observer variation in image interpretation and the prognostic importance of non‐expansile lung in malignant pleural effusion
Author(s) -
Martin Geoffrey A.,
Kidd Andrew C.,
Tsim Selina,
Halford Paul,
Bibby Anna,
Maskell Nick A.,
Blyth Kevin G.
Publication year - 2020
Publication title -
respirology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.857
H-Index - 85
eISSN - 1440-1843
pISSN - 1323-7799
DOI - 10.1111/resp.13681
Subject(s) - medicine , cohort , hazard ratio , pleural effusion , proportional hazards model , retrospective cohort study , pleural disease , cohort study , malignant pleural effusion , surgery , radiology , lung , confidence interval , respiratory disease
Background and objective Non‐expansile lung (NEL) frequently complicates management of malignant pleural effusion (MPE) and is an important factor in clinical practice and trials. NEL is frequently diagnosed on a single radiographic observation, but neither the inter‐observer agreement of this approach nor the prognostic importance of NEL in MPE has been reported. Methods A multicentre retrospective cohort study was performed in two UK pleural centres. NEL was defined as <50% pleural re‐apposition on post‐drainage radiographs by primary and secondary assessors at each site. Inter‐observer agreement was assessed by Cohen's kappa (κ). Kaplan–Meier methodology and multivariate Cox models were used to assess the prognostic impact of NEL versus no NEL and ‘complete NEL’ versus ‘complete expansion’, based on a single assessor's results from each site. Results NEL was identified by the primary assessor in 33 of 97 (34%) in Cohort 1 and 15 of 86 (17%) in Cohort 2. Inter‐observer agreement between assessors was only fair‐to‐moderate (Cohort 1 κ: 0.38 (95% CI: 0.21–0.55), Cohort 2 κ: 0.51 (95% CI: 0.30–0.72)). In both cohorts, NEL was associated with shorter median overall survival (Cohort 1: 188 vs 371 days, Cohort 2: 192 vs 412 days). This prognostic association was independent in Cohort 1 (hazard ratio (HR): 2.19, 95% CI: 1.31–3.66) but not in Cohort 2 (HR: 1.42, 95% CI: 0.71–2.87). Survival was inferior in both cohorts in cases of complete NEL versus complete expansion. Conclusion Radiographic NEL is common but inter‐observer agreement is only fair‐to‐moderate. NEL is associated with adverse survival. These data do not support the use of single radiographic assessments to classify NEL.