Diagnostic Accuracy Of Fecal Occult Blood Tests For Detecting Proximal Versus Distal Colorectal Neoplasia: A Systematic Review And Meta-Analysis

Interval cancer after two rounds of a Swedish population-based screening program using gender-specific cut-off levels in fecal immunochemical test

OBJECTIVE

To evaluate interval cancer (IC) after two screening rounds of the Swedish population-based screening program of Stockholm-Gotland applying gender-specific cut-off levels in the fecal immunochemical test (FIT).

METHODS

All 60- to 69-year-olds invited to screening 2015-2019 were included. The cut-off level for a positive test was 40 µg/g in women and 80 µg/g in men. Screening-detected colorectal cancers (SD CRCs) and ICs were verified in the Swedish Colorectal Cancer Register, and the follow-up time was two years from invitation. The test sensitivity, the IC rate (ICs per 10,000 screening negatives) and the IC incidence (ICs per 100,000 person-years) relative to the background CRC incidence were assessed by gender and age. The FIT levels were compared in men and women for CRCs diagnosed within one year of the sample.

RESULTS

In the second screening round, 229,187 were invited, and SD CRCs and ICs were diagnosed in 193 and 144, respectively. The IC rate was 8.9 (7.4-10.3) and test sensitivity 0.61 (0.55-0.66), and was similar in men and women. For two screening rounds, the IC rate was significantly higher in men than in women, but the IC incidence/ background CRC incidence was similar in both genders. The FIT levels in female participants with CRC were significantly lower overall, and in early-staged CRCs as compared to men, and proximal localization was more common in women. In multivariable analysis, FIT levels were significantly lower in proximal CRCs.

CONCLUSION

Over two rounds, the IC incidence relative to the background CRC incidence was similar in men and women supporting a gender-specific screening strategy. The results could be explained by lower FIT levels in women due to proximal CRC localization.

Colorectal cancer incidence trends by tumour location among adults of screening-age in England: a population-based study

AIM

Proximal and distal colorectal cancers (CRCs) exhibit different clinical, molecular and biological patterns. The aim of this study was to determine temporal trends in the age-standardized incidence rates (ASIRs) of proximal and distal CRC following the introduction of the English Bowel Cancer Screening Programme (BCSP) in 2006.

METHOD

The National Cancer Registration and Analysis Service database was used to identify incident cases of CRC among adults of screening age (60-74 years) between 2001 and 2017. ASIRs were calculated using the European Standard Population 2013 and incidence trends analysed by anatomical subsite (proximal, caecum to descending colon; distal, sigmoid to rectum), sex and Index of Multiple Deprivation (IMD) quintile using Joinpoint regression software.

RESULTS

Between 2001 and 2017, 541 515 incident cases of CRC were diagnosed [236 167 proximal (43.6%) and 305 348 distal (56.4%)]. A marginal reduction in the proximal ASIR was noted from 2008 [annual percentage change (APC) -1.4% (95% CI -2.0% to -0.9%)] compared with a greater reduction in distal ASIR from 2011 to 2014 [APC -6.6% (95% CI -11.5% to -1.5%)] which plateaued thereafter [APC -0.5% (95% CI -3.2% to 2.2%)]. Incidence rates decreased more rapidly in men than women. Adults in IMD quintiles 4-5 experienced the greatest reduction in distal tumours [APC -3.5% (95% CI -4.3% to -2.7%)].

CONCLUSION

Following the introduction of the English BCSP, the incidence of CRC has subsequently reduced among adults of screening age, with this trend being most pronounced in distal tumours and in men. There is also evidence of a reduction in the deprivation gap for distal tumour incidence. Strategies to improve the detection of proximal tumours are warranted.

Interval cancers in a population-based screening program for colorectal cancer with gender-specific cut-off levels for fecal immunochemical test

Objective

To evaluate interval cancers (IC) in the population-based Swedish regional colorectal cancer (CRC) screening program of Stockholm-Gotland, which uses gender-specific cut-off levels for the fecal immunochemical test (FIT).

Methods

All individuals aged 60–69 in Stockholm-Gotland invited to the screening program in October 2015 to September 2017 were followed up 2 years after invitation. Cut-off level for a positive FIT was 40 µg/g in women and 80 µg/g in men. Those with a positive FIT were referred to colonoscopy. Screening-detected CRC (SD-CRC) and IC after negative FIT (FIT-IC) or negative screening colonoscopy (Colonoscopy-IC) were identified in the Swedish colorectal cancer register. The IC rate was calculated as IC/(FIT negatives + negative screening colonoscopies). The IC incidence rate (ICs among negatives per 100,000 person-years) in different sex and age groups was compared to the mean CRC incidence before regional screening implementation. Test sensitivity was defined as SD-CRC/(SD-CRC + FIT-IC).

Results

Approximately 214,400 individuals were invited, and in 3521 screening colonoscopies 257(6.3%) SD-CRCs were detected. During follow-up, 124 FIT-IC and 7 Colonoscopy-IC were diagnosed, yielding an IC rate of 12.6 and 6.0 per 10,000 negatives (p = 0.00005) and a test sensitivity of 62% and 75% (p = 0.01) in men and women respectively. The IC incidence rate compared to CRC incidence was non-significantly lower in women.

Conclusion

In the population-based screening program of Stockholm-Gotland with a cut-off of 40 µg/g in women and 80 µg/g in men, the test sensitivity was higher and the IC rate was lower in women, which might imply lowering the cut-off level in men. However, the IC incidence rate relative to the CRC incidence was similar in both genders.

Comparison of faecal protein biomarkers' diagnostic accuracy for colorectal advanced neoplasms: a systematic review and meta-analysis

Early diagnosis of colorectal advanced neoplasms (ANs), including colorectal cancer (CRC) and advanced adenoma (AA), has a positive effect on the survival rate. As a first attempt, the aim of this meta-analysis was to compare the diagnostic accuracy of faecal protein biomarkers for the detection of colorectal neoplasms with consideration of a wide range of covariates. A systematic literature search was performed up to Jun 10, 2021 on Web of Sciences, Scopus and PubMed. The diagnostic accuracies were calculated using the bivariate/hierarchical random effect model. Biomarkers were determined to be clinically applicable (CA) if they had areas under the curve > 0.70 and positive and negative likelihood ratios > 2 and < 0.5, respectively. A total of 47,059 test results were extracted from 16 immunochemical faecal occult blood test (iFOBT), 26 pyruvate kinase-M2 (PK-M2) and 23 faecal calprotectin (FC) studies. Only iFOBT, PK-M2 and FC for CRC plus iFOBT and PK-M2 for AN were CA. iFOBT had significantly superior accuracy (P = 0.02 versus PK-M2 and P < 0.01 versus FC for CRC; P < 0.01 versus PK-M2 for AN). Regarding covariates, the lateral flow method of PK-M2 measurement increased its accuracy for CRC detection compared to the enzyme-linked immunosorbent assay (P < 0.01). iFOBT is recommended as the most accurate faecal biomarker for CRC and AN diagnosis.

Significant decrease in interval colorectal cancer incidence after implementing immunochemical testing in a multiple-round guaiac-based screening programme

BACKGROUND AND AIMS

We aimed to evaluate the effects of switching to faecal immunochemical testing (FIT) on the cumulative 2-year incidence rate of interval cancers, interval cancer rate and test sensitivity within a mature population-based colorectal cancer screening programme consisting of six rounds of biennial guaiac faecal occult blood testing (gFOBT).

METHODS

The FIT results were compared with those of gFOBT used in each of the previous two rounds. For the three rounds analysed, 279,041 tests were performed by 156,186 individuals. Logistic regression analysis was used to determine interval cancer risk factors (Poisson regression) and to compare the sensitivity of FIT to gFOBT.

RESULTS

There were 612 cases of screen-detected cancers and 209 cases of interval cancers. The sex- and age-adjusted cumulative 2-year incidence rates of interval cancers were 55.7 (95% CI, 45.3-68.5), 42.4 (95% CI, 32.6-55.2) and 15.8 (95% CI, 10.9-22.8) per 100,000 person-years after the last two rounds of gFOBT and FIT, respectively. The FIT/gFOBT incidence rate ratio was 0.38 [95% CI, 0.27-0.54] (P < 0.001). Sex- and age-adjusted sensitivity was significantly higher with FIT than with gFOBT (OR = 6.70 [95% CI, 4.48-10.01], P < 0.0001).

CONCLUSIONS

This population-based study revealed a dramatic decrease in the cumulative incidence rates of interval cancers after switching from gFOBT to FIT. These data provide an additional incentive for countries still using gFOBT to switch to FIT.

Optimizing Positivity Thresholds for a Risk-Adapted Screening Strategy in Colorectal Cancer Screening

INTRODUCTION

Risk-adapted screening combining the Asia-Pacific Colorectal Screening score, fecal immunochemical test (FIT), and colonoscopy improved the yield of colorectal cancer screening than FIT. However, the optimal positivity thresholds of risk scoring and FIT of such a strategy warrant further investigation.

METHODS

We included 3,407 participants aged 50-74 years undergoing colonoscopy from a colorectal cancer screening trial. For the risk-adapted screening strategy, subjects were referred for subsequent colonoscopy or FIT according to their risk scores. Diagnostic performance was evaluated for FIT and the risk-adapted screening method with various positivity thresholds. Furthermore, a modeled screening cohort was established to compare the yield and cost using colonoscopy, FIT, and the risk-adapted screening method in a single round of screening.

RESULTS

Risk-adapted screening method had higher sensitivity for advanced neoplasm (AN) (27.6%-76.3% vs 13.8%-17.3%) but lower specificity (46.6%-90.8% vs 97.4%-98.8%) than FIT did. In a modeled screening cohort, FIT-based screening would be slightly affected because the threshold varied with a reduction of 76.0%-80.9% in AN detection and 82.0%-84.4% in cost when compared with colonoscopy. By contrast, adjusting the threshold of Asia-Pacific Colorectal Screening score from 3 to 5 points for risk-adapted screening varied from an increase of 12.6%-14.1% to a decrease of 55.6%-60.1% in AN detection, with the reduction of cost from 4.2%-5.3% rising to 66.4%-68.5%.

DISCUSSION

With an appropriate positivity threshold tailored to clinical practice, the risk-adapted screening could save colonoscopy resources and cost compared with the colonoscopy-only and FIT-only strategies.

Gender-specific cut-off levels in colorectal cancer screening with fecal immunochemical test: A population-based study of colonoscopy findings and costs

OBJECTIVE

In the population-based Swedish regional colorectal cancer (CRC) screening program of Stockholm-Gotland using the fecal immunochemical test (FIT), gender-specific cut-off levels of fecal hemoglobin are applied, since previous studies have indicated a lower sensitivity of FIT for CRC in women. The aim was to evaluate the diagnostic yield and the screening costs overall and per detected CRC of this strategy.

METHODS

All individuals aged 60-69 invited to screening in 2015-2017 were included. Cut-off level for positive FIT was 40 µg/g in women and 80 µg/g in men. Those with a positive FIT were referred to colonoscopy. The yield of CRC and screening cost for the study period were assessed and compared to cut-off levels of 80 µg/g in both genders.

RESULTS

Approximately 230,000 individuals were invited. Overall participation rates were 72% in women and 65% in men (p < 0.05). FIT was positive in 4256 individuals (2.7% in both genders). In 3758 colonoscopies, 258 (6.9%) CRCs were detected. The positive predictive value for CRC was significantly higher in men (8.3% vs. 5.8%). In 120 women with CRC, 28 (23%) had FIT < 80 µg/g. Negative colonoscopies were more common in women (24% vs. 17%, p < 0.05). Total costs for the study period were 52,000,000SEK (≈5,200,000€), i.e. 16% higher compared to using cut-off levels of 80 µg/g in both genders, and corresponding to a 3% increment in cost per detected CRC.

CONCLUSION

The high rate of CRC detected in women in the lowest FIT category outweighs the minor reduction in screening costs if the same cut-off level was used as for men.

Clinical characteristics, medical service utilization, and expenditure for colorectal cancer in China, 2005 to 2014: Overall design and results from a multicenter retrospective epidemiologic survey

BACKGROUND

Colorectal cancer (CRC) is the third most common cancer in China, however, publicly available, descriptive information on the clinical epidemiology of CRC is limited.

METHODS

Patients diagnosed with primary CRC during 2005 through 2014 were sampled from 13 tertiary hospitals in 9 provinces across China. Data related to sociodemographic characteristics, the use of diagnostic technology, treatment adoption, and expenditure were extracted from individual medical records.

RESULTS

In the full cohort of 8465 patients, the mean ± SD age at diagnosis was 59.3 ± 12.8 years, 57.2% were men, and 58.7% had rectal cancer. On average, 14.4% of patients were diagnosed with stage IV disease, and this proportion increased from 13.5% in 2005 to 20.5% in 2014 (P value for trend < .05). For diagnostic techniques, along with less use of x-rays (average, 81.6%; decreased from 90.0% to 65.7%), there were increases in the use of computed tomography (average, 70.4%; increased from 4.5% to 90.5%) and magnetic resonance imaging (average, 8.8%; increased from 0.1% to 20.4%) over the study period from 2005 to 2014. With regard to treatment, surgery alone was the most common (average, 50.1%), but its use decreased from 51.3% to 39.8% during 2005 through 2014; and the use of other treatments increased simultaneously, such as chemotherapy alone (average, 4.1%; increased from 4.1% to 11.9%). The average medical expenditure per patient was 66,291 Chinese Yuan (2014 value) and increased from 47,259 to 86,709 Chinese Yuan.

CONCLUSIONS

The increasing proportion of late-stage diagnoses presents a challenge for CRC control in China. Changes in diagnostic and treatment options and increased expenditures are clearly illustrated in this study. Coupled with the recent introduction of screening initiatives, these data provide an understanding of changes over time and may form a benchmark for future related evaluations of CRC interventions in China.

Future Prospects of Colorectal Cancer Screening: Characterizing Interval Cancers

Tumors that are not detected by screening tests are known as interval cancers and are diagnosed clinically after a negative result in the screening episode but before the next screening invitation. Clinical characteristics associated with interval colorectal cancers have been studied, but few molecular data are available that describe interval colorectal cancers. A better understanding of the clinical and biological characteristics associated with interval colorectal cancer may provide new insights into how to prevent this disease more effectively. This review aimed to summarize the current literature concerning interval colorectal cancer and its epidemiological, clinical, and molecular features.

Comparative evaluation of two colorectal cancer screening campaigns using different faecal occult blood tests in a French area

OBJECTIVE

The aim of this study was to compare quality performance of the first colorectal cancer (CRC) screening campaigns (C) with the OC Sensor® Faecal Immunological Test (FIT) (C7 from 2016 to 2017) and the Hemoccult® guaiac-based test (C1 from 2004 to 2006).

METHODS

The participation rate of the eligible population, screening fecal occult blood test (FOBT) performance indices, CRC and adenoma detection rate and time interval between test positivity and colonoscopy were studied.

RESULTS

In C7, 35.9 % of the eligible population completed the screening process versus 47.6 % in C1 (p < 0.0001). The positivity rate was of 4.3 % for OC Sensor® FIT and 2.3 % for Hemoccult® test (p < 0.0001). A total of 3,252 colonoscopies were performed in C7 versus 2,005 in C1; 246 CRCs and 1,160 advanced adenomas (AA) were detected in C7 compared to 140 CRCs and 491 AA in C1 (p < 0.0001). The FOBT cancer detection rate increased significantly from 1.4 ‰ to 2.9 ‰ between the two campaigns, as did the FOBT AA detection rate, from 5.7 ‰ to 13.7 ‰. During C7, the mean time for colonoscopy after a positive FIT result was 84.3 days [95 % CI: 77.9-90.7]. There was no significant difference between the stages at diagnosis according to the time for colonoscopy within the first 6 months.

CONCLUSIONS

CRC and AA detection rates increased significantly between the two campaigns. Longer follow-up will be required to show a potential decrease in the incidence of invasive CRCs.