A RETROSPECTIVE COHORT STUDY INVESTIGATING CYTOLOGICAL SENSITIVITY IN MALIGNANT PLEURAL EFFUSION

Abstract

TYPE: Abstract TOPIC: Disorders of the Pleura PURPOSE: Cytological analysis of pleural fluid is a first line investigation for evaluating a unilateral pleural effusion. Despite long-standing use, diagnostic sensitivity of pleural fluid sampling for malignant pleural effusions (MPEs) is highly variable, between 46-91%. Our objective was to analyse cytological sensitivity in patients with confirmed malignancy using a large retrospective cohort, comparing to previous studies including Arnold et al [1]. METHODS: Consecutive patients with unilateral pleural effusions who underwent thoracocentesis at a district general hospital between 2015-2020 were recruited. Cytology was reported by consultant histopathologists. Sensitivity was calculated based on final diagnosis, confirmed by medical consultants. All data was collected retrospectively using an electronic records system. RESULTS: Of 419 patients recruited, 162 had confirmed malignancy and 146 had cytology reported. Overall sensitivity for pleural cytology to diagnose MPEs was 48.8%. Sensitivity varied according to cancer primary with gynaecological malignancy most sensitive (78%), then lung adenocarcinoma (72%) and breast cancer (68%). Mesothelioma (26%) and Haematological malignancy (20%) had comparatively lower sensitivity which reflects results in previous studies. CONCLUSIONS: Cytological sensitivity for MPEs varies according to cancer primary. CLINICAL IMPLICATIONS: Our results are comparative to previous studies and further highlight the importance of pleural analysis and further diagnostic testing in the diagnosis of MPEs. DISCLOSURE: Nothing to declare. KEYWORD: pleural effusion