Eftychios Manoli1, Afeez Adebesin1, Sam Mason1, Zsolt Bodai1, Julia Balog2, Hiromi Kudo1, Steven Pringle2, Robert Goldin1, Ara Darzi1, Jamie Murphy1, Zoltan Takats1, James Kinross1. 1Imperial College London, London, United Kingdom, 2Waters Research Center, Budapest, Hungary
Introduction: The presence of peritoneal and omental metastatic disease from primary colorectal cancer alters a patient’s optimal treatment strategy. Indeterminate lesions found at staging laparoscopy or at the time of resection can undergo subjective visual assessment and postoperative histological analysis – an approach that is time-consuming and costly. There is an unmet need for novel tools that provide real-time tissue phenotyping. Rapid Evaporative Ionisation Mass Spectrometry (REIMS) performs real-time chemical analysis of biological tissues utilising electrosurgery-generated aerosols. This study aimed to integrate REIMS with the Harmonic® scalpel, assessing its efficacy in diagnosing omental metastases.
Methods: Patients undergoing surgical resection for colorectal cancer with suspected omental metastasis were recruited at St Marys Hospital, UK, as part of a prospective cohort study. Fresh frozen normal and tumour-infiltrated omentum samples were analysed ex vivo using a Harmonic ACE® +7 fitted with a tapered-tip blade (Ethicon Endo-Surgery, JnJ). Sampling was performed at 5W, with aerosols aspirated into a Xevo G2-XS QToF mass spectrometer (Waters Corporation). The relative abundance of cellular metabolites was subjected to multivariate statistical analyses including principle components analysis and orthogonal partial least squares discriminant analysis in SIMCA (Umetrics). The ability of REIMS to predict the presence of tumour infiltration was assessed using leave-one-seventh-patient-out cross-validation.
Results: 14 patients (10 females, median age 58, range 25-82) with primary colorectal cancer were included. 88 normal and 51 tumour-infiltrated omentum samples were analysed generating 139 spectra. REIMS was able to accurately distinguish normal from tumour-infiltrated omentum with an accuracy of 99.3%, sensitivity of 98.8%, specificity of 100%, PPV of 100% and NPV of 98.8%. The relative abundance of metabolites in the mass-to-charge range of 600-1000Da were responsible for differentiating the normal and tumour groups; corresponding to a variety of cellular lipid species. This platform has been deployed in three human studies as a proof of concept, for providing real-time chemical staging of advanced colorectal cancer.
Conclusions: REIMS can be coupled to the Harmonic surgical device to accurately distinguish tumour-infiltrated and normal omentum in patients with colorectal cancer. This may provide the surgeon with real-time tissue feedback of indeterminant lesions, allowing intra-operative decision making to improve clinical outcomes.
Presented at the SAGES 2017 Annual Meeting in Houston, TX.
Abstract ID: 94952
Program Number: P675
Presentation Session: Poster Session (Non CME)
Presentation Type: Poster