Micro- and nanoscale sensing of volatile organic compounds for early-stage cancer diagnosis

A longstanding goal of oncology has been to accurately diagnose cancer at an early stage to improve clinical outcomes. Ideally, such testing would be inexpensive, non-invasive, involve minimal risk, and be scalable to large populations. Volatile biomarkers for early detection can be sampled readily from breath and bodily fluids non-invasively. Herein, the major advances in metabolomics for early-stage cancer detection by sampling volatile organic compounds in breath and bodily fluids are critically reviewed. The operating principles of different sensing methods, including their advantages and limitations are discussed. The primary challenges to developing routine, accurate, portable, and scalable diagnostic methods are detailed. Furthermore, future directions of research to enable the widescale usage of different methods in clinical diagnosis are discussed.