Validation of serrated polyps (SPs) in Swedish pathology registers

Inflammatory Bowel Disease and Risk of Colorectal Polyps: A Nationwide Population-Based Cohort Study From Sweden

BACKGROUND

Inflammatory bowel disease [IBD] has been linked to an increased risk of colorectal neoplasia. However, the types and risks of specific polyp types in IBD are less clear.

METHODS

We identified 41 880 individuals with IBD (Crohn's disease [CD: n = 12 850]; ulcerative colitis [UC]: n = 29 030]) from Sweden matched with 41 880 reference individuals. Using Cox regression, we calculated adjusted hazard ratios [aHRs] for neoplastic colorectal polyps [tubular, serrated/sessile, advanced and villous] defined by histopathology codes.

RESULTS

During follow-up, 1648 [3.9%] IBD patients and 1143 [2.7%] reference individuals had an incident neoplastic colorectal polyp, corresponding to an incidence rate of 46.1 and 34.2 per 10 000 person-years, respectively. This correlated to an aHR of 1.23 (95% confidence interval [CI] 1.12-1.35) with the highest HRs seen for sessile serrated polyps [8.50, 95% CI 1.10-65.90] and traditional serrated adenomas [1.72, 95% CI 1.02-2.91]. aHRs for colorectal polyps were particularly elevated in those diagnosed with IBD at a young age and at 10 years after diagnosis. Both absolute and relative risks of colorectal polyps were higher in UC than in CD [aHRs 1.31 vs 1.06, respectively], with a 20-year cumulative risk difference of 4.4% in UC and 1.5% in CD, corresponding to one extra polyp in 23 patients with UC and one in 67 CD patients during the first 20 years after IBD diagnosis.

CONCLUSIONS

In this nationwide population-based study, there was an increased risk of neoplastic colorectal polyps in IBD patients. Colonoscopic surveillance in IBD appears important, especially in UC and after 10 years of disease.

Target trial emulation of aspirin after diagnosis of colorectal polyps

BACKGOUND AND AIMS

Previous research on the potential chemoprotective effect of aspirin for colorectal cancer (CRC) shows conflicting results. We aimed to emulate a trial of aspirin intiation in individuals with incident polyps.

METHODS

We identified individuals registered with their first colorectal polyp in the nationwide gastrointestinal ESPRESSO histopathology cohort in Sweden. Individuals aged 45-79 years diagnosed with colorectal polyps 2006-2016 in Sweden without CRC or contraindications for preventive aspirin (cerebrovascular disease, heart failure, aortic aneurysms, pulmonary emboli, myocardial infarction, gastric ulcer, dementia, liver cirrhosis, or any other metastatic cancer) registered until the month of first polyp detection were eligible. Using duplication and inverse probability weighting, we emulated a target trial of aspirin initiation within 2 years of initial polyp detection. The main outcome measures were incident CRC, CRC mortality and all-cause mortality registered until 2019.

RESULTS

Of 31,633 individuals meeting our inclusion criteria, 1716 (5%) initiated aspirin within 2 years of colon polyp diagnosis. Median follow-up was 8.07 years. The 10-year cumulative incidence in initiators versus non-initiators was 6% versus 8% for CRC incidence, 1% versus 1% for CRC mortality and 21% versus 18% for all-cause mortality. The corresponding hazard ratios were 0.88 (95% confidence interval, 95%CI = 0.86-0.90), 0.90 (95%CI = 0.75-1.06) and 1.18 (95%CI = 1.12-1.24).

CONCLUSION

Aspirin initiation in individuals with polyp removal was linked to 2% lower cumulative incidence of CRC after 10 years but did not alter CRC mortality. We also observed a 4% increased risk difference of all-cause mortality at 10 years after the initiation of aspirin.

Diagnostic yield of endoscopy in irritable bowel syndrome: A nationwide prevalence study 1987-2016

INTRODUCTION

Symptoms of irritable bowel syndrome (IBS) are common reasons for endoscopic procedures. We examined the yield of colonoscopy and upper endoscopy in IBS for several organic diseases.

METHODS

Matched population-based prevalence study in Sweden. We identified 21,944 participants diagnosed with IBS from 1987 to 2016 undergoing colonoscopy with a biopsy from all of Sweden's 28 pathology departments within 6 months of diagnosis. We compared prevalence of histopathology-proven diagnoses of inflammatory bowel disease (IBD), colorectal cancer, precancerous polyps, and microscopic colitis between patients recently diagnosed with IBS and matched controls without IBS (n = 81,101) undergoing colonoscopy. We also compared prevalence of celiac disease between patients diagnosed with IBS (n = 9,965) and matched controls (n = 45,584) undergoing upper endoscopy with biopsy. IBS patients were also compared to their siblings. Conditioned logistic regression estimated adjusted odds ratios (aORs).

RESULTS

Biopsy-proven IBD was seen in 1.6% of IBS and in 5.9% of controls (aOR=0.21; 95%CI=0.19-0.24). The prevalence of precancerous polyps was 4.1% vs. 13.0% (aOR=0.28; 95%CI=0.26-0.30), colorectal cancer 0.8% vs. 6.3% (aOR=0.17; 95%CI=0.14-0.20) and celiac disease 1.9% vs. 3.4% (aOR=0.54; 95%CI=0.47-0.63). Conversely, the prevalence of microscopic colitis was 2.9% vs. 1.7% (aOR=1.77; 95%CI=1.61-1.95), with higher prevalence in older patients and patients with IBS with diarrhea. Yield of colonoscopy for precancerous polyps, colorectal cancer, and microscopic colitis increased by age. Our findings were consistent using unaffected siblings as the comparator group.

DISCUSSION

The diagnostic yield of upper endoscopy and colonoscopy for organic disease is low in patients with a first-time diagnosis of IBS, though increases with age.

Antibiotic Use Associated With Risk of Colorectal Polyps in a Nationwide Study

BACKGROUND & AIMS

Use of antibiotics affects the composition of the microbiome and might affect development of colorectal polyps, which are precursors to colorectal cancer.

METHODS

We performed a nested case-control study in Sweden of 45,744 patients with a colorectal polyp (cases) in the nationwide gastrointestinal ESPRESSO histopathology cohort, using unaffected full siblings as controls (n = 93,307). Polyps were classified by morphology SnoMed codes into conventional adenomas and serrated polyps. Through linkage to the Prescribed Drug Register, we assessed use and cumulative dispensations of antibiotic until 1 year prior to polyp diagnosis for cases and their sibling controls.

RESULTS

During a median study period of 6.9 years, compared with non-users, users of antibiotics (including 28,884 cases [63.1%] and 53,222 sibling controls [57.0%]) had a higher risk of colorectal polyps (odds ratio [OR], 1.08; 95% CI, 1.04-1.13). Risk increased with higher number of dispensations (OR for ≥ 6 dispensations, 1.33; 95% CI, 1.25-1.43) (P_trend < .0001). We observed a stronger association with polyps for broad-spectrum antibiotics (OR comparing users to non-users, 1.23; 95% CI, 1.18-1.29) than for narrow-spectrum antibiotics (OR, 1.05; 95% CI, 1.01-1.10), and for tetracyclines and quinolones (OR, 1.21) than penicillin and other classes (ORs ranged from 1.04 to 1.16). The findings remained robust with several sensitivity analyses, including use of a 2-year lead-in period for antibiotic assessment and correction for misclassification in controls. Use of broad-spectrum antibiotics was more strongly associated with risk of serrated polyps (OR, 1.29; 95% CI, 1.21-1.38) compared with risk of conventional adenomas (OR, 1.17; 95% CI, 1.11-1.24). We found no differences in risk of colon vs rectal polyps with antibiotic use (P_{heterogeneity} > .10). We found stronger associations for younger (<50 years) vs older adults (≥50 years) for users of quinolones, sulfonamides, trimethoprim, and cephalosporins (P_interaction < .001).

CONCLUSIONS

In a nationwide case-control study in Sweden, after accounting for hereditary and early life environmental factors, antibiotic use was associated with increased risk of colorectal polyps. Our findings indicate a role for intestinal dysbiosis in early stages of colorectal carcinogenesis.

Risk of colorectal cancer in first degree relatives of patients with colorectal polyps: nationwide case-control study in Sweden

OBJECTIVE

To assess the risk of colorectal cancer (CRC) in first degree relatives (parents and full siblings) of patients with precursor lesions (polyps) for CRC.

DESIGN

Case-control study.

SETTING

Linkage to the multi-generation register and gastrointestinal ESPRESSO (Epidemiology Strengthened by histoPathology Reports in Sweden) histopathology cohort in Sweden.

PARTICIPANTS

68 060 patients with CRC and 333 753 matched controls.

MAIN OUTCOME MEASURES

Multivariable adjusted odds ratios of CRC according to the number of first degree relatives with a colorectal polyp and the histology of polyps and age at diagnosis in first degree relatives. Subgroup analysis was also performed according to age at CRC diagnosis and evaluated the joint association of family history of colorectal polyps and family history of CRC.

RESULTS

After adjusting for family history of CRC and other covariates, having a first degree relative with a colorectal polyp (8.4% (5742/68 060) in cases and 5.7% (18 860/333 753) in controls) was associated with a higher risk of CRC (odds ratio 1.40, 95% confidence interval 1.35 to 1.45). The odds ratios ranged from 1.23 for those with hyperplastic polyps to 1.44 for those with tubulovillous adenomas. To better put this risk in perspective, the age specific absolute risk of colon and rectal cancers was estimated according to family history of polyps based on the 2018 national CRC incidence in Sweden. For example, the absolute risk of colon cancer in individuals aged 60-64 years with and without a family history of colorectal polyp was, respectively, 94.3 and 67.9 per 100 000 for men and 89.1 and 64.1 per 100 000 for women. The association between family history of polyps and CRC risk was strengthened by the increasing number of first degree relatives with polyps (≥2 first degree relatives: 1.70, 1.52 to 1.90, P<0.001 for trend) and decreasing age at polyp diagnosis (<50 years: 1.77, 1.57 to 1.99, P<0.001 for trend). A particularly strong association was found for early onset CRC diagnosed before age 50 years (≥2 first degree relatives: 3.34, 2.05 to 5.43, P=0.002 for heterogeneity by age of CRC diagnosis). In the joint analysis, the odds ratio of CRC for individuals with two or more first degree relatives with polyps but no CRC was 1.79 (1.52 to 2.10), with one first degree relative with CRC but no polyps was 1.70 (1.65 to 1.76), and with two or more first degree relatives with both polyps and CRC was 5.00 (3.77 to 6.63) (P<0.001 for interaction).

CONCLUSIONS

After adjusting for family history of CRC, the siblings and children of patients with colorectal polyps are still at higher risk of CRC, particularly early onset CRC. Early screening for CRC might be considered for first degree relatives of patients with polyps.

A Novel Method for Quantifying Intestinal Inflammatory Burden in Inflammatory Bowel Disease Using Register Data

Background

The Swedish Quality Register for Inflammatory Bowel Disease (SWIBREG) contains clinical data for the study of inflammatory bowel disease (IBD). The Epidemiology Strengthened by histoPathology Reports in Sweden (ESPRESSO) cohort was recently established for the study of gastrointestinal histopathology. We aimed to develop and validate a histology score from ESPRESSO using clinical information from SWIBREG, and secondarily, to evaluate the association of the score on IBD-related hospitalization.

Methods

In a nationwide, population-based cohort study of patients with IBD during 1969-2017, we linked endoscopic inflammation in SWIBREG with histologic inflammation in ESPRESSO. We established a clinically interpretable model for predicting the endoscopic score from histology using scalable Bayesian rule lists to define a SNOMED-based histology score applicable to the ESPRESSO cohort. We also assessed the impact of baseline endoscopic and histology scores on time to IBD-related hospitalization.

Results

We identified 5225 individuals with IBD comprising 11,051 endoscopic assessments in SWIBREG linked to a histopathology record in ESPRESSO. We created predictive models to calculate a SNOMED-based histology score which predicted the endoscopic score. Split-sample validated areas under the ROC curves for the score predicting a non-zero endoscopic score were 0.80 (0.78-0.81) in UC, 0.70 (0.68-0.72) in CD, and 0.76 (0.73-0.78) in IBD-U. In a subset of 2741 individuals with an initial IBD diagnosis and a corresponding record in ESPRESSO with an endoscopic assessment in SWIBREG, the baseline endoscopic and histology scores were associated with time to IBD-related hospitalization (endoscopy log-rank UC p<0.001, CD p=0.020, IBD-U p<0.001; histology log-rank UC p=0.018, CD p=0.960, IBD-U p=0.034).

Conclusion

Histopathology data in ESPRESSO accurately predict endoscopic scores in SWIBREG. Baseline endoscopic and histologic scores were associated with time to IBD-related hospitalization, particularly in UC. The SNOMED-based histology score can be used as a measure of disease activity in future register-based IBD studies.

Risk of colorectal cancer incidence and mortality after polypectomy: a Swedish record-linkage study

BACKGROUND

Long-term colorectal cancer incidence and mortality after colorectal polyp removal remains unclear. We aimed to assess colorectal cancer incidence and mortality in individuals with removal of different histological subtypes of polyps relative to the general population.

METHODS

We did a matched cohort study through prospective record linkage in Sweden in patients aged at least 18 years with a first diagnosis of colorectal polyps in the nationwide gastrointestinal ESPRESSO histopathology cohort (1993-2016). For each polyp case, we identified up to five matched reference individuals from the Total Population Register on the basis of birth year, age, sex, calendar year of biopsy, and county of residence. We excluded patients and reference individuals with a diagnosis of colorectal cancer either before or within the first 6 months after diagnosis of the index polyp. Polyps were classified by morphology codes into hyperplastic polyps, sessile serrated polyps, tubular adenomas, tubulovillous adenomas, and villous adenomas. Colorectal cancer cases were identified from the Swedish Cancer Registry, and cause-of-death data were retrieved from the Cause of Death Register. We collected information about the use of endoscopic examination before and after the index biopsy from the Swedish National Patient Registry, and counted the number of endoscopies done before and after the index biopsies. We calculated cumulative risk of colorectal cancer incidence and mortality at 3, 5, 10, and 15 years, and computed hazard ratios (HRs) and 95% CIs for colorectal cancer incidence and mortality using a stratified Cox proportional hazards model within each of the matched pairs.

FINDINGS

178 377 patients with colorectal polyps and 864 831 matched reference individuals from the general population were included in our study. The mean age of patients at polyp diagnosis was 58·6 (SD 13·9) years for hyperplastic polyps, 59·7 (14·2) years for sessile serrated polyps, 63·9 (12·9) years for tubular adenomas, 67·1 (12·1) years for tubulovillous adenomas, and 68·9 (11·8) years for villous adenomas. During a median of 6·6 years (IQR 3·0-11·6) of follow-up, we documented 4278 incident colorectal cancers and 1269 colorectal cancer-related deaths in patients with a polyp, and 14 350 incident colorectal cancers and 5242 colorectal cancer deaths in general reference individuals. The 10-year cumulative incidence of colorectal cancer was 1·6% (95% CI 1·5-1·7) for hyperplastic polyps, 2·5% (1·9-3·3) for sessile serrated polyps, 2·7% (2·5-2·9) for tubular adenomas, 5·1% (4·8-5·4) for tubulovillous adenomas, and 8·6% (7·4-10·1) for villous adenomas compared with 2·1% (2·0-2·1) in reference individuals. Compared with reference individuals, patients with any polyps had an increased risk of colorectal cancer, with multivariable HR of 1·11 (95% CI 1·02-1·22) for hyperplastic polyps, 1·77 (1·34-2·34) for sessile serrated polyps, 1·41 (1·30-1·52) for tubular adenomas, 2·56 (2·36-2·78) for tubulovillous adenomas, and 3·82 (3·07-4·76) for villous adenomas (p<0·05 for all polyp subtypes). There was a higher proportion of incident proximal colon cancer in patients with serrated (hyperplastic and sessile) polyps (52-57%) than in those with conventional (tubular, tubulovillous, and villous) adenomas (30-46%). For colorectal cancer mortality, a positive association was found for sessile serrated polyps (HR 1·74, 95% CI 1·08-2·79), tubulovillous adenomas (1·95, 1·69-2·24), and villous adenomas (3·45, 2·40-4·95), but not for hyperplastic polyps (0·90, 0·76-1·06) or tubular adenomas (0·97, 0·84-1·12).

INTERPRETATION

In a largely screening-naive population, compared with individuals from the general population, patients with any polyps had a higher colorectal cancer incidence, and those with sessile serrated polyps, tubulovillous adenomas, and villous adenomas had a higher colorectal cancer mortality.

FUNDING

US National Institutes of Health, American Cancer Society, American Gastroenterological Association, Union for International Cancer Control.