Small Cell Lung Cancer and Pleural Effusion: An Analysis from a District General Hospital

The incidence of malignant pleural effusion (MPE) in patients with small cell lung cancer (SCLC) in an American population is approximately 11%, and overall survival in that group is 3 months (compared to 7 months without an effusion. To our knowledge, no study has been done in the United Kindgom and we thus sought to determine the characteristics of the local population.

All patients coded as having small cell lung cancer from Somerset register from January 2012-September 2021 were reviewed. We excluded those with indeterminate pathology reports, carcinoid or large cell neuroendocrine cancers. Basic demographics, presence of an MPE and any interventions and outcomes were collected for descriptive analysis. Continuous variables are presented as mean (±) range, median (± IQR) when outliers were present and categorical variables as percentages where appropriate. Caldicott reference C3905.

Four hundred one patients with SCLC were identified (11% of all patients, median time to death from presentation 208 days, IQR 304 [many outliers); 224 (55.9%) were female, 177 male [median age 75 years, IQR 13]. One hundred seven (27%) presented with an effusion: 23 were sampled, 10 had positive cytology, all were exudates, 8 required chest drainage, the mean performance status (PS) was 2 (range 1-4) and the median time to death 142 days, IQR 45. Of the 294 with no initial effusions, 70 (24%) developed a pleural effusion with progressive disease (mean PS 1, median age 71.5 years, IQR 14, median to death 327 days, IQR 395, 1 outlier); 224 patients never had a MPE with a median time to death of 212 days, IQR 305, multiple outliers and, when compared to those with a MPE at any point, median time to death was 211 days, IQR 295.5 (multiple outliers).

Meaningful analysis was difficult because of the presence of multiple outliers in values collected and not correcting for stage at presentation or treatment modalities and previous studies did not correct for those either. Those presenting with an MPE had a poorer prognosis, probably signifying advanced disease and the presence of MPE in our SCLC cohort seems higher. Large prospective databases for this are required.