Oliver Old

Vibrational spectroscopy for cancer diagnostics

The vibrational spectroscopy techniques of Raman spectroscopy and Fourier-transform infrared spectroscopy offer a number of potential advantages as tools for clinical diagnosis. The ability of these methods to detect subtle biochemical changes relating to pathology opens the possibility of their use in tissue diagnosis. Potential applications include use as an ‘optical biopsy’ technique for in vivo tissue diagnosis or to guide therapy, as a ‘digital staining’ method to assist a histopathologist in analysing a sample, or as an entirely automated process for histopathology classification. To date, much work has been undertaken in applying these spectroscopic methods to discriminate between disease states across a wide range of pathologies and organ systems, but as yet none have entered routine clinical practice. There is a pressing clinical need for real-time, accurate tissue diagnosis, especially in malignant conditions for which rapid diagnosis and comprehensive identification and treatment of diseased tissue are of paramount importance. Cancer diagnostics remains reliant on analysis of tissue samples by histopathologists to confirm malignancy, based on morphological tissue changes and immunohistochemical staining techniques. There is increasing evidence that vibrational spectroscopy, in combination with chemometric data analysis, is a powerful and accurate technique for detecting cancerous and pre-cancerous biochemical changes both in vitro and in vivo, for a range of malignant conditions. This review examines the progress of vibrational spectroscopy towards selected clinical applications, with a particular focus on cancer diagnostics.

Barrett's Oesophagus Surveillance versus endoscopy at need Study (BOSS): protocol and analysis plan for a multicentre randomized controlled trial

Objectives The absolute annual risk of patients with Barretts oesophagus (BO) developing oesophageal adenocarcinoma (OAC) is ≤0.5%. Screening BO patients for malignant progression using endoscopic surveillance is widely practised. To assess the efficacy and cost-effectiveness of this, we developed a protocol for a randomized controlled trial of surveillance versus ‘at need’ endoscopy. Methods In a multicentre trial, 3400 BO patients randomized to either 2-yearly endoscopic surveillance or ‘at need’ endoscopy will be followed up for 10 years. Urgent endoscopy will be offered to all patients who develop symptoms of dysphagia, unexplained weight loss >7lb (3.2kg), iron deficiency anaemia, recurrent vomiting, or worsening upper gastrointestinal symptoms. Participants must have endoscopically and histologically confirmed BO, with circumferential BO ≥1cm or maximal tongue/island length ≥2 cm. Candidates with existing oesophageal high-grade dysplasia or cancer, or previous upper gastrointestinal cancer will be excluded. Primary outcome will be overall survival. Secondary outcomes will be cost effectiveness (cost per life year saved and quality adjusted life years); cancer-specific survival; time to OAC diagnosis and stage at diagnosis; morbidity and mortality related to any interventions; and frequency of endoscopy. Conclusions This randomized trial will provide data to evaluate the efficacy and cost-effectiveness of screening BO patients for OAC.

Multi-centre Raman spectral mapping of oesophageal cancer tissues: a study to assess system transferability.

The potential for Raman spectroscopy to provide early and improved diagnosis on a wide range of tissue and biopsy samples in situ is well documented. The standard histopathology diagnostic methods of reviewing H&E and/or immunohistochemical (IHC) stained tissue sections provides valuable clinical information, but requires both logistics (review, analysis and interpretation by an expert) and costly processing and reagents. Vibrational spectroscopy offers a complimentary diagnostic tool providing specific and multiplexed information relating to molecular structure and composition, but is not yet used to a significant extent in a clinical setting. One of the challenges for clinical implementation is that each Raman spectrometer system will have different characteristics and therefore spectra are not readily compatible between systems. This is essential for clinical implementation where classification models are used to compare measured biochemical or tissue spectra against a library training dataset. In this study, we demonstrate the development and validation of a classification model to discriminate between adenocarcinoma (AC) and non-cancerous intraepithelial metaplasia (IM) oesophageal tissue samples, measured on three different Raman instruments across three different locations. Spectra were corrected using system transfer spectral correction algorithms including wavenumber shift (offset) correction, instrument response correction and baseline removal. The results from this study indicate that the combined correction methods do minimize the instrument and sample quality variations within and between the instrument sites. However, more tissue samples of varying pathology states and greater tissue area coverage (per sample) are needed to properly assess the ability of Raman spectroscopy and system transferability algorithms over multiple instrument sites.

The road map towards providing a robust Raman spectroscopy-based cancer diagnostic platform and integration into clinic

Despite the demonstrated potential as an accurate cancer diagnostic tool, Raman spectroscopy (RS) is yet to be adopted by the clinic for histopathology reviews. The Stratified Medicine through Advanced Raman Technologies (SMART) consortium has begun to address some of the hurdles in its adoption for cancer diagnosis. These hurdles include awareness and acceptance of the technology, practicality of integration into the histopathology workflow, data reproducibility and availability of transferrable models. We have formed a consortium, in joint efforts, to develop optimised protocols for tissue sample preparation, data collection and analysis. These protocols will be supported by provision of suitable hardware and software tools to allow statistically sound classification models to be built and transferred for use on different systems. In addition, we are building a validated gastrointestinal (GI) cancers model, which can be trialled as part of the histopathology workflow at hospitals, and a classification tool. At the end of the project, we aim to deliver a robust Raman based diagnostic platform to enable clinical researchers to stage cancer, define tumour margin, build cancer diagnostic models and discover novel disease bio markers.

Automated cytological detection of Barrett's neoplasia with infrared spectroscopy.

BackgroundDevelopment of a nonendoscopic test for Barrett’s esophagus would revolutionize population screening and surveillance for patients with Barrett’s esophagus. Swallowed cell collection devices have recently been developed to obtain cytology brushings from the esophagus: automated detection of neoplasia in such samples would enable large-scale screening and surveillance.MethodsFourier transform infrared (FTIR) spectroscopy was used to develop an automated tool for detection of Barrett’s esophagus and Barrett’s neoplasia in esophageal cell samples. Cytology brushings were collected at endoscopy, cytospun onto slides and FTIR images were measured. An automated cell recognition program was developed to identify individual cells on the slide.ResultsCytology review and contemporaneous histology was used to inform a training dataset containing 141 cells from 17 patients. A classification model was constructed by principal component analysis fed linear discriminant analysis, then tested by leave-one-sample-out cross validation. With application of this training model to whole slide samples, a threshold voting system was used to classify samples according to their constituent cells. Across the entire dataset of 115 FTIR maps from 66 patients, whole samples were classified with sensitivity and specificity respectively as follows: normal squamous cells 79.0% and 81.1%, nondysplastic Barrett’s esophagus cells 31.3% and 100%, and neoplastic Barrett’s esophagus cells 83.3% and 62.7%.ConclusionsAnalysis of esophageal cell samples can be performed with FTIR spectroscopy with reasonable sensitivity for Barrett’s neoplasia, but with poor specificity with the current technique.

Risk of post-ERCP pancreatitis declines with age

presented the data is valid. (4) Regarding use of percentage EWL as a measure of efficacy, this was not defined by our study but rather by expert consensus from the American Society of Metabolic and Bariatric Surgery and the American Society for Gastrointestinal Endoscopy. We realize that at the present time research in this space is moving toward total weight loss as a more accepted measure of efficacy, and we endeavored to include total weight loss in our analysis as well. We also recognize that it is not methodologically sound to use the newer measure in a meta-analysis of older studies that used percentage EWL as their endpoints.

Chemoprevention for Esophageal Carcinoma

Prevention is the most desirable strategy for nearly all disease processes, but this is especially true for a malignancy with a tendency for metastasis and a correspondingly poor prognosis. Chemoprevention through appropriate drug treatment is a potentially powerful means of radically reducing the incidence of esophageal cancer, and the search for clinically effective agents has now led to large multicenter randomized controlled trials.

Strategies for the prevention of oesophageal adenocarcinoma

The incidence of oesophageal adenocarcinoma has increased by 500% over the past 30 years [1]. Improved understanding of the mechanisms of neoplastic progression provides an opportunity to reverse this trend. A thorough review of emerging strategies aiming to prevent the formation of oesophageal malignancy is presented. These include dietary modification, chemoprevention, early endoscopic identification and treatment of premalignant disease, and the potential for a non-endoscopic screening test. Oesophageal adenocarcinoma has become a major public health problem in the West and it is essential that clinicians are fully informed of risk reduction strategies so that they can be actively promoted in the community.