Systematic review with meta-analysis: faecal occult blood tests show lower colorectal cancer detection rates in the proximal colon in colonoscopy-verified diagnostic studies

BACKGROUND

The performance of faecal occult blood tests (FOBTs) to screen proximally located colorectal cancer (CRC) has produced inconsistent results.

AIM

To assess in a meta-analysis, the diagnostic accuracy of FOBTs for relative detection of CRC according to anatomical location of CRC.

METHODS

Diagnostic studies including both symptomatic and asymptomatic cohorts assessing performance of FOBTs for CRC were searched from MEDINE and EMBASE. Primary outcome was accuracy of FOBTs according to the anatomical location of CRC. Bivariate random-effects model was used. Subgroup analyses were performed to evaluate test performance of guaiac-based FOBT (gFOBT) and immunochemical-based FOBT (iFOBT).

RESULTS

Thirteen studies, with 17 cohorts, reporting performance of FOBT were included; a total of 26 342 patients (mean age 58.9 years; 58.1% male) underwent both colonoscopy and FOBT. Pooled sensitivity, specificity, positive likelihood ratio and negative likelihood ratio of FOBTs for CRC detection in the proximal colon were 71.2% (95% CI 61.3-79.4%), 93.6% (95% CI 90.7-95.7%), 11.1 (95% CI 7.8-15.8) and 0.3 (95% CI 0.2-0.4) respectively. Corresponding findings for CRC detection in distal colon were 80.1% (95% CI 70.9-87.0%), 93.6% (95% CI 90.7-95.7%), 12.6 (95% CI 8.8-18.1) and 0.2 (95% CI 0.1-0.3). The area-under-curve for FOBT detection for proximal and distal CRC were 90% vs. 94% (P = 0.0143). Both gFOBT and iFOBT showed significantly lower sensitivity but comparable specificity for the detection of proximally located CRC compared with distal CRC.

CONCLUSION

Faecal occult blood tests, both guaiac- and immunochemical-based, show better diagnostic performance for the relative detection of colorectal cancer in the distal colon than in the proximal bowel.

Diagnostic accuracy of faecal immunochemical test for screening individuals with a family history of colorectal cancer

BACKGROUND

The role of a faecal immunochemical test (FIT) in screening individuals with a positive family history of colorectal cancer (CRC) is not clear.

AIM

To assess the diagnostic accuracy of FIT using colonoscopy findings as the gold standard in identifying colorectal neoplasms.

METHODS

We analysed data from 4539 asymptomatic subjects aged 50-70 years who had both colonoscopy and FIT (Hemosure; W.H.P.M., Inc, El Monte, CA, USA) at our bowel cancer screening centre between 2008 and 2012. A total of 572 subjects (12.6%) had a family history of CRC. Our primary outcome was the sensitivity of FIT in detecting advanced neoplasms and cancers in subjects with a family history of CRC. A family history of CRC was defined as any first-degree relative with a history of CRC.

RESULTS

Among 572 subjects with a family history of CRC, adenoma, advanced neoplasm and cancer were found at screening colonoscopy in 29.4%, 6.5% and 0.7% individuals, respectively. The sensitivity of FIT in detecting adenoma, advanced neoplasm and cancer was 9.5% [95% confidence interval (CI), 5.7-15.3], 35.1% (95% CI, 20.7-52.6) and 25.0% (95% CI, 1.3-78.1), respectively. Among FIT-negative subjects who have a family history of CRC, adenoma was found in 152 (29.6%), advanced neoplasm in 24 (4.7%) and cancer in 3 (0.6%) individuals.

CONCLUSION

Compared with colonoscopy, FIT is more likely to miss advanced neoplasms or cancers in individuals with a family history of CRC.

Meta-analysis: comparison of oral vs. intravenous proton pump inhibitors in patients with peptic ulcer bleeding

BACKGROUND

The efficacy of adjuvant use of intravenous proton pump inhibitors (PPIs) after endoscopic therapy has been proved in peptic ulcer bleeding patients, but the efficacy of oral PPIs is uncertain.

AIM

To compare the clinical outcomes of oral PPIs vs. intravenous PPIs in patients with peptic ulcer bleeding.

METHODS

Prospective randomised controlled trials were systematically searched from OVID databases until June 2012. Trials comparing oral and intravenous PPIs among patients with peptic ulcer bleeding were included. Recurrent bleeding, length of hospitalisation, blood transfusion, requirement of surgery and mortality were measured. The risk of bias, study quality and heterogeneity were also evaluated.

RESULTS

Six randomised trials from 2006 to 2011 were included. A total of 615 patients were randomly assigned to receive oral PPIs (n = 302) or intravenous PPIs (n = 313). The mean age was 60 years and 71.1% was male. No significant difference between oral and intravenous PPIs was observed regarding recurrent bleeding (RR: 0.92, 95% CI: 0.56-1.50), mean volume of blood transfused (-0.02 unit, 95% CI: -0.29-0.24 unit), requirement of surgery (RR: 0.82, 95% CI: 0.19-3.61) and all-cause mortality (RR: 0.88, 95% CI: 0.29-2.71). The duration of hospital stay in days was significantly shortened in those using oral PPIs (-0.74 day, 95% CI: -1.10 day to -0.39 day).

CONCLUSION

Oral PPIs demonstrate a similar effectiveness to intravenous PPIs among patients with peptic ulcer bleeding, but the results were combined from open-labelled trials with limited sample size. A large double-blind non-inferiority trial is required to better assess the role of oral PPIs.