Gastrointestinal cancer imaging: deeper than the eye can see

Polymer-coated BiOCl nanosheets for safe and regioselective gastrointestinal X-ray imaging

Bismuth-based compounds are considered to be the best candidates for computed tomography (CT) imaging of gastrointestinal (GI) tract due to high X-ray absorption. Here, we report the introduction of polymer-coated bismuth oxychloride (BiOCl) nanosheets for highly efficient CT imaging in healthy mice and animal with colitis. We demonstrate simple, low cost and fast aqueous synthesis protocol which provides gram-quantity yield of chemically stable BiOCl nanosheets. The developed contrast gives 2.55-fold better CT enhancement compared to conventional contrast with negligible in vivo toxicity. As a major finding we report a regioselective CT imaging of GI tract by using nanoparticles coated with differentially charged polymers. Coating of nanoparticles with a positively charged polymer leads to their fast accumulation in small intestine, while the coating with negatively charged polymers stimulates prolonged stomach retention. We propose that this effect may be explained by a pH-controlled aggregation of nanoparticles in stomach. This feature may become the basis for advancement in clinical diagnosis of entire GI tract.

A Bi2S3@mSiO2@Ag nanocomposite for enhanced CT visualization and antibacterial response in the gastrointestinal tract

The non-invasive imaging of the gastrointestinal (GI) tract is highly desired for clinical research due to the various GI tract bacterial infection-induced diseases. To treat GI tract infections, various antibiotics have been used in the clinic. The growing problem of multidrug-resistant bacteria calls for effective antibiotic alternatives. Here, we construct a dual-functional Bi₂S₃@mSiO₂@Ag nanocomposite for simultaneous enhanced X-ray computed tomography (CT) imaging and efficient antibacterial activity in the GI tract. The nanocomposite also has good stability, low cytotoxicity, and negligible hemolysis. Moreover, the investigation of the long-term toxicity and biodistribution of the Bi₂S₃@mSiO₂@Ag nanocomposite after oral administration confirms its safety at the tested dosage. In particular, Ag nanoparticles (NPs) well dispersed on a silica substrate can reduce the antibacterial dosage and enhance the antibacterial activity of the Bi₂S₃@mSiO₂@Ag nanocomposite. Furthermore, we have established bacterially infected enteritis animal models to confirm the antibacterial ability of the nanocomposite. This work opens up a new avenue for the design of a nanotheranostic agent that acts as both a contrast agent for the enhanced visualization of the GI tract and an antibacterial agent as an alternative to antibiotics.

Protein-directed synthesis of Bi2S3 nanoparticles as an efficient contrast agent for visualizing the gastrointestinal tract

BSA@Bi₂S₃ nanoparticles can be applied for CT imaging of the gastrointestinal tract, realizing the visualization of gastrointestinal structures.

Value of screening endoscopy in evaluation of esophageal, gastric and colon cancers

Esophageal, gastric, and colorectal cancers are deadly diseases that continue to plague our world today. The value of screening endoscopy in evaluating these types of cancers is a critical area of discussion due to a potential reduction in morbidity and mortality. This article describes how to identify a good screening test and explains what are important criteria in the field of screening endoscopy. Furthermore, the current status and progress of screening endoscopy for esophageal, gastric, and colorectal cancer will be evaluated and discussed. Mass screening programs have not been implemented for esophageal and gastric carcinomas in those with average or low risk populations. However, studies of high-risk populations have found value and a cost-benefit in conducting screening endoscopy. Colorectal cancer, on the other hand, has had mass screening programs in place for many years due to the clear evidence of improved outcomes. As the role of endoscopy as a screening tool has continued to develop, newer technology and techniques have emerged to improve its utility. Many new image enhancement techniques and computer processing programs have shown promise and may have a significant role in the future of endoscopic screening. These developments are paving the way for improving the diagnostic and therapeutic capability of endoscopy in the field of gastroenterology.

Systematic review of the diagnosis of gastric premalignant conditions and neoplasia with high-resolution endoscopic technologies

AIM. The aim of the article is to systematically review the current evidence on the diagnostic use of narrow band imaging (NBI), flexible spectral imaging color enhancement (FICE) and endoscopic image enhancement technology i-scan endoscopies for gastric precancerous and cancerous lesions. MATERIALS AND METHODS. Original manuscripts were searched in PubMed until October 2012. Pertinent data were collected and pooled diagnostic accuracy measures were estimated when possible. RESULTs. In total, 38 studies were evaluated. Thirty-one studies were included for NBI and 7 studies for FICE assessment in this systematic review. No article was found meeting inclusion criteria for i-scan endoscopy. The most defined and evaluated outcomes were cancer-related (n = 26). Quality Assessment of Diagnostic Accuracy Studies score varied from 9 to 12 (out of 14). Only few studies assessed the interobserver reliability. On a patient level analysis, NBI's pooled sensitivity, specificity and diagnostic odds ratio were 0.67 (95% CI: 0.61-0.73), 0.81 (95% CI: 0.76-0.85) and 22.71 (95% CI: 12.53-41.1), respectively for diagnosing normal mucosa; 0.86 (95% CI: 0.82-0.90), 0.77 (95% CI: 0.73-0.80) and 17.01 (95% CI: 1.4-207.2) for intestinal metaplasia and 0.90 (95% CI: 0.84-0.94), 0.83 (95% CI: 0.80-0.86) and 47.61 (95% CI: 4.61-491.34) for dysplasia. Owing to the insufficient data and different definitions, we could not aggregate the results for FICE. CONCLUSION. Gastric pattern descriptions have been proposed for NBI and FICE studies by gathering all descriptions in one single description. The classification systems varied between studies, a single description of gastric mucosal features with HR--scopes or at least per technology--will have to be agreed on.

Screening for cancer with molecular markers: progress comes with potential problems

Recent research has raised hopes for impressively accurate screening for cancer with molecular biomarkers. These molecular markers will probably be more sensitive and specific than older screening modalities, as well as easier to use. In this Essay, I argue that these sensitive screening tests might be clinically valuable - but that they will present unique issues in implementation and interpretation. These issues are likely to affect the way clinicians conduct screening and the way that they make diagnoses in individuals who screen positive for cancer.

Discriminating adenocarcinoma from normal colonic mucosa through deconvolution of Raman spectra

In this work, we considered the feasibility of Raman spectroscopy for discriminating between adenocarcinomatous and normal mucosal formalin-fixed colonic tissues. Unlike earlier studies in colorectal cancer, a spectral deconvolution model was implemented to derive spectral information. Eleven samples of human colon were used, and 55 spectra were analyzed. Each spectrum was resolved into 25 bands from 975 to 1720 cm(-1), where modes of proteins, lipids, and nucleic acids are observed. From a comparative study of band intensities, those presenting higher differences between tissue types were correlated to biochemical assignments. Results from fitting procedure were further used as inputs for linear discriminant analysis, where combinations of band intensities and intensity ratios were tested, yielding accuracies up to 81%. This analysis yields objective discriminating parameters after fitting optimization. The bands with higher diagnosis relevance detected by spectra deconvolution enable to confine the study to some spectral regions instead of broader ranges. A critical view upon limitations of this approach is presented, along with a comparison of our results to earlier ones obtained in fresh colonic tissues. This enabled to assess the effect of formalin fixation in colonic tissues, and determine its relevance in the present analysis.

Colorectal cancer screening: update for 2011

Colorectal cancer is the third most common cancer in the United States. Although mortality and incidence rates are declining in the United States, colorectal cancer screening remains underused. In addition, recent data suggest that colonoscopy, which is often considered the gold standard for colorectal cancer screening, is less protective for right-sided tumors, which are more likely to be flat or depressed and are more affected by an inadequate bowel preparation. Imaging technologies such as chromoendoscopy and narrow band imaging have been developed to improve delineation of suspicious lesions during colonoscopy. In addition, other new modalities such as computed tomography colonography (CTC), capsule endoscopy, fecal immunochemical tests, and fecal DNA tests may offer less invasive screening options for patients who decline colonoscopy.

Multimodality assessment of esophageal cancer: preoperative staging and monitoring of response to therapy

Esophageal cancer is a leading cause of cancer mortality worldwide. Complete resection of esophageal cancer and adjacent malignant lymph nodes is the only potentially curative treatment. Accurate preoperative staging and assessment of therapeutic response after neoadjuvant therapy are crucial in determining the most suitable therapy and avoiding inappropriate attempts at curative surgery. Computed tomography (CT) is recommended for initial imaging following confirmation of malignancy at pathologic analysis, primarily to rule out unresectable or distant metastatic disease. With the advent of multidetector CT, use of thin sections and multiplanar reformation allows more accurate staging of esophageal cancer. Endoscopic ultrasonography (US) is the best modality for determining the depth of tumor invasion and presence of regional lymph node involvement. Combined use of fine-needle aspiration and endoscopic US can improve assessment of lymph node involvement. Positron emission tomography (PET) is useful for assessment of distant metastases but is not appropriate for detecting and staging primary tumors. PET may also be helpful in restaging after neoadjuvant therapy, since it allows identification of early response to treatment and detection of interval distant metastases. Each imaging modality has its advantages and disadvantages; therefore, CT, endoscopic US, and PET should be considered complementary modalities for preoperative staging and therapeutic monitoring of patients with esophageal cancer.

Further validation of magnifying chromocolonoscopy for differentiating colorectal neoplastic polyps in a health screening center

BACKGROUND AND AIM

The accuracy of conventional colonoscopy to differentiate neoplastic and non-neoplastic polyps is limited, justifying a biopsy for histologic analysis. Magnifying chromocolonoscopy has emerged as the best tool available for differentiating adenomatous and hyperplastic polyps during colonoscopy; however, magnifying endoscopes are rarely used in endoscopy units. This study aimed to further validate the effectiveness of magnifying chromocolonoscopy in the diagnosis of neoplastic colorectal polyps in a screening center.

METHOD

Five hundred average-risk subjects were randomly divided into two groups: a magnifying chromocolonoscopy group and a conventional chromocolonoscopy group, each of 250 subjects. Lesions were analyzed according to Kudo's classification of pit pattern (types I-V) and additionally subdivided into non-neoplastic (types I-II) and neoplastic (types III-V). Lesions judged as neoplastic were resected and those judged as non-neoplastic were left in situ. Only lesions < or =10 mm were included in the study. Resected lesions were analyzed with histopathological examination.

RESULTS

The overall accuracy of magnifying chromocolonoscopy for differentiating neoplastic lesions (95%, 135 of 142), was significantly higher than that of conventional chromocolonoscopy (84%, 102 of 122; P < 0.01). The accuracy of magnifying chromocolonoscopy for differentiating neoplastic lesions < or =5 mm was 94% (135 of 142), whereas that of conventional chromocolonoscopy was only 78% (69 of 89; P < 0.001). Results were not affected by the macroscopic types.

CONCLUSION

Magnifying chromocolonoscopy is superior to conventional chromocolonoscopy for the diagnosis of colorectal neoplastic lesions in the setting of a health testing center.

Antiviral response of HCV genotype 1 to consensus interferon and ribavirin versus pegylated interferon and ribavirin

Achieving an antiviral response at a reasonable cost is a challenge in the treatment of patients with chronic hepatitis C. A previous study indicated that consensus interferon with ribavirin had promising activity against hepatitis C virus (HCV) genotype 1. The objective of this study was to determine the virologic response with consensus interferon or pegylated interferon alpha-2b plus weight-ribavirin in patients chronically infected with HCV genotype 1. Intention-to-treat analysis showed response in 37% and 41% of subjects treated with consensus interferon/ribavirin or pegylated interferon/ribavirin, respectively, with response rates of 42% and 44% observed in analysis of the per-protocol population, not a significant difference. Tolerability of the two treatment regimens was similar. In conclusion, both treatment regimens were safe and gave a similar antiviral response. It is possible that if consensus interferon is administered daily rather than three times weekly, eradication of HCV could be achieved in a larger proportion of patients infected with HCV genotype 1.

ROLE OF ENDOSCOPIC ULTRASOUND IN STAGING UPPER GASTROINTESTINAL CANCERS

The key clinical management points in this article are that (i) endoscopic ultrasound is the most accurate imaging method for local staging of oesophageal, gastric and pancreatic neoplasms; (ii) addition of fine-needle aspiration biopsy to the technique is safe and well tolerated and increases diagnostic accuracy for nodal staging purposes; and (iii) endoscopic ultrasound +/- fine-needle aspiration has the capacity to influence significantly, the management of patients with malignancies of the upper gastrointestinal tract, particularly with respect to selection for surgery. The learning objectives were that at the end of this paper the reader should be able to (i) understand the usefulness and limitations of various imaging methods in the staging of upper gastrointestinal cancers; and (ii) incorporate the various imaging methods, particularly endoscopic ultrasound, into management algorithms for oesophageal cancer, gastric cancer, mucosa-associated lymphoid tissue lymphomas, gastrointestinal stromal tumours, pancreatic cystic lesions and pancreatic cancer.

Asymptomatic familial colon cancer with FDG-PET scanning for recurrent disease

A 57-yr-old female was referred for screening colonoscopy because of a positive family history of colon cancer. A lobulated tumor mass was detected in the sigmoid colon. The resected specimen showed an invasive adenocarcinoma without lymph node involvement. Later colonoscopic evaluations and CT imaging failed to reveal definite evidence of recurrent disease but a late rising carcinoembryonic antigen level led to FDG-PET scanning and the detection of suspect lymph nodes in the retroperitoneum. Further histopathological and immunohistochemical evaluation of resected lymph nodes confirmed metastatic carcinoma from the primary colon carcinoma with extra-nodal spread. This case underscores the ongoing need for additional evidence-based studies on evolving imaging modalities used in the diagnosis and management of colonic cancer.