The profile of pleural effusions in oncological patients referred to the cardiothoracic surgery department in a tertiary hospital in Pretoria, South Africa: A retrospective study.

BACKGROUND: The presence of a pleural effusion in any oncological patient (patient with known underlying current or previous malignancy) tends to be classified as advanced disease with few curative measures. OBJECTIVES: To establish the aetiology of pleural effusions in oncological patients in our subpopulation. The primary objective was to determine the percentage of proven malignant pleural effusions (MPEs). Secondary objectives were to determine the causes of proven MPEs and proven benign (non-malignant) pleural effusions (non-MPEs), and to determine whether proven non-MPEs change the initial cancer staging of patients. METHODS: This was a retrospective record review of oncological patients admitted with suspected MPE to the Steve Biko Academic Hospital Cardiothoracic Surgery Unit during the period January 2018 - June 2020. RESULTS: Ninety-one patients met the inclusion criteria. The median (interquartile range) age was 56 (41 - 66) years, and there were 54 females (59.3%) and 37 males (40.7%). Pleural biopsy results confirmed MPE in 80.2% (95% confidence interval 70.6 - 87.8) of cases (n=73/91) and non-MPE in 19.8% (n=18/91). The aetiologies of MPEs in descending order were breast (42.5%), lung (24.7%), genitourinary tract (15.1%), lymphoma (9.6%), other (6.8%) and gastrointestinal tract (1.4%) carcinomas. The aetiologies of the non-MPEs were inflammatory (88.9%) and infective (11.1%) in nature. Among the proven non-MPEs, the results led to a possible cancer downstaging in 6/18 patients (33.3%). CONCLUSION: Among oncological patients with pleural effusions referred to our unit, a statistically significant proportion (80.2%) had MPE by pleural tissue confirmation, with breast carcinoma being the most common cause. Of those with proven non-MPE, only a third had a possible cancer downstaging. STUDY SYNOPSIS: What the study adds. This study adds to the growing local evidence-based research by various authors that can be compared with other local and international literature. It also adds to the information needed when establishing or revising protocols in oncological patients with pleural effusions.Implications of the findings. In our population subgroup, the pleural effusions in oncological patients were mostly malignant in nature. The most common cause was breast carcinoma. This is not just a reflection of local referrals, as our unit also receives referrals from other provinces such as Mpumalanga, and sometimes Limpopo.