Colorectal cancer: screening

Colorectal Cancer Prevention in Inflammatory Bowel Disease: A Systematic Analysis of the Overall Quality of Guideline Recommendations

BACKGROUND

Owing to the increased risk of colorectal cancer (CRC) in patients with inflammatory bowel disease (IBD), numerous societies developed preventative guidelines. We aimed to assess the overall quality of CRC prevention guidelines in IBD.

METHODS

A systematic search was performed in multiple databases to identify all guidelines pertaining to CRC prevention in IBD in September 2020. All guidelines were reviewed for conflicts of interest (COIs)/funding, recommendation quality/strength, external guideline review, use of patient representation, and plans for update-as per Institute of Medicine standards. In addition, recommendations were compared amongst societies.

RESULTS

One hundred forty-nine recommendations from 14 different guidelines/societies were included. Not all guidelines provided recommendations on key elements surrounding (1) screening initiation and surveillance, (2) screening modality, (3) pharmacological chemoprevention, (4) dysplasia management and follow-up, and (5) molecular marker use. Only 71% of guidelines disclosed COIs, 43% reported industry funding, 14% were externally reviewed, 7% included patient representation, and 36% had plans for update. Of the total recommendations, 7.4%, 23.5%, and 69.1% were based on high,- moderate-, and low-quality evidence, respectively. Additionally, 20.1% of recommendations were strong, 14.1%, were weak/conditional, and 65.8% did not provide a strength. The proportion of high-quality evidence (P = 0.34) and strong recommendations (P = 0.57) did not significantly differ across societies.

CONCLUSIONS

Many guidelines do not provide recommendations on key aspects of CRC prevention in IBD. Over 90% of recommendations are based on low- to moderate-quality evidence; therefore, further studies on CRC prevention in IBD are needed to improve the overall quality of evidence.

Familial and non-familial risk factors associated with incidence of colorectal cancer in young and middle-aged persons in Western Australia

AIMS

The aim of this study was to examine factors including family history, medical history and comorbidities associated with the risk of colorectal cancer (CRC) in young (18-49 years) and middle-age (50-69 years) individuals.

METHODS

State records were used to identify individuals born in Western Australia between 1945 and 1996, and their first-degree relatives. Individuals in the cohort and their relatives were linked to State cancer registry, hospital and mortality data to identify diagnoses of CRC and other risk factors. The associations between CRC and identified risk factors were examined using multivariable logistic regression.

RESULTS

For both young and middle-aged patients, family history of CRC, and a history of smoking, inflammatory bowel disease, liver disease and non-CRC cancer were associated with a significant increase in odds of CRC. In middle-aged patients, having a colonoscopy in the previous 10 years was associated with a reduced odds of CRC regardless of the detection of polyps. However, in young patients only the absence of polyps as confirmed by colonoscopy was associated with a decreased risk of CRC (OR: 0.38, 95%CI: 0.26 - 0.54, p < 0.001).

CONCLUSIONS

Many of the risk factors associated with CRC were similar in young and middle-aged persons, and should be used to identify high risk young patients for screening. The association between colonoscopy and polyps with CRC was modified by age, likely as the result of routine screening in middle-aged patients.

Serum Unsaturated Free Fatty Acids: A Potential Biomarker Panel for Early-Stage Detection of Colorectal Cancer

Background: To screen biomarkers to differentiate early-stage colorectal cancer (CRC) from benign colorectal disease (BCD) and healthy controls.

Materials & Methods: Quantitative and qualitative analysis of C_16:1, C_18:3, C_18:2, C_18:1, C_20:4, and C_22:6 in 185 healthy controls, 55 patients with BCD, and 139 patients with CRC was performed. Comparisons of their levels in between CRC patients, BCD patients, and healthy controls were performed using Mann-Whitney U test.

Results: Serum levels of C_16:1, C_18:3, C_18:2, C_18:1, C_20:4, and C_22:6 in CRC patients were significantly decreased compared with healthy controls and BCD patients. A combination of C_16:1, C_18:2, C_20:4, and C_22:6 has excellent diagnostic performance to differentiate early-stage CRC patients from healthy controls plus BCD patients, with an AUC of 0.926, a sensitivity of 84.6%, and a specificity of 89.8%.

Conclusions: Serum levels of C_16:1, C_18:2, C_20:4, and C_22:6 could be diagnostic indicators of early-stage CRC patients.

Synthesis and characterization of bioactive conjugated near-infrared fluorescent proteinoid-poly(L-lactic acid) hollow nanoparticles for optical detection of colon cancer

Colon cancer is one of the major causes of death in the Western world. Early detection significantly improves long-term survival for patients with colon cancer. Near-infrared (NIR) fluorescent nanoparticles are promising candidates for use as contrast agents for tumor detection. Using NIR offers several advantages for bioimaging compared with fluorescence in the visible spectrum: lower autofluorescence of biological tissues and lower absorbance and, consequently, deeper penetration into biomatrices. The present study describes the preparation of new NIR fluorescent proteinoid-poly(L-lactic acid) (PLLA) nanoparticles. For this purpose, a P(EF-PLLA) random copolymer was prepared by thermal copolymerization of L-glutamic acid (E) with L-phenylalanine (F) and PLLA. Under suitable conditions, this proteinoid-PLLA copolymer can self-assemble to nanosized hollow particles of relatively narrow size distribution. This self-assembly process was used for encapsulation of the NIR dye indocyanine green. The encapsulation process increases significantly the photostability of the dye. These NIR fluorescent nanoparticles were found to be stable and nontoxic. Leakage of the NIR dye from these nanoparticles into phosphate-buffered saline containing 4% human serum albumin was not detected. Tumor-targeting ligands such as peanut agglutinin and anticarcinoembryonic antigen antibodies were covalently conjugated to the surface of the NIR fluorescent P(EF-PLLA) nanoparticles, thereby increasing the fluorescent signal of tumors with upregulated corresponding receptors. Specific colon tumor detection by the NIR fluorescent P(EF-PLLA) nanoparticles was demonstrated in a chicken embryo model. In future work, we plan to extend this study to a mouse model, as well as to encapsulate a cancer drug such as doxorubicin within these nanoparticles for therapeutic applications.

Engineering of near infrared fluorescent proteinoid-poly(L-lactic acid) particles for in vivo colon cancer detection

Background

The use of near-infrared (NIR) fluorescence imaging techniques has gained great interest for early detection of cancer owing to the negligible absorption and autofluorescence of water and other intrinsic biomolecules in this region. The main aim of the present study is to synthesize and characterize novel NIR fluorescent nanoparticles based on proteinoid and PLLA for early detection of colon tumors.

Methods

The present study describes the synthesis of new proteinoid-PLLA copolymer and the preparation of NIR fluorescent nanoparticles for use in diagnostic detection of colon cancer. These fluorescent nanoparticles were prepared by a self-assembly process in the presence of the NIR dye indocyanine green (ICG), a FDA-approved NIR fluorescent dye. Anti-carcinoembryonic antigen antibody (anti-CEA), a specific tumor targeting ligand, was covalently conjugated to the P(EF-PLLA) nanoparticles through the surface carboxylate groups using the carbodiimide activation method.

Results and discussion

The P(EF-PLLA) nanoparticles are stable in different conditions, no leakage of the encapsulated dye into PBS containing 4% HSA was detected. The encapsulation of the NIR fluorescent dye within the P(EF-PLLA) nanoparticles improves significantly the photostability of the dye. The fluorescent nanoparticles are non-toxic, and the biodistribution study in a mouse model showed they evacuate from the body over 24 h. Specific colon tumor detection in a chicken embryo model and a mouse model was demonstrated for anti-CEA-conjugated NIR fluorescent P(EF-PLLA) nanoparticles.

Conclusions

The results of this study suggest a significant advantage of NIR fluorescence imaging using NIR fluorescent P(EF-PLLA) nanoparticles over colonoscopy. In future work we plan to broaden this study by encapsulating cancer drugs such as paclitaxel and/or doxorubicin, within these biodegradable NIR fluorescent P(EF-PLLA) nanoparticles, for both detection and therapy of colon cancer.

Association between health-related quality of life and colorectal cancer screening

Conflicting information currently exists about the role played by health-related quality of life (HRQOL) in influencing colorectal cancer screening. The current study aimed to determine the relationship between HRQOL and colorectal cancer screening, using nationally representative public data from the Behavioral Risk Factor Surveillance System (BRFSS). The 2010 BRFSS data were used for this study. Individuals younger than age 50 years were excluded from the study. Missing data were imputed using the multiple imputation technique. Multiple multivariate logistic regression models were fitted to the data to determine the association between different components of HRQOL (physical HRQOL, mental HRQOL, activity limitation caused by poor mental or physical HRQOL, and general health status) and receipt of colorectal cancer screening tests (fecal occult blood testing [FOBT] in the past year, sigmoidoscopy in the past 5 years, and colonoscopy in the past 10 years). The study sample comprised 301,488 individuals. Approximately 12% of the respondents had received FOBT in the past year, 62.6% had received sigmoidoscopy in the past 5 years, or colonoscopy in the past 10 years, and 65.4% had received either of the screening tests within appropriate time frames. After controlling for demographic and health-related covariates, an inverse relationship was observed between HRQOL and colorectal cancer screening with the exception of mental HRQOL and FOBT. The relationship between mental HRQOL and FOBT was found to be nonsignificant. Policy makers should consider including HRQOL as an important parameter when designing interventions aimed at improving colorectal cancer screening rates.

Engineering of near IR fluorescent albumin nanoparticles for in vivo detection of colon cancer

BACKGROUND

The use of near-infrared (NIR) fluorescence imaging techniques has gained great interest for early detection of cancer because water and other intrinsic biomolecules display negligible absorption or autofluorescence in this region. Novel fluorescent nanoparticles with potential to improve neoplasm detection sensitivity may prove to be a valuable tool in early detection of colon tumors.

METHODS

The present study describes the synthesis and use of NIR fluorescent albumin nanoparticles as a diagnostic tool for detection of colon cancer. These fluorescent nanoparticles were prepared by a precipitation process of human serum albumin (HSA) in aqueous solution in the presence of a carboxylic acid derivative of the NIR dye IR-783 (CANIR). Tumor-targeting ligands such as peanut agglutinin (PNA), anti-carcinoembryonic antigen antibodies (anti-CEA) and tumor associated glycoprotein-72 monoclonal antibodies (anti-TAG-72) were covalently conjugated to the albumin nanoparticles via the surface carboxylate groups by using the carbodiimide activation method.

RESULTS AND DISCUSSION

Leakage of the encapsulated dye into PBS containing 4% HSA or human bowel juice was not detected. This study also demonstrates that the encapsulation of the NIR fluorescent dye within the HSA nanoparticles reduces the photobleaching of the dye significantly. Specific colon tumor detection in a mouse model was demonstrated for PNA, anti-CEA and anti-TAG-72 conjugated NIR fluorescent HSA nanoparticles. These bioactive NIR fluorescent albumin nanoparticles also detected invisible tumors that were revealed as pathological only subsequent to histological analysis.

CONCLUSIONS

These results may suggest a significant advantage of NIR fluorescence imaging using NIR fluorescent nanoparticles over regular colonoscopy. In future work we plan to broaden this study by encapsulating cancer drugs, such as paclitaxel and doxorubicin, within these biodegradable NIR fluorescent HSA nanoparticles, in order to use them for both detection as well as therapy of colon cancer and others.

Label-free serum ribonucleic acid analysis for colorectal cancer detection by surface-enhanced Raman spectroscopy and multivariate analysis

Studies with circulating ribonucleic acid (RNA) not only provide new targets for cancer detection, but also open up the possibility of noninvasive gene expression profiling for cancer. In this paper, we developed a surface-enhanced Raman scattering (SERS), platform for detection and differentiation of serum RNAs of colorectal cancer. A novel three-dimensional (3-D), Ag nanofilm formed by dry MgSO(4) aggregated silver nanoparticles, Ag NP, as the SERS-active substrate was presented to effectively enhance the RNA Raman signals. SERS measurements were performed on two groups of serum RNA samples. One group from patients, n=55 with pathologically diagnosed colorectal cancer and the other group from healthy controls, n=45. Tentative assignments of the Raman bands in the normalized SERS spectra demonstrated that there are differential expressions of cancer-related RNAs between the two groups. Linear discriminate analysis, based on principal component analysis, generated features can differentiate the colorectal cancer SERS spectra from normal SERS spectra with sensitivity of 89.1 percent and specificity of 95.6 percent. This exploratory study demonstrated great potential for developing serum RNA SERS analysis into a useful clinical tool for label-free, noninvasive screening and detection of colorectal cancers.

Colorectal cancer epidemiology: incidence, mortality, survival, and risk factors

In this article, the incidence, mortality, and survival rates for colorectal cancer are reviewed, with attention paid to regional variations and changes over time. A concise overview of known risk factors associated with colorectal cancer is provided, including familial and hereditary factors, as well as environmental lifestyle-related risk factors such as physical inactivity, obesity, smoking, and alcohol consumption.

Colorectal cancer detection by gold nanoparticle based surface-enhanced Raman spectroscopy of blood serum and statistical analysis

The capabilities of using gold nanoparticle based surface-enhanced Raman spectroscopy (SERS) to obtain blood serum biochemical information for non-invasive colorectal cancer detection were presented in this paper. SERS measurements were performed on two groups of blood serum samples: one group from patients (n = 38) with pathologically confirmed colorectal cancer and the other group from healthy volunteers (control subjects, n = 45). Tentative assignments of the Raman bands in the measured SERS spectra suggested interesting cancer specific biomolecular changes, including an increase in the relative amounts of nucleic acid, a decrease in the percentage of saccharide and proteins contents in the blood serum of colorectal cancer patients as compared to that of healthy subjects. Both empirical approach and multivariate statistical techniques, including principal components analysis (PCA) and linear discriminant analysis (LDA) were employed to develop effective diagnostic algorithms for classification of SERS spectra between normal and colorectal cancer serum. The empirical diagnostic algorithm based on the ratio of the SERS peak intensity at 725 cm(-1) for adenine to the peak intensity at 638 cm(-1) for tyrosine achieved a diagnostic sensitivity of 68.4% and specificity of 95.6%, whereas the diagnostic algorithms based on PCA-LDA yielded a diagnostic sensitivity of 97.4% and specificity of 100% for separating cancerous samples from normal samples. Receiver operating characteristic (ROC) curves further confirmed the effectiveness of the diagnostic algorithm based on PCA-LDA technique. The results from this exploratory study demonstrated that gold nanoparticle based SERS serum analysis combined with PCA-LDA has tremendous potential for the non-invasive detection of colorectal cancers.

Effectiveness of the immunofecal occult blood test for colorectal cancer screening in a large population

BACKGROUND

Guaiac tests are the most widely used tests to detect colorectal cancer (CRC). However, their sensitivity is relatively low and results may be affected by various factors. Immunofecal occult blood test (IFOBT) is specific for human hemoglobin and does not require dietary restrictions.

AIMS

The aim of this study was to evaluate the effectiveness of IFOBT for the screening of precancerous lesions and CRC.

METHODS

From July 2006 to June 2007, IFOBT was performed on 5,919 adults who received periodic health examinations in our hospital. The positive cases were examined by colonoscopy and a double-contrast barium enema. Diagnosis was confirmed by histopathological analysis.

RESULTS

Positive IFOBT was detected in 314 of 5,919 cases (5.30%). Further examinations were made in 264 IFOBT-positive cases. Of these, 116 cases with colorectal cancer (16 cases) or precancerous lesions (94 cases with colorectal adenomatous polyps and 6 cases with active ulcerative colitis) were detected. The total detection rate of CRC and precancerous lesions was 43.94% (116/264). TNM classification of 16 CRC cases was as follows: TNM I in eight cases (50.00%), TNM II in seven cases (43.75%) and TNM III in one case (6.25%), indicating IFOBT can detect CRC in the early stages.

CONCLUSION

Regular IFOBT can detect precancerous lesions and CRC in early stages and can thus reduce mortality from CRC.

Colon cancer in inflammatory bowel disease: recent trends, questions and answers

Patients with chronic colitis (ulcerative colitis or colonic Crohn's disease) have an increased risk of colorectal cancer (CRC). Although most of the molecular alterations reported in sporadic CRC have also been observed in colitis-associated CRC, they do not occur at the same timing and frequency, indicating a different pathophysiology. In particular, recent work highlighted the importance of chronic mucosal inflammation as a key factor favouring colorectal carcinogenesis in these patients. This may also be one of the reasons explaining the role of 5-aminosalicylates as chemopreventive agents for CRC in inflammatory bowel disease (IBD) patients with colonic involvement. Beside chemoprevention, colonoscopic screening and surveillance have been shown to be the cornerstone for CRC prevention and early detection in this particular patients' population. Periodic surveillance colonoscopy to detect dysplasia has been shown to decrease the mortality attributed to CRC. More recently, progress in imaging techniques increased our ability to identify dysplasia, and should probably now be considered to be an integral part of surveillance colonoscopy. In the future, further improvement of our knowledge of CRC biology, refinement of imaging techniques, as well as molecular discovery (e.g. identification of specific mutations in stool DNA extracts), might lead to develop more accurate diagnostic strategies to reduce the morbidity and mortality related to CRC in patients with ulcerative colitis or colonic Crohn's disease.

A prospective evaluation of the feasibility of primary screening with unsedated colonoscopy

BACKGROUND

Colonoscopy is the most effective screening tool for colorectal cancer. In Taiwan, colonoscopy is used much less than sigmoidoscopy for screening because sedation significantly increases the cost and is not readily available, and unsedated colonoscopy is considered to be poorly tolerated. However, unsedated colonoscopy has been shown to be well accepted and may improve the cost-effectiveness and access to colonoscopic screening.

OBJECTIVES

To compare the feasibility of unsedated colonoscopy and sigmoidoscopy for primary screening and to analyze factors associated with acceptance of the procedures and need for sedation.

DESIGN

Single center, prospective.

SETTING

National Taiwan University Medical Center. POPULATION AND INTERVENTIONS: A consecutive series of 261 subjects without history of colonoscopy or sigmoidoscopy who underwent unsedated colonoscopy (n = 176) or sigmoidoscopy (n = 85) for primary screening.

MAIN OUTCOME MEASUREMENTS

Pain scores, acceptance, and need for sedation.

RESULTS

No significant differences in pain, acceptance, and need for sedation were found between the colonoscopy and sigmoidoscopy groups. Only 9.6% in the colonoscopy group and 10.1% in the sigmoidoscopy group considered sedation necessary. Multivariate analyses revealed that the examinee's sex and the endoscopist, but not the type of endoscopic examination, were associated with the severity of pain and need for sedation.

LIMITATIONS

Nonrandomized study design.

CONCLUSIONS

Unsedated colonoscopy for primary screening is well accepted in nine tenths of examinees who accept this option and is similar to sigmoidoscopy in pain, acceptance, and need for sedation. Primary screening with unsedated colonoscopy is feasible, as with sigmoidoscopy.

Current concepts in colorectal cancer prevention

Colorectal cancer chemoprevention, or chemoprophylaxis, is a drug-based approach to prevent colorectal cancer. Preventing colorectal adenomas with currently available agents demonstrates the promise of pharmacologic strategies directed at critical regulatory pathways. However, agent toxicity, lesion breakthrough and competing efficacy from endoscopy procedures challenge population-based implementation. This article reviews the role of colorectal cancer chemoprevention in the context of existing screening and surveillance guidelines and practice. Emphasis is placed on the role of the colorectal adenoma as a cancer precursor and its surrogacy in assessing individual risk and for evaluating chemoprevention efficacy. We discuss the importance of risk stratification for identifying subjects at moderate-to-high risk for colorectal cancer who are most likely to benefit from chemoprevention at an acceptable level of risk.

Review article: New developments in colonic imaging

BACKGROUND

Colonoscopic detection and removal of neoplasia from the colorectum prevent the development of colorectal cancer. Sporadic adenomas and neoplasia associated with ulcerative colitis are frequently missed during colonoscopy, as a result of which, interval cancers might develop.

AIM

To review new developments in colonoscopic imaging concerning the detection of neoplasia.

METHODS

Medical databases were searched for relevant publications, dealing with advanced endoscopic imaging techniques during colonoscopy.

RESULTS

Pancolonic chromoendoscopy has shown to increase the detection of sporadic adenomas and ulcerative colitis associated neoplasia, at the expense of longer examination times. As chromoendoscopy is labour intensive and time-consuming, its widespread use has been hampered. Narrow band imaging is a novel endoscopic imaging technique, which enhances mucosal and vascular details. Recent studies indicate that narrow band imaging has a high yield for neoplasia; however, no improvement compared to standard colonoscopy has been demonstrated. Autofluorescence imaging is another new technique for which blue endoscopic light is used to induce mucosal autofluorescence. So far, preliminary results have shown promising results of autofluorescence imaging for neoplasia detection.

CONCLUSION

Whether chromoendoscopy or novel advanced imaging techniques will change current colonoscopic practice depends on results of future studies comparing these different colonoscopic techniques.