Methods
EHR notes from US representative ConcertAI network were accessed for patients with a C34 code. A training set of 7,914 patients was used. For each EHR document, snippets were labeled into NSCLC or SCLC based on exact tumor name or synonyms, stage (extensive, limited for SCLC), or histology (eg: adenocarcinoma for NSCLC). Evidence of subtype is first asserted, then associated temporally and semantically with primary tumor. Then a hybrid rules+ML model is applied at patient level to integrate evidence and resolve contradictions; if unresolved, no prediction is made. A sample of 50 patients predicted as NSCLC and SCLC each (validation set) were compared to expert determined subtype from the EHR. Finally, the model was applied to a larger test cohort and clinical relevance assessed via systemic treatment distribution.