Automatic trial eligibility surveillance based on unstructured clinical data

Insufficient patient enrollment in clinical trials remains a serious and costly problem and is often considered the most critical issue to solve for the clinical trials community. In this project, we assessed the feasibility of automatically detecting a patient's eligibility for a sample of breast cancer clinical trials by mapping coded clinical trial eligibility criteria to the corresponding clinical information automatically extracted from text in the EHR.

Three open breast cancer clinical trials were selected by oncologists. Their eligibility criteria were manually abstracted from trial descriptions using the OHDSI ATLAS web application. Patients enrolled or screened for these trials were selected as 'positive' or 'possible' cases. Other patients diagnosed with breast cancer were selected as 'negative' cases. A selection of the clinical data and all clinical notes of these 229 selected patients was extracted from the MUSC clinical data warehouse and stored in a database implementing the OMOP common data model. Eligibility criteria were extracted from clinical notes using either manually crafted pattern matching (regular expressions) or a new natural language processing (NLP) application. These extracted criteria were then compared with reference criteria from trial descriptions. This comparison was realized with three different versions of a new application: rule-based, cosine similarity-based, and machine learning-based.

For eligibility criteria extraction from clinical notes, the machine learning-based NLP application allowed for the highest accuracy with a micro-averaged recall of 90.9% and precision of 89.7%. For trial eligibility determination, the highest accuracy was reached by the machine learning-based approach with a per-trial AUC between 75.5% and 89.8%.

NLP can be used to extract eligibility criteria from EHR clinical notes and automatically discover patients possibly eligible for a clinical trial with good accuracy, which could be leveraged to reduce the workload of humans screening patients for trials.