Evaluation of FTIR Spectroscopy as a diagnostic tool for lung cancer using sputum

Sputum was collected from 25 lung cancer patients in the Medlung observational study and 25 healthy controls. FTIR spectra were generated from sputum cell pellets using infrared wavenumbers within the 1800 to 950 cm-1 "fingerprint" region.A panel of 92 infrared wavenumbers had absorbances significantly different between cancer and normal sputum spectra and were associated with putative changes in protein, nucleic acid and glycogen levels in tumours. Five prominent significant wavenumbers at 964 cm-1, 1024 cm-1, 1411 cm-1, 1577 cm-1 and 1656 cm-1 separated cancer spectra from normal spectra into two distinct groups using multivariate analysis (group 1: 100% cancer cases; group 2: 92% normal cases). Principal components analysis revealed that these wavenumbers were also able to distinguish lung cancer patients who had previously been diagnosed with breast cancer. No patterns of spectra groupings were associated with inflammation or other diseases of the airways.Our results suggest that FTIR applied to sputum might have high sensitivity and specificity in diagnosing lung cancer with potential as a non-invasive, cost-effective and high-throughput method for screening.ClinicalTrials.gov: NCT00899262Lung cancer is the most common cancer in the world where 1.3 million deaths are recorded each year [1]. It is the second most common cancer in the UK and most common cause of cancer mortality with 34,500 deaths per annum [2]. Survival time is also poor with over 90% of patients dying within five years of diagnosis. Besides co-morbid conditions, poor survival rates primarily reflect the fact that over two thirds of patients are diagnosed at a stage that is currently not amenable to potentially curative treatment.A number of reasons exist as to why so many lung cancers are diagnosed at late stage. The aetiology of lung cancer is well established with approximately 90% of tumours occurring in smokers [3]. Smoking is not just problematic in terms of the causation of lung cancer as