Colorectal cancer (CRC) screening using sigmoidoscopy followed by colonoscopy: a feasibility and efficacy study on a cancer institute based population

Familial colorectal cancer screening: When and what to do?

Colorectal cancer (CRC) is the third leading cause of death worldwide and represents a clinical challenge. Family members of patients affected by CRC have an increased risk of CRC development. In these individuals, screening is strongly recommended and should be started earlier than in the population with average risk, in order to detect neoplastic precursors, such as adenoma, advanced adenoma, and nonpolypoid adenomatous lesions of the colon. Fecal occult blood test (FOBT) is a non invasive, widespread screening method that can reduce CRC-related mortality. Sigmoidoscopy, alone or in addition to FOBT, represents another screening strategy that reduces CRC mortality. Colonoscopy is the best choice for screening high-risk populations, as it allows simultaneous detection and removal of preneoplastic lesions. The choice of test depends on local health policy and varies among countries.

Comparing the effectiveness of competing tests for reducing colorectal cancer mortality: a network meta-analysis

BACKGROUND

Comparative effectiveness data pertaining to competing colorectal cancer (CRC) screening tests do not exist but are necessary to guide clinical decision making and policy.

OBJECTIVE

To perform a comparative synthesis of clinical outcomes studies evaluating the effects of competing tests on CRC-related mortality.

DESIGN

Traditional and network meta-analyses. Two reviewers identified studies evaluating the effect of guaiac-based fecal occult blood testing (gFOBT), flexible sigmoidoscopy (FS), or colonoscopy on CRC-related mortality.

INTERVENTIONS

gFOBT, FS, colonoscopy.

MAIN OUTCOME MEASUREMENTS

Traditional meta-analysis was performed to produce pooled estimates of the effect of each modality on CRC mortality. Bayesian network meta-analysis (NMA) was performed to indirectly compare the effectiveness of screening modalities. Multiple sensitivity analyses were performed.

RESULTS

Traditional meta-analysis revealed that, compared with no intervention, colonoscopy reduced CRC-related mortality by 57% (relative risk [RR] 0.43; 95% confidence interval [CI], 0.33-0.58), whereas FS reduced CRC-related mortality by 40% (RR 0.60; 95% CI, 0.45-0.78), and gFOBT reduced CRC-related mortality by 18% (RR 0.82; 95% CI, 0.76-0.88). NMA demonstrated nonsignificant trends favoring colonoscopy over FS (RR 0.71; 95% CI, 0.45-1.11) and FS over gFOBT (RR 0.74; 95% CI, 0.51-1.09) for reducing CRC-related deaths. NMA-based simulations, however, revealed that colonoscopy has a 94% probability of being the most effective test for reducing CRC mortality and a 99% probability of being most effective when the analysis is restricted to screening studies.

LIMITATIONS

Randomized trials and observational studies were combined within the same analysis.

CONCLUSION

Clinical outcomes studies demonstrate that gFOBT, FS, and colonoscopy are all effective in reducing CRC-related mortality. Network meta-analysis suggests that colonoscopy is the most effective test.

Changing epidemiology of colorectal cancer makes screening sigmoidoscopy less useful for identifying carriers of colorectal neoplasms

BACKGROUND

There is renewed interest in flexible sigmoidoscopy (FS) colorectal cancer (CRC) screening following trials showing significantly reduced CRC incidence and mortality.

AIMS

To evaluate the potential usefulness of FS screening in our population.

METHODS

We examined rectosigmoid (RS) cancer epidemiology in our Jewish population using Israel National Cancer Registry data, computed by CRC site, age groups, and gender. We also reviewed endoscopy-screening publications for prevalence of RS and proximal advanced adenomas (AAP) and having both or either.

RESULTS

During 1980-2008, there were 64,559 CRCs registered; 31.6 % were RS cancer which has now decreased to 29 % of men's and 26 % of women's CRC (both P < 0.01). In <50 year olds, RS cancer occurred in 42 % of males' and 35 % of females' CRC, and in the last 2 decades this ratio is unchanged. In 50-74 year olds, RS cancer decreased to stable levels of 32 % of males' and 29 % females' CRC (both P < 0.01). In ≥75 year olds, RS cancer progressively decreased to 24 % of males' and 22 % females' CRC (both P < 0.001). From endoscopy screening reports in 40-79 year olds, RS AAPs occurred in 2.0-5.8 %, being least in women, most in men, and not increased with aging. Some 50-57 % of screenees had both RS and proximal AAPs, least when aged 40-49 years at 25 %, women were 35 %, and with aging 40 %, but most in men at 70 %.

CONCLUSIONS

With the changing CRC epidemiology, having fewer RS neoplasms but more proximal cancer, the effectiveness of FS screening for identifying significant neoplasms decreases with screenees' age and especially in females. These make FS screening less suitable for our aging and increasingly female population.

Effect of flexible sigmoidoscopy-based screening on incidence and mortality of colorectal cancer: a systematic review and meta-analysis of randomized controlled trials

BACKGROUND

Randomized controlled trials (RCTs) have yielded varying estimates of the benefit of flexible sigmoidoscopy (FS) screening for colorectal cancer (CRC). Our objective was to more precisely estimate the effect of FS-based screening on the incidence and mortality of CRC by performing a meta-analysis of published RCTs.

METHODS AND FINDINGS

Medline and Embase databases were searched for eligible articles published between 1966 and 28 May 2012. After screening 3,319 citations and 29 potentially relevant articles, two reviewers identified five RCTs evaluating the effect of FS screening on the incidence and mortality of CRC. The reviewers independently extracted relevant data; discrepancies were resolved by consensus. The quality of included studies was assessed using criteria set out by the Evidence-Based Gastroenterology Steering Group. Random effects meta-analysis was performed. The five RCTs meeting eligibility criteria were determined to be of high methodologic quality and enrolled 416,159 total subjects. Four European studies compared FS to no screening and one study from the United States compared FS to usual care. By intention to treat analysis, FS-based screening was associated with an 18% relative risk reduction in the incidence of CRC (0.82, 95% CI 0.73-0.91, p<0.001, number needed to screen [NNS] to prevent one case of CRC = 361), a 33% reduction in the incidence of left-sided CRC (RR 0.67, 95% CI 0.59-0.76, p<0.001, NNS = 332), and a 28% reduction in the mortality of CRC (relative risk [RR] 0.72, 95% CI 0.65-0.80, p<0.001, NNS = 850). The efficacy estimate, the amount of benefit for those who actually adhered to the recommended treatment, suggested that FS screening reduced CRC incidence by 32% (p<0.001), and CRC-related mortality by 50% (p<0.001). Limitations of this meta-analysis include heterogeneity in the design of the included trials, absence of studies from Africa, Asia, or South America, and lack of studies comparing FS with colonoscopy or stool-based testing.

CONCLUSIONS

This meta-analysis of randomized controlled trials demonstrates that FS-based screening significantly reduces the incidence and mortality of colorectal cancer in average-risk patients.

Uptake of colorectal cancer screening: system, provider and individual factors and strategies to improve participation

Colorectal cancer (CRC) accounts for 9% of all new cancer cases worldwide and affects over 1 million people each year. Screening can reduce the mortality associated with the disease, yet participation rates are suboptimal. Compliers with CRC screening are less deprived; they have higher education than noncompliers and tend to be male, white and married. Likely reasons for nonparticipation encompass several 'modifiable' factors that could be targeted in interventions aimed at increasing participation rates. Successful intervention strategies include organizational changes, such as increasing access to fecal occult blood test (FOBT) kits, providing reminders to healthcare providers or users about screening opportunities, and educational strategies to improve awareness and attitudes towards CRC screening. Multifactor interventions that target more than one level of the screening process are likely to have larger effects. The biggest challenge for future research will be to reduce inequalities related to socio-economic position and ethnicity in the uptake of screening.

Risk analyses for screening sigmoidoscopy based on a colorectal cancer (CRC) population

OBJECTIVE

Although colonoscopy can be effective in the prevention of colorectal cancer (CRC), it requires many endoscopic facilities, has a high patient burden and risk of complications, and it is expensive. The aim of this study was to determine the risk for proximal CRC and to identify subgroups in which screening sigmoidoscopy can be effective.

MATERIAL AND METHODS

A database search was carried out on all patients who underwent endoscopy of the lower gastrointestinal (GI) tract between 1997 and 2005. All patients diagnosed with CRC were included. Variables including age, gender and the presence of distal colonic neoplasia were used for risk analyses.

RESULTS

In total, 783 patients were diagnosed with CRC. Tumour was located in the proximal colon in 68/255 (27%) of the patients <65 years. Of the patients <65 years, 22% (57/255) had proximal CRC without synchronous distal lesions and would thus have been missed by sigmoidoscopy screening. Among patients >65 years, 41% (216/528) were diagnosed with proximal CRC, significantly more often in women than in men (p <0.001). In 35% of patients (185/528) proximal CRC without distal colonic neoplasia was found, significantly more than in those under 65 years of age (p <0.001).

CONCLUSIONS

Significantly more proximal localized CRC would have been missed by sigmoidoscopy screening in elderly patients, especially in women. In subjects <65 years of age, sigmoidoscopy screening allows detection of almost 80% of CRC cases and might suffice as a screening method.

Participation in screening colonoscopy in first-degree relatives from patients with colorectal cancer

BACKGROUND

Current guidelines recommend screening colonoscopy in first-degree relatives of patients with colon cancer. The aim of this state-wide study was to investigate the compliance for colonoscopic in first-degree relatives, who were younger than 60 years of age.

METHODS

A total of 602 patients were identified from the tumor registry of the public health insurance of Lower Saxony. A questionnaire was sent to these patients, which included a number of different questions regarding their knowledge about the risk of colon cancer for their family members, as well as their participation in screening colonoscopy.

RESULTS

Data from 442 patients and their first-degree relatives (1005 siblings and 354 parents) were available; 178 parents had undergone screening colonoscopy and 344 siblings. Interestingly, the percentage of siblings who underwent screening colonoscopy was significantly higher (27%) among those siblings where the index patients were aware of the increased risk for the first-degree relatives, in contrast to the siblings of the index patients who were not aware of this risk (20%).

CONCLUSION

This study demonstrates that only a minority of first-degree relatives undergo screening colonoscopy and that informing patients about the potential risk for their relatives will increase participation in screening colonoscopy in first-degree relatives of the patients.