Colonoscopy as a triage screening test

The "unnatural" history of colorectal cancer in Lynch syndrome: Lessons from colonoscopy surveillance

Individuals with Lynch syndrome (LS), one of the most common inherited cancer syndromes, are at increased risk of developing malignancies, in particular colorectal cancer (CRC). Regular colonoscopy with polypectomy is recommended to reduce CRC risk in LS individuals. However, recent independent studies demonstrated that a substantial proportion of LS individuals develop CRC despite regular colonoscopy. The reasons for this surprising observation confirmed by large prospective studies are a matter of debate. In this review, we collect existing evidence from clinical, epidemiological and molecular studies and interpret them with regard to the origins and progression of LS-associated CRC. Alongside with hypotheses addressing colonoscopy quality and pace of progression from adenoma to cancer, we discuss the role of alternative precursors and immune system in LS-associated CRC. We also identify gaps in current knowledge and make suggestions for future studies aiming at improved CRC prevention for LS individuals.

Adenoma detection rate as a quality indicator for colonoscopy: a descriptive cross-sectional study from a tertiary care hospital in Pakistan

Background and study aims  Adenoma detection rate (ADR) is validated for measuring quality of colonoscopy, however there is lack of colorectal cancer (CRC) screening program in South Asia. The purpose of this study is to analyze and review the polyp detection rate (PDR) and ADR and provide insight into the factors that influence them in Pakistan. Patients and methods  This retrospective, cross-sectional study was performed at the Aga Khan University Hospital, Karachi, Pakistan, on patients ≥ 18 years, who underwent colonoscopy between January 1, 2017 and June 30, 2018. Results  Of 1985 patients, 59 % were male and 41 % female, with mean age of 47.8 ± 16.2 years. The most common indication for colonoscopy was bleeding-per-rectum (28.0 %) and overall PDR and ADR were 17.9 % and 9.9 %, respectively. There was no significant difference between genders for either PDR ( P  = 0.378) or ADR ( P  = 0.574). Significantly higher PDR and ADR were found for patients ≥ 50 years ( P  < 0.001), as well as for suboptimal bowel preparation [PDR (25.7 %; P  = 0.007) and ADR (18.6 %; P  = 0.014)]. Interestingly, endoscopists with < 500 colonoscopy-procedural-experience reported a higher PDR (21.6 %; P  = 0.020) and ADR (14.4 %; P = 0.049), corresponding to a significantly higher PDR (20.6 %; P  = 0.005) and ADR (11.7 %; P  = 0.02) for endoscopists in practice for ≤ 10 years. Conclusions  We have noticed low PDR and ADR, which require further investigation and research. In addition, we believe there should be a different baseline ADR and PDR as a quality indicator for colonoscopy in our region, where no internationally recommended colonoscopic screening programs have been implemented.

Surveillance after colorectal polyp removal

Surveillance colonoscopy is aimed to reduce CRC incidence and mortality by removing adenomas and detecting CRC in early stage. However, colonoscopy is an invasive and expensive procedure and surveillance colonoscopy should be targeted at those who are most likely to benefit at the minimum frequency required to protect for cancer. Surveillance recommendations are based on guidelines, but the recommendations in those guidelines are based on moderate to low quality evidence and adherence to these guidelines is poor. As surveillance colonoscopy is one of the main indications for colonoscopy and surveillance colonoscopies are filling colonoscopy lists, the current surveillance practice results in spending lots of money and capacity in a suboptimal way. Randomized controlled trials to compare surveillance intervals are not available. However, current evidence based on several case-control and cohort studies suggests there is no need for surveillance in patients with low-risk adenomas, i.e. 1-2 adenomas smaller than 10 mm. Patients with 3 or more adenomas or any adenoma larger than 10 mm seem to be the ones at real risk for metachronous adenomas or cancer. In those patients, surveillance colonoscopy is indicated at 3 years after baseline until ongoing studies will confirm the safety of enlarging this interval. Randomized controlled trials and experimental research are important in order to provide the necessary scientific evidence for the optimization of follow-up strategies for patients with adenomas and serrated polyps.

Appropriateness of endoscopic surveillance recommendations in organised colorectal cancer screening programmes based on the faecal immunochemical test

OBJECTIVES

To assess the appropriateness of recommendations for endoscopic surveillance in organised colorectal cancer (CRC) screening programmes based on the faecal immunochemical test (FIT).

DESIGN

74 Italian CRC screening programmes provided aggregated data on the recommendations given after FIT-positive colonoscopies in 2011 and 2013. Index colonoscopies were divided into negative/no adenoma and low- risk, intermediate-risk and high-risk adenomas. Postcolonoscopy recommendations included a return to screening (FIT after 2 years or 5 years), an endoscopic surveillance after 6 months or after 1 year, 3 years or 5 years, surgery or other. We assessed the deviation from the postcolonoscopy recommendations of the European Guidelines in 2011 and 2013 and the correlation between overuse of endoscopic surveillance in 2011 and the process indicators associated with the endoscopic workload in 2013.

RESULTS

49 704 postcolonoscopy recommendations were analysed. High-risk, intermediate-risk and low-risk adenomas, and no adenomas were reported in 5.9%, 19.3%, 15.3% and 51.5% of the cases, respectively. Endoscopic surveillance was inappropriately recommended in 67.4% and 7%, respectively, of cases with low-risk and no adenoma. Overall, 37% of all endoscopic surveillance recommendations were inappropriate (6696/17 860). Overuse of endoscopic surveillance was positively correlated with the extension of invitations (correlation coefficient (cc) 0.29; p value 0.03) and with compliance with post-FIT+ colonoscopy (cc 0.25; p value 0.05), while it was negatively correlated with total colonoscopy waiting times longer than 60 days (cc -0.26; p value 0.05).

CONCLUSIONS

In organised screening programmes, a high rate of inappropriate recommendations for patients with low risk or no adenomas occurs, affecting the demand for endoscopic surveillance by a third.

Surveillance of colonic polyps: Are we getting it right?

Colorectal cancer (CRC) is the third most commonly diagnosed cancer worldwide. The identification of colonic polyps can reduce CRC mortality through earlier diagnosis of cancers and the removal of polyps: the precursor lesion of CRC. Following the finding and removal of colonic polyps at an initial colonoscopy, some patients are at an increased risk of developing CRC in the future. This is the rationale for post-polypectomy surveillance colonoscopy. However, not all individuals found to have colonic adenomas have a risk of CRC higher than that of the general population. This review examines the literature on post-polypectomy surveillance including current international clinical guidelines. The potential benefits of surveillance procedures must be weighed against the burden of colonoscopy: resource use, the potential for patient discomfort, and the risk of complications. Therefore surveillance colonoscopy is best utilised in a selected group of individuals at a high risk of developing cancer. Further study is needed into the specific factors conferring higher risk as well as the efficacy of surveillance in mitigating this risk. Such evidence will better inform clinicians and patients of the relative benefits of colonoscopic surveillance for the individual. In addition, the decision to continue with surveillance must be informed by the changing profile of risks and benefits of further procedures with the patient’s advancing age.

Long-term colorectal-cancer mortality after adenoma removal

BACKGROUND

Although colonoscopic surveillance of patients after removal of adenomas is widely promoted, little is known about colorectal-cancer mortality among these patients.

METHODS

Using the linkage of the Cancer Registry and the Cause of Death Registry of Norway, we estimated colorectal-cancer mortality among patients who had undergone removal of colorectal adenomas during the period from 1993 through 2007. Patients were followed through 2011. We calculated standardized incidence-based mortality ratios (SMRs) using rates for the Norwegian population at large for comparison. Norwegian guidelines recommended colonoscopy after 10 years for patients with high-risk adenomas (adenomas with high-grade dysplasia, a villous component, or a size ≥10 mm) and after 5 years for patients with three or more adenomas; no surveillance was recommended for patients with low-risk adenomas. Polyp size and exact number were not available in the registry. We defined high-risk adenomas as multiple adenomas and adenomas with a villous component or high-grade dysplasia.

RESULTS

We identified 40,826 patients who had had colorectal adenomas removed. During a median follow-up of 7.7 years (maximum, 19.0), 1273 patients were given a diagnosis of colorectal cancer. A total of 398 deaths from colorectal cancer were expected and 383 were observed, for an SMR of 0.96 (95% confidence interval [CI], 0.87 to 1.06) among patients who had had adenomas removed. Colorectal-cancer mortality was increased among patients with high-risk adenomas (expected deaths, 209; observed deaths, 242; SMR, 1.16; 95% CI, 1.02 to 1.31), but it was reduced among patients with low-risk adenomas (expected deaths, 189; observed deaths, 141; SMR, 0.75; 95% CI, 0.63 to 0.88).

CONCLUSIONS

After a median of 7.7 years of follow-up, colorectal-cancer mortality was lower among patients who had had low-risk adenomas removed and moderately higher among those who had had high-risk adenomas removed, as compared with the general population. (Funded by the Norwegian Cancer Society and others.).

Overexpression of PTP1B in human colorectal cancer and its association with tumor progression and prognosis

Protein tyrosine phosphatase 1B (PTP1B) is a non-transmembrane protein tyrosine phosphatase that has been implicated in cancer pathogenesis. However, the expression level and the role of PTP1B in the development and prognosis of colorectal cancer (CRC) remain unclear. In this study, the expression of PTP1B in CRC tissues and matched noncancerous tissues were detected by using immunohistochemistry, real-time PCR and Western blotting. The correlations between PTP1B expression level and clinicopathologic characteristics and patient survival were analyzed. We found that PTP1B expression was significantly higher in CRC tissues compared with matched non-tumour tissues. Statistical analysis showed that the PTP1B expression was correlated with tumor differentiation, tumor invasion, lymph node metastasis, and TNM stage. Patients with higher expressions of PTP1B had the lower survival (P = 0.012). Taken together, our results suggest that PTP1B expression might play a critical role in the progression of CRC and may serve as a valuable prognostic biomarker for CRC.

Microbial dysbiosis and colon carcinogenesis: could colon cancer be considered a bacteria-related disease?

Colorectal cancer (CRC) is posing an increasingly important burden on the health care system, with western countries seeing a growing incidence of the disease. Except for germline DNA mutations which have been attributed to less than 5% of patients, little is known about the main causes of CRC. However, environment factors such as food, lifestyle and medication are now suspected to have a major influence on inducing cancers. Today, exhaustive quantitative and qualitative evaluation of all environmental factors is not possible. Various environment-induced diseases have been characterized based on colon microflora, also called microbiota, analyses. Growing data have shown specific changes in microflora (i.e. dysbiosis) in the stools of patients with colon cancer or those adherent to the colonic mucosa. Thus, it appears that microbiota may be considered a platform offering host and environment interactions for studying CRCs. The hypothesis that colon cancer might be a bacteria-related disease is suggested and perspectives are discussed.

Microbial dysbiosis and colon carcinogenesis: could colon cancer be considered a bacteria-related disease?

Colorectal cancer (CRC) is posing an increasingly important burden on the health care system, with western countries seeing a growing incidence of the disease. Except for germline DNA mutations which have been attributed to less than 5% of patients, little is known about the main causes of CRC. However, environment factors such as food, lifestyle and medication are now suspected to have a major influence on inducing cancers. Today, exhaustive quantitative and qualitative evaluation of all environmental factors is not possible. Various environment-induced diseases have been characterized based on colon microflora, also called microbiota, analyses. Growing data have shown specific changes in microflora (i.e. dysbiosis) in the stools of patients with colon cancer or those adherent to the colonic mucosa. Thus, it appears that microbiota may be considered a platform offering host and environment interactions for studying CRCs. The hypothesis that colon cancer might be a bacteria-related disease is suggested and perspectives are discussed.

Cancer screening in the United States, 2013: a review of current American Cancer Society guidelines, current issues in cancer screening, and new guidance on cervical cancer screening and lung cancer screening

Each year the American Cancer Society (ACS) publishes a summary of its recommendations for early cancer detection, a report on data and trends in cancer screening rates, and select issues related to cancer screening. In this issue of the journal, current ACS cancer screening guidelines are summarized, as are updated guidelines on cervical cancer screening and lung cancer screening with low-dose helical computed tomography. The latest data on the use of cancer screening from the National Health Interview Survey also are described, as are several issues related to screening coverage under the Patient Protection and Affordable Care Act of 2010.