1192P Smoking adversely affects survival of metastatic lung carcinoid patients: Analysis of a large international audit

Among neuroendocrine lung cancers, lung carcinoids (LC, further divided into typical [TC] and atypical [AC]) are rare, representing only the 2% of all bronchopulmonary malignancies, and lack prognostic classification and stratification. We audited two international cohorts of patients with a confirmed diagnosis of LC for prognostic analysis. We used data from The Christie Hospital (Manchester, UK; N=282) and validated our findings using the cohort of Vall d’Hebron Hospital patients (Barcelona, Spain, N=80). We collected patient data and applied modelling strategies to identify a prognostic model for metastasis-free survival (MFS) and overall survival (OS) from metastatic disease. Blood lactic dehydrogenase (LDH) and tumour Ki67% were significant at multivariable analysis (stratified for stage) for MFS (C-index=0.69, P=0.0016), while histological subtype (TC vs AC) and other clinical variables were not. Independent prognostic factors for OS from onset of metastases included smoking history, along with known factors (patient age and performance status, proliferation index, PET maximum SUV). The model C-index was 0.84 (P=0.01678), with optimal concordance when applied to the external validation cohort from Vall d’Hebron. Previously undescribed, patients with smoking history lived shorter (median OS 34 months vs not reached, P<0.0001), and our data also suggested that the median OS could be shorter in current smokers (26.2 months) compared to ex-smokers (35.3 months). We provide a novel prognostic tool to estimate patient risk, clinical trial stratification and assist clinical decisions in the rarest lung tumours. LDH blood levels have not been described as prognostic in this disease, so provide a new reliable biomarker to stratify MFS. We also describe for the first time that smoking history is an independent prognostic factor for overall survival in this cancer. Our results warrant to update the prognostic factors for LC and provide evidence to recommend that patients should stop smoking.