Sex differences in performance of fecal occult blood testing

The Association of Metabolic Risk Factors with Advanced Adenomas in Hispanic Patients

BACKGROUND

Obesity and metabolic syndrome (MetS) have been implicated as rising risk factors for the development of colorectal cancers. A rapid increase in the prevalence of obesity and severe obesity among Hispanic patients in the United States may present substantially increased risk for advanced colorectal neoplasia in this population. Currently, there is very little research in this area.

AIMS

We sought to identify metabolic risk factors for advanced adenomas (AA) in Hispanic Americans.

METHODS

We retrospectively reviewed data from the Los Angeles General (LAG) Medical Center of asymptomatic Hispanic patients above 45 years of age who underwent their first colonoscopies following a positive screening FBT. Patient demographics, metabolic characteristics, as well as colon polyp size and histology were recorded. Polyps were classified as adenomas or AA (including both high-risk adenomas and high-risk serrated polyps). Relative risk for AA was assessed by multivariate logistical regression analyses.

RESULTS

Of the 672 patients in our study, 41.4% were male, 67% had adenomas, and 16% had AA. The mean BMI was 31.2 kg/m2. The mean HDL-C was 49.5 mg/dL (1.28 mmol/L) and the mean triglyceride level was 151 mg/dL. 44.6% had diabetes and 64.1% had hypertension. When comparing patients with AA to patients with no adenoma, male sex, BMI > 34.9 kg/m2, and elevated fasting triglyceride levels were associated with an increased risk of AA. FIB-4 ≥1.45 was also associated with an increased risk of AA in males. There was no significant difference in the risk of AA with diabetes, hypertension, FIB-4 score, LDL-C level, and HDL-C level.

CONCLUSIONS

Hispanic patients with a positive FBT were observed to have a high incidence of AA. Class II obesity (BMI ≥ 35 kg/m2), elevated triglyceride levels were identified as risk factors among males in our study. Early interventions to address these modifiable risk factors in at-risk populations, such as multi-disciplinary weight management programs for the treatment of obesity and related co-morbidities, could potentially lead to risk reduction and CRC prevention.

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.

Connecting the mechanisms of tumor sex differences with cancer therapy

Sex differences in cancer incidence and survival are constant and pronounced globally, across all races and all age groups of cancer types. In 2016, after the National Institutes of Health proposed a policy of utilizing sex as a biological variable, researchers started paying more attention to the molecular mechanisms behind gender variations in cancer. Historically, most previous studies investigating sex differences have been centered on gonadal sex hormones. Nevertheless, sex differences also involve genetic and molecular pathways that run throughout the entire process of cancer cell proliferation, metastasis, and treatment response, in addition to sex hormones. In particular, there is significant gender dimorphism in the efficacy and toxicity of oncology treatments, including conventional radiotherapy and chemotherapy, as well as the emerging targeted therapies and immunotherapy. To be clear, not all mechanisms will exhibit gender bias, and not all gender bias will affect cancer risk. Our goal in this review is to discuss some of the significant sex-related changes in fundamental cancer pathways. To this purpose, we summarize the differential impact of gender on cancer development in three dimensions: sex hormones, genetics, and epigenetics, and focus on current hot subjects including tumor suppressor function, immunology, stem cell renewal, and non-coding RNAs. Clarifying the essential mechanisms of gender differences will help guide the clinical treatment of both sexes in tumor radiation and chemotherapy, medication therapy with various targets, immunotherapy, and even drug development. We anticipate that sex-differentiated research will help advance sex-based cancer personalized medicine models and encourage future basic scientific and clinical research to take sex into account.

Thirty-two-year trends of cancer incidence by sex and cancer site in the Veneto Region from 1987 to 2019

Background

This observational study considers the sex-specific incidence of the most incident cancers as recorded in the population-based Veneto Regional Cancer Registry over a period of more than 30 years (1987-2019).

Methods

The Veneto Regional Cancer Registry collected data for the time interval 1987-2019. Significant changes in incidence trends calculated on age-standardized incidence rates (Annual Percent Change-APC) were identified by join point regression analysis.

Results

Overall, the incidence trend for all cancers decreased in males and remained stable in females. In nine cancer sites, the incidence trends showed consistent differences by sex (oral cavity, esophagus, colon rectum and anus, liver, larynx, lung, cutaneous malignant melanoma, bladder, and thyroid gland). Other malignancies did not show significant sex-related differences (stomach, pancreas, biliary tract, kidney/urinary tract, central nervous system, multiple myeloma, non-Hodgkin lymphoma, and leukemia).

Conclusion

In the period 1987-2019, this study revealed sex-related differences in cancer incidence trends. Over time, cancer incidence remained higher in males, with a decreasing epidemiological impact, plausibly resulting from prevention campaigns against environmental cancer risk factors, as tobacco and alcohol. Conversely, a significant decrease was not observed in the incidence trend in females. These findings contribute essential insights for profiling the epidemiological map of cancer in a large Italian population, allowing comparison with other European cancer epidemiology studies and providing updated data supporting sex-related primary and secondary cancer prevention strategies.

Trends in pathology diagnoses during 10 years of a colorectal cancer screening programme

AIMS

We report pathology findings from the first 10 years of the faecal-occult blood-based Northern Ireland Bowel Cancer Screening Programme, presenting summary data and trends in pathology diagnoses and clinicopathological features of screen-detected cancers.

METHODS AND RESULTS

Data were analysed from a comprehensive polyp-level pathology database representing all endoscopy specimens from programme inception in 2010 until 2021. A total of 9800 individuals underwent 13 472 endoscopy procedures, yielding 25 967 pathology specimens and 32 119 diagnoses. Index specimen diagnoses (4.1%) and index colonoscopies (10.4%) yielded a diagnosis of colorectal cancer, representing 1045 cancers from 1020 individuals (25 with synchronous cancers). A further 13 index cancers were identified via computed tomography colonography; 65.3% of cancer diagnoses were in males; 41.7% were stage I, 23.1% stage II, 25.8% stage III and 1.8% stage IV (7.6% unstaged). Of 233 pT1 cancers diagnosed within local excision specimens, 79 (33.9%) had completion surgery. Ten-year trends showed a steady decline in the proportion of index colonoscopies that yielded a diagnosis of cancer (14.7% in year 1; 4.8% in year 11) or advanced colorectal polyp. There was a strong upward trend in diagnoses of sessile serrated lesions, which overtook hyperplastic polyps in proportions of total index diagnoses by the end of the study time-frame (8.7% compared to 8.5%).

CONCLUSIONS

Over the first 10 years of a population colorectal cancer screening programme, 'real world' pathology data demonstrate success in the form of reduced diagnoses of cancer and advanced colorectal polyp with passage of successive screening rounds. Interesting trends with respect to serrated polyp diagnoses are also evident, probably related to pathologist and endoscopist behaviour.

P32: a sex- and gender-sensitive model for evidence-based precision medicine: from knowledge generation to implementation in the field of kidney transplantation

Precision medicine emerged as a promising approach to identify suitable interventions for individual patients with a particular health concern and at various time points. Technology can enable the acquisition of increasing volumes of clinical and "omics" data at the individual and population levels and support advanced clinical decision making. However, to keep pace with evolving societal realities and developments, it is important to systematically include sex- and gender-specific considerations in the research process, from the acquisition of knowledge to implementation. Building on the foundations of evidence-based medicine and existing precision medicine frameworks, we propose a novel evidence-based precision medicine framework in the form of the P3²model, which considers individual sex-related (predictive [P1], preventive [P2], and personalized [P3] medicine) and gender-related (participatory [P4], psychosocial [P5], and percipient [P6] medicine) domains and their intersection with ethnicity, geography, and other demographic and social variables, in addition to population, community, and public dimensions (population-informed [P7], partnered with community [P8], and public-engaging [P9] medicine, respectively). Through its ability to contextualize and reflect on societal realities and developments, our model is expected to promote consideration of diversity, equity, and inclusion principles and, thus, enrich science, increase reproducibility of research, and ensure its social impact.

Gender Medicine in Clinical Radiology Practice

Gender Medicine is rapidly emerging as a branch of medicine that studies how many diseases common to men and women differ in terms of prevention, clinical manifestations, diagnostic-therapeutic approach, prognosis, and psychological and social impact. Nowadays, the presentation and identification of many pathological conditions pose unique diagnostic challenges. However, women have always been paradoxically underestimated in epidemiological studies, drug trials, as well as clinical trials, so many clinical conditions affecting the female population are often underestimated and/or delayed and may result in inadequate clinical management. Knowing and valuing these differences in healthcare, thus taking into account individual variability, will make it possible to ensure that each individual receives the best care through the personalization of therapies, the guarantee of diagnostic-therapeutic pathways declined according to gender, as well as through the promotion of gender-specific prevention initiatives. This article aims to assess potential gender differences in clinical-radiological practice extracted from the literature and their impact on health and healthcare. Indeed, in this context, radiomics and radiogenomics are rapidly emerging as new frontiers of imaging in precision medicine. The development of clinical practice support tools supported by artificial intelligence allows through quantitative analysis to characterize tissues noninvasively with the ultimate goal of extracting directly from images indications of disease aggressiveness, prognosis, and therapeutic response. The integration of quantitative data with gene expression and patient clinical data, with the help of structured reporting as well, will in the near future give rise to decision support models for clinical practice that will hopefully improve diagnostic accuracy and prognostic power as well as ensure a more advanced level of precision medicine.

Advanced serrated polyps as a target of screening: detection rate and positive predictive value within a fecal immunochemical test-based colorectal cancer screening population

BACKGROUND : Advanced serrated polyps (ASPs) have a comparable risk to advanced adenomas for progression to colorectal cancer (CRC). The yield of most CRC screening programs, however, is based on advanced adenomas and CRC only. We assessed the ASP detection rate, and positive predictive value (PPV) including ASPs in a fecal immunochemical test (FIT)-based screening program. METHODS : We analyzed the findings of follow-up colonoscopies of FIT-positive screenees in the Dutch CRC screening program from 2014 until 2020. Data were retrieved from the national screening and pathology database. An ASP was defined as any serrated polyp of ≥ 10 mm, sessile serrated lesion with dysplasia, or traditional serrated adenoma. The ASP detection rate was defined as the proportion of colonoscopies with ≥ 1 ASP. PPV was originally defined as the proportion of individuals with a CRC or advanced adenoma. The updated PPV definition included CRCs, advanced adenomas, and/or ASPs. RESULTS : 322 882 colonoscopies were included in the analyses. The overall detection rate of ASPs was 5.9 %. ASPs were detected more often in women than men (6.3 % vs. 5.6 %; P < 0.001). ASP detection rates in individuals aged 55-59, 60-64, 65-69, and 70 + were 5.2 %, 6.1 %, 6.1 %, and 5.9 %, respectively (P < 0.001). The PPV for CRCs and advanced adenomas was 41.1 % and increased to 43.8 % when including ASPs. The PPV increase was larger in women than in men (3.2 vs. 2.4 percentage points). CONCLUSIONS : 5.9 % of FIT-positive screenees had ASPs, but half of these were detected in combination with a CRC or advanced adenoma. Therefore, including ASPs results in a small increase in the yield of FIT-based screening.

Guaiac-based faecal occult blood tests versus faecal immunochemical tests for colorectal cancer screening in average-risk individuals

BACKGROUND

Worldwide, many countries have adopted colorectal cancer (CRC) screening programmes, often based on faecal occult blood tests (FOBTs). CRC screening aims to detect advanced neoplasia (AN), which is defined as CRC or advanced adenomas. FOBTs fall into two categories based on detection technique and the detected blood component: qualitative guaiac-based FOBTs (gFOBTs) and faecal immunochemical tests (FITs), which can be qualitative and quantitative. Screening with gFOBTs reduces CRC-related mortality.

OBJECTIVES

To compare the diagnostic test accuracy of gFOBT and FIT screening for detecting advanced colorectal neoplasia in average-risk individuals.

SEARCH METHODS

We searched CENTRAL, MEDLINE, Embase, BIOSIS Citation Index, Science Citation Index Expanded, and Google Scholar. We searched the reference lists and PubMed-related articles of included studies to identify additional studies.

SELECTION CRITERIA

We included prospective and retrospective studies that provided the number of true positives, false positives, false negatives, and true negatives for gFOBTs, FITs, or both, with colonoscopy as reference standard. We excluded case-control studies. We included studies in which all participants underwent both index test and reference standard ("reference standard: all"), and studies in which only participants with a positive index test underwent the reference standard while participants with a negative test were followed for at least one year for development of interval carcinomas ("reference standard: positive"). The target population consisted of asymptomatic, average-risk individuals undergoing CRC screening. The target conditions were CRC and advanced neoplasia (advanced adenomas and CRC combined).

DATA COLLECTION AND ANALYSIS

Two review authors independently screened and selected studies for inclusion. In case of disagreement, a third review author made the final decision. We used the Rutter and Gatsonis hierarchical summary receiver operating characteristic model to explore differences between tests and identify potential sources of heterogeneity, and the bivariate hierarchical model to estimate sensitivity and specificity at common thresholds: 10 µg haemoglobin (Hb)/g faeces and 20 µg Hb/g faeces. We performed indirect comparisons of the accuracy of the two tests and direct comparisons when both index tests were evaluated in the same population.

MAIN RESULTS

We ran the initial search on 25 June 2019, which yielded 63 studies for inclusion. We ran a top-up search on 14 September 2021, which yielded one potentially eligible study, currently awaiting classification. We included a total of 33 "reference standard: all" published articles involving 104,640 participants. Six studies evaluated only gFOBTs, 23 studies evaluated only FITs, and four studies included both gFOBTs and FITs. The cut-off for positivity of FITs varied between 2.4 μg and 50 µg Hb/g faeces. For each Quality Assessment of Diagnostic Accuracy Studies (QUADAS)-2 domain, we assessed risk of bias as high in less than 20% of studies. The summary curve showed that FITs had a higher discriminative ability than gFOBTs for AN (P < 0.001) and CRC (P = 0.004). For the detection of AN, the summary sensitivity of gFOBTs was 15% (95% confidence interval (CI) 12% to 20%), which was significantly lower than FITs at both 10 μg and 20 μg Hb/g cut-offs with summary sensitivities of 33% (95% CI 27% to 40%; P < 0.001) and 26% (95% CI 21% to 31%, P = 0.002), respectively. Results were simulated in a hypothetical cohort of 10,000 screening participants with 1% CRC prevalence and 10% AN prevalence. Out of 1000 participants with AN, gFOBTs missed 850, while FITs missed 670 (10 μg Hb/g cut-off) and 740 (20 μg Hb/g cut-off). No significant differences in summary specificity for AN detection were found between gFOBTs (94%; 95% CI 92% to 96%), and FITs at 10 μg Hb/g cut-off (93%; 95% CI 90% to 95%) and at 20 μg Hb/g cut-off (97%; 95% CI 95% to 98%). So, among 9000 participants without AN, 540 were offered (unnecessary) colonoscopy with gFOBTs compared to 630 (10 μg Hb/g) and 270 (20 μg Hb/g) with FITs. Similarly, for the detection of CRC, the summary sensitivity of gFOBTs, 39% (95% CI 25% to 55%), was significantly lower than FITs at 10 μg and 20 μg Hb/g cut-offs: 76% (95% CI 57% to 88%: P = 0.001) and 65% (95% CI 46% to 80%; P = 0.035), respectively. So, out of 100 participants with CRC, gFOBTs missed 61, and FITs missed 24 (10 μg Hb/g) and 35 (20 μg Hb/g). No significant differences in summary specificity for CRC were found between gFOBTs (94%; 95% CI 91% to 96%), and FITs at the 10 μg Hb/g cut-off (94%; 95% CI 87% to 97%) and 20 μg Hb/g cut-off (96%; 95% CI 91% to 98%). So, out of 9900 participants without CRC, 594 were offered (unnecessary) colonoscopy with gFOBTs versus 594 (10 μg Hb/g) and 396 (20 μg Hb/g) with FITs. In five studies that compared FITs and gFOBTs in the same population, FITs showed a higher discriminative ability for AN than gFOBTs (P = 0.003). We included a total of 30 "reference standard: positive" studies involving 3,664,934 participants. Of these, eight were gFOBT-only studies, 18 were FIT-only studies, and four studies combined both gFOBTs and FITs. The cut-off for positivity of FITs varied between 5 µg to 250 µg Hb/g faeces. For each QUADAS-2 domain, we assessed risk of bias as high in less than 20% of studies. The summary curve showed that FITs had a higher discriminative ability for detecting CRC than gFOBTs (P < 0.001). The summary sensitivity for CRC of gFOBTs, 59% (95% CI 55% to 64%), was significantly lower than FITs at the 10 μg Hb/g cut-off, 89% (95% CI 80% to 95%; P < 0.001) and the 20 μg Hb/g cut-off, 89% (95% CI 85% to 92%; P < 0.001). So, in the hypothetical cohort with 100 participants with CRC, gFOBTs missed 41, while FITs missed 11 (10 μg Hb/g) and 11 (20 μg Hb/g). The summary specificity of gFOBTs was 98% (95% CI 98% to 99%), which was higher than FITs at both 10 μg and 20 μg Hb/g cut-offs: 94% (95% CI 92% to 95%; P < 0.001) and 95% (95% CI 94% to 96%; P < 0.001), respectively. So, out of 9900 participants without CRC, 198 were offered (unnecessary) colonoscopy with gFOBTs compared to 594 (10 μg Hb/g) and 495 (20 μg Hb/g) with FITs. At a specificity of 90% and 95%, FITs had a higher sensitivity than gFOBTs.

AUTHORS' CONCLUSIONS

FITs are superior to gFOBTs in detecting AN and CRC in average-risk individuals. Specificity of both tests was similar in "reference standard: all" studies, whereas specificity was significantly higher for gFOBTs than FITs in "reference standard: positive" studies. However, at pre-specified specificities, the sensitivity of FITs was significantly higher than gFOBTs.

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.

Factors associated with positive predictive value of preliminary screening in a two-step screening strategy for colorectal neoplasms in China

BACKGROUND

The positive predictive value (PPV) of high risk factor questionnaire (HRFQ) plus fecal immunochemical test (FIT) as preliminary screening strategy for colorectal-related neoplasia is relatively low. We aim to explore independent factors associated with PPVs of HRFQ combined FIT for selecting high risk individuals for colonoscopy.

METHODS

A total of 6971 residents were enrolled in a community-based screening program. Participants who had positive results of HRFQ and/or FIT and subsequently received colonoscopy were involved. The associations of socio-demographic factors, lifestyle behaviors, and high risk factors of colorectal cancer with PPVs of HRFQ, FIT, and their combination were evaluated by multivariable logistic regression models.

RESULTS

Among 572 involved cases, 249 (43.5%) colorectal neoplasms were detected by colonoscopy, including 71 advanced adenoma (12.4%) and 9 colorectal cancer (CRC) (1.6%). The PPVs of preliminary screening were 43.5% for total colorectal neoplasms, 14.0% for advanced neoplasm, and 1.6% for CRC. Adding positive HRFQ to FIT could improve the PPV from 3.5 to 8.0% for detecting CRC. Preliminarily screened positive individuals who were males [adjusted odds ratio (AOR): 1.95, 95% CI 1.31, 2.90; p  < 0.001], elders (> 60 years) (AOR: 1.70, 95% CI 1.17, 2.46; p  = 0.005), or ex-/current smokers (AOR: 3.04, 95% CI 1.31, 7.09; p  = 0.10) had higher odds of PPVs of detecting colorectal neoplasms.

CONCLUSIONS

Combining HRFQ and FIT could largely improve PPVs for screening advanced neoplasm and CRC. Gender and age-specific FIT cut-off values as well as initiating ages for CRC screening might be recommended to improve the accuracy and effectiveness of current screening algorithm.

International Socioeconomic Predictors of Colon and Rectal Cancer Mortality: Is Colorectal Cancer a First World Problem?

PURPOSE

Colorectal cancer (CRC) is a leading cause of international morbidity and is the second highest cause of cancer-related mortality in the world. The purpose of this study was to investigate the relationship between international health care spending on CRC mortality over time.

METHODS

This is a retrospective study using a publicly available data from the WHO Global Health Observatory database. General estimating equations were used to analyze the relationship between total health care expenditure per capita (THEpc) and CRC mortality at the country level. The primary predictors of interest were quartiles of THEpc. Other exposure variables included gross domestic product per capita (GDPpc), smoking (% of adult population smoking), physician density (per 10,000), and time.

RESULTS

Mortality decreased significantly from 2000 to 2016 (coefficient [95% CI], −2.2 [−3.3 to −1.1]; P < .001). THEpc, GDPpc, time, and percentage of adult population smoking were significant predictors of CRC mortality. Patients in the top two quartiles of THEpc had 3% higher rates of CRC mortality compared with countries in Q1 THEpc (Q3: 3.4 [1.9-4.8], P < .001; Q4: 3.2 [1.4-5.0], P = .001). Similar trends were seen in GDPpc (Q4: 3.2 [1.4-5.0], P = .001; Q3: 3.4 [1.9-4.8], P < .001; Q2: 1.7 [0.7-2.6], P < .001; Q1: reference).

CONCLUSION

Overall, mortality decreased significantly over the study period. Countries with higher health expenditures and higher gross domestic products experienced higher rates of CRC mortality. Further research will be necessary to determine the cause for this, but we postulate that it may be a result of more robust diagnostic and follow-up methods in countries with more resources.

Colorectal Cancer mortality decreased between 2000-2016 but only among developed nations.

Faecal haemoglobin concentrations in women and men diagnosed with colorectal cancer in a national screening programme

Objective

There is evidence that colorectal cancer screening using faecal haemoglobin is less effective in women than men. The faecal haemoglobin concentrations were therefore examined in women and men with screen-detected colorectal cancer.

Setting

Scottish Bowel Screening Programme, following the introduction of a faecal immunochemical test from November 2017, to March 2020.

Methods

Data were collated on faecal haemoglobin concentrations, pathological stage and anatomical site of the main lesion in participants who had colorectal cancer detected. The data in women and men were compared.

Results

For the faecal haemoglobin concentrations studied (>80 µg Hb/g faeces), the distributions indicated lower concentrations in women. Marked differences were found between women and men diagnosed with colorectal cancer. The median faecal haemoglobin concentration for women (n = 720) was 408 µg Hb/g faeces compared to 473 µg Hb/g faeces for men (n = 959) (p = 0.004) and 50.6% of the results were >400 µg Hb/g faeces in women; in men, this was 57.8%. The difference in faecal haemoglobin concentrations in women and men became less statistically significant as stage advanced from stages I–IV. For right-sided, left-sided and rectal colorectal cancer, a similar gender difference persisted in all sites. Differences in faecal haemoglobin between the genders were significant for left-sided cancers and stage I and approached significance for rectal cancers and stage II, but all sites and stages showed lower median faecal haemoglobin concentrations for women.

Conclusions

To minimise gender inequalities, faecal immunochemical test-based colorectal cancer screening programmes should evaluate a strategy of using different faecal haemoglobin concentration thresholds in women and men.

A sex-specific propensity-adjusted analysis of colonic adenoma detection rates in a screening cohort

The prevalence of colorectal adenoma and advanced adenoma (AA) differs between sexes. Also, the optimal age for the first screening colonoscopy is under debate. We, therefore, performed a sex-specific and age-adjusted comparison of adenoma, AA and advanced neoplasia (AN) rates in a real-world screening cohort. In total, 2824 asymptomatic participants between 45- and 60-years undergoing screening colonoscopy at a single-centre in Austria were evaluated. 46% were females and mean age was 53 ± 4 years. A propensity score for being female was calculated, and adenoma, AA and AN detection rates evaluated using uni- and multivariable logistic regression. Sensitivity analyses for three age groups (group 1: 45 to 49 years, n = 521, 41% females, mean age 47 ± 1 years; group 2: 50 to 54 years, n = 1164, 47% females, mean age 52 ± 1 years; group 3: 55 to 60 years, n = 1139, 46% females, mean age 57 ± 2 years) were performed. The prevalence of any adenoma was lower in females (17% vs. 30%; OR 0.46, 95% CI 0.38–0.55; p < 0.001) and remained so after propensity score adjustment for baseline characteristics and lifestyle factors (aOR 0.52, 95% CI 0.41–0.66; p < 0.001). The same trend was seen for AA with a significantly lower prevalence in females (3% vs. 7%; OR 0.38, 95% CI 0.26–0.55; p < 0.001) that persisted after propensity score adjustment (aOR 0.54, 95% CI 0.34–0.86; p = 0.01). Also, all age-group sensitivity analyses showed lower adenoma, AA and AN rates in females. Similar numbers needed to screen to detect an adenoma, an AA or AN were found in female age group 3 and male age group 1. Colorectal adenoma, AA and AN were consistently lower in females even after propensity score adjustment and in all age-adjusted sensitivity analyses. Our study may add to the discussion of the optimal age for initial screening colonoscopy which may differ between the sexes.

Should colorectal cancer screening start at different ages for men and women? Cost-effectiveness analysis for a resource-constrained service

BACKGROUND

Men have a greater risk of colorectal cancer (CRC) than women, but population screening currently starts at the same age for both sexes.

AIM

This analysis investigates whether, in a resource-constrained setting, it would be more effective and cost-effective for men and women to start screening for CRC at different ages.

METHODS AND RESULTS

An economic modeling analysis was carried out using the Microsimulation Model in Cancer of the Bowel to compare sex-stratification against screening everyone from the same age, taking an English National Health Service perspective. Screening men from age 56 and women from age 60, rather than screening everyone from age 58 using a Fecal Immunochemical Test (FIT) threshold of 120 μg/g is expected to produce an additional 0.0004 QALYs for a cost of £0.55 per person at model start (Incremental Cost-effectiveness Ratio = £1392), and to reduce CRC cases and mortality by 25 and 19 per 100 000 people respectively, while using a similar amount of screening resources. Probabilistic sensitivity analysis indicates a 61% probability that sex-stratification is more cost-effective than screening everyone at age 58. Similar benefits of sex-stratification are found at other FIT thresholds, but become negligible if mean screening start age is reduced to 50.

CONCLUSION

Where resources are constrained and it is not feasible to screen everyone from the age of 50, starting screening earlier in men than women is likely to be more cost-effective and gain more health benefits overall than strategies where men and women start screening at the same age.

Consistent Major Differences in Sex- and Age-Specific Diagnostic Performance among Nine Faecal Immunochemical Tests Used for Colorectal Cancer Screening

Evidence on diagnostic performance of faecal immunochemical tests (FITs) by sex and age is scarce. We aimed to evaluate FIT performance for detection of advanced colorectal neoplasia (AN) by sex and age across nine different FIT brands in a colonoscopy-controlled setting. The faecal samples were obtained from 2042 participants of colonoscopy screening. All eligible cases with AN (n = 216) and 300 randomly selected participants without AN were included. Diagnostic performance for detection of AN was assessed by sex and age (50-64 vs. 65-79 years for each of the nine FITs individually and for all FITs combined. Sensitivity was consistently lower, and specificity was consistently higher for females as compared with males (pooled values at original FIT cutoffs, 25.7% vs. 34.6%, p = 0.12 and 96.2% vs. 90.8%, p < 0.01, respectively). Positive predictive values (PPVs) were similar between both sexes, but negative predictive values (NPVs) were consistently higher for females (pooled values, 91.8% vs. 86.6%, p < 0.01). Sex-specific cutoffs attenuated differences in sensitivities but increased differences in predictive values. According to age, sensitivities and specificities were similar, whereas PPVs were consistently lower and NPVs were consistently higher for the younger participants. A negative FIT is less reliable in ruling out AN among men than among women and among older than among younger participants. Comparisons of measures of diagnostic performance among studies with different sex or age distributions should be interpreted with caution.

Community Health Behaviors and Geographic Variation in Early-Onset Colorectal Cancer Survival Among Women

INTRODUCTION:

Despite overall reductions in colorectal cancer (CRC) morbidity and mortality, survival disparities by sex persist among young patients (age <50 years). Our study sought to quantify variance in early-onset CRC survival accounted for by individual/community-level characteristics among a population-based cohort of US women.

METHODS:

Geographic hot spots—counties with high early-onset CRC mortality rates among women—were derived using 3 geospatial autocorrelation approaches with Centers for Disease Control and Prevention national mortality data. We identified women (age: 15–49 years) diagnosed with CRC from 1999 to 2016 in the National Institutes of Health/National Cancer Institute's Surveillance, Epidemiology, and End Results program. Patterns of community health behaviors by hot spot classification were assessed by Spearman correlation (ρ). Generalized R² values were used to evaluate variance in survival attributed to individual/community-level features.

RESULTS:

Approximately 1 in every 16 contiguous US counties identified as hot spots (191 of 3,108), and 52.9% of hot spot counties (n = 101) were located in the South. Among 28,790 women with early-onset CRC, 13.7% of cases (n = 3,954) resided in hot spot counties. Physical inactivity and fertility were community health behaviors that modestly correlated with hot spot residence among women with early-onset CRC (ρ = 0.21 and ρ = −0.23, respectively; P < 0.01). Together, individual/community-level features accounted for distinct variance patterns in early-onset CRC survival among women (hot spot counties: 33.8%; non–hot spot counties: 34.1%).

DISCUSSION:

Individual/community-level features accounted for approximately one-third of variation in early-onset CRC survival among women and differed between hot spot vs non–hot spot counties. Understanding the impact of community health behaviors—particularly in regions with high early-onset CRC mortality rates—is critical for tailoring strategies to reduce early-onset CRC disparities.

Faecal haemoglobin distributions by sex, age, deprivation and geographical region: consequences for colorectal cancer screening strategies

Objectives Faecal immunochemical tests for haemoglobin (FIT) are becoming widely used in colorectal cancer (CRC) screening and assessment of symptomatic patients. Faecal haemoglobin concentration (f-Hb) thresholds are used to guide subsequent investigation. We established the distributions of f-Hb in a large screening population by sex, age, deprivation and geography. Methods Single estimates of f-Hb were documented for all individuals participating in the first 18 months of the Scottish Bowel Screening Programme (SBoSP). The distributions of f-Hb were generated for all participants, all men and women, and men and women by age quintile and deprivation quintile. Distributions were also generated by geographical region for all participants, men and women, and by deprivation. Comparisons of f-Hb distributions with those found in a pilot evaluation of FIT and three other countries were performed. Results f-Hb was documented for 887,248 screening participants, 422,385 men and 464,863 women. f-Hb varied by sex, age, deprivation quintile and geographical region. The f-Hb distributions by sex and age differed between the SBoSP and the pilot evaluation and the three other countries. Conclusions f-Hb is higher in men than in women and increases with age and deprivation in both sexes. f-Hb also varies by geographical region, independently of deprivation, and by country. The f-Hb distribution estimated by pilot evaluation may not represent the population distribution. Decision limits have advantages over reference intervals. Use of partitioned f-Hb thresholds for further investigation, based on the data generated, has advantages and disadvantages, as do risk scores based on a spectrum of influencing variables.

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.

Population-based organized screening by faecal immunochemical testing and colorectal cancer mortality: a natural experiment

BACKGROUND

Population-based organized screening programmes for colorectal cancer (CRC) are underway worldwide, with many based on the faecal immunochemical test (FIT). No clinical trials assessing FIT compared with no screening are planned, and few studies have assessed the population impact of such programmes.

METHODS

Before 2010, 11 out of 50 Spanish provinces initiated population-based organized screening programmes with FIT for an average-risk population aged 50-69 years. We used a quasi-experimental design across Spanish provinces between 1999 and 2016 to evaluate their impact on population age-standardized mortality and incidence rates due to CRC. Difference-in-differences and synthetic control analyses were performed to test for validation of statistical assumptions and to assess the dynamics of screening-associated changes in outcomes over time.

RESULTS

No differences in outcome trends between exposed (n = 11) and control (n = 36) provinces were observed for up to 7 years preceding the implementation of screening. Relative to controls, exposed provinces experienced a mean increase in age-standardized incidence of 10.08% [95% confidence interval (CI) (5.09, 15.07)] 2 years after implementation, followed by a reduction in age-standardized mortality rates due to CRC of 8.82% [95% CI (3.77, 13.86)] after 7 years. Results were similar for both women and men. No associated changes were observed in adjacent age bands not targeted by screening, nor for 10 other major causes of death in the exposed provinces.

CONCLUSIONS

FIT-based organized screening in Spain was associated with reductions in population colorectal cancer mortality. Further research is warranted in order to assess the replicability and external validity of our findings, and on gender-specific use of FIT in organized screening.

Head-to-head comparison of the test performance of self-administered qualitative vs. laboratory-based quantitative fecal immunochemical tests in detecting colorectal neoplasm

Background:

Fecal immunochemical tests (FITs) are the most widely used non-invasive tests in colorectal cancer (CRC) screening. However, evidence about the direct comparison of the test performance of the self-administered qualitative a laboratory-based quantitative FITs in a CRC screening setting is sparse.

Methods:

Based on a CRC screening trial (TARGET-C), we included 3144 pre-colonoscopy fecal samples, including 24 CRCs, 230 advanced adenomas, 622 non-advanced adenomas, and 2268 participants without significant findings at colonoscopy. Three self-administered qualitative FITs (Pupu tube) with positivity thresholds of 8.0, 14.4, or 20.8 μg hemoglobin (Hb)/g preset by the manufacturer and one laboratory-based quantitative FIT (OC-Sensor) with a positivity threshold of 20 μg Hb/g recommended by the manufacturer were tested by trained staff in the central laboratory. The diagnostic performance of the FITs for detecting colorectal neoplasms was compared in the different scenarios using the preset and adjusted thresholds (for the quantitative FIT).

Results:

At the thresholds preset by the manufacturers, apart from the qualitative FIT-3, significantly higher sensitivities for detecting advanced adenoma were observed for the qualitative FIT-1 (33.9% [95% CI: 28.7–39.4%]) and qualitative FIT-2 (22.2% [95% CI: 17.7–27.2%]) compared to the quantitative FIT (11.7% [95% CI: 8.4–15.8%]), while at a cost of significantly lower specificities. However, such difference was not observed for detecting CRC. For scenarios of adjusting the positivity thresholds of the quantitative FIT to yield comparable specificity or comparable positivity rate to the three qualitative FITs accordingly, there were no significant differences in terms of sensitivity, specificity, positive/negative predictive values and positive/negative likelihood ratios for detecting CRC or advanced adenoma between the two types of FITs, which was further evidenced in ROC analysis.

Conclusions:

Although the self-administered qualitative and the laboratory-based quantitative FITs had varied test performance at the positivity thresholds preset by the manufacturer, such heterogeneity could be overcome by adjusting thresholds to yield comparable specificities or positivity rates. Future CRC screening programs should select appropriate types of FITs and define the thresholds based on the targeted specificities and manageable positivity rates.

Screening for Colorectal Cancer: Updated Evidence Report and Systematic Review for the US Preventive Services Task Force

IMPORTANCE

Colorectal cancer (CRC) remains a significant cause of morbidity and mortality in the US.

OBJECTIVE

To systematically review the effectiveness, test accuracy, and harms of screening for CRC to inform the US Preventive Services Task Force.

DATA SOURCES

MEDLINE, PubMed, and the Cochrane Central Register of Controlled Trials for relevant studies published from January 1, 2015, to December 4, 2019; surveillance through March 26, 2021.

STUDY SELECTION

English-language studies conducted in asymptomatic populations at general risk of CRC.

DATA EXTRACTION AND SYNTHESIS

Two reviewers independently appraised the articles and extracted relevant study data from fair- or good-quality studies. Random-effects meta-analyses were conducted.

MAIN OUTCOMES AND MEASURES

Colorectal cancer incidence and mortality, test accuracy in detecting cancers or adenomas, and serious adverse events.

RESULTS

The review included 33 studies (n = 10 776 276) on the effectiveness of screening, 59 (n = 3 491 045) on the test performance of screening tests, and 131 (n = 26 987 366) on the harms of screening. In randomized clinical trials (4 trials, n = 458 002), intention to screen with 1- or 2-time flexible sigmoidoscopy vs no screening was associated with a decrease in CRC-specific mortality (incidence rate ratio, 0.74 [95% CI, 0.68-0.80]). Annual or biennial guaiac fecal occult blood test (gFOBT) vs no screening (5 trials, n = 419 966) was associated with a reduction of CRC-specific mortality after 2 to 9 rounds of screening (relative risk at 19.5 years, 0.91 [95% CI, 0.84-0.98]; relative risk at 30 years, 0.78 [95% CI, 0.65-0.93]). In observational studies, receipt of screening colonoscopy (2 studies, n = 436 927) or fecal immunochemical test (FIT) (1 study, n = 5.4 million) vs no screening was associated with lower risk of CRC incidence or mortality. Nine studies (n = 6497) evaluated the test accuracy of screening computed tomography (CT) colonography, 4 of which also reported the test accuracy of colonoscopy; pooled sensitivity to detect adenomas 6 mm or larger was similar between CT colonography with bowel prep (0.86) and colonoscopy (0.89). In pooled values, commonly evaluated FITs (14 studies, n = 45 403) (sensitivity, 0.74; specificity, 0.94) and stool DNA with FIT (4 studies, n = 12 424) (sensitivity, 0.93; specificity, 0.85) performed better than high-sensitivity gFOBT (2 studies, n = 3503) (sensitivity, 0.50-0.75; specificity, 0.96-0.98) to detect cancers. Serious harms of screening colonoscopy included perforations (3.1/10 000 procedures) and major bleeding (14.6/10 000 procedures). CT colonography may have harms resulting from low-dose ionizing radiation. It is unclear if detection of extracolonic findings on CT colonography is a net benefit or harm.

CONCLUSIONS AND RELEVANCE

There are several options to screen for colorectal cancer, each with a different level of evidence demonstrating its ability to reduce cancer mortality, its ability to detect cancer or precursor lesions, and its risk of harms.

Aspects of colorectal cancer screening, methods, age and gender

Colorectal cancer (CRC) is, besides breast, prostate, lung and skin cancers, the most common cancer worldwide and is suitable for screening. The incidence of CRC varies considerably in different parts of the world: in well-developed countries, the incidence is between 30 and 70 per 100 000 inhabitants, whereas in less-developed countries such as sub-Saharan Africa, it is 10-20/100 000 inhabitants. Women have a lower incidence of CRC, which is usually one-third of total incidence. Several studies have shown that it is possible to decrease mortality from CRC with about 20%, which is evidenced through the data from countries with screening programmes. Though the method of choice to identify blood samples in faecal matter is under debate, the most feasible way is to perform colonoscopy. Other methods include more advanced faecal analyses, testing for mutations from CRC, sigmoidoscopy, CT colonoscopy or optical colonoscopy. Colonoscopy is in most countries not available in sufficient amount and has to be carried out with great accuracy; otherwise, lesions will be missed to identify, thus leading to complications. Gender is an issue in CRC screening, as women have about 20% fewer colorectal adenomas and CRCs, but they also have more right-sided lesions, which are more difficult to detect with tests for faecal blood since they create less blood in faeces. Thus, other strategies may have to be developed for women in order for screening to have the same effect. It is essential to introduce colorectal cancer screening in all countries together with other clinical pieces of advice such as information on smoking, obesity and exercise in order to reduce one of the most dangerous cancers.

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.

Piloting gender-oriented colorectal cancer screening with a faecal immunochemical test: population-based registry study from Finland

OBJECTIVE

To assess the feasibility and evaluate the performance of a relaunched colorectal cancer (CRC) screening programme with different cut-offs for men and women.

DESIGN

Population-based registry study.

SETTING

Nine municipalities in Finland which started CRC screening with faecal immunochemical test (FIT) in April 2019 with cut-off levels 70 µg Hg/g faeces for men and 25 µg Hg/g faeces for women.

PARTICIPANTS

Men (n=13 059) and women (n=14 669) aged 60-66 years invited to screening during the first programme year.

OUTCOME MEASURES

Participation rates, positivity rates, detection rates of CRC and advanced adenoma (AA), and positive predictive values (PPV) of FIT for CRC and AA.

RESULTS

Altogether 21 993 invitees returned stool samples. The participation rate of women (83.4%; 95% CI 82.8 to 84.0) was significantly higher than that of men (74.7%; 95% CI 73.9 to 75.4). The positivity rates were 2.4% (2.2 to 2.7) and 2.8% (2.5 to 3.1), respectively. In total, 37 CRCs and 116 AAs were detected. The detection rates of CRC and AA per 1000 participants were 1.8 (1.1 to 2.9) and 7.2 (5.6 to 9.1) for men and 1.6 (0.9 to 2.4) and 3.8 (2.8 to 5.0) for women. The PPVs per 100 positive tests were 6.6 (4.0 to 10.3) and 25.7 (20.6 to 31.4) for men and 6.4 (3.9 to 9.8) and 15.5 (11.6 to 20.2) for women.

CONCLUSIONS

The chosen FIT strategy narrowed the gap in the diagnostic performance between men and women especially in the detection of CRC. The participation rates were excellent. The levels of positivity and detection rates were moderate and need further action. The results indicate that gender-specific protocols can be introduced to organised CRC screening. It is yet to be seen whether they are more effective than a uniform screening protocol.

Fecal Immunochemical Tests Detect Screening Participants with Multiple Advanced Adenomas Better than T1 Colorectal Cancers

BACKGROUND

Fecal immunochemical tests (FITs) are widely used for colorectal cancer (CRC) screening. The detection of early-stage cancer and advanced adenoma (AA), the most important premalignant lesion, is highly relevant to reducing CRC-related deaths. We aimed to assess sensitivity for the detection of CRC and AA stratified by tumor stage; number; size; histology of AA; and by location, age, sex, and body mass index (BMI).

METHODS

Participants of screening colonoscopy (n = 2043) and newly diagnosed CRC patients (n = 184) provided a stool sample before bowel preparation or CRC surgery. Fecal hemoglobin concentration was determined in parallel by nine different quantitative FITs among 94 CRC patients, 200 AA cases, and 300 participants free of advanced neoplasm. Sensitivities were calculated at original cutoffs and at adjusted cutoffs, yielding 93% specificity among all FITs.

RESULTS

At adjusted cutoffs, UICC stage I cancers yielded consistently lower sensitivities (range: 62-68%) compared to stage II-IV cancers (range: 73-89%). An even stronger gradient was observed according to T status, with substantially lower sensitivities for T1 (range: 39-57%) than for T2-T4 cancers (range: 71-100%). Sensitivities for the detection of participants with multiple AAs ranged from 55% to 64% and were by up to 25% points higher than sensitivities for T1 cancers.

CONCLUSIONS

FITs detect stage I cancers and especially T1 cancers at substantially lower sensitivities than more advanced cancer stages. Participants with multiple AAs were detected with slightly lower sensitivities than stage I cancers and with even higher sensitivities than T1 cancers. Further research should focus on improving the detection of early-stage cancers.

Impact of antithrombotics on the fecal immunochemical test for colorectal cancer screening : a multi-center Belgian experience

Background

Impact of antithrombotics on the fecal immunochemical test (FIT) for colorectal cancer (CRC) screening remains unclear.

Methods

Patients undergoing colonoscopy for positive FIT in 2015 were assessed at 3 Belgian centers. Significant findings were advanced polyps (AP) (sessile serrated, tubular or villous adenomas >1cm or high-grade dysplasia) and CRC. False positive FIT and detection of AP/CRC with antithrombotics were calculated.

Results

510 patients (64% male, median (IQR) age 63.2 (60.2 - 66.4) years) were included. Colorectal pathology in 371/510 (73%) was associated with male gender (70% vs. 48% ; p= .0001) and family history (16% vs. 8% ; p= .02). Antithrombotics in 125/510 (25%) were associated with male gender (78% vs. 59% ; p= .0001), older age (65.2 (62.2-70.3) vs. 62.3 (58.7-66.3) years ; p= .0001) and GI-symptoms (18% vs. 11% ; p= .04). False positive FIT (25% vs. 28% ; p= .52) and detection of AP (42% vs. 36% ; p=.27) or CRC (6% vs. 5% ; p= .69) were similar in patients with vs. no antithrombotics. Use of antithrombotics did not predict a higher chance of colorectal pathology after adjusting for confounders.

Conclusion

Although antithrombotics were prescribed more frequently in male and older patients, detection of AP/CRC was similar. Despite increased GI symptoms, false positive FIT was similar with antithrombotics.

Gender differences in stage at diagnosis and preoperative radiotherapy in patients with rectal cancer

Background

Few studies have examined gender differences in the clinical management of rectal cancer. We examine differences in stage at diagnosis and preoperative radiotherapy in rectal cancer patients.

Methods

A prospective cohort study was conducted in 22 hospitals in Spain including 770 patients undergoing surgery for rectal cancer. Study outcomes were disseminated disease at diagnosis and receiving preoperative radiotherapy. Age, comorbidity, referral from a screening program, diagnostic delay, distance from the anal verge, and tumor depth were considered as factors that might explain gender differences in these outcomes.

Results

Women were more likely to be diagnosed with disseminated disease among those referred from screening (odds ratio, confidence interval 95% (OR, CI = 7.2, 0.9–55.8) and among those with a diagnostic delay greater than 3 months (OR, CI = 5.1, 1.2–21.6). Women were less likely to receive preoperative radiotherapy if they were younger than 65 years of age (OR, CI = 0.6, 0.3–1.0) and if their tumors were cT3 or cT4 (OR, CI = 0.5, 0.4–0.7).

Conclusions

The gender-specific sensitivity of rectal cancer screening tests, gender differences in referrals and clinical reasons for not prescribing preoperative radiotherapy in women should be further examined. If these gender differences are not clinically justifiable, their elimination might enhance survival.

Risk-Adapted Cutoffs in Colorectal Cancer Screening by Fecal Immunochemical Tests

INTRODUCTION

Fecal immunochemical tests (FITs) for hemoglobin are increasingly used in colorectal cancer (CRC) screening. The use of uniform positivity thresholds (cutoffs) within screening populations is expected to imply lower positive predictive values (PPVs) and higher numbers of colonoscopies needed (numbers needed to scope [NNSs]) to detect advanced neoplasms among screening participants at lower risk compared with those at higher risk. We aimed to assess such variation and its potential implications in a large screening cohort.

METHODS

A quantitative FIT (FOB Gold; Sentinel Diagnostics, Milan, Italy) was conducted in fecal samples collected by 4,332 participants of screening colonoscopy before bowel preparation. Participants were classified into 3 risk groups (low, medium, and high) by tertiles of a previously derived risk-factor-based risk score. We determined the variation of PPVs and NNSs for detecting advanced neoplasms (i.e., CRC or advanced adenoma) when using the same FIT cutoffs and variation of FIT cutoffs that would yield uniform PPVs across risk groups.

RESULTS

When a fixed FIT cutoff of 10 μg/g was used, the PPV increased from 23.3% to 41.8% from the low- to the high-risk group, with NNS decreasing from 4.3 to 2.4 (P < 0.001). Similar variations of PPVs and NNSs across risk groups were observed at higher FIT cutoffs. When risk group-specific cutoffs were defined to achieve fixed PPVs of 25%, 30%, and 35% across all risk groups, cutoffs varied from 5.3 to 11.4, 6.5 to 18.7, and 7.5 to 31.0 μg hemoglobin/g feces, respectively, between high- and low-risk groups (P < 0.05 for all differences).

DISCUSSION

Using risk-adapted cutoffs may help to achieve target levels of PPV and NNS and might be an option to consider for personalized FIT-based CRC screening.

KCNB1 gene polymorphisms and related indel as predictor biomarkers of treatment response for colorectal cancer - toward a personalized medicine

The KCNB1 gene variants were differentially associated with cancers. However, their association with colorectal cancer has not yet been explored. We investigated the contribution of the KCNB1 gene variants rs3331, rs1051295, and indel (insertion/deletion) rs11468831 Polymorphism as predictors of the treatment response in colorectal cancer patients. A retrospective study, which involved 291 Tunisian colorectal cancer patients (aged 60.0 ± 13.1 years), who were stratified into responder and non-responder groups, according to TNM stages and their responsiveness to chemotherapy based on fluorouracil. KCNB1 genotyping was performed with amplification-refractory mutation system-polymerase chain reaction, and was confirmed by Sanger sequencing. Sex-specific response was found and colorectal cancer females are less likely to achieve a positive response during the chemotherapy strategy, compared to males. Weight and body mass index, tumor size, and tumor localization are considered as predictive factors to treatment responsiveness. Carriage of rs11468831 Ins allele was significantly associated with successful therapy achievement (p adjusted < 0.001). Stratification of colorectal cancer patients' response according to tumor localization and TNM stages reveals negative association of rs3331 Major allele to treatment response among the patients with advanced cancer stages (subgroup G2). The presence of rs3331 (homozygous minor) C/C genotype was positively associated with decline in carcino-embryonic antigen (p = 0.043) and CA19-9 (p = 0.014) serum levels. On the other hand, the presence of rs1051295 (homozygous minor) A/A genotype was correlated with marked decline in CA19-9 serum levels. KCNB1 haplotype did not reveal any association between haplotypes and treatment response. The results obtained suggest that gender-specific strategies for screening treatment and prevention protocols as well as KCNB1 variants may constitute an effective model for ongoing personalization medicine.

The cumulative false-positive rate in colorectal cancer screening: a Markov analysis

BACKGROUND

Faecal occult blood testing is widely used in colorectal cancer screening. However, there is little empirical long-term evidence on the accumulation of false-positive test results over several screening rounds. We aimed to systematically explore and quantify the cumulative false-positive rate for various scenarios of colorectal cancer screening.

METHODS

Using a Markov analysis, we estimated the lifetime cumulative number of false-positive test results (cumFP) per 100 000 50-year-old persons. We varied the screening interval and the specificity of a single screening test and the starting age of screening.

RESULTS

For a test with a specificity of 98% used from 50 to 74 years, the cumFP at age 74 was 26 260 (1-year interval), 15 102 (2-year interval), and 10 819 (3-year interval), respectively. For a test with a specificity of, respectively, 95 and 92% used at a 2-year interval, the cumFP at age 74 was 2.2 times and 3.0 times higher as compared to a test with a specificity of 98%. The cumFP at age 74 was 18% lower for screening persons aged 54-74 years vs. 50-74 years.

CONCLUSION

Our findings quantitatively illustrate the large variation of the cumFP in colorectal cancer screening between screening strategies, which is relevant to informed decision making and adequate resource planning.

Global Prevalence of Colorectal Neoplasia: A Systematic Review and Meta-Analysis

BACKGROUND & AIMS

Most colorectal cancers (CRC) arise from colorectal adenomas, yet there is not enough information on global prevalence to inform health care policy. We examined the prevalence of any type of adenomas, advanced adenomas (AADs), and CRC according to age, sex, ethnicity, geographic regions, and anatomic location (proximal vs distal).

METHODS

MEDLINE and Embase were searched from their inception through May 1, 2018, to identify population-based, observational studies that reported the prevalence of colorectal neoplasia. Studies on participants 15 years or older, with a sample size of 500 persons or more, were included. Metaprop (College Station, TX) was used to model within-study variability by binomial distribution and Freeman-Tukey Double Arcsine Transformation to stabilize the variances. The prevalence figures were presented by proportions and their 95% CIs using random-effects models.

RESULTS

Our meta-analysis included 70 studies involving 637,414 individuals. The overall prevalence rates of adenoma (23.9%; 95% CI, 22.2%-25.8%), AAD (4.6%; 95% CI, 3.8%-5.5%), and CRC (0.4%, 95% CI, 0.3%-0.5%) were calculated. Subgroup analysis indicated that prevalence values (adenomas, AADs, and CRCs) were higher among men (29.7%, 6.5%, and 0.8%, respectively) than women (19.3%, 3.8% and 0.4%, respectively), among older adults (25.9%, 5.2%, and 0.6%, respectively) than younger adults (14.6%, 1.6%, and 0.1%, respectively), among Caucasians (23.7%, 6.6%, and 0.5%, respectively) than other ethnicities, in European countries (25.9%, 8.4%, and 0.8%, respectively) than other countries, and among patients with proximal (25.9%, 5.3%, and 0.1%, respectively) vs distal neoplasia.

CONCLUSIONS

In a systematic review and meta-analysis, we found a high prevalence of colorectal neoplasia among some populations. This indicates a need to expand CRC screening programs for these groups. The pooled prevalence estimates can be used as quality indicators for established CRC screening programs.

Effect of Sex, Age, and Positivity Threshold on Fecal Immunochemical Test Accuracy: A Systematic Review and Meta-analysis

BACKGROUND & AIMS

Quantitative fecal immunochemical tests (FITs) for hemoglobin are commonly used for colorectal cancer (CRC) screening. We aimed to quantify the change in CRC and advanced adenoma detection and number of positive test results at different positivity thresholds and by sex and age.

METHODS

We searched MEDLINE and EMBASE, selecting articles of FIT for CRC detection in asymptomatic adults undergoing screening. We calculated sensitivity and specificity, as well as detected number of cancers, advanced adenomas, and positive test results at positivity thresholds ≤10 μg hemoglobin/g feces, 10 to ≤20 μg/g, 20 to ≤30 μg/g, and >30 μg/g. We also analyzed results from stratified by patient sex, age, and reference standard.

RESULTS

Our meta-analysis comprised 46 studies with 2.4 million participants and 6478 detected cancers. Sensitivity for detection of CRC increased from 69% (95% confidence interval [CI], 63%-75%) at thresholds >10 μg/g and ≤20 μg/g to 80% (95% CI, 76%-83%) at thresholds ≤10 μg/g. At these threshold values, sensitivity for detection of advanced adenomas increased from 21% (95% CI, 18%-25%) to 31% (95% CI, 27%-35%), whereas specificity decreased from 94% (95% CI, 93%-96%) to 91% (95% CI, 89%-93%). In 3 studies stratified by sex, sensitivity of CRC detection was 77% in men (95% CI, 75%-79%) and 81% in women (95% CI, 60%-100%) (P = .68). In 3 studies stratified by age groups, sensitivity of CRC detection was 85% for ages 50-59 years (95% CI, 71%-99%) and 73% for ages 60-69 years (95% CI, 71%-75%) (P = .10). All studies with colonoscopy follow-up had similar sensitivity levels for detection of CRC to studies that analyzed 2-year registry follow-up data (74%; 95% CI, 68%-78% vs 75%; 95% CI, 73%-77%).

CONCLUSIONS

In a meta-analysis of studies that analyzed detection of CRC and advanced adenomas at different FIT positivity thresholds, we found the sensitivity and specificity of detection to vary with positive cutoff value. It might be possible to decrease positive threshold values for centers with sufficient follow-up colonoscopy resources. More research is needed to precisely establish FIT thresholds for each sex and age subgroup.

PROTOCOL

PROSPERO CRD42017068760.

Colorectal carcinoma screening: Established methods and emerging technology

Colorectal carcinoma screening programs have shown success in lowering both the incidence and mortality rate of colorectal carcinoma at a population level, in part because this carcinoma is relatively slow growing and has an identifiable premalignant lesion. Still, many patients do not undergo the recommended screening for colorectal carcinoma, and of those who do, a subset may be over- or under-diagnosed by the currently available testing methods. The primary purpose of this article is to review the data regarding currently available colorectal cancer screening modalities, which include fecal occult blood testing, direct colonic visualization, and noninvasive imaging techniques. In addition, readers will be introduced to a variety of biomarkers that may serve as stand-alone or adjunct tests in the future. Finally, there is a brief discussion of the current epidemiologic considerations that public health officials must address as they create population screening guidelines. The data we provide as laboratory physicians and scientists are critical to the construction of appropriate recommendations that ultimately decrease the burden of disease from colorectal carcinoma.

Continuous development of colorectal cancer screening programs

Colorectal cancer (CRC) screening programs are far from perfect. Many crucial questions remain, yet expensive CRC screening services are implemented throughout the world without a plan on how to evaluate and improve the service. The time is ripe for improving the design of CRC screening programs.

Factors related to the participation and detection of lesions in colorectal cancer screening programme-based faecal immunochemical test

Background

The overall aim of this study was to describe trends in participation rates and detection of lesions in a colorectal cancer (CRC) screening programme, during three rounds, using faecal immunochemical test (FIT).

Methods

National registers were used to collect data on invitations for CRC screening in the Basque Country (Spain) from 2009 to 2014. Information about participation, age, gender and lesions in each round were collected.

Results

A total of 961.533 individuals were included in the analysis; respectively, 584.950, 298.143 and 78.440 in the first, second and third rounds. The average participation rate was 68.4% (66.8, 70.4 and 72.3%, respectively by round; P < 0.001) and the positivity rate was 6.3% (7, 5.5 and 5.4%, respectively by round; P < 0.001). The participation rate increased significantly with age and was found to be higher in women versus men. A total of 15.144 advanced adenomas and 2.131 CRCs were diagnosed, leading to a detection rate of 23.9 and 3.4‰, respectively. Regarding gender, men had the highest rates in all periods and rounds. The detection rate of advanced neoplasia was lower in the regular when compared with irregular paricipants.

Conclusions

In a CRC screening, this organization obtained high FIT participation rates. Older participants and women were associated with a higher participation. The detection rate of lesions was higher in men, independent on age and round.

Effects of Oral Anticoagulants and Aspirin on Performance of Fecal Immunochemical Tests in Colorectal Cancer Screening

BACKGROUND & AIMS

The fecal immunochemical test (FIT) is the tool most frequently used for colorectal cancer (CRC) screening worldwide. It is unclear how the use of aspirin and oral anticoagulants in the screening population affects the diagnostic performance of FIT.

METHODS

We performed a cross-sectional study in an ongoing CRC screening trial in Norway. Participants aged 50-74 years with a positive result from an FIT (>15 μg hemoglobin/g feces) and subsequent colonoscopy (reference standard) were included. Those who used regular aspirin, warfarin, or direct-acting oral anticoagulants (DOACs) were defined as users. Non-users were matched according to age, sex, screening center, and screening round. The primary outcomes were the positive predictive value (PPV) for CRC and advanced adenoma.

RESULTS

Among 4908 eligible participants, 1008 used aspirin, 147 used warfarin, 212 used DOACs, and 3541 were non-users. CRCs were found in 234 individuals and advanced adenomas in 1305 individuals. The PPV for CRC was 3.8% for aspirin users vs 6.4% for matched non-users (P = .006), The PPV for advanced adenoma in aspirin users was 27.2% vs 32.6% for matched non-users (P = .011). For DOAC, the PPV for CRC was 0.9% in users vs 6.8% in matched non-users (P = .001). The PPV for advanced adenoma in DOAC users was 20.5% vs 32.4% in matched non-users (P = .002). There was no significant difference in PPV for CRC or advanced adenoma in warfarin users compared to non-users.

CONCLUSIONS

In a large screening cohort in Norway, regular use of aspirin and particularly DOACs, were associated with lower PPV of FIT for detection of CRCs and advanced adenomas. ClinicalTrials.gov ID NCT01538550.

Fecal immunochemical test in cancer screening - colonoscopy outcome in FIT positives and negatives

Objectives: Fecal immunochemical test (FIT) is used in colorectal cancer (CRC) screening, but evaluations of multiple sample strategies in colonoscopy screening cohorts are rare. The aim of this study was to assess accuracy of FIT for advanced neoplasia (AN) with two fecal samples in a colonoscopy screening cohort. Materials and methods: The study comprised 1155 participants of the colonoscopy arm in SCREESCO (Screening of Swedish Colons, NCT02078804), a randomized controlled study on CRC screening of 60-year-olds from the Swedish average-risk population. Participants provided two FIT samples prior to colonoscopy. First sample, mean of two, and any of the two samples above cut off level were assessed. Colonoscopy findings (CRC, advanced adenoma (AA), AN (CRC + AA) and adenoma characteristics) were evaluated in uni- and multivariable analysis in relation to FIT positivity (at ≥10 µg hemoglobin (Hb)/g). Results: Of 1155 invited, 806 (416 women, 390 men) participated. CRC, AA and non-AA were found in one (0.1%), 80 (9.9%) and 145 (18%), respectively. Sensitivity and specificity for AN were 20%/93%, 25%/92% and 26%/89% for first, mean of two and any of the two samples respectively at cut off level 10 µg/g, corresponding to 60 (74%)-65 (80%) participants with missed AN. The difference in sensitivity between screening strategies was non-significant. The specificity for first sample was significantly higher than for any of the two samples at cut off 10 µg/g (p = .02) and 20 µg/g (p = .04). FIT positivity in participants with adenoma was associated with pedunculated shape (p = .007) and high-risk dysplasia (p = .009). Conclusions: In an average-risk colonoscopy screening cohort of 60-year-olds, sensitivity for AN was modest and did not increase when using two samples instead of one. FIT predominantly detected adenomas with pedunculated shape and high-risk dysplasia, and participants with flat or broad based adenomas may thus be missed in screening.

Combination of Different Fecal Immunochemical Tests in Colorectal Cancer Screening: Any Gain in Diagnostic Performance?

A variety of fecal immunochemical tests (FITs) are used for colorectal cancer screening. FIT performance could be improved further. It is unclear, whether the combination of different FITs with different analytical characteristics (such as, different antibodies for the detection of fecal hemoglobin) can yield a better diagnostic performance. Fecal samples were obtained from 2042 participants of screening colonoscopy. All participants with advanced neoplasm (AN, colorectal cancer (n = 16) or advanced adenoma (n = 200)) and 300 randomly selected participants without AN were included. Nine quantitative FITs were evaluated simultaneously. Sensitivity and specificity was calculated for single tests (n = 9) and for their pairwise test combinations (n = 36) (requiring either both FITs (P++) or at least one FIT (P+) to be positive for defining a positive test result). Mean age of the participants (n = 516) was 63 (range: 50–79) years and 56% were men. At cutoffs yielding a specificity of 96.7% for single FITs, the median gain in specificity by P++ combination was +1.0%, whereas the median loss in sensitivity for AN was −4.2%. For P+ combination the median gain in sensitivity for AN was +2.8%, at a prize of median loss of −1.0% of specificity. Combinations of different FITs do not yield any relevant gain in diagnostic performance.

Fecal immunochemical test in colorectal cancer screening: Colonoscopy findings by different cut-off levels

BACKGROUND AND AIM

Fecal immunochemical test (FIT) is used in colorectal cancer (CRC) screening, but number of tests and cut-off level differ by program. The aim was to evaluate CRC screening with two FIT samples in average-risk 60-year-old men and women and to investigate hemoglobin (Hb) level in correlation to adenoma characteristics.

METHODS

We analyzed a cohort from Screening of Swedish Colons trial where participants with at least one of two FIT samples ≥10 μg Hb/g are offered colonoscopy. FIT levels and colonoscopy findings were assessed in multivariable analyses. Cut-off levels 10-80 μg Hb/g for one and two samples were assessed. FIT levels and advanced neoplasia (AN) were investigated by gender.

RESULTS

A total of 12 383 participated and 1182 positives (551 women) completed colonoscopy diagnosing 27 (2.3%) CRC and 269 (23%) advanced adenomas (AA). Median FIT level was 241.0 and 23.8 for CRC and AA compared with 13.4-15.8 in other subgroups (P = 0.002) correlating with adenoma size (P = 0.038). CRC was detected in 22 and 19 subjects for the first sample at cut-off 20 and 40 μg Hb/g, compared with 20 and 17 for the mean of two samples at cut-off 40 and 80 μg Hb/g (P < 0.05). Men had more AN (CRC + AA), (P = 0.003). In women, similar number of AN would be detected with cut-off lowered from 40 to 20 or from 80 to 40 μg Hb/g, requiring additional 26-34% colonoscopies.

CONCLUSION

In average-risk 60-year-olds, FIT was higher in participants with AN and correlated with adenoma size. FIT screening with one sample at low cut-off detected more CRC than two samples at higher cut-off. Applying lower cut-off in women to equalize gender differences in AN would result in considerable increase in colonoscopy workload.

Participant-Related Risk Factors for False-Positive and False-Negative Fecal Immunochemical Tests in Colorectal Cancer Screening: Systematic Review and Meta-Analysis

OBJECTIVES

Colorectal cancer (CRC) screening using fecal immunochemical tests (FIT) may reduce CRC-related mortality but its effectiveness is influenced by the limited accuracy of FIT. Identifying individuals at increased risk of a false FIT result could improve screening, but the available evidence is conflicting. We performed a systematic review and meta-analysis on risk factors for false-positive and false-negative FIT results in CRC screening.

METHODS

A systematic search in MEDLINE, EMBASE, and Cochrane Library identified publications (before 29 January 2017) on risk factors (known at time of FIT invitation) associated with false FIT results (presence/absence of advanced neoplasia) in a CRC screening setting. Risk of bias was assessed using QUIPS. In meta-analysis, summary relative risk ratios and corresponding 95% confidence intervals were calculated for each risk factor.

RESULTS

Of 518 records identified, 14 studies with 54,499 participants in total were included for analysis. In meta-analysis, male sex was associated with a significantly lower risk of false-positivity (RR 0.84, CI 0.74-0.94), whereas participants using non-steroidal anti-inflammatory drugs (NSAIDs) had a higher risk (RR 1.16, CI 1.06-1.27). The use of anticoagulants was most frequently studied, without a significant effect on FIT positivity. Males (RR 1.83, CI 1.53-2.19), participants with a family history for CRC (RR 1.61, CI 1.19-2.15), hyperglycemia (RR 1.29, CI 1.02-1.65), hypertension (RR 1.50, CI 1.14-1.98), obesity (RR 1.38, CI 1.11-1.71), and (former) smokers (RR 1.93, CI 1.52-2.45) were all at significantly higher risk for false-negative results. Age was not found to have a systematic effect on either FIT false-positivity or false-negativity in meta-analysis.

CONCLUSIONS

Multiple risk factors, known at time of FIT invitation, are associated with false FIT results in CRC screening. This information can be used to identify populations risking false reassurance after a negative result or unnecessary colonoscopy after a positive result, and to further optimize CRC screening effectiveness.

An evaluation of the SENTiFIT 270 analyser for quantitation of faecal haemoglobin in the investigation of patients with suspected colorectal cancer

BACKGROUND

An evaluation of SENTiFIT® 270 (Sentinel Diagnostics, Italy; Sysmex, Spain) analyser for the quantitation of faecal haemoglobin (f-Hb) was performed.

METHODS

The analytical imprecision, linearity, carry over and f-Hb stability were determined. Evaluation of the diagnostic accuracy was performed on 487 patients.

RESULTS

Within-run and between-run imprecision ranged 1.7%-5.1% and 3.8%-6.2%, respectively. Linearity studies revealed a mean recovery of 101.1% (standard deviation, 6.7%) for all dilutions. No carry over was detected below 7650 μg Hb/g faeces. Decay of f-Hb in refrigerated samples ranged 0.2%-0.5% per day. f-Hb in patients with advanced colorectal neoplasia (ACRN) (colorectal cancer [CRC] plus advanced adenoma [AA]) were significantly higher than from those with a normal colonoscopy. Sensitivity for ACRN at f-Hb cutoffs from 10 to 60 μg Hb/g faeces ranged from 28.9% (95% confidence interval [CI], 21.7%-37.2%) to 46.5% (95% CI, 38.1%-55%), the specificity ranged from 85% (95% CI, 82.3%-87.3%) to 93.2% (95% CI, 91.2%-94.8%), positive predictive values for detecting CRC and AA ranged from 11.6% (95% CI, 7.6%-17.2%) to 20.6% (95% CI, 13.3%-30.3%) and from 34.7% (95% CI, 28.1%-42%) to 42.3% (95% CI, 32.4%-52.7%), respectively, and the negative predictive value for ACRN ranged from 90.2% (95% CI, 87.9%-92.2%) to 88.4% (95% CI, 86%-90.4%). Using two samples per patient sensitivity increased with a slight decrease in specificity.

CONCLUSIONS

The analytical and clinical performances of SENTiFIT assay demonstrate a specific and accurate test for detecting ACRN in symptomatic patients and those undergoing surveillance.

Gender-specific cut-offs in colorectal cancer screening with FIT: Increased compliance and equal positivity rate

OBJECTIVE

Using quantitative Faecal Immunochemical Test (FIT) in colorectal cancer screening enables adjustment of the cut-off for a positive test. As men have higher stool blood levels and higher prevalence of colorectal neoplasia, different cut-off levels can be chosen for men and women. We evaluated participation and positivity rates switching from guaiac-based faecal occult blood test (gFOBT) (Hemoccult®) to FIT (OC-Sensor), using gender-specific cut-offs.

METHODS

The colorectal cancer screening programme of Stockholm-Gotland, Sweden, started in 2008 and invited individuals aged 60-69 to biennial testing using gFOBT. From 1 October 2015 the test was switched to FIT, with positivity cut-offs of 40 (200) and 80 (400) µg Hb/g (ng/mL) faeces for women and men, respectively. The first year was evaluated for compliance and positivity, number of reminders and incorrect/inadequate tests, compared with gFOBT in the preceding 12-month period.

RESULTS

There were 127,030 and 87,269 individuals invited to screening with gFOBT and FIT, respectively. The change of test increased overall participation by 11.9% (95% confidence interval 11.5%-12.3%) from 56.5% to 68.4% ( p < 0.001). The increase was larger in men (14.3%) than women (9.7%), and in those aged 60-64 (14.2%) than those aged 65-69 (8.7%). The positivity rate was 2.6% in women and 2.5% in men. There was a lower rate of reminders and incorrect/inadequate tests with FIT.

CONCLUSIONS

Within a well-organised colorectal cancer screening programme, changing the test from gFOBT to FIT markedly increased participation, especially among men, and in the younger age group. With a lower cut-off in women than men, the positivity rate was similar.

Influence of Varying Quantitative Fecal Immunochemical Test Positivity Thresholds on Colorectal Cancer Detection: A Community-Based Cohort Study

Background

The fecal immunochemical test (FIT) is commonly used for colorectal cancer (CRC) screening. Despite demographic variations in stool hemoglobin concentrations, few data exist regarding optimal positivity thresholds by age and sex.

Objective

To identify programmatic (multitest) FIT performance characteristics and optimal FIT quantitative hemoglobin positivity thresholds in a large, population-based, screening program.

Design

Retrospective cohort study.

Setting

Kaiser Permanente Northern and Southern California.

Participants

Adults aged 50 to 75 years who were eligible for screening and had baseline quantitative FIT results (2013 to 2014) and 2 years of follow-up. Nearly two thirds (411 241) had FIT screening in the previous 2 years.

Measurements

FIT programmatic sensitivity for CRC and number of positive test results per cancer case detected, overall and by age and sex.

Results

Of 640 859 persons who completed a baseline FIT and were followed for 2 years, 481 817 (75%) had at least 1 additional FIT and 1245 (0.19%) received a CRC diagnosis. Cancer detection (programmatic sensitivity) increased at lower positivity thresholds, from 822 in 1245 (66.0%) at 30 µg/g to 925 (74.3%) at 20 µg/g and 987 (79.3%) at 10 µg/g; the number of positive test results per cancer case detected increased from 43 at 30 µg/g to 52 at 20 µg/g and 85 at 10 µg/g. Reducing the positivity threshold from 20 to 15 µg/g would detect 3% more cancer cases and require 23% more colonoscopies. At the conventional FIT threshold of 20 µg/g, programmatic sensitivity decreased with increasing age (79.0%, 73.4%, and 68.9% for ages 50 to 59, 60 to 69, and 70 to 75 years, respectively; P = 0.009) and was higher in men than women (77.0% vs. 70.6%; P = 0.011).

Limitation

Information on advanced adenoma was lacking.

Conclusion

Increased cancer detection at lower positivity thresholds is counterbalanced by substantial increases in positive tests. Tailored thresholds may provide screening benefits that are more equal among different demographic groups, depending on local resources.

Primary Funding Source

National Cancer Institute.

Variation of diagnostic performance of fecal immunochemical testing for hemoglobin by sex and age: results from a large screening cohort

Objective

Fecal immunochemical tests (FITs) for hemoglobin in stool are increasingly used for colorectal cancer screening. Reported sensitivities and specificities have strongly varied between studies, but it is unclear to what extent such variation reflects differences between tests or between study population characteristics. We aimed to evaluate the key parameters of FIT performance for detecting advanced neoplasia (AN) according to sex and age.

Methods

Sex- and age-specific sensitivity, specificity, positive predictive values (PPVs) and negative predictive values (NPVs) for detecting AN of a quantitative FIT (FOB Gold®) were evaluated among 3211 men and women aged 50–79 years who underwent screening colonoscopy in Germany.

Results

At the cutoff recommended by the manufacturer (17 µg hemoglobin/g feces), sensitivity was higher (51.2% versus 34.7%, p=0.004) and specificity was lower (91.0% versus 94.8%, p<0.001) among 65–79 year-old participants compared with 50–64 year-old participants. PPVs and NPVs did not differ significantly between age groups. However, higher NPVs were observed among women compared with men (94.7% versus 92.5%, p=0.015). Specificity was also higher among women compared with men (94.7% versus 92.3%, p=0.007), while there was only a little variation in sensitivity (40.3% versus 41.8%, p=0.789) according to sex. In joint stratification by both factors, sensitivity ranged from 34.1% (95% CI 24.2%–45.2%) in 50–64 year-old women to 51.4% (95% CI 39.3%–63.3%) in 65–79 year-old men (p=0.029). The observed age and sex differences were highly consistent across a wide range of alternative cutoffs from 10 to 50 µg hemoglobin/g feces.

Conclusion

There are major differences in diagnostic performance parameters according to sex and age, which should receive careful attention in the interpretation and comparison of results of FIT-based colorectal cancer screening studies.