Screen-detected colorectal cancers are associated with an improved outcome compared with stage-matched interval cancers

Screening History and 7-Year Survival in 32,099 Colorectal Cancer Patients: A Population-Based Cohort Study

Background

It is unclear whether colorectal cancer screening history, regardless of stage, is an independent predictor of survival, and if the screening advantage persists after diagnosis. 32 099 patients with colorectal cancer were enrolled in this population-based cohort study.

Methods

We used data from the Taiwan Cancer Registry on patients with a first-time diagnosis of colorectal cancer between 2013 and 2015. In addition, we utilized data from a nationwide database of colorectal cancer screening programs to evaluate patients' screening histories, and sourced outcome data from the National Death Registry, tracking patients up to the last day of 2019.

Results

Compared with fecal immunochemical testing (FIT)-positive patients with a follow-up examination, the adjusted hazard ratios (95% confidence intervals) for death from colorectal cancer were 1.40 (1.26-1.56) for FIT-positive patients without a follow-up examination, 1.63 (1.48-1.78) for FIT-negative patients, and 1.76 (1.65-1.89) for never screened patients. The adjusted hazard ratios for the FIT-positive patients with a follow-up examination increased when diagnosis was delayed by more than 12 months and were 1.2 after a 2-year delay. The adjusted hazard ratios for FIT-negative patients were approximately 2.0, decreased rapidly to 1.6, and stabilized after the 9th time-to-diagnosis month.

Conclusion

In colorectal cancer patients, screening history prior to diagnosis is an independent prognostic factor, regardless of cancer stage or other variables. This study recommends that physicians take screening history into account during diagnosis to optimize follow-up and management for patients at higher risk.

Modifiable patient-reported factors associated with cancer-screening knowledge and participation in a community-based health assessment

BACKGROUND

We sought to identify modifiable factors associated with cancer screening in a community-based health assessment.

METHODS

24 organizations at 47 community events in central North Carolina distributed a 91-item survey from April-December 2017. Responses about (1) interest in disease prevention, (2) lifestyle choices (e.g., diet, tobacco), and (3) perceptions of primary care access/quality were abstracted to examine their association with self-reported screening participation and knowledge about breast, prostate, and colorectal cancer.

RESULTS

2135/2315 participants (92%; 38.5% White, 38% Black, 9.9% Asian) completed screening questions. >70% of screen-eligible respondents reported guideline-concordant screening. Healthy dietary habits were associated with greater knowledge about breast and colorectal cancer screening; reporting negative attitudes about and barriers to healthcare were associated with less breast, prostate, and colorectal cancer screening. Having a place to seek medical care (a proxy for primary care access) was independently associated with being ∼5 times as likely to undergo colorectal screening (OR 4.66, 95% CI 1.58-13.79, all p < 0.05).

CONCLUSIONS

In this diverse, community-based sample, modifiable factors were associated with screening engagement, highlighting opportunities for behavioral intervention.

Resection margin involvement after endoscopic excision of malignant colorectal polyps: definition of margin involvement and its impact upon tumour recurrence

AIMS

Malignant polyps are examined to assess histological features which predict residual tumour in the unresected bowel and guide surgical decision-making. One of the most important of these features is resection margin involvement, although the best definition of margin involvement is unknown. In this study we aimed to investigate three different definitions and determine their impact on clinical outcomes.

METHODS AND RESULTS

One hundred and sixty-five malignant polyps removed endoscopically were identified and histological features correlated with either residual tumour in subsequent surgical resections or tumour recurrence following a period of clinical follow-up. Involvement of the polyp margin by cancer was defined in three different ways and outcomes compared. Tumour recurrence was associated with tumour grade, mucinous histology and resection margin involvement. All three definitions of margin involvement separated polyps into clinically significant categories; however, a margin ≤ 1 mm identified 73% of polyps as 'high-risk' compared with 59.1% when involvement was defined as tumour within the zone of coagulation artefact at the polyp base or 50% when tumour was present at the margin. All three 'low-risk' groups had a locoregional recurrence rate < 6.5%.

CONCLUSIONS

Definitions of margin involvement for endoscopically removed malignant polyps in the colon and rectum vary between health-care systems, but a 1-mm clearance is widely used in Europe and North America. Our results suggest that a 1-mm margin is unnecessary and should be replaced by a definition based on tumour at the margin or within coagulation artefact at the polyp base.

Overall and stage-specific survival of patients with screen-detected colorectal cancer in European countries: A population-based study in 9 countries

Background

An increasing proportion of colorectal cancers (CRCs) are detected through screening due to the availability of organised population-based programmes. We aimed to analyse survival probabilities of patients with screen-detected CRC in European countries.

Methods

Data from CRC patients were obtained from 16 population-based cancer registries in nine European countries. We included patients with cancer diagnosed from the year organised CRC screening programmes were introduced until the most recent year with available data at the time of analysis, whose ages at diagnosis fell into the age groups targeted by screening. Patients were followed up with regards to vital status until 2016-2020 across the various countries. Overall and CRC-specific survival were analysed by mode of detection and stage at diagnosis for all countries combined and for each country separately using the Kaplan-Meier method.

Findings

We included data from 228 134 patients, of whom 134 597 (aged 60-69 years at diagnosis targeted by screening in all countries) were considered in analyses for all countries combined. 22·3% (38 080/134 597) of patients had cancer detected through screening. Most screen-detected cancers were found at stages I-II (65·6% [12 772/19 469 included in stage-specific analyses]), while the majority of non-screen-detected cancers were found at stages III-IV (56·4% [31 882/56 543 included in stage-specific analyses]). Five-year overall and CRC-specific survival rates for patients with screen-detected cancer were 83·4% (95% CI 82·9-83·9) and 89·2% (88·8-89·7), respectively; for patients with non-screen-detected cancer, they were much lower (57·5% [57·2-57·8] and 65·7% [65·4-66·1], respectively). The favourable survival of patients with screen-detected cancer was also seen within each stage – five-year overall survival rates for patients with screen-detected stage I, II, III, and IV cancers were 92.4% (95% CI 91·6-93·1), 87·9% (86·6-89·1), 80·7% (79·3-82·0), and 32·3 (29·4-35·2), respectively. These patterns were also consistently seen for each individual country.

Interpretation

Patients with cancer diagnosed at screening have a very favourable prognosis. In the rare case of detection of advanced stage cancer, survival probabilities are still much higher than those commonly reported for all patients regardless of mode of detection. Although these results cannot be taken to quantify screening effects, they provide useful and encouraging information for patients with screen-detected CRC and their physicians.

Funding

This study was supported in part by grants from the German Federal Ministry of Education and Research and the German Cancer Aid.

Biology and Clinical Implications of Fecal Occult Blood Test (FOBT) Screen-Detected Colorectal Cancer

Background

Fecal occult blood test (FOBT) based screening for colorectal cancer (CRC) reduces mortality, with earlier stage at diagnosis a prominent feature. Other characteristics of FOBT screen-detected cancers and any implications for clinical management have not been well explored.

Methods

We examined a multi-site clinical registry to compare the characteristics and outcomes of FOBT screen-detected CRC via the Australian National Bowel Cancer Screening Program (NBCSP), which is offered biennially to 50-74 year olds, and age matched non-screen detected cases in the same registry. All statistical tests were 2-sided. Odds Ratios were calculated using the Baptista-Pike method and Hazard Ratios via the log-rank method.

Results

Of 7,153 registry patients diagnosed June 1, 2006 to June 30, 2020, 4142 (57.9%) were aged between 50-74 years old. Excluding 406 patients with non-NBCSP screen-detected cancers and 35 patients with unknown method of detection, 473 (12.8%) were screen-detected via the NBCSP and 3228 (87.2%) were non screen-detected. Screen-detected patients were younger (mean age= 62.4 vs 64.2 years, P&lt;.001) and more medically fit (Odds Ratio [OR] for ASA score 1-2 = 1.91, 95% confidence interval [CI] = 1.51 to 2.41, P&lt;.001). Pathologic characteristics within each stage favoured the screen-detected cases. Stage III screen-detected colon cancers were more likely to receive adjuvant therapy (OR = 3.58, 95% CI = 1.52 to 8.36, P=.002). Screen-detected patients had superior relapse free (HR = 0.41, 95% CI = 0.29 to 0.60, P&lt;.001) and overall survival (HR = 0.22, 95% CI = 0.15 to 0.35, P&lt;.001), which was maintained in matched stage comparisons and multivariate analysis.

Conclusions

Beyond stage at diagnosis multiple other factors associated with a favourable outcome are observed in FOBT screen-detected CRC. Given the substantial stage by stage differences in survival outcomes, if independently confirmed, individualised adjuvant therapy and surveillance strategies could be warranted for FOBT screen-detected cancers.

More Favorable Short and Long-Term Outcomes for Screen-Detected Colorectal Cancer Patients

Background

Screening significantly reduces mortality from colorectal cancer (CRC). Screen detected (SD) tumors associate with better prognosis, even at later stage, compared to non-screen detected (NSD) tumors. We aimed to evaluate the association between diagnostic modality (SD vs. NSD) and short- and long-term outcomes of patients undergoing surgery for CRC.

Materials and Methods

This retrospective cohort study involved patients aged 50–69 years, residing in Veneto, Italy, who underwent curative-intent surgery for CRC between 2006 and 2018. The clinical multi-institutional dataset was linked with the screening dataset in order to define diagnostic modality (SD vs. NSD). Short- and long-term outcomes were compared between the two groups.

Results

Of 1,360 patients included, 464 were SD (34.1%) and 896 NSD (65.9%). Patients with a SD CRC were more likely to have less comorbidities (p = 0.013), lower ASA score (p = 0.001), tumors located in the proximal colon (p = 0.0018) and earlier stage at diagnosis (p < 0.0001). NSD patients were found to have more aggressive disease at diagnosis, higher complication rate and higher readmission rate due to surgical complications (all p < 0.05). NSD patients had a significantly lower Disease Free Survival and Overall Survival (all p < 0.0001), even after adjusting by demographic, clinic-pathological, tumor, and treatment characteristics.

Conclusions

SD tumors were associated with better long-term outcomes, even after multiple adjustments. Our results confirm the advantages for the target population to participate in the screening programs and comply with their therapeutic pathways.

Sudden PSA rise to ≥20 ng/ml and prostate cancer diagnosis in the United States: A population-based study

PURPOSE

While prostate-specific antigen (PSA) screening protocols vary, many clinicians have anecdotes of screened men with low PSA levels that rise significantly and are associated with high-risk prostate cancer (PC). We sought to better understand the frequency of high-risk cases that appear suddenly in a screened population.

METHODS

We utilized data from a Commercial and Medicare advantage claims database to identify all US men ages 50 and above undergoing PSA screening who then had a sudden interval rise in PSA (e.g., PSA ≥ 20) and diagnosis of PC. We determined associations with age, race, screening intensity, and baseline PSA levels.

RESULTS

In all, 526,120 men met entry criteria with an average age of 60.7 and follow-up of 5.6 years. As the baseline PSA increased, the rate of high-risk PC increased from 2/10,000 persons among men with the lowest baseline PSA (<1 ng/ml) to 14/10,000 person-years among men with a baseline PSA < 5 ng/ml. Moreover, as a man's age at baseline PSA increased, the rate of high-risk PC also increased. In contrast, the incidence of high-risk PC did not vary significantly by race/ethnicity. More screening PSAs and shorter intervals between PSA screenings were associated with a lower incidence of high-risk PC.

CONCLUSIONS

The incidence of high-risk PC in a screened population is low (<0.1%). Our findings suggest that systematic screening cannot eliminate all PC deaths and provide an estimate for the risk of the rapid development of high-risk cancers that is comparable to that observed in active surveillance populations.

Validation of Microsimulation Models against Alternative Model Predictions and Long-Term Colorectal Cancer Incidence and Mortality Outcomes of Randomized Controlled Trials

Background. This study aimed to assess the validity of 2 microsimulation models of colorectal cancer (CRC), Policy1-Bowel and ASCCA. Methods. The model-estimated CRC risk in population subgroups with different health statuses, "dwell time" (time from incident precancerous polyp to symptomatically detected CRC), and reduction in symptomatically detected CRC incidence after a one-time complete removal of polyps and/or undetected CRC were compared with published findings from 3 well-established models (MISCAN, CRC-SPIN, and SimCRC). Furthermore, 6 randomized controlled trials (RCTs) that provided screening using a guaiac fecal occult blood test (Funen trial, Burgundy trial, and Minnesota Colon Cancer Control Study [MCCCS]) or flexible sigmoidoscopy (NORCCAP, SCORE, and UKFSST) with long-term follow-up were simulated. Model-estimated long-term relative reductions of CRC incidence (RR_inc) and mortality (RR_mort) were compared with the RCTs' findings. Results. The Policy1-Bowel and ASCCA estimates showed more similarities to CRC-SPIN and SimCRC. For example, overall dwell times estimated by Policy1-Bowel (24.0 years) and ASCCA (25.3) were comparable to CRC-SPIN (25.8) and SimCRC (25.2) but higher than MISCAN (10.6). In addition, ∼86% of Policy1-Bowel's and ∼74% of ASCCA's estimated RR_inc and RR_mort were consistent with the RCTs' long-term follow-up findings. For example, at 17 to 18 years of follow-up, the MCCCS reported RR_mort of 0.67 (95% confidence interval [CI], 0.51-0.83) and 0.79 (95% CI, 0.62-0.97) for the annual and biennial screening arm, respectively, and the UKFSST reported RR_mort of 0.70 (95% CI, 0.62-0.79) for CRC at all sites and 0.54 (95% CI, 0.46-0.65) for distal CRC. The corresponding model estimates were 0.65, 0.74, 0.81, and 0.61, respectively, for Policy1-Bowel and 0.65, 0.70, 0.75, and 0.58, respectively, for ASCCA. Conclusion. Policy1-Bowel and ASCCA's estimates are largely consistent with the data included for comparisons, which indicates good model validity.

Colorectal Cancer Survival in 50- to 69-Year-Olds after Introducing the Faecal Immunochemical Test

Population screening has improved early diagnosis of colorectal cancer (CRC). Nonetheless, most cases are diagnosed in symptomatic patients. Faecal immunochemical testing has been recommended for assessing patients with lower gastrointestinal symptoms, but whether it improves patient survival is unknown. Our objective was to compare CRC survival in 50- to 69-year-olds between asymptomatic screen-detected patients and symptomatic patients by route to diagnosis. Methods: We identified all cases of CRC diagnosed in 50-to 69-year-olds between 2009 and 2016, in Donostialdea (Gipuzkoa, Spain). Three groups were created: 1-screen-detected CRC; 2-CRC detected in symptomatic patients after a positive faecal immunochemical test(FIT); and 3-CRC detected in symptomatic patients without a FIT or after a negative result. We analysed survival using the Kaplan-Meier method and log-rank tests. Results: Of 930 patients diagnosed with CRC, 433 cases were detected through screening and 497 in symptomatic patients, 7.9% after a positive FIT and 45.5% by other means. The 3-year CRC survival was significantly lower in group 3 (69.5%) than groups 1 (93%; p = 0.007) or 2 (87.5%; p = 0.02). The risk of death was lower in groups 1 (HR 0.42, 95% CI 0.30–0.58) and 2 (HR 0.51; 95% CI 0.29–0.87). Conclusion: Half of CRC cases in 50- to 69-year-olds are diagnosed outside screening. Use of the FIT as a diagnostic strategy in symptomatic patients may improve survival.

Gender- and Race-Based Differences in Barriers and Facilitators to Early Detection of Colon Cancer

Background: Early detection of colon cancer is essential to successful treatment and survival, yet most patients are diagnosed only after onset of symptoms. Previous studies suggest differences in colon cancer screening and presentation by gender and race, but reasons for this are not understood. The purpose of this study was to identify barriers and facilitators to early detection of colon cancer and to compare by gender and race. Materials and Methods: In the Colon Cancer Patterns of Care in Chicago study, non-Hispanic Black and White (NHB, NHW) patients aged 30-79 newly diagnosed with colon cancer between 2010 and 2014 (n = 249) underwent in-depth semistructured interviews regarding the pathway to colon cancer diagnosis. Mixed qualitative and quantitative methods were used to analyze patient narratives and to compare response patterns by gender and race within prespecified domains: health care access factors, provider-related factors, patient-related factors, and diagnostic workup factors. Results: Women reported more barriers than facilitators to early detection than men (barrier: facilitator ratio of 0.60 vs. 0.48). Thematic differences were seen, with women reporting more barriers related to health care access, scheduling of follow-ups, symptom recognition, and inappropriate or inconclusive diagnostic tests. Fewer women than men reported facilitators related to provider factors such as ease of scheduling follow-ups and receiving referrals for screening or a specialist. NHBs and NHWs reported similar ratios of barriers to facilitators (0.55 vs. 0.53), but more NHBs than NHWs reported barriers related to health care access, scheduling follow-ups, and clinical delays, and fewer NHBs reported facilitators related to health care accessibility (existing relationship with provider, ease of scheduling follow-ups). Conclusions: In this diverse population of patients recently diagnosed with colon cancer, we identified substantive gender- and race-based differences in the types and burden of barriers and facilitators to early detection experienced in the path to diagnosis. These differences should be explored further as they may contribute to disparities in the diagnosis and prognosis of colon cancer.

Improving Australian National Bowel Cancer Screening Program outcomes through increased participation and cost-effective investment

BACKGROUND

The Australian National Bowel Cancer Screening Program (NBCSP) provides biennial immunochemical faecal occult blood test (iFOBT) screening for people aged 50-74 years. Previous work has quantified the number of colorectal cancer (CRC) deaths prevented by the NBCSP and has shown that it is cost-effective. With a 40% screening participation rate, the NBCSP is currently underutilised and could be improved by increasing program participation, but the maximum appropriate level of spending on effective interventions to increase adherence has not yet been quantified.

OBJECTIVES

To estimate (i) reductions in CRC cases and deaths for 2020-2040 attributable to, and (ii) the threshold for cost-effective investment (TCEI) in, effective future interventions to improve participation in the NBCSP.

METHODS

A comprehensive microsimulation model, Policy1-Bowel, was used to simulate CRC natural history and screening in Australia, considering currently reported NBCSP adherence rates, i.e. iFOBT participation (∼40%) and diagnostic colonoscopy assessment rates (∼70%). Australian residents aged 40-74 were modelled. We evaluated three scenarios: (1) diagnostic colonoscopy assessment increasing to 90%; (2) iFOBT screening participation increasing to 60% by 2020, 70% by 2030 with diagnostic assessment rates of 90%; and (3) iFOBT screening increasing to 90% by 2020 with diagnostic assessment rates of 90%. In each scenario, we estimated CRC incidence and mortality, colonoscopies, costs, and TCEI given indicative willingness-to-pay thresholds of AUD$10,000-$30,000/LYS.

RESULTS

By 2040, age-standardised CRC incidence and mortality rates could be reduced from 46.2 and 13.5 per 100,000 persons, respectively, if current participation rates continued, to (1) 44.0 and 12.7, (2) 36.8 and 8.8, and (3) 31.9 and 6.5. In Scenario 2, 23,000 lives would be saved from 2020-2040 vs current participation rates. The estimated scenario-specific TCEI (Australian dollars or AUD$/year) to invest in interventions to increase participation, given a conservative willingness-to-pay threshold of AUD$10,000/LYS, was (1) AUD$14.9M, (2) AUD$72.0M, and (3) AUD$76.5M.

CONCLUSION

Significant investment in evidence-based interventions could be used to improve NBCSP adherence and help realise the program's potential. Such interventions might include mass media campaigns to increase program participation, educational or awareness interventions for practitioners, and/or interventions resulting in improvements in referral pathways. Any set of interventions which achieves at least 70% iFOBT screening participation and a 90% diagnostic assessment rate while costing under AUD$72 million annually would be highly cost-effective (<AUD$10,000/LYS) and save 23,000 additional lives from 2020-2040.

Characteristics of Advanced Colorectal Cancer Detected by Fecal Immunochemical Test Screening in Participants with a Negative Result the Previous Year

BACKGROUND

There is sufficient evidence to show the mortality reduction effect of colorectal cancer (CRC) screening programs using the fecal occult blood test (FOBT). However, we see cases that are found to be advanced CRC despite yearly FOBT screening.

METHODS

The aim of this study was to investigate the characteristics of advanced CRC detected by a fecal immunochemical test (FIT) screening program in participants with a negative screening result the previous year, which we call "Negative advanced CRC". A total of 109,639 participants (10.0% required colonoscopy, of whom 76.9% received one) underwent a CRC screening program using a FIT from fiscal 2009 to 2017. Negative advanced CRC was compared with advanced CRC (First advanced CRC) found at the first visit in a person who had not had a FIT screening history for more than 3 years. In addition, we compared the characteristics of Negative advanced CRC with those of interval cancer: cancer cases detected after a negative screening result and before the date of the next recommended screening.

RESULTS

A total of 339 cases of CRC (175 male: 164 female, 173 early stage: 166 advanced stage) were detected in the nine-year CRC screening period. The rate of right-sided CRCs was significantly higher in female (P < 0.01), advanced stage (P < 0.01), negative result previous year (P < 0.01), and symptom-negative (P < 0.01) participants than in each counterpart, respectively. The ratio of female (22/35; 62.9%) patients in Negative advanced CRCs tended to be high compared with that (40/83; 48.2%) in First advanced CRCs (P = 0.145). Overall, 22 (62.9%) of 35 Negative advanced CRCs and 28 (33.7%) of 83 First advanced CRCs were located in the right-sided colon, and the rate was significantly higher in Negative advanced CRCs (P < 0.01). In addition, the frequency of female patients was significantly higher in right-sided Negative advanced CRCs than in right-sided First advanced CRCs (P = 0.03).

CONCLUSION

The characteristics of Negative advanced CRC cases (female and right-sided colon) were similar to those of interval cancer reported so far. In the future, it will be necessary to introduce a screening program that is highly sensitive to right-sided CRC.

Impact of socioeconomic deprivation on short-term outcomes and long-term overall survival after colorectal resection for cancer

PURPOSE

The aim of this study was to assess the effects of socioeconomic deprivation on short-term outcomes and long-term overall survival following major resection of colorectal cancer (CRC) at a tertiary hospital in England.

METHOD

This was an observational cohort study of patients undergoing resection for colorectal cancer from January 2010 to December 2017. Deprivation was classified into quintiles using the English Indices of Multiple Deprivation 2010. Primary outcome was overall complications (Clavien-Dindo grades 1 to 5). Secondary outcomes were the major complications (Clavien-Dindo 3 to 5), length of hospital stay and overall survival. Outcomes were compared between most affluent group and most deprived group. Multivariate regression models were used to establish the relationship taking into account confounding variables.

RESULTS

One thousand eight hundred thirty-five patients were included. Overall and major complication rates were 44.9% and 11.5% respectively in the most affluent, and 54.6% and 15.6% in the most deprived group. Most deprived group was associated with higher overall complications (odds ratio 1.48, 95% CI 1.13-1.95, p = 0.005), higher major complications (odds ratio 1.49, 1.01-2.23, p = 0.048) and longer hospital stay (adjusted ratio 1.15, 1.06-1.25, p < 0.001) when compared with most affluent group. Median follow period was 41 months (interquartile range 20-64.5). Most deprived group had poor overall survival compared with most affluent, but it was not significant at the 5% level (hazard ratio 1.27, 0.99-1.62, p = 0.055).

CONCLUSION

Deprivation was associated with higher postoperative complications and longer hospital stay following major resection for CRC. Its relationship with survival was not statistically significant.

Screen-detected and interval colorectal cancers in England: Associations with lifestyle and other factors in women in a large UK prospective cohort

Faecal occult blood (FOB) - based screening programmes for colorectal cancer detect about half of all cancers. Little is known about individual health behavioural characteristics which may be associated with screen-detected and interval cancers. Electronic linkage between the UK National Health Service Bowel Cancer Screening Programme (BCSP) in England, cancer registration and other national health records, and a large on-going UK cohort, the Million Women Study, provided data on 628,976 women screened using a guaiac-FOB test (gFOBt) between 2006 and 2012. Relative risks (RRs) and 95% confidence intervals (CIs) were estimated by logistic and Cox regression for associations between individual lifestyle factors and risk of colorectal tumours. Among screened women, 766 were diagnosed with screen-detected colorectal cancer registered within 2 years after a positive gFOBt result, and 749 with interval colorectal cancers registered within 2 years after a negative gFOBt result. Current smoking was significantly associated with risk of interval cancer (RR 1.64, 95%CI 1.35-1.99) but not with risk of screen-detected cancer (RR 1.03, 0.84-1.28), and was the only factor of eight examined to show a significant difference in risk between interval and screen-detected cancers (p for difference, 0.003). Compared to screen-detected cancers, interval cancers tended to be sited in the proximal colon or rectum, to be of non-adenocarcinoma morphology, and to be of higher stage.

Biological and prognostic differences between symptomatic colorectal carcinomas and those detected by screening

INTRODUCTION

Few studies have been conducted to establish the relationship between colorectal cancer screening programmes and survival adjusting by stage and, to determine whether there are differences, at a biological level, between the tumours of asymptomatic and symptomatic patients. Accordingly, the aim of this study is to evaluate clinical, biological and survival differences between symptomatic colorectal tumours and those detected by screening.

STUDY METHOD

A prospective cohort study was performed of patients subjected to surgical intervention during the period 2010-2012, at different hospitals in Spain. In every case, clinical, pathological, biological and survival-related variables were obtained.

RESULTS

A total of 2634 patients from the CARESS-CCR cohort were analysed; of these, 220 were diagnosed through screening. The asymptomatic patients were younger, had a higher Body Mass Index (BMI), a lower degree of perineural invasion and a less advanced T stage and nodular stage, and the tumour was frequently located on the right side of the colon. All of these differences were statistically significant. The serum tumour marker carbohydrate antigen 19.9 (CA 19.9) was found more frequently in the symptomatic patients (p < 0.05). However, no significant differences were found regarding the markers of tumour biology: Ki67 (proliferation), CD105 (angiogenesis) and the Terminal deoxynucleotidyl transferase (TdT) dUTP Nick-End Labeling (TUNEL) assay (apoptosis). The patients with asymptomatic tumours had a lower mortality at five years than those diagnosed presenting symptoms.

CONCLUSIONS

The detection method employed influenced the survival of patients with colorectal cancer and there were no significant biological differences between the study groups.

Combinations of single nucleotide polymorphisms identified in genome-wide association studies determine risk for colorectal cancer

Genome-wide association studies (GWASs) have identified single nucleotide polymorphisms (SNPs) associated with colorectal cancer (CRC) risk, but whether these SNPs have additive effects on the risk of CRC remains unclear. We performed a systematic analysis of GWAS-identified SNPs using GWAS datasets from China (2,248 patients and 3,173 controls) and Europe (4,461 patients and 4,140 controls). We analyzed 58 independent variants from DNA samples from Chinese populations and found 19 SNPs that were significantly associated with CRC risk. We identified two genetic risk scores (GRSs) based on 58 and 19 SNPs, which were significantly associated with an increased risk of CRC. A decision curve analysis showed higher predictive power for the 58 SNPs. Using all the 58 SNPs to assess 5-year absolute risk (AR), we found that, at a cutoff of 0.4% (two times the median AR) and 0.6% (three times the median AR), approximately 32.76 and 16.45% of Chinese individuals were grouped as high risk for developing CRC, respectively. Risk stratification analysis further indicated that the population in the top 30% risk group accounted for 46.71% of the CRC cases. In addition, the 58 SNPs could explain approximately 1.13% of the phenotypic variance in Chinese populations. Similar findings were found in European populations. Combinations of SNPs identified in GWASs may therefore be useful for identifying individuals at high risk for CRC.

Impact of a higher fecal immunochemistry test cut-off on pathology detected in subsequent rounds of a colorectal screening program

BACKGROUND AND AIMS

Fecal immunochemical test (FIT)-based colorectal cancer (CRC) screening is superior to the traditional binary fecal occult blood test. Its quantitative nature allows the investigator to choose a positivity threshold to match cost and endoscope capacity. The optimal threshold is still debated. BowelScreen, the Irish national colorectal cancer screening program, has a cut-off of 45 μg Hb/g feces, and in this study we investigated the impact of this threshold on pathology detected in round 2 in individuals who had a negative result for round 1 FIT (FIT¹).

METHODS

All individuals with a negative FIT¹ result who completed a round 2 FIT (FIT²) 2 years later were included. Pathology outcomes for individuals who had positive FIT² results were correlated with FIT¹ levels.

RESULTS

A total of 37,877 individuals had negative FIT¹ results and completed FIT². One thousand two hundred thirty (3.2%) had positive FIT² results (702 men [57%], median age 69, age range 60-70 years). Quantitative analysis showed that at an FIT¹ level <5 μg Hb/g feces, 2.3% had positive FIT² results. At a higher cut-off of 40.1 to 45 μg Hb/g feces, 15.6% of individuals had positive FIT² results. One thousand two (81.5%) underwent colonoscopy, with clinical outcomes in all cases. Three hundred fifty-one (35%) had normal colonoscopy results. The proportion of individuals with normal colonoscopy results decreased as FIT¹ levels rose. Conversely, advanced pathology (CRC + high-risk adenomas) rates rose from 7% to 50% when FIT¹ was <5 compared with 40.1 to 45 μg Hb/g feces, respectively. There were 51 screen-detected cancers in round 2 among individuals with negative FIT¹ results (22 stage I, 12 stage II, 14 stage III, 3 stage IV). All 3 stage IV individuals had FIT¹ results <20 μg Hb/g feces.

CONCLUSIONS

Varying rates of pathology are observed in round 2 of a screening program based on the quantitative level of a negative round 1 FIT result when the positivity threshold is relatively high. A CRC rate of 5.1% within this group appears acceptable. Although patients with incurable cancer were observed, the positivity threshold to capture these cases within round 1 would have been so sensitive that it would create an unsustainable endoscopy referral burden.

Participation in a population-based screening for colorectal cancer using the faecal immunochemical test decreases mortality in 5 years

BACKGROUND

The steady increase in colorectal cancer (CRC) could be reversed through timely secondary prevention (screening) as a main strategy. The aims of this study were to determine the main features of CRC, survival rate and related factors for different types of identified CRCs in a population-based screening programme using the faecal immunochemical test (FIT).

MATERIALS AND METHODS

The CRCs in the susceptible population to be screened between 2009 and 2014 were identified and classified into four groups: (a) nonscreening-detected CRC (diagnosed before first screening invitation and nonparticipants), (b) screening-detected CRC, (c) interval cancer (IC) FIT (diagnosed between screening rounds after a negative FIT) and (d) IC colonoscopy (diagnosed before the colonoscopy surveillance, which is recommended after the screening colonoscopy). Patient demographics and epidemiological characteristics, tumour characteristics and survival were compared between the four groups.

RESULTS

5909 individuals were diagnosed with a CRC. The median follow-up of survival was 4.6 years (range: 0-9 years). The study highlights a significant difference (P<0.0001) in the 5-year survival in the screening-detected CRC group compared with those who had nonscreening-detected CRCs (90.1 vs. 66.7%). Although ICs are not desirable events, the 5-year survival rate is significantly higher with respect to nonparticipants (P<0.0001) (76.3 vs. 60.5%), this being the group with the lowest survival rate.

CONCLUSION

The significantly higher 5-year survival rate of 23.4% of the participants in the screening programme suggests that incidence and mortality rates of CRC will decrease in the near future for participants in screening programmes. A high participation rate is essential to achieve health benefits, irrespective of the type of participation.

The NHS Bowel cancer screening programme achieves the anticipated survival improvement, but participation must be improved

Purpose The NHS Bowel cancer screening programme (NHSBCSP) aims to reduce colorectal cancer (CRC) cumulative mortality by up to 23 per cent; long-term outcomes at national level are not yet known. The purpose of this paper is to examine a local population of CRC patients of screening age for their characteristics and long-term survival in relation to their presentation, including through the NHSBCSP. Design/methodology/approach Retrospective analysis of a prospectively maintained CRC database for the years 2009-2014 in a single district hospital providing bowel cancer screening and tertiary rectal cancer services. Findings Of 528 CRC patients diagnosed in the screening age range, 144(27.3 per cent) presented through NHSBCSP, 308(58.3 per cent) electively with symptoms and 76(14.4 per cent) as emergency. NHSBCSP-diagnosed patients were younger (median 66 vs 68 and 69 years, respectively, p=0.001), had more often left-sided cancers (59(41.0 per cent) vs 82(26.6 per cent) and 24(31.6 per cent), respectively, p=0.001), more UICC-stage I (42(29.2 per cent) vs 49(15.9 per cent) and 2(2.6 per cent)), stage III (59(41.0 per cent) vs 106(34.4 per cent) and 20(26.3 per cent)) and less stage IV disease (8(5.6 per cent) vs 61(19.8 per cent) and 34 (44.7 per cent), respectively, p<0.001). Three-year overall survival was best for NHSBCSP and worst for emergency patients (87.5 per cent vs 69.0 per cent and 35.3 per cent, respectively, LogRank p<0.001). Originality/value Patients diagnosed within the NHSBCSP have improved outcome compared to both symptomatic elective and emergency presentations. A reduction in overall cumulative mortality in order of 25 per cent may well be achieved, but continuing high levels of emergency presentations and undetected right-sided disease emphasise need for further improvement in public participation in the NHSBCSP and research into more sensitive and acceptable alternative screening methods.

Colorectal cancer screening and survival

It is difficult to resist the undeniable allure of screening as a means to diagnose common, potentially serious diseases before their natural history reaches an incurable stage. Colorectal cancer (CRC) is a classical example where the benefits seem to be within reach: we have technologies available that allow its diagnosis before symptoms or signs develop, at a reasonable cost, and using methods acceptable by a significant percentage of the population.

Benefits, Harms, and Cost-Effectiveness of Potential Age Extensions to the National Bowel Cancer Screening Program in Australia

BACKGROUND

The Australian National Bowel Cancer Screening Program (NBCSP) is rolling out 2-yearly immunochemical fecal occult blood test screening in people aged 50 to 74 years. This study aimed to evaluate the benefits, harms, and cost-effectiveness of extending the NBCSP to younger and/or older ages.

METHODS

A comprehensive validated microsimulation model, Policy1-Bowel, was used to simulate the fully rolled-out NBCSP and alternative strategies assuming screening starts at 40 or 45 years and/or ceases at 79 or 84 years given three scenarios: (i) perfect adherence (100%), (ii) high adherence (60%), and (ii) low adherence (40%, as currently achieved).

RESULTS

The current NBCSP will reduce colorectal cancer incidence (mortality) by 23% to 51% (36% to 74%) compared with no screening (range reflects participation); extending screening to younger or older ages would result in additional reductions of 2 to 6 (2 to 9) or 1 to 3 (3 to 7) percentage points, respectively. With an indicative willingness-to-pay threshold of A$50,000/life-year saved (LYS), only screening from 50 to 74 years [incremental cost-effective ratio (ICER): A$2,984-5,981/LYS) or from 45 to 74 years (ICER: A$17,053-29,512/LYS) remained cost-effective in all participation scenarios. The number-needed-to-colonoscope to prevent a death over the lifetime of a cohort in the current NBCSP is 35 to 49. Starting screening at 45 years would increase colonoscopy demand for program-related colonoscopies by 3% to 14% and be associated with 55 to 170 additional colonoscopies per additional death prevented.

CONCLUSIONS

Starting screening at 45 years could be cost-effective, but it would increase colonoscopy demand and would be associated with a less favorable incremental benefits-to-harms trade-off than screening from 50 to 74 years.

IMPACT

The study underpins recently updated Australian colorectal cancer management guidelines that recommend that the NBCSP continues to offer bowel screening from 50 to 74 years.

Screening-detected colorectal cancers show better long-term survival compared with stage-matched symptomatic cancers

PURPOSE

the aim of this study was to compare overall and disease-free survival among patients with colorectal cancer detected via a screening program as compared to those with symptomatic cancer.

MATERIAL AND METHODS

patients diagnosed via colonoscopy (screening group) and those with clinical symptoms (non-screening) were identified from 1995 to 2014. Demographic, clinical, surgical and pathologic variables were recorded. Stage I, II and III cancers were included. Overall and disease-free survival were calculated at five and ten years after tumor resection and survival was calculated by matching both groups for cancers at stage I, II and III.

RESULTS

two hundred and fifty patients were identified as a result of screening procedures and 1,330 patients presented with symptomatic cancers. There were no significant differences in the baseline characteristics between the two groups. Pathologic stage, degree of differentiation, perineural invasion and lymphovascular invasion were lower in the screening group (p < 0.01). Overall and disease-free survival at five and ten years were higher in the screening group (p < 0.01). However, when the subjects were matched for pathologic stage, significant differences were found between the two groups with regard to stage I and III tumors. Disease-free survival in stage III at five years (79.1 vs 61.7%; p < 0.001) and ten years (79.1% vs 58.5%; p < 0.001) were significantly higher in the screening group.

CONCLUSIONS

patients with stage I and III tumors that were diagnosed via a screening program have a higher overall and disease-free survival at five and ten years.

Evaluating the effect of multiple genetic risk score models on colorectal cancer risk prediction

Currently, genetic risk score (GRS) model has been a widely used method to evaluate the genetic effect of cancer risk prediction, but seldom studies investigated their discriminatory power, especially for colorectal cancer (CRC) risk prediction. In this study, we applied both simulation and real data to comprehensively compare the discriminability of different GRS models. The GRS models were fitted by logistic regression with three scenarios, including simple count GRS (SC-GRS), logistic regression weighted GRS (LR-GRS, including DL-GRS and OR-GRS) and explained variance weighted GRS (EV-GRS, including EV_DL-GRS and EV_OR-GRS) models. The model performance was evaluated by receiver operating characteristic (ROC) curves and area under curves (AUC) metric, net reclassification improvement (NRI) and integrated discrimination improvement (IDI). In real data analysis, as DL-GRS and EV_DL-GRS models were carried with serious over-fitting, the other three models were kept for further comparison. Compared to unweighted SC-GRS model, reclassification was significantly decreased in OR-GRS model (NRI = -0.082, IDI = -0.002, P < 0.05), while EV_OR-GRS model showed negative NRI and IDI (NRI = -0.077, IDI = -5.54E-04, P < 0.05) compared to OR-GRS model. Besides, traditional model with smoking status (AUC = 0.523) performed lower discriminability compared to the combined model (AUC = 0.607) including genetic (i.e., SC-GRS) and smoking factors. Similarly, the findings from simulation were all consistent to real data results. It is plausible that SC-GRS model could be optimal for predicting genetic risk of CRC. Moreover, the addition of more significant genetic variants to traditional model could further improve predictive power on CRC risk prediction.

Evaluation of the benefits, harms and cost-effectiveness of potential alternatives to iFOBT testing for colorectal cancer screening in Australia

The Australian National Bowel Cancer Screening Program (NBCSP) will fully roll-out 2-yearly screening using the immunochemical Faecal Occult Blood Testing (iFOBT) in people aged 50 to 74 years by 2020. In this study, we aimed to estimate the comparative health benefits, harms, and cost-effectiveness of screening with iFOBT, versus other potential alternative or adjunctive technologies. A comprehensive validated microsimulation model, Policy1-Bowel, was used to simulate a total of 13 screening approaches involving use of iFOBT, colonoscopy, sigmoidoscopy, computed tomographic colonography (CTC), faecal DNA (fDNA) and plasma DNA (pDNA), in people aged 50 to 74 years. All strategies were evaluated in three scenarios: (i) perfect adherence, (ii) high (but imperfect) adherence, and (iii) low adherence. When assuming perfect adherence, the most effective strategies involved using iFOBT (annually, or biennially with/without adjunct sigmoidoscopy either at 50, or at 54, 64 and 74 years for individuals with negative iFOBT), or colonoscopy (10-yearly, or once-off at 50 years combined with biennial iFOBT). Colorectal cancer incidence (mortality) reductions for these strategies were 51-67(74-80)% in comparison with no screening; 2-yearly iFOBT screening (i.e. the NBCSP) would be associated with reductions of 51(74)%. Only 2-yearly iFOBT screening was found to be cost-effective in all scenarios in context of an indicative willingness-to-pay threshold of A$50,000/life-year saved (LYS); this strategy was associated with an incremental cost-effectiveness ratio of A$2,984/LYS-A$5,981/LYS (depending on adherence). The fully rolled-out NBCSP is highly cost-effective, and is also one of the most effective approaches for bowel cancer screening in Australia.

The contribution of a negative colorectal screening test result to symptom appraisal and help-seeking behaviour among patients subsequently diagnosed with an interval colorectal cancer

Background

Colorectal cancer (CRC) screening programmes using a guaiac faecal occult blood test (gFOBt) reduce CRC mortality. Interval cancers are diagnosed between screening rounds: reassurance from a negative gFOBt has the potential to influence the pathway to diagnosis of an interval colorectal cancer.

Methods

Twenty‐six semi‐structured face‐to‐face interviews were carried out in Scotland and England, with individuals diagnosed with an interval colorectal cancer following a negative gFOBt result.

Results

Participants reported they were reassured by a negative gFOBt, interpreting their result as an “all clear”. Therefore, most did not suspect cancer as a possible cause of symptoms and many did not recall their screening result during symptom appraisal. Among those who did consider cancer, and did think about their screening test result, reassurance from a negative gFOBt led some to “downplay” the seriousness of their symptoms with some interviewees explicitly stating that their negative test result contributed to a delayed decision to seek help.

Conclusion

Screening participants need to be informed of the limitations of screening and the ongoing risk of developing colorectal cancer even when in receipt of a negative result: the importance of minimizing delay in seeking medical advice for colorectal symptoms should be emphasized.

Survival of patients with symptom- and screening-detected colorectal cancer

Background

An increasing proportion of colorectal cancer (CRC) patients are diagnosed by screening rather than symptoms.

Aims

We aimed to assess and compare prognosis of patients with screen-detected CRC and symptom-detected CRC.

Methods

Overall and CRC specific mortality over a median follow-up of 4.8 years was assessed according to mode of diagnosis (symptoms, screening colonoscopy, fecal occult blood test [FOBT], other) in a multi-center cohort of 2,450 CRC patients aged 50-79 years recruited in Germany in 2003-2010.

Results

68%, 11% and 10% were detected by symptoms, screening colonoscopy and FOBT, respectively. The screen-detected cancers had a more favorable stage distribution than the symptom-detected cancers (68% versus 50% in stage I or II). Age- and sex adjusted hazard ratios (HRs) of total mortality with 95% confidence intervals (95% CIs) compared to symptom-detected cancers were 0.35 (0.24-0.50) and 0.36 (0.25-0.53) for screening colonoscopy and FOBT detected CRCs, respectively. HRs were only slightly attenuated and remained highly significant after adjustment for stage and multiple other covariates (0.50 (0.34-0.73) and 0.54 (0.37-0.80), respectively). Even stronger associations were seen for CRC specific mortality. Patients with screen-detected stage III CRC had as good CRC specific survival as patients with symptom-detected stage I or II CRC.

Conclusions

Patients with screen-detected CRC have a very good prognosis far beyond the level explained by their more favorable stage distribution. Mode of detection is an important, easy-to-obtain proxy indicator for favorable diagnosis beyond earlier stage at diagnosis and as such may be useful for risk stratification in treatment decisions.

The NHS Bowel Cancer Screening Program: current perspectives on strategies for improvement

Colorectal cancer (CRC) is the third most common cancer in the UK. The English National Health Service (NHS) Bowel Cancer Screening Program (BCSP) was introduced in 2006 to improve CRC mortality by earlier detection of CRC. It is now offered to patients aged 60-74 years and involves a home-based guaiac fecal occult blood test (gFOBt) biennially, and if positive, patients are offered a colonoscopy. This has been associated with a 15% reduction in mortality. In 2013, an additional arm to BCSP was introduced, Bowelscope. This offers patients aged 55 years a one-off flexible sigmoidoscopy, and if several adenomas are found, the patients are offered a completion colonoscopy. BCSP has been associated with a significant stage shift in CRC diagnosis; however, the uptake of bowel cancer screening remains lower than that for other screening programs. Further work is required to understand the reasons for nonparticipation of patients to ensure optimal uptake. A change of gFOBt kit to the fecal immunochemical tests (FIT) in the English BCSP may further increase patient participation. This, in addition to increased yield of neoplasia and cancers with the FIT kit, is likely to further improve CRC outcomes in the screened population.

Interval Colorectal Cancer Incidence Among Subjects Undergoing Multiple Rounds of Fecal Immunochemical Testing

BACKGROUND & AIMS

Among subjects screened for colorectal cancer (CRC) by the guaiac fecal occult blood test, interval cancers develop in 48% to 55% of the subjects. Data are limited on how many persons screened by fecal immunochemical tests (FIT), over multiple rounds, develop interval cancers. In the Netherlands, a pilot FIT-based biennial CRC screening program was conducted between 2006 and 2014. We collected and analyzed data from the program on CRCs detected during screening (SD-CRC) and CRCs not detected within the screening program (non-SD-CRC; such as FIT interval cancers, colonoscopy interval cancers, and cancer in nonparticipants).

METHODS

Screenees with a negative FIT result received a letter explaining that no blood had been detected in the stool sample and were re-invited, if eligible, for screening biennially. Screenees with a positive FIT result (hemoglobin concentration of 10 μg Hb/g feces) were invited for consultation and scheduled for colonoscopy; results were collected. After the fourth round of FIT screening, the cohort was linked to the Netherlands Cancer Registry, through March 31, 2015; participant characteristics, data on tumor stage, location (at time of resection), and survival status were collected for all identified CRC cases. A reference group comprised all persons with CRC diagnosed in the Netherlands general population during the same period, in the same age range (50-76 years), who had not been offered CRC screening. The median time between invitations (2.37 years) was used as a cutoff to categorize participants within the FIT interval cancer category. We compared participant characteristics, tumor characteristics, and mortality among subjects with SD-CRC and with non-SD-CRC.

RESULTS

A total of 27,304 eligible individuals were invited for FIT screening, of whom 18,716 (69%) participated at least once. Of these, 3005 (16%) had a positive result from the FIT in 1 of the 4 screening rounds. In total, CRC was detected in 261 participants: 116 SD-CRCs and 145 non-SD-CRCs (27 FIT interval cancers, 9 colonoscopy interval cancers, and 109 CRCs in nonparticipants). The FIT interval cancer proportion after 3 completed screening rounds was 23%. Participants with SD-CRC had more early-stage tumors than participants with non-SD-CRCs (P < .001). Of persons with SD-CRC and FIT interval cancers, significantly higher proportions survived (89% and 81%, respectively) compared with persons with colonoscopy interval cancers (44% survival) and nonparticipants with CRC (60% survival) (P < .001).

CONCLUSIONS

In an analysis of data from a pilot FIT-based biennial screening program, we found that among persons screened by FIT, 23% developed FIT interval cancer. FIT therefore detects CRC with 77% sensitivity. The proportion of FIT interval cancers in FIT screening appears to be lower than that with guaiac fecal occult blood testing. Clinical trial registry: yes, www.trialregister.nl, trial number: NTR5385.

Long-term evaluation of benefits, harms, and cost-effectiveness of the National Bowel Cancer Screening Program in Australia: a modelling study

BACKGROUND

No assessment of the National Bowel Screening Program (NBCSP) in Australia, which considers all downstream benefits, costs, and harms, has been done. We aimed to use a comprehensive natural history model and the most recent information about cancer treatment costs to estimate long-term benefits, costs, and harms of the NBCSP (2 yearly immunochemical faecal occult blood testing screening at age 50-74 years) and evaluate the incremental effect of improved screening participation under different scenarios.

METHODS

In this modelling study, a microsimulation model, Policy1-Bowel, which simulates the development of colorectal cancer via both the conventional adenoma-carcinoma and serrated pathways was used to simulate the NBCSP in 2006-40, taking into account the gradual rollout of NBCSP in 2006-20. The base-case scenario assumed 40% screening participation (currently observed behaviour) and two alternative scenarios assuming 50% and 60% participation by 2020 were modelled. Aggregate year-by-year screening, diagnosis, treatment and surveillance-related costs, resource utilisation (number of screening tests and colonoscopies), and health outcomes (incident colorectal cancer cases and colorectal cancer deaths) were estimated, as was the cost-effectiveness of the NBCSP.

FINDINGS

With current levels of participation (40%), the NBCSP is expected to prevent 92 200 cancer cases and 59 000 deaths over the period 2015-40; an additional 24 300 and 37 300 cases and 16 800 and 24 800 deaths would be prevented if participation was increased to 50% and 60%, respectively. In 2020, an estimated 101 000 programme-related colonoscopies will be done, associated with about 270 adverse events; an additional 32 500 and 49 800 colonoscopies and 88 and 134 adverse events would occur if participation was increased to 50% and 60%, respectively. The overall number needed to screen (NNS) is 647-788 per death prevented, with 52-59 colonoscopies per death prevented. The programme is cost-effective due to the cancer treatment costs averted (cost-effectiveness ratio compared with no screening at current participation, AUS$3014 [95% uncertainty interval 1807-5583] per life-year saved) in the cost-effectiveness analysis. In the budget impact analysis, reduced annual expenditure on colorectal cancer control is expected by 2030, with expenditure reduced by a cumulative AUS$1·7 billion, AUS$2·0 billion, and AUS$2·1 billion (2015 prices) between 2030 and 2040, at participation rates of 40%, 50%, and 60%, respectively.

INTERPRETATION

The NBCSP has potential to save 83 800 lives over the period 2015-40 if coverage rates can be increased to 60%. By contrast, the associated harms, although an important consideration, are at a smaller magnitude at the population level. The programme is highly cost-effective and within a decade of full roll-out, there will be reduced annual health systems expenditure on colorectal cancer control due to the impact of screening.

FUNDING

Australia Postgraduate Award PhD Scholarship, Translational Cancer Research Network Top-up scholarship (supported by Cancer Institute NSW) and Cancer Council NSW.

Faecal occult blood testing screening for colorectal cancer and 'missed' interval cancers: are we ignoring the elephant in the room? Results of a multicentre study

AIM

Biennial faecal occult blood testing (FOBT) is used to screen for colorectal cancer throughout the UK. Interval cancers are tumours that develop in patients between screening rounds who have had a negative FOBT. Through a multicentre study, we compared the demographics of patients with interval cancers, FOBT screen detected cancers and cancers that developed in patients who chose not to participate in the screening programme.

METHOD

Five hundred and sixteen colorectal cancers were detected in the screening age group (60-74 years) population in three UK National Health Service hospitals over 2 years. One hundred and twenty seven (25%) were interval cancers, 161 (31%) were screen detected and 228 (44%) were cancers that developed in patients who had declined FOBT. The interval cancer group had a higher incidence of right-sided cancers (38% vs 29% and 24%), a higher proportion of high tumour stages (Dukes C and D) (70% vs 53% and 33%) and a shorter time from diagnosis to death (10 months vs 13 months and 24 months) compared to patients who had declined the FOBT and the FOBT screen detected cancers. Of all the patients studied, those with right-sided interval cancers had the worst outcome.

CONCLUSION

A quarter of the colorectal cancers diagnosed in our study were interval cancers. Patients with right-sided interval cancers had the highest proportion of Dukes C and D tumours coupled with the shortest survival time after diagnosis compared with the other groups.

Colorectal and interval cancers of the Colorectal Cancer Screening Program in the Basque Country (Spain)

AIM

To assess proportions, related conditions and survival of interval cancer (IC).

METHODS

The programme has a linkage with different clinical databases and cancer registers to allow suitable evaluation. This evaluation involves the detection of ICs after a negative faecal inmunochemical test (FIT), interval cancer FIT (IC-FIT) prior to a subsequent invitation, and the detection of ICs after a positive FIT and confirmatory diagnosis without colorectal cancer (CRC) detected and before the following recommended colonoscopy, IC-colonoscopy. We conducted a retrospective observational study analyzing from January 2009 to December 2015 1193602 invited people onto the Programme (participation rate of 68.6%).

RESULTS

Two thousand five hundred and eighteen cancers were diagnosed through the programme, 18 cases of IC-colonoscopy were found before the recommended follow-up (43542 colonoscopies performed) and 186 IC-FIT were identified before the following invitation of the 769200 negative FITs. There was no statistically significant relation between the predictor variables of ICs with sex, age and deprivation index, but there was relation between location and stage. Additionally, it was observed that there was less risk when the location was distal rather than proximal (OR = 0.28, 95%CI: 0.20-0.40, P < 0.0001), with no statistical significance when the location was in the rectum as opposed to proximal. When comparing the screen-detected cancers (SCs) with ICs, significant differences in survival were found (P < 0.001); being the 5-years survival for SCs 91.6% and IC-FIT 77.8%.

CONCLUSION

These findings in a Population Based CRC Screening Programme indicate the need of population-based studies that continue analyzing related factors to improve their detection and reducing harm.

Appearances of screen-detected versus symptomatic colorectal cancers at CT colonography

OBJECTIVES

The aim of this study was to compare the morphology, radiological stage, conspicuity, and computer-assisted detection (CAD) characteristics of colorectal cancers (CRC) detected by computed tomographic colonography (CTC) in screening and symptomatic populations.

METHODS

Two radiologists independently analyzed CTC images from 133 patients diagnosed with CRC in (a) two randomized trials of symptomatic patients (35 patients with 36 tumours) and (b) a screening program using fecal occult blood testing (FOBt; 98 patients with 100 tumours), measuring tumour length, volume, morphology, radiological stage, and subjective conspicuity. A commercial CAD package was applied to both datasets. We compared CTC characteristics between screening and symptomatic populations with multivariable regression.

RESULTS

Screen-detected CRC were significantly smaller (mean 3.0 vs 4.3 cm, p < 0.001), of lower volume (median 9.1 vs 23.2 cm3, p < 0.001) and more frequently polypoid (34/100, 34 % vs. 5/36, 13.9 %, p = 0.02) than symptomatic CRC. They were of earlier stage than symptomatic tumours (OR = 0.17, 95 %CI 0.07-0.41, p < 0.001), and were judged as significantly less conspicuous (mean conspicuity 54.1/100 vs. 72.8/100, p < 0.001). CAD detection was significantly lower for screen-detected (77.4 %; 95 %CI 67.9-84.7 %) than symptomatic CRC (96.9 %; 95 %CI 83.8-99.4 %, p = 0.02).

CONCLUSIONS

Screen-detected CRC are significantly smaller, more frequently polypoid, subjectively less conspicuous, and less likely to be identified by CAD than those in symptomatic patients.

KEY POINTS

• Screen-detected colorectal cancers (CRC) are significantly smaller than symptomatic CRC. • Screening cases are significantly less conspicuous to radiologists than symptomatic tumours. • Screen-detected CRC have different morphology compared to symptomatic tumours (more polypoid, fewer annular). • A commercial computer-aided detection (CAD) system was significantly less likely to note screen-detected CRC.

Assessments and skills improvement for endoscopists

Different countries employ a range of assessment methods to monitor trainees from novice to independent practice. The optimal method to monitor and assess individuals' training in endoscopy has not been formally determined. The UK has developed a competency based assessment training and certification (credentialing) programme. The tools developed to provide endoscopy work based assessments (DOPS) have been validated and are used for trainees and independent endoscopists, providing formative feedback for targeted training. Summative assessments are used for trainee certification and independent colonoscopists wishing to provide part of the National Bowel Cancer Screening Programme. The UK was able to develop both clinical standards and an endoscopy training and certification process applied to all individuals and monitored by a single professional body. The supporting IT system enabled a structured and robust quality assurance process to be applied to all individuals and endoscopy units. Assessment of practising endoscopists relies on the development and measurement of surrogate measures, which represent key performance indicators for those individuals. These surrogates for performance are still evolving although they are now well established for colonoscopy practice. Monitoring of independent practice is dependent on clinical audit of these key performance indicators. Feedback of data to individuals helps benchmarking and identification of those with sub-optimal performance. Independent endoscopists now recognize the benefit of on-going training to help both skills development and to address sub-optimal performance. This chapter describes how the UK developed a web-based integrated training and certification system.

Are there biological differences between screen-detected and interval colorectal cancers in the English Bowel Cancer Screening Programme?

Background:

We measured biomarkers of tumour growth and vascularity in interval and screen-detected colorectal cancers (CRCs) in the English Bowel Cancer Screening Programme in order to determine whether rapid tumour growth might contribute to interval CRC (a CRC diagnosed between a negative guaiac stool test and the next scheduled screening episode).

Methods:

Formalin-fixed, paraffin-embedded sections from 71 CRCs (screen-detected 43, interval 28) underwent immunohistochemistry for CD31 and Ki-67, in order to measure the microvessel density (MVD) and proliferation index (PI), respectively, as well as microsatellite instability (MSI) testing.

Results:

Interval CRCs were larger (P=0.02) and were more likely to exhibit venous invasion (P=0.005) than screen-detected tumours. There was no significant difference in MVD or PI between interval and screen-detected CRCs. More interval CRCs displayed MSI-high (14%) compared with screen-detected tumours (5%). A significantly (P=0.005) higher proportion (51%) of screen-detected CRC resection specimens contained at least one polyp compared with interval CRC (18%) resections.

Conclusions:

We found no evidence of biological differences between interval and screen-detected CRCs, consistent with the low sensitivity of guaiac stool testing as the main driver of interval CRC. The contribution of synchronous adenomas to occult blood loss for screening requires further investigation.

Interval Colorectal Cancers following Guaiac Fecal Occult Blood Testing in the Ontario ColonCancerCheck Program

Background. This work examines the occurrence of interval colorectal cancers (CRCs) in the Ontario ColonCancerCheck (CCC) program. We define interval CRC as CRC diagnosed within 2 years following normal guaiac fecal occult blood testing (gFOBT). Methods. Persons aged 50-74 who completed a baseline CCC gFOBT kit in 2008 and 2009, without a prior history of CRC, or recent colonoscopy, flexible sigmoidoscopy, or gFOBT, were identified. Rates of CRC following positive and normal results at baseline and subsequent gFOBT screens were computed and overall survival was compared between those following positive and normal results. Results. Interval CRC was diagnosed within 24 months following the baseline screen among 0.16% of normals and following the subsequent screen among 0.18% of normals. Interval cancers comprised 38.70% of CRC following the baseline screen and 50.86% following the subsequent screen. Adjusting for age and sex, the hazard ratio (HR) for death following interval cancer compared to CRC following positive result was 1.65 (1.32, 2.05) following the first screen and 1.71 (1.00, 2.91) following the second screen. Conclusion. Interval CRCs following gFOBT screening comprise a significant proportion of CRC diagnosed within 2 years after gFOBT testing and are associated with a higher risk of death.

CD90(+) stromal cells are the major source of IL-6, which supports cancer stem-like cells and inflammation in colorectal cancer

IL-6 is a pleiotropic cytokine increased in CRC and known to directly promote tumor growth. Colonic myofibroblasts/fibroblasts (CMFs or stromal cells) are CD90(+) innate immune cells representing up to 30% of normal colonic mucosal lamina propria cells. They are expanded in CRC tumor stroma, where they also known as a cancer associated fibroblasts (CAFs). Cells of mesenchymal origin, such as normal myofibroblasts/fibroblasts, are known to secrete IL-6; however, their contribution to the increase in IL-6 in CRC and to tumor-promoting inflammation is not well defined. Using in situ, ex vivo and coculture analyses we have demonstrated that the number of IL-6 producing CMFs is increased in CRC (C-CMFs) and they represent the major source of IL-6 in T2-T3 CRC tumors. Activity/expression of stem cell markers-aldehyde dehydrogenase and LGR5- was significantly up-regulated in colon cancer cells (SW480, Caco-2 or HT29) cultured in the presence of conditioned medium from tumor isolated C-CMFs in an IL-6 dependent manner. C-CMF and its derived condition medium, but not normal CMF isolated from syngeneic normal colons, induced differentiation of tumor promoting inflammatory T helper 17 cells (Th17) cell responses in an IL-6 dependent manner. Our study suggests that CD90(+) fibroblasts/myofibroblasts may be the major source of IL-6 in T2-T3 CRC tumors, which supports the stemness of tumor cells and induces an immune adaptive inflammatory response (a.k.a. Th17) favoring tumor growth. Taken together our data supports the notion that IL-6 producing CAFs (a.k.a. C-CMFs) may provide a useful target for treating or preventing CRCs.

Interval colorectal carcinoma: An unsolved debate

Colorectal carcinoma (CRC), as the third most common new cancer diagnosis, poses a significant health risk to the population. Interval CRCs are those that appear after a negative screening test or examination. The development of interval CRCs has been shown to be multifactorial: location of exam-academic institution versus community hospital, experience of the endoscopist, quality of the procedure, age of the patient, flat versus polypoid neoplasia, genetics, hereditary gastrointestinal neoplasia, and most significantly missed or incompletely excised lesions. The rate of interval CRCs has decreased in the last decade, which has been ascribed to an increased understanding of interval disease and technological advances in the screening of high risk individuals. In this article, we aim to review the literature with regard to the multifactorial nature of interval CRCs and provide the most recent developments regarding this important gastrointestinal entity.