Adherence to follow-up and resource use after abnormal FIT-screening: Evaluation of the Danish colorectal cancer screening program.

Background and study aims The effectiveness of colorectal cancer screening programs depends on adherence to surveillance protocols for screening-positive individuals. We evaluated adherence in the Danish population-based screening program and estimated the volume of diagnostic resources required to achieve this adherence. Patients and methods In this register- and population-based study, we included individuals with a positive fecal immunochemical test (FIT) screening from 2014 to 2017 and followed them until mid-2022. All endoscopic, imaging, and surgical procedures performed at public and private hospitals were identified. Adherence to national protocols was reported in terms of proportions and timeliness. Use of diagnostic and surveillance procedures was estimated during a 4-year post-screening period. Results Among 82,221 individuals with a positive FIT test, 84% had a baseline colonoscopy within 1 month. After removal of intermediate or high-risk adenomas, 12% and 6%, respectively, did not have any follow-up. Only ~50% had timely surveillance. Approximately 10% to 20%, depending on their referral diagnosis, did not have a second surveillance colonoscopy. In addition, 12% with a negative colonoscopy had a second colonoscopy within 4 years. Conclusions High adherence to baseline colonoscopy after positive FIT-screening is followed by lower adherence throughout the adenoma surveillance program. Better adherence to the guidelines could potentially improve the effectiveness and efficiency of the screening program.

Effect of colorectal cancer screening on colorectal cancer surgery outcomes: nationwide cohort study.

BACKGROUND: National colorectal cancer screening commenced in Denmark in 2014. Little is known about the effects of organized colorectal cancer screening on intraoperative and postoperative events. The aim of this nationwide cohort study was to evaluate the difference in intraoperative and postoperative outcomes between patients with screen-detected colorectal cancer and non-screen-detected colorectal cancer within the first 90 days after surgery. METHODS: National register data were collected for Danish residents diagnosed with colorectal cancer between January 2014 and March 2018. Outcomes for the two cohorts were reported as relative risk or weighted mean difference. Intraoperative outcomes were blood loss, blood transfusion, tumour perforation, and organ lesion. Postoperative outcomes were complications (surgical and non-surgical) and 90-day mortality. Discrete data estimates were calculated from a general linear model. Analyses were adjusted for potential healthy user bias with respect to sex, age, location of the cancer (colon/rectum), and Charlson co-morbidity index. RESULTS: In total, 10 606 patients were included. Compared with patients in the non-screen-detected colorectal cancer group (4497 patients), patients in the screen-detected colorectal cancer group (6109 patients) had reduced intraoperative blood loss (-52 mL, 95% c.i. -67 to -37, P < 0.001), a shorter duration of hospitalization (-2.3 days, 95% c.i. -2.8 to -1.8, P < 0.001), and reduced rates of intraoperative organ lesion (0.76, 95% c.i. 0.59 to 0.99, P = 0.042), surgical complications (0.79, 95% c.i. 0.73 to 0.87, P < 0.001), non-surgical complications (0.68, 95% c.i. 0.60 to 0.78, P < 0.001), and 90-day mortality (0.29, 95% c.i. 0.21 to 0.39, P < 0.001). CONCLUSION: In comparison with non-screen-detected colorectal cancer, surgery for screen-detected colorectal cancer remains associated with improvement in several intraoperative and early postoperative outcomes after considering healthy user bias.

How follow-up rates in cervical cancer screening depend on organizational factors: A comparison of two population-based organized screening programmes.

OBJECTIVES: This study compares the follow-up rates of non-normal cervical screening samples between Denmark and Flanders (Belgium) to illuminate whether organizational differences between the health systems might affect the follow-up rates, e.g. sending of reminders in Denmark since 2012 compared to Flanders with no such system in place. METHODS: The study population included 48,082 Danish women and 22,271 Flemish women who received abnormal or inadequate primary screening results from 2014 to 2016. The participants were followed for 24 months, and the timeliness and appropriateness of the recommended follow-up, according to national guidelines, were evaluated. RESULTS: After 18 months over 90% of the Danish women had received some form of follow-up, while in Flanders, this level is achieved only for those who test positive for human papillomavirus. The analysis also revealed that 10-28% of follow-ups were performed too early, with Danish women showing the highest proportions. In both regions, general practitioners (GPs) exhibited better follow-up rates compared to gynaecologists, with gynaecologists displaying a tendency towards earlier re-testing than recommended. CONCLUSIONS: An important factor influencing the follow-up rate may be the sending of reminders in Denmark since 2012, as the follow-up rates in general were higher in this period. It is noteworthy that a reminder system is currently being implemented in Flanders and further studies on the potential effects should be studied. Additionally, the organization of the health system might influence the follow-up rate, as engaging the GP for screening in Denmark may have had a positive effect.

Comparisons of assessment pathways after abnormal mammography screening in Denmark, Norway, and Spain.

PURPOSE: To ensure high-quality screening programmes and effective utilization of resources, it is important to monitor how cancer detection is affected by different strategies performed at recall assessment. This study aimed to describe procedures performed at recall assessment and compare and evaluate the performance of the assessment in Denmark, Norway, and Spain in terms of screen-detected cancer (SDC) and interval cancer (IC) rates. METHODS: We included women aged 50-69 years from Denmark, Norway, and Spain, who were recalled for assessment after screening mammography, and recorded all procedures performed during six months after diagnosis, and the timing of the procedures. Women were followed for two years and screen-detected and interval cancer, and sensitivity of recall was calculated and compared. RESULTS: In total, data from 24,645 Danish, 30,050 Norwegian, and 41,809 Spanish women were included in the study. Most of the women had some assessment within 2 months in all three countries. SDC rates were higher in Denmark (0.57) and Norway (0.60) compared to Spain (0.38), as were the IC rates, i.e. 0.25 and 0.18 vs. 0.12, respectively. The sensitivity of the diagnostic follow-up was somewhat higher in Denmark (98.3%) and Norway (98.2%), compared to Spain (95.4%), but when excluding non-invasive assessment pathways, the sensitivities were comparable. CONCLUSION: This comparison study showed variation in the assessment procedures used in the three countries as well as the SDC and IC rates and the sensitivity of recall.

Differences in mammography screening attendance among non-Western immigrants in Denmark, Finland, Iceland and Norway.

Several studies have shown that attendance rates are lower among non-Western immigrants than among natives. As the Nordic countries have quite similar health systems and populations but also differences in the organisation of their organised mammography screening programmes, differences in attendance rates could highlight organisational factors that might increase the attendance rates. Mammography screening is offered free of charge in Denmark and Finland, but not in Iceland and Norway. Contrarily to the other countries, Iceland do not send out pre-booked appointment. The study population included natives and non-Western immigrants aged 50-69 years, who had at least one invitation to the national mammography screening programmes in Denmark (2008-2017), Finland (2001-2017), Iceland (2001-2020) or Norway (2001-2015). Relative risks (RRs) of attendance were estimated and adjusted for age group and calendar period. The study population included 116.033 non-Western immigrants and more than 2 million natives. The attendance rates were significantly lower among non-Western immigrants than among natives, with an adjusted relative risk of 0.81/0.80 in Denmark and Finland, 0.62 in Norway, and 0.40 in Iceland. The lower attendance rates among immigrants in Norway and Iceland did not seem to be due to differences in birth country, immigration age, or educational level, but might be explained by organisational factors. Offering free-of-charge mammography screening in Norway and Iceland and/or including a pre-booked appointment in the invitation letters in Iceland might increase the attendance rate among non-Western immigrants.

Nationwide mammography screening participation in Denmark during the COVID-19 pandemic: An observational study.

Background: In most of the world, the mammography screening programmes were paused at the start of the pandemic, whilst mammography screening continued in Denmark. We examined the mammography screening participation during the COVID-19 pandemic in Denmark. Methods: The study population comprised all women aged 50-69 years old invited to participate in mammography screening from 2016 to 2021 in Denmark based on data from the Danish Quality Database for Mammography Screening in combination with population-based registries. Using a generalised linear model, we estimated prevalence ratios (PRs) and 95% confidence intervals (CIs) of mammography screening participation within 90, 180, and 365 d since invitation during the pandemic in comparison with the previous years adjusting for age, year and month of invitation. Results: The study comprised 1,828,791 invitations among 847,766 women. Before the pandemic, 80.2% of invitations resulted in participation in mammography screening within 90 d, 82.7% within 180 d, and 83.1% within 365 d. At the start of the pandemic, the participation in screening within 90 d was reduced to 69.9% for those invited in pre-lockdown and to 76.5% for those invited in first lockdown. Extending the length of follow-up time to 365 d only a minor overall reduction was observed (PR = 0.94; 95% CI: 0.93-0.95 in pre-lockdown and PR = 0.97; 95% CI: 0.96-0.97 in first lockdown). A lower participation was, however, seen among immigrants and among women with a low income. Conclusions: The short-term participation in mammography screening was reduced at the start of the pandemic, whilst only a minor reduction in the overall participation was observed with longer follow-up time, indicating that women postponed screening. Some groups of women, nonetheless, had a lower participation, indicating that the social inequity in screening participation was exacerbated during the pandemic. Funding: The study was funded by the Danish Cancer Society Scientific Committee (grant number R321-A17417) and the Danish regions.

Less Invasive Primary Treatment for Colorectal Cancer After Implementation of National Screening: A Nationwide Cohort Study.

BACKGROUND: The effect of organized colorectal cancer (CRC) screening on type of primary treatment remains sparsely investigated. This study evaluated the difference in primary treatment strategy between patients diagnosed with screen-detected (SD-CRC) and non-screen-detected colorectal cancer (NSD-CRC) in a national CRC screening program. METHODS: This was a retrospective national register-based cohort study. Data on patients aged between 50 and 75 years and diagnosed with SD-CRC or NSD-CRC were retrieved from the national colorectal cancer screening database and the Danish Colorectal Cancer Group database. Outcomes related to surgical invasiveness were compared between the two cohorts. Differences were expressed as relative risks using log-binomial generalized linear regression models. UICC stage IV specific outcomes were analyzed using the same method. All analyses were adjusted for sex, age, type of cancer (colonic/rectal), and Charlson comorbidity index. RESULTS: The study included 4707 patients with SD-CRC and 7328 with NSD-CRC. Therapeutic flexible endoscopy (SD-CRC: n = 636 vs. NSD-CRC: n = 334, RR: 2.50, P < 0.001), (robotic-assisted) laparoscopic resection ((n = 616 vs. n = 773, RR: 1.27, P < 0.001), n = 2759 vs. n = 3471, RR: 1.11, P < 0.001), and radical resection (n = 3890 vs. n = 4834, RR: 1.02, P = 0.002) were significantly more frequent in the SD-CRC group. The rates of emergency priority (n = 32 vs. n = 562, RR: 0.09, P < 0.001), open surgery (n = 391 vs. n = 1410, RR: 0.53, P < 0.001), supplementary organ resection (n = 259 vs. n = 860, RR: 0.56, P < 0.001), and stoma formation (n = 526 vs. n = 1040, RR: 0.89, P = 0.007) were significantly lower in the SD-CRC group. The rate of patients undergoing surgery with UICC stage IV disease was significantly higher in the SD-CRC group (SD-CRC: n = 262, NSD-CRC: n = 994, RR: 1.43, P < 0.001). CONCLUSION: SD-CRC remained associated with less invasive primary surgical treatment following adjustment for potential healthy user bias. UICC stage IV disease may be less advanced in patients with SD-CRC.

Cervical, liver and stomach cancer incidence and mortality in non-Western immigrant women: a retrospective cohort study from four Nordic countries.

BACKGROUND: Cervical, liver and stomach cancers are the most common infection-associated malignancies and the leading cause of morbidity in non-Western regions. We compared the incidence and mortality of these cancers between non-Western immigrant and non-immigrant Nordic female populations. We also analysed the effect of age at immigration, duration of residence and education on cancer burden. MATERIAL AND METHODS: Study population consisted of women residents in Denmark, Finland, Iceland and Norway in 1973-2020. Non-Western women contributed 3.1% of the total 260 million person-years at risk. All women were followed from their 20th birthday, or from the date of immigration if after, until the date of their first primary cancer diagnosis, death, emigration, or the end of the country-specific study period. All data were adjusted for 10-year age groups and calendar periods, and immigrant data was further broken down by region of birth, age at immigration and education level. Country-specific estimates were produced by multivariable Poisson regression and pooled in Finland with a random effects model. RESULTS: Altogether, there were 60 982 cases of cervical, liver and stomach cancer in the study population, causing 36 582 deaths. The immigrant women had significantly higher liver (rate ratio [RR] 1.78, 95% confidence interval (CI) 1.03-3.06) and stomach cancer incidence (RR 1.68, CI 1.29-2.18), and stomach cancer mortality (RR 1.49, CI 1.17-1.92) than non-immigrant women. In the immigrant population, high education was related to lower incidence and mortality of studied cancers. The rate ratio of cervical cancer decreased with duration of residence and increased with rising age at immigration. CONCLUSION: Due to the increased incidence and mortality of infection-related cancers and changes in cancer patterns by age at immigration and duration of residence, attention should be paid to targeted health care services for immigrants. Special efforts should be given to women who have spent their youth in high-risk areas.

A population-based cohort study on changes in breast, lung and colorectal cancer incidence and mortality among non-Western immigrant women.

BACKGROUND: Cancer risk varies geographically, and migrants are influenced by different risk factors before, during and after migration. Increased migration from non-Western countries to the Nordic countries calls for a better understanding of the migrants' cancer risk and the change in risk patterns over time. The aim of this study was to compare the incidence and mortality of breast, colorectal and lung cancer between non-Western immigrant and the native female population in Denmark, Finland, Iceland, and Norway. MATERIAL AND METHODS: Data from national registries were processed and pre-analysed in each country. Multivariate Poisson regression models were used to model the relative differences in incidence and mortality as rate ratios (RR). The country-specific estimates and summary statistics were pooled together using a random effects model. RESULTS: Non-Western immigrant women had significantly lower breast (RR 0.71, 0.65-0.78), colorectal (RR 0.72, 0.57-0.92) and lung (RR 0.55, 0.42-0.72) cancer incidence rates than native women, and the risk of these cancers among immigrant women increased with duration of residence. Differences were parallel in breast, colorectal and lung cancer mortality (RR 0.64, 0.55-0.74; RR 0.66, 0.48-0.92; RR 0.51, 0.34-0.79). Among immigrant women, higher education increased the risk for breast cancer and decreased it for lung cancer. CONCLUSION: The results significantly complement and add to the previous findings of cancer burden and cancer burden transition among migrants and provide evidence of a prolonged cancer risk advantage among non-Western immigrant women. However, the findings show an increasing risk of lifestyle-related cancers with increasing duration of residence in the host country. Further studies are needed to discover underlying reasons for this phenomenon.

Choice of Assessment and Subsequent Risk of Breast Cancer among Women with False-Positive Mammography Screening.

Women with false-positive mammography screening results have a two- to four-fold higher risk of breast cancer. This study aimed to investigate if the subsequent risk of breast cancer after a false-positive mammography screening is associated with the received diagnostic assessment. The study population consisted of women who underwent false-positive mammography screening from January 2010 to June 2019. They were categorised into seven groups depending on the elements in the assessment (standard care: additional mammography, ultrasound, and if they had a relevant biopsy). Risks of interval cancer, next-round screen-detected cancer, and long-term breast cancer for non-standard care assessments were compared to standard care assessments using Binomial and Cox regression models. We included 44,279 women with a false-positive result. Invasive assessments that lacked an ultrasound or additional mammography were not more associated with an increased risk of subsequent cancers compared to that of 'all three elements'. The few assessments that included 'only ultrasound' or 'only mammography' resulted in higher relative risks of next-round screen-detected cancer of 1.52 (95% CI: 0.93-2.47) and 1.67 (95% CI: 0.54-5.16), respectively, compared to that of standard care. The increased subsequent risk of breast cancer among women with a previous false-positive result was not found to be correlated with the choice of elements in the assessment process.

Subsequent participation in organized FIT based screening following screen-derived colonoscopy - A Danish nationwide cohort study.

Introduction: In the Danish National Colorectal Cancer (CRC) screening program, participants with screen-detected low-risk adenomas are invited to a new faecal immunochemical test (FIT) screening after two years. However, participation rate in next FIT screening is unknown. We aimed to investigate this subsequent participation rate within the Danish CRC screening program. Methods: This nationwide register-based study included participants aged 50-72 years registered with FIT screening in the Danish CRC screening program between January 1, 2016, and June 30, 2017. Participants were included if their index FIT was negative or if it was positive and the subsequent colonoscopy detected low-risk adenomas. Invitees were categorized as subsequent participants if they returned a FIT within 135 days following the invitation to screening. We estimated the relative risk for participation depending on screening outcome, age, and sex. Result: 415,107 with a negative result and 5,550 with low-risk adenomas were included. 86.0% (85.9;86.1) of the invitees with a negative result participated in the subsequent screening, while 71.8% (70.6;73.0) of the invitees with low-risk adenomas participated subsequently. The risk of participation in the subsequent screening was significantly lower among all age groups of men and women with low-risk adenomas compared to similar groups with negative results. Conclusion: Invitees with low-risk adenomas detected at their initial colonoscopy are less likely to participate in the subsequent screening than invitees with negative results. This association was found in all age groups and for both sexes. Further studies are necessary to assess whether non-attendance is more pronounced in specific subgroups.

Does full HPV genotyping perform similarly well in clinician-collected cervical samples and self-collected vaginal samples when using the CLART HPV4S assay?

BACKGROUND: Studies comparing self-collected vaginal samples with clinician-collected cervical samples with respect to high-risk human papillomavirus (HPV) detection and genotype agreement based on clinically validated full HPV genotype assays (e.g. the CLART HPV4S) are limited. This study compared the two types of samples using the CLART assay with respect to HPV detection and genotype agreement in a referral population. METHODS: A total of 212 women aged 30-59 years and diagnosed with atypical squamous cells of undetermined significance (ASC-US) within the Danish cervical cancer screening programme had a cervical sample taken at their general practitioner. Afterwards, the women took a vaginal sample with the Evalyn Brush device at home. The paired samples were HPV-tested with the full genotyping CLART HPV4S assay. Histological results, i.e. cervical intraepithelial neoplasia of grade 2 or worse (CIN2+) were available for 14 women with HPV-positive clinician-collected samples. RESULTS: The study found the same HPV prevalence in self-collected vaginal samples compared to clinician-collected cervical samples (19.3%, 95% CI 14.3-25.3% vs 18.4%, 95% CI 13.4-24.3%). The CLART HPV4S assay detected approximately the same number of CIN2+ cases in the self-collected vaginal samples compared to the clinician-collected cervical samples (13 vs 11 cases). Exactly the same genotypes were detected in 75% (21/28) of the HPV-positive paired samples, while at least one identical genotype was found in the remaining 25% (7/28) of the paired samples. CONCLUSIONS: The CLART HPV4S assay performed similarly well in self-collected vaginal samples as in clinician-collected cervical samples with respect to both HPV detection and genotype agreement when using the Evalyn Brush and the CLART HPV4S assay in a referral population. Although further evaluation is needed, the findings suggest that full HPV genotyping based on the CLART assay can be useful when establishing HPV genotype-specific referral strategies for women tested HPV-positive by self-sampling.

Concurrent participation in breast, cervical, and colorectal cancer screening programmes in Denmark: A nationwide registry-based study.

Women in Denmark are invited to breast, cervical, and colorectal cancer screening in their fifties and sixties. We determined the patterns of concurrent participation in the three programmes. Participation in organised cancer screening was determined using the highly complete Danish population and health care registers for all women aged 53-65 years on 31 March 2018 who continuously resided in Denmark since 1 April 2012. Data were linked using unique personal identification numbers. We studied overall and cancer-specific proportions of women undergoing screening for all three, two, one, and none of the cancers. Among all 468,507 women, 406,306 (87%) participated in breast, 345,768 (74%) in cervical, and 316,496 (68%) in colorectal cancer screening. Despite high participation, only 255,698 (55%) women were screened for all three cancers, while 123,469 (26%) were screened for two, 54,538 (12%) for one, and 34,802 (7%) were not screened for any cancer. Cancer-specific patterns were highly heterogeneous across the population but changed little after accounting for women's medical history. A significant proportion of women who are screened for a specific cancer remain unscreened for other cancers. The consistency of these data at the international level requires a reconsideration of invitational practices for organised screening.

Widening the offer of human papillomavirus self-sampling to all women eligible for cervical screening: Make haste slowly.

Self-collection of samples for human papillomavirus (HPV) testing has the potential to increase the uptake of cervical screening among underscreened women and will likely form a crucial part of the WHO's strategy to eliminate cervical cancer by 2030. In high-income countries with long-standing, organised cervical screening programmes, self-collection is increasingly becoming available as a routine offer for women regardless of their screening histories, including under- and well-screened women. For these contexts, a validated microsimulation model determined that adding self-collection to clinician collection is likely to be cost-effective on the condition that it meets specific thresholds relating to (1) uptake and (2) sensitivity for the detection of high-grade cervical intraepithelial neoplasia (CIN2+). We used these thresholds to review the 'early-adopter' programme-level evidence with a mind to determine how well and how consistently they were being met. The available evidence suggested some risk to overall programme performance in the situation where low uptake among underscreened women was accompanied by a high rate of substituting clinician sampling with self-collection among well-screened women. Risk was further compounded in a situation where the slightly reduced sensitivity of self-sampling vs clinician sampling for the detection of CIN2+ was accompanied with lack of adherence to a follow-up triage test that required a clinician sample. To support real-world programmes on their pathways toward implementation and to avoid HPV self-collection being introduced as a screening measure in good faith but with counterproductive consequences, we conclude by identifying a range of mitigations and areas worthy of research prioritisation.

Three birds with one stone: a protocol for a randomised intervention study to increase participation in cervical and colorectal cancer screening among women attending breast cancer screening.

INTRODUCTION: The participation rate is higher in breast cancer screening than in cervical cancer (CCU) and colorectal cancer (CRC) screening. In this cluster-randomised study, we aim to evaluate an intervention offering home-based CCU and CRC screening to women when attending breast cancer screening if they are overdue for CCU and/or CRC screening. METHODS AND ANALYSIS: On intervention days, one of the five breast cancer screening units in the Central Denmark Region will be randomly allocated to intervention, whereas the remaining units will serve as control. Women attending breast cancer screening in the intervention unit will be offered information regarding their CCU and CRC screening history, and, if overdue, they will be offered self-sampling screening kits. For CCU screening, women aged 50-64 years will be offered a vaginal self-sampling kit for human papillomavirus testing. For CRC screening, women aged 50-69 years will be offered a kit to obtain a faecal immunochemical test. Women attending the control units will receive only standard care.After the intervention, a survey will be sent to all women in the intervention and control group, asking about their experience while attending breast cancer screening.Primary outcomes will be difference in the coverage in CCU and CRC screening 6 months after intervention between the intervention and the control group, and difference in participation rates 6 months after intervention for those who were overdue for CCU and/or CRC screening at the time of the intervention. ETHICS AND DISSEMINATION: The project is listed in the record of processing activities for research projects in the Central Denmark Region (R. No.: 1-16-02-217-21). According to the Danish Consolidation Act on Research Ethics Review of Health Research Project, this study was not notifiable to the Committee (R. No.: 1-10-72-1-21). The findings will be disseminated in peer-reviewed scientific journals. TRIAL REGISTRATION NUMBER: NCT05022511.

Colorectal cancer mortality after randomized implementation of FIT-based screening - a nationwide cohort study.

OBJECTIVE: Evidence of reduction in colorectal cancer (CRC) mortality following CRC screening based on the faecal immunochemical test (FIT) is insufficient. This study aimed to analyse if CRC mortality was reduced after implementing FIT-based screening. SETTING: The Danish national CRC screening programme. METHODS: This nationwide cohort study included residents aged 50-71 years invited to the prevalence round of the screening programme. Invitation order was decided by randomising on birth month; the first two birth months to be invited were classified as invited and the five last were classified as not-yet-invited and given a pseudo invitation data. Follow-up was from (pseudo)invitation date until 31 December 2017, emigration or death. Relative risk (RR) of CRC death was calculated with 95% confidence intervals (CIs). RESULTS: A total of 897,812 residents were included (29% invited and 71% not-yet-invited). The median follow-up was 3.3 years. The RR of CRC death at end of follow-up was 0.83 (95% CI 0.66; 1.03) among those invited to screening compared with those not yet invited. For men aged 60-71 years, this RR was 0.68 (95% CI 0.49; 0.94). For those participating in screening compared with a similar group of not-yet-invited residents, the RR was 0.71 (95% CI 0.46-1.08). For male participants aged 60-71 years, this RR was 0.49 (95% CI 0.27-0.89). For women and men aged 50-59 years, RRs were small and statistically non-significant. CONCLUSION: This nationwide study showed that even within a median follow-up of only 3.3 years, implementing FIT-based CRC screening reduced CRC mortality among older men.

Colorectal cancer screening participation among citizens not recommended to be screened: a cohort study.

BACKGROUND: Guidelines on colorectal cancer (CRC) screening recommend screening of average-risk adults only. In addition, screening of individuals with active inflammatory bowel disease (IBD) might result in too many false-positive cases. However, the organisers of CRC screening programmes are often uninformed of whom to exclude due to an elevated CRC risk or active IBD. It is therefore unknown how often high-risk individuals (i.e. individuals with a previous diagnosis of CRC or polyps associated with hereditary CRC syndromes and certain patient groups with a diagnosis of inflammatory bowel disease (IBD) or multiple polyps) and individuals with active IBD participate in CRC screening following invitation. MATERIALS AND METHODS: We used data from the first two years of the Danish CRC screening programme (2014-2015). Information on invitations, participations and FIT test results were obtained from the national screening database, while information on previous CRC, hereditary CRC syndromes, IBD or multiple polyps diagnoses were obtained from the Danish Cancer Registry and the Danish Patient Register. Screening participation rates and FIT-positive rates were calculated and compared for high-risk invitees, invitees having IBD and an average risk group of remaining invitees not diagnosed with colorectal polyps in 10 years preceding the invitation. RESULTS: When invited to CRC screening, 28-48% of high-risk residents (N: 29; 316; 5584) and 55% of residents with IBD (N: 2217; 6927) chose to participate. The participation rate was significantly higher (67%) among residents without previous colorectal disease, i.e. the average risk group (N = 585,624). In this average group 6.7% of the participants had a positive FIT test. The proportion of positive FIT results was higher among all disease groups (7.7-14.8%), though not statistically significant for participants with prior CRC diagnosis and participants with high-risk IBD. CONCLUSION: When high-risk residents and residents with IBD receive an invitation to CRC screening, many participate despite being recommended not to. The screening program was not intended for these groups and further research is needed as several of these groups have a higher rate of positive screening result than the average risk population.

The relative effectiveness of fecal immunochemical test-based colorectal cancer screening to detect adenomas and cancer in different demographic and socioeconomic groups. A nationwide cohort study.

INTRODUCTION: This study aimed at analyzing the relative effectiveness in removal of adenomas and detection of cancer of implementing colorectal cancer (CRC) screening in different demographic and socioeconomic groups. METHODS: This register-based retrospective cohort study included residents aged 50-72 years. Those randomly selected to be invited for CRC screening from 1 March 2014 to 30 June 2015 were classified as invited; those invited from 1 January 2016 to 31 December 2017 were classified as not yet invited. Strata-specific relative risks (RRs) of having adenomas removed and CRC detected were estimated. RESULTS: A total of 1 343 090 individuals were included. The RR of having adenomas removed were higher among men compared with women [RR women = 6.41 (95% confidence interval [CI]: 5.08-8.09), RR men = 7.74 (95% CI: 6.16-9.73), P < 0.01] and among Danes compared with immigrants [RR Danes = 4.71 (95% CI: 3.73-5.93), RR Western = 4.76 (95% CI: 3.39-6.69), RR non-Western = 3.35 (95% CI: 2.39-4.69), P = 0.03]. Regarding detection of CRC, the effectiveness increased with increasing age ranging from RR = 1.53 (95% CI: 0.93- 2.51) to RR = 1.97 (95% CI: 1.22-3.17) ( P = 0.04) and was higher among men compared with women (RR women = 1.75 (95% CI: 1.10-2.76), RR men = 2.07 (95% CI: 1.32-3.26), P = 0.02. CONCLUSION: Attention must be paid to the potential differences in screening effectiveness among diverse subpopulations; first, by securing equal opportunities for participation across subpopulations and second, by considering sex and age-specific screening programs.

Varying fecal immunochemical test screening cutoffs by age and gender: a way to increase detection rates and reduce the number of colonoscopies.

BACKGROUND AND AIMS: Most colorectal cancer (CRC) screening programs based on the fecal immunochemical test (FIT) use the same cutoff value for all participants. This study aimed at finding age- and gender-specific cutoff values that can improve population-based CRC screening. METHODS: This observational study used data from the first 2 years of the Danish FIT-based CRC screening program to estimate sensitivity, specificity, number of positive tests, number of screen-detected cancers and adenomas, and number of interval cancers for various cutoff values for different male and female age groups. RESULTS: Data from 531,828 participants showed that lower cutoff values for older residents and higher cutoff values for younger residents increased the overall sensitivity and specificity, decreased the number of needed colonoscopies by 7%, increased the number of screen-detected cancer by 1.1%, increased the number of screen-detected adenomas by 5%, and decreased the number of interval cancers by approximately 1.5%. However, these cutoff values also increased an inequality in sensitivity and specificity. Choosing cutoff values that ensured equal sensitivity between the groups, however, did increase inequality in, for example, the interval cancer rate. CONCLUSIONS: In a FIT-based CRC program it is possible to decrease the number of needed colonoscopies while at the same time to increase overall sensitivity and specificity and detect more cancers and adenomas by using different cutoff values for different male and female age groups. However, this increases inequality in sensitivity and specificity, whereas other strategies like ensuring equal sensitivity could be considered.

Adherence to follow-up after the exit cervical cancer screening test at age 60-64: A nationwide register-based study.

BACKGROUND: In Denmark, human papillomavirus (HPV) testing has replaced cytology in primary cervical cancer screening for women aged 60-64; at this age, women are invited for the last (exit) screening test within the national organized program. AIM: We investigated the adherence of these women to the recommended follow-up after a non-negative (positive or inadequate) HPV test and the overall resource use during that follow-up. MATERIALS & METHODS: We included all 2926 women aged 60-64 years with nonnegative HPV screening tests between March 2012 and December 2016. All relevant follow-up tests and procedures were retrieved until the end of 2020 from the highly complete Danish administrative health registers, and the data were linked at the individual level. We determined the extent to which the adherence patterns followed the national recommendations for follow-up and estimated the total numbers of tests and diagnostic procedures utilized during the entire process. RESULTS: In total, only 26% of women had follow-up in accordance with the recommendations; 4% had no follow-up, 46% had insufficient follow-up, and 24% had more follow-up than recommended. We estimated that 17% of women remained in follow-up for longer than 4 years. The average numbers of diagnostic tests and procedures used after positive HPV screening were higher than expected, even among women who had insufficient follow-up, that is, those who received less invasive procedures than recommended, or experienced delays in receiving those procedures. CONCLUSION: To conclude, we found that the patterns of follow-up of women with nonnegative primary HPV screening tests at 60-64 often diverged from the recommendations. Addressing these inconsistencies in follow-up by providing evidence for optimal clinical management should help improve the quality of screening programs and secure an equal and reliable follow-up care service for all women.