Detection Of Gastrointestinal Cancers Research Articles

TERT Promoter Hypermethylation in Gastrointestinal Cancer: A Potential Stool Biomarker.

There is a high demand for noninvasive screening tools for gastrointestinal cancer (GIC) detection, and GIC-specific markers are required for such purposes. It is established that induction of the telomerase reverse transcriptase gene (TERT) coupled with telomerase activation is essential for cancer development/progression and aberrant TERT promoter methylation of specific 5'-C-phosphate-G-3' (CpGs) has been linked to TERT induction in oncogenesis. Here we analyzed TERT promoter methylation in fecal samples from GIC patients and healthy adults and determined its value as a stool biomarker for GIC detection. Sixty-nine GIC patients (34 colorectal carcinoma and 35 gastric cancer) and 62 healthy adults were recruited and fecal samples were collected. Paired tumors and adjacent non-cancerous tissues from 34 patients and normal mucosa tissues from 12 healthy individuals were collected. TERT promoter methylation density was determined using pyrosequencing. We identified two GIC-specific methylation sites at -218 (CpG site 1) and -210 (CpG site 2) in the TERT promoter in tumor tissues. Methylated TERT promoter CpG sites 1 and 2 were also detectable in patient stool, while only background levels were observed in healthy individuals. The overall sensitivity reached 52.2% (95% confidence interval [CI]: 48.3-56.0) for fecal methylated TERT promoter assays at 90% specificity, which was comparable to other known stool methylation markers for GIC detection. The combined assays of fecal TERT promoter methylation and occult blood (OB) significantly improved sensitivity and specificity in colorectal cancer (area under curves for methylation alone: 0.798, 95% CI: 0.707-0.889 vs. methylation + OB: 0.920, 95% CI: 0.859-0.981; p = .028), but not in gastric cancer. This proof-of-concept study suggests the feasibility of stool TERT promoter methylation analyses as an additional tool in noninvasive GIC screening. Induction of telomerase reverse transcriptase (TERT) expression coupled with telomerase activation is essential for cancer development/progression, while aberrant TERT promoter methylation has been linked to TERT induction in oncogenesis. We identified two cancer-specific methylation sites (CpG1 and 2) in the TERT promoter in tumors from GIC patients. Methylated TERT promoter CpG sites 1 and 2 were detectable in patient stool, while only background levels were observed in healthy individuals. The sensitivity and specificity was comparable to other known stool methylation markers for GIC detection. This proof-of-concept study suggests the feasibility of stool TERT promoter methylation analyses for noninvasive screening of GIC.

Biomedical optical spectroscopy for the early diagnosis of gastrointestinal neoplasms.

Gastrointestinal cancer is a leading contributor to cancer-related morbidity and mortality worldwide. Early diagnosis currently plays a key role in the prognosis of patients with gastrointestinal cancer. Despite the advances in endoscopy over the last decades, missing lesions, undersampling and incorrect sampling in biopsies, as well as invasion still result in a poor diagnostic rate of early gastrointestinal cancers. Accordingly, there is a pressing need to develop non-invasive methods for the early detection of gastrointestinal cancers. Biomedical optical spectroscopy, including infrared spectroscopy, Raman spectroscopy, diffuse scattering spectroscopy and autofluorescence, is capable of providing structural and chemical information about biological specimens with the advantages of non-destruction, non-invasion and reagent-free and waste-free analysis and has thus been widely investigated for the diagnosis of oesophageal, gastric and colorectal cancers. This review will introduce the advances of biomedical optical spectroscopy techniques, highlight their applications for the early detection of gastrointestinal cancers and discuss their limitations.

Gastrointestinal Cancers: Screening and Early Detection.

To present an overview of current practices in the screening and early detection of gastrointestinal cancers. Literature reviews. Screening for gastrointestinal cancers is less than desirable, particularly in underserved populations. There are inadequate methods of screening for early detection of esophageal and gastric cancers. Education of patients is needed to reinforce the importance of screening for gastrointestinal cancers.

Stimulated Raman microscopy and endoscopy: A route toward real-time intraoperative histology?

We present advances in multiphoton and coherent Raman microscopy and endoscopy for gastrointestinal cancer detection. We use stimulated Raman scattering combined with second harmonic generation to reveal cell nuclei, cytoplasm, and collagen simultaneously in human tissues. For the first time, cell nuclei, cytoplasm, and extracellular matrix can be visualized in real time with image quality similar to histology.

Variant Alleles in XRCC1 Arg194Trp and Arg399Gln Polymorphisms Increase Risk of Gastrointestinal Cancer in Sabah, North Borneo.

The XRCC1 protein facilitates various DNA repair pathways; single-nucleotide polymorphisms (SNPs) in this gene are associated with a risk of gastrointestinal cancer (GIC) with inconsistent results, but no data have been previously reported for the Sabah, North Borneo, population. We accordingly investigated the XRCC1 Arg194Trp and Arg399Gln SNPs in terms of GIC risk in Sabah. We performed genotyping for both SNPs for 250 GIC patients and 572 healthy volunteers using a polymerase chain reaction- restriction fragment length polymorphism approach. We validated heterozygosity and homozygosity for both SNPs using direct sequencing. The presence of a variant 194Trp allele in the Arg194Trp SNP was significantly associated with a higher risk of GIC, especially with gastric and colorectal cancers. We additionally found that the variant 399Gln allele in Arg399Gln SNP was associated with a greater risk of developing gastric cancer. Our combined analysis revealed that inheritance of variant alleles in both SNPs increased the GIC risk in Sabah population. Based on our etiological analysis, we found that subjects ≥50 years and males who carrying the variant 194Trp allele, and Bajau subjects carrying the 399Gln allele had a significantly increased risk of GIC. Our findings suggest that inheritance of variant alleles in XRCC1 Arg194Trp and Arg399Gln SNPs may act as biomarkers for the early detection of GIC, especially for gastric and colorectal cancers in the Sabah population.

Trends in Gastrointestinal Cancer Mortality Rate in Hungary.

The aim of this study was to investigate the annual death trends for gastrointestinal cancer in Hungary between 1963 and 2012. Data on the numbers of cancer deaths were obtained from the published nationwide population register. Numbers of deaths from esophageal, gastric and colorectal cancer were available during the study period. However, the mortality data for hepatic, pancreatic and gallbladder cancer have been published only since 1979. Joinpoint regression was applied to investigate the annual trends in the rates of cancer mortality. The annual mortality rates of gastric and gallbladder cancer decreased throughout the study period. Furthermore, declines in mortality from esophageal and hepatic cancers have been observed since 1998 and 1995, respectively. However, the rates of colorectal and pancreatic cancer mortality have been increasing in the past few years. Nevertheless, the mortality rates of colorectal and pancreatic cancers have increased in males aged 40-59years during the study period. Moreover, significantly higher risks of gastrointestinal cancer-related deaths have been observed in males as compared with females except for death related to cancer of the gallbladder. The presented data suggest that the Hungarian mortality rates are particularly high. The detection of gastrointestinal cancers at an early stage would significantly improves the outcome of these malignancies.

Optimizing early upper gastrointestinal cancer detection at endoscopy.

Survival rates for upper gastrointestinal cancers are poor and oesophageal cancer incidence is increasing. Upper gastrointestinal cancer is also often missed during examinations; a predicament that has not yet been sufficiently addressed. Improvements in the detection of premalignant lesions, early oesophageal and gastric cancers will enable organ-preserving endoscopic therapy, potentially reducing the number of advanced upper gastrointestinal cancers and resulting in improved prognosis. Japan is a world leader in high-quality diagnostic upper gastrointestinal endoscopy and the clinical routine in this country differs substantially from Western practice. In this Perspectives article, we review lessons learnt from Japanese gastroscopy technique, training and screening for risk stratification. We suggest a key performance indicator for upper gastrointestinal endoscopy with a minimum total procedure time of 8 min, and examine how quality assurance concepts in bowel cancer screening in the UK could be applied to upper gastrointestinal endoscopy and improve clinical practice.

Circulating microRNAs as a novel class of diagnostic biomarkers in gastrointestinal tumors detection: a meta-analysis based on 42 articles.

ObjectiveMicroRNAs (miRNAs) have become the focus of most recent efforts in cancer research. However, there have been inconsistencies in the literature regarding the suitability of circulating miRNAs for early detection of gastrointestinal cancers. This study aims to assess the diagnostic performance of circulating miRNAs in detection of gastrointestinal cancer through a meta-analysis.MethodsEligible studies were selected by conducting a systematic literature search of public databases. The sensitivity and specificity were used to plot the summary receiver operator characteristic (SROC) curve and calculate the area under the SROC curve (AUC). The between-study heterogeneity was evaluated by Q test and I 2 statistics. Subgroup analyses and meta-regression were further performed to explore the potential sources of heterogeneity. All analyses were performed using the STATA 12.0 software.ResultsA total of 107 studies from 42 articles were included for the meta-analysis according to the inclusion criteria. The overall analysis of all gastrointestinal cancers showed that circulating miRNAs have a relatively good diagnostic performance in gastrointestinal cancers, with a sensitivity of 0.75, a specificity of 0.81 and an AUC of 0.85. In addition, subgroup analyses based on different type of miRNA assay suggested that single-miRNA assay displayed a relatively low diagnostic performance with the AUC values of 0.84 for gastric cancer (GC) and 0.79 for colorectal cancer (CRC), while multiple-miRNAs assay significantly improved the diagnosing accuracy with AUC rising to 0.92 for GC and 0.89 for CRC. Another interesting finding was that plasma-based miRNA assay reach a higher accuracy compared with serum-based one for GC, while opposite conclusion was drawn for CRC.ConclusionsIn conclusion, circulating miRNAs, particularly the combination of multiple miRNAs, may present as promising biomarkers for the diagnosis of gastrointestinal cancers. Further large-scale prospective studies are necessary to validate their potential applicability in human cancer diagnosis.

Anticoagulant-related gastrointestinal bleeding—could this facilitate early detection of benign or malignant gastrointestinal lesions?

Introduction. The higher incidence of gastrointestinal (GI) bleeding with the non-vitamin K oral anticoagulants (NOACs) may be related to pre-existing malignancies; diagnostic measures triggered by these bleedings could lead to early detection of these malignancies.Methods. We retrieved the preferred terms on GI bleeding and GI cancer reported as adverse events (AEs) from phase III studies in patients with atrial fibrillation for each NOAC on ClinicalTrials.gov. We also analyzed the RE-LY trial database.Results. From ClinicalTrials.gov, AE-GI bleeding incidence was: dabigatran 110 mg b.i.d. (D110: 1.42% versus 1.37%), dabigatran 150 mg b.i.d. (D150: 1.93% versus 1.37%), rivaroxaban (3.52% versus 2.68%), and apixaban (1.93% versus 1.59%), compared with warfarin, respectively. The incidence of AE-GI cancer was similar between the NOACs (D110 [0.79%], D150 [0.61%], rivaroxaban [0.83%], and apixaban [0.69%]), but numerically higher compared with warfarin (0.37%; 0.73%; 0.57%, respectively). In the RE-LY database, the same pattern was seen for dabigatran, with an association between GI bleeding and GI cancer diagnosis.Conclusion. Anticoagulant-related GI bleeding may represent the unmasking of pre-existing malignancies leading to increased detection of GI cancer. This may be especially in the first month of treatment and could explain the numerically higher numbers of GI malignancies observed with NOACs.

Has the Two Week Rule Improved Cancer Detection Rates for Gastrointestinal Cancers? A Systematic Literature Review

Introduction: The UK government introduced the two-week rule (TWR) to improve the diagnosis and treatment of gastrointestinal (GI) cancers. This updated review systematically identifies new articles since 2009 and presents an overview of the previous and new findings combined for both upper GI cancer (UGCs) and colorectal cancers (CRCs). Methods: We analysed all peer-reviewed articles and conference abstracts with GI cancer detection rates following TWR referral and/or the proportion of TWR-referred GI cancers from the total number diagnosed during the study period. We reported average cancer detection rates and split the data according to four time periods to determine whether TWR effectiveness improved over time. Results: The average cancer detection rate by the TWR for all studies was 11.6% for CRC and 8.3% for UGC. We found a decrease in cancer detection rates over time for CRC from 14.4% in 2000-2002 to 7.2% in 2009-2012. However, UGC detection rates increased over time from 8.5% in 2000-2002 to 11.4% in 2005-2008. We found that on average, 30.8% of CRCs and 28.8% of UGCs were detected following referrals using the TWR system and that these proportions had increased over time from 30.6% to 38.4% for CRC and from 26.8% to 52% for UGC. Conclusion: The TWR is not still sufficiently effective in diagnosing GI cancers in patients, suggesting that the referral guidelines need to be improved. Our findings do suggest that the TWR is being used more frequently than alternative routes. Keywords: Gastrointestinal cancer, two-week referral, fast-track, cancer detection rate.

Diagnoses of Gastrointestinal Cancers After Gastrointestinal Bleeding in Patients Receiving Clopidogrel or Warfarin

The association between gastrointestinal (GI) bleeding and subsequent detection of GI cancer in patients using antiplatelet/anticoagulant medications is unclear. We investigated the association between the occurrence of GI bleeding and the detection of GI cancer and assessed whether this association differs in patients treated with clopidogrel or warfarin compared to non-treated patients. A claims analysis was conducted using the Truven Health MarketScan(®) Research databases. Patients were grouped into the treatment cohort if they received a prescription for clopidogrel or warfarin or into the non-treatment cohort if they did not receive these medications. Hazard ratios (HRs) and 95% confidence intervals (CIs) were calculated for GI cancer diagnosed after GI bleeding. Overall, in the treatment cohort, patients who experienced a GI bleed were 6 times (HR: 5.64, 95% CI, 5.12, 6.21) more likely to be diagnosed with GI cancer compared with those without bleeding. In the non-treatment cohort patients were 13 times (HR: 13.34, 95% CI, 12.21, 14.58) more likely to be diagnosed with GI cancer after GI bleeding. The HRs of GI cancer were higher within 6 months of the first GI bleed and decreased remarkably thereafter. This study suggests that an episode of GI bleeding increased the rates of detection of GI cancers.

EUS-Guided Transesophageal Study of the Human Thoracic Duct Diameter After Instillation of Intraduodenal Fatty Acids (EUS-TEST Study)

The accession of the thoracic duct (TD) may be vital for obtaining lymph samples, which may be potentially important for early detection of gastrointestinal cancers. The feasibility and safety of endoscopic ultrasound (EUS)-guided TD puncture were recently demonstrated in a swine model. However, the actual process of lymph aspiration is difficult because of small TD diameter (TDD) as well as sluggish flow. This study was designed to examine the change in TDD following intraduodenal instillation of fatty acids (Intralipid(®); manufactured by Fresenius Kabi [Uppsala, Sweden] for Baxter Healthcare [Deerfield, IL]) in patients undergoing diagnostic EUS. Ten patients undergoing EUS for routine indications were enrolled in this interventional study at a tertiary-care center in the United States. Baseline TDD was first recorded with EUS in the mediastinum, and the endoscope was advanced into the second part of the duodenum, where 20% Intralipid was instilled. Patients then underwent the complete EUS procedure, and TDD was again measured at 30, 45, 60, 75, and 90 minutes. Mean age of the patients was 63 years (range, 46-83 years). The mean (±2 standard deviation) TDD at baseline was 0.17±0.04 cm (range, 0.11-0.23 cm). Values for TDD at 30 minutes (0.22±0.03 cm; P=.11), 60 minutes (0.35±0.08 cm; P=.0007), and 90 minutes (0.27±0.08 cm; P=.04) were all higher than the baseline measurement. Maximum increase in TDD was observed at 60 minutes, after which TD started returning toward baseline. TDD increases after intraduodenal instillation of Intralipid in human subjects. This change was statistically most significant at 60 minutes. These observations may be critical for aspiration of lymph samples for early detection of gastrointestinal cancers in humans.

The sensitivity and specifity of DR-70 as a tumor marker for gastrointestinal cancers.

e22061 Background: There is a great need to detect gastrointestinal cancers at an early stage, reduce morbidity and mortality. CEA and CA 19-9 are widely used serological markers for gastrointestinal cancers during follow-up. Their utility are limited because of their low sensitivity. In this study, a novel tumor marker DR-70 is evaluated for the sensitivity and specificity, relationship between clinical parameters and compared with CEA and CA 19-9. Methods: Blood sera of 101 histologically proven gastrointestinal cancer patients (38 female, 63 male; 42 colon, 25 rectum, 18 stomach, 9 pancreas, 4 esophagus and 3 cholangiocellular carcinomas) and 105 healthy blood donors were included. The TNM stage of the disease and histologic grade was shown. All patients and controls were also tested for CEA and CA 19-9 levels. In DR-70 immunoassay, the fibrin degradation products were quantitatively measured using ELISA DR-70 kits. Results: The median DR-70, CEA and CA19-9 levels were 1.6 µg/mL, 3.05 ng/mL and 22.2 IU/L in cancer patients, they were lower in healthy control 0.5 µg/mL, 0.9 ng/mL, 1.9 IU/L; p < 0.001. While the stage and grade increased, the levels of DR-70, CEA and CA-19-9 (p < 0.05) were increased significantly. DR-70 and CA19-9 values were highest in patients with pancreas, and lowest in rectum cancer, there was no statistically significant difference between tumor localization and CEA levels.The sensitivity, specificity and the cut-off value of DR-70, in patients with malignancy by using ROC analysis were found as 97%, 95% and < 0.75 µg/mL, respectively. The positive and negative predictive values were 95%, and 97% and the efficacy was 96%. Sensitivities of CEA (cut off value 3ng/mL) and CA 19-9 (cut off value 37 U/ml) were 52% and 39% respectively, the specificities were 94% and 99% for CEA and CA 19-9, respectively; sensitivity increased by combined use of both of them. Conclusions: Due to its high sensitivity and specificity, high positive and negative predictive values DR-70 can be used more frequently as a tumor marker for detection of gastrointestinal cancer. It can also be used in tumor progression and treatment follow-up because of positive correlation between DR-70 levels and the tumor stage.

Tumour M2-pyruvate kinase: a gastrointestinal cancer marker

Gastrointestinal cancer tumour markers are valuable in the detection of recurrence following resection or in monitoring response to chemotherapy. CEA, CA19-9, CA-50 and CA72-4 are currently available but are nonspecific and have a low sensitivity. 'Tumour M2-pyruvate kinase' was described by Eigenbrodt around 1985. In cancers the active tetrameric form of the M2 isoenzyme of pyruvate kinase converted to an inactive dimeric form by direct interaction with oncoproteins to channel glucose carbons into DNA synthesis. This review summarizes the current knowledge of this unique tumour marker with regard to its biochemistry, assay and potential use as a diagnostic and screening tool in gastrointestinal cancer. A literature search was conducted for entries from 1980 to 2005 using PubMed and NeLH databases using tumour M2-pyruvate kinase, faecal tumour M2-pyruvate kinase, tumour metabolism, tumour markers and carcinoembryonic antigen as keywords. A total of 56 references relevant to tumour M2-pyruvate kinase were retrieved. Eighteen references were clinical studies involving plasma/faecal tumour M2-pyruvate kinase and gastrointestinal cancer. The remaining 38 references were clinical/nonclinical trials and reviews on tumour metabolism and plasma/faecal tumour M2-pyruvate kinase assay. Seven of the 18 clinical studies involved faecal M2-pyruvate kinase. Three of the 11 plasma tumour M2-pyruvate kinase studies were non-English language and were excluded. The sensitivity, specificity, positive predictive and negative predictive value for plasma/serum tumour M2-pyruvate kinase in the detection of gastrointestinal cancer was determined for each of the remaining eight studies. Data for gastrointestinal cancer M2-pyruvate kinase were compared with other gastrointestinal cancer markers. Data from three of the eight studies using a diagnostic cut-off value of 15 U/ml for ethylenediaminetetraacetic acid (EDTA) plasma tumour M2-pyruvate kinase were analysed together as a small meta-analysis. At a diagnostic cut-off value of 15 U/ml for tumour M2-pyruvate kinase in EDTA plasma the sensitivity, specificity, positive predictive and negative predictive value was 57.3, 89, 85.7 and 64.8%, respectively, for colorectal cancers, 62.1, 89, 88 and 64%, respectively, for gastric/oesophageal cancers and 72.5, 89, 58 and 94%, respectively, for pancreatic cancers. As a faecal marker for colorectal cancers, faecal tumour M2-pyruvate kinase has a sensitivity of 73-92% at a cut-off value of 4 U/ml as against 50% sensitivity for Guaiac faecal test. Circulating tumour M2-pyruvate kinase is more commonly elevated in oesophageal, gastric and colorectal cancer patients than conventional tumour markers. Faecal M2-pyruvate kinase is a sensitive marker of colorectal cancer. The clinical role of tumour M2-pyruvate kinase in gastrointestinal cancer management should be investigated in large-scale clinical trials.

Advanced Imaging and Technology in Gastrointestinal Neoplasia: Summary of the AGA-NCI Symposium October 4–5, 2004

Imaging and other advanced technologies for detection of gastrointestinal cancers are undergoing a major revolution on several fronts. This is facilitated by convergence of key technologies including advanced endoscopic-detection systems, more specific contrast agents, rapid and high-resolution cross-sectional imaging, and miniaturization of construction systems for making all imaging equipment smaller and less invasive. This convergence is occurring along traditional translational research pathways (clinical medicine-molecular biology) as well as nontraditional lines (clinical medicine-optical physics/engineering and molecular biology-optical physics/engineering). These new efforts are producing a wide array of technologies aimed at improving detection, classification, and monitoring of gastrointestinal neoplasia, especially for colorectal and esophageal cancer because of easier accessibility. A critical goal is to detect lesions at their premalignant stages, thereby permitting meaningful intervention. Inspired by these advances, the American Gastroenterological Association and the National Cancer Institute sponsored a symposium held in Bethesda, MD, from October 4-5, 2004, bringing together leading investigators with diverse backgrounds in imaging technology. The aims of this symposium were to summarize the state of the art and priorities for research in the coming decade in the field of imaging and advanced technology for gastrointestinal neoplasia. In this overview, we summarize the salient results of that symposium. The initial sections discuss the major technologies in each area of endoluminal imaging and molecular imaging followed by applications to specific diseases such as Barrett's esophagus and colon neoplasia. Each section focuses on the current state of the art then lists major priorities for research in the field.

Fluorescence Lifetime Imaging for Detection of Gastrointestinal Cancer

Fluorescence Lifetime Imaging for Detection of Gastrointestinal Cancer

Tumor type M2 pyruvate kinase expression in gastric cancer, colorectal cancer and controls.

Tumor formation is generally linked to an expansion of glycolytic phosphometabolite pools and aerobic glycolytic flux rates. To achieve this, tumor cells generally overexpress a special glycolytic isoenzyme, termed pyruvate kinase type M(2). The present study was designed to evaluate the use of a new tumor marker, tumor M(2)-PK, in discriminating gastrointestinal cancer patients from healthy controls, and to compare with the reference tumor markers CEA and CA72-4. The concentration of tumor M(2)-PK in body fluids could be quantitatively determined by a commercially available enzyme-linked immunosorbent assay (ELISA)-kit (ScheBo Tech, Giessen, Germany). By using this kit, the tumor M(2)-PK concentration was measured in EDTA-plasma of 108 patients. For the healthy blood donors a cut-off value of 15 U/mL was evaluated, which corresponded to 90% specificity. Overall 108 patients were included in this study, 54 patients had a histological confirmed gastric cancer, 54 patients colorectal cancer, and 20 healthy volunteers served as controls. The cut-off value to discriminate patients from controls was established at 15 U/mL for tumor M(2)-PK. The mean tumor M(2)-PK concentration of gastric cancer was 26.937 U/mL. According to the TNM stage system, the mean tumor M(2)-PK concentration of stage I was 16.324 U/mL, of stage II 15.290 U/mL, of stage III 30.289 U/mL, of stage IV 127.31 U/mL, of non-metastasis 12.854 U/mL and of metastasis 35.711 U/mL. The mean Tumor M(2)-PK concentration of colorectal cancer was 30.588 U/mL. According to the Dukes stage system, the mean tumor M(2)-PK concentration of Dukes A was 16.638 U/mL, of Dukes B 22.070 U/mL, and of Dukes C 48.024 U/ml, of non-metastasis 19.501 U/mL, of metastasis 49.437 U/mL. The mean tumor M(2)-PK concentration allowed a significant discrimination of colorectal cancers (30.588 U/mL) from controls (10.965 U/mL) (P<0.01), and gastric cancer (26.937 U/mL) from controls (10.965 U/mL) (P<0.05). The overall sensitivity of tumor M(2)-PK for colorectal cancer was 68.52%, while that of CEA was 43.12%. In gastric cancer, tumor M(2)-PK showed a high sensitivity of 50.47%, while CA72-4 showed a sensitivity of 35.37%. Tumor M(2)-PK has a higher sensitivity than markers CEA and CA72-4, and is a valuable tumor marker for the detection of gastrointestinal cancer.

Endoscopic fluorescence imaging and point spectroscopy system for the detection of gastro-intestinal cancers

We describe a combined endoscopic fluorescence imaging and spectroscopy system for the detection of gastro-intestinal cancers, utilizing the fluorescence from aminolaevulinic acid-induced protoporphyrin IX. Both the imaging and spectroscopy systems are controlled by a single desktop PC, which also carries out image processing and stores spectral data, enabling real-time display of images and spectra on one monitor. These systems have been tested in vivo and the results illustrate the potential of both systems in the detection of early cancers. Preliminary testing of the combined system using a foam model has shown that the combined system may better facilitate cancer detection than the use of either system individually.

Clinical Experience Using a Real Time Autofluorescence Endoscopy System in the Gastrointestinal Tract

Autofluorescence spectra of neoplastic tissues have been reported to be significantly different from those of normal tissues when excited by blue or violet light. From this concept, a light-induced autofluorescence endoscopic imaging system for gastrointestinal mucosa (LIFE-GI; Xillix, Canada and Olympus, Japan) has been newly developed and the clinical evaluation of the prototype system has been conducted in hospitals in Canada, Netherlands and Japan. We examined the clinical usefulness of the prototype LIFE-GI system for the detection of gastrointestinal cancer and high and low grade dysplasia. The LIFE-GI system was also applied to the early detection of remnant lesions after endoscopic treatment of early gastric cancer and to the detection of laterally spreading superficial colonic tumors. This system has potential application for the diagnosis of dysplastic lesions and early cancers in the gastrointestinal tract as an adjunct to ordinary white light endoscopy. This system, which needs no administration of a photosensitive agent, may be suitable as a screening method for the early detection of neoplastic tissues.

Emerging Techniques for Optical Detection of Early Mucosal Cancer

Most methods of optical detection of gastrointestinal cancer are aimed at improving the contrast between malignant lesions and normal or metaplastic tissue. Although almost any optical property of matter can theoretically be exploited in this manner, recent work has focused on the use of exogenous fluorescent substances or their metabolic precursors to provide this contrast.