CRCBaSe: a Swedish register-based resource for colorectal adenocarcinoma research.

OBJECTIVES: To facilitate high-quality register-based research on colorectal cancer (CRC) in Sweden by constructing a database consisting of CRC patients, matched comparators, and relatives. MATERIAL AND METHODS: Patients with adenocarcinoma in the colon and/or rectum were identified in the Swedish Colorectal Cancer Register, a nationwide quality-of-care register. For each patient, six comparators from the general population were matched on birth year, sex, year of CRC diagnosis, and county. Comparators were free from CRC at the time of matching, but could later become cases. For both patients and comparators, first-degree relatives (parents, siblings, and children) were identified. Information from nationwide population-based registers was retrieved and linked to each individual in the database using the personal identification number unique to all Swedish residents. RESULTS: A total of 76,831 CRC patients diagnosed between 1995 and 2016 were identified (51% colon, 49% rectal; before 2007 only rectal cancer patients were included). Among all patients, 37% were stage I-II, 22% stage III, and 22% stage IV. The median follow-up time was 11.9 years (inter-quartile range, IQR: 8.6-15.3). Together with comparators and relatives, the database contains 2,413,139 individuals with information on demographics, dates and causes of death, in- and outpatient healthcare records, cancer diagnoses, prescribed and dispensed drugs, childbirths (among women), and social security information (such as sick leave and early retirement). CONCLUSION: The Colorectal Cancer Database Sweden (CRCBaSe) is a large and unique register-based data research platform, which opens up for clinically important, large epidemiological studies with innovative design in the field of colorectal adenocarcinoma.

Long-term prescribed drug use in stage I-III rectal cancer patients in Sweden, with a focus on bowel-regulating drugs after surgical and oncological treatment.

PURPOSE: To describe long-term prescribed drug use after rectal cancer treatment. METHODS: We identified 12,871 rectal cancer patients without distant metastasis between 2005 and 2016 and 64,341 matched population comparators using CRCBaSe (a Swedish nationwide register linkage of colorectal cancer patients). Mean defined daily doses (DDDs) of drug dispensing during relapse-free follow-up were calculated by Anatomical Therapeutic Chemical drug categories. Incidence rate ratios (IRRs) and 95% confidence intervals (CIs) from negative binomial regression were used to compare drug dispensing between patients and comparators. RESULTS: The overall pattern of drug dispensing was similar among cancer survivors and comparators, although patients had higher mean DDDs of drugs regulating the digestive system. Excess dispensing of drugs for constipation (IRR, 3.35; 95% CI, 3.12-3.61), diarrhea (IRR, 6.43; 95% CI, 5.72-7.22), functional gastrointestinal disorders (IRR, 3.78; 95% CI, 3.15-4.54), and vitamin and mineral supplements (IRR, 1.37; 95% CI, 1.24-1.50) was observed up to 10 years after surgery. Treatment with Hartmann's procedure was associated with higher dispensing rates of digestive drugs compared to surgery with anterior resection and abdominoperineal resection but the association was attributed to higher use of diabetic drugs. Additionally, excess digestive drug dispensing was associated with more advanced cancer stage but not with (chemo)radiotherapy treatment. CONCLUSIONS: Excess drug use after rectal cancer is primarily driven by bowel-regulating drugs and is not modified by surgical or oncological treatment. IMPLICATIONS FOR CANCER SURVIVORS: The excess use of bowel-regulating drugs after rectal cancer indicated long-standing postsurgical gastrointestinal morbidity and need of prophylaxis. Reassuringly, no excess use of other drug classes was noted long term.

Autoimmune and Metabolic Diseases and the Risk of Early-Onset Colorectal Cancer, a Nationwide Nested Case-Control Study.

Incidence of early-onset (<50 years) colorectal cancer (EOCRC) is increasing in developed countries. The aim was to investigate autoimmune and metabolic conditions as risk factors for EOCRC. In a nationwide nested case-control study, we included all EOCRC cases in Sweden diagnosed during 2007-2016, together with controls, matched for birth year, sex, and county. Information on exposure of autoimmune or metabolic disease was collected from the National Patient Register and Prescribed Drugs Registry. Hazard ratios (HR) as measures of the association between EOCRC and the exposures were estimated using conditional logistic regression. In total, 2626 EOCRC patients and 15,756 controls were included. A history of metabolic disease nearly doubled the incidence hazard of EOCRC (HR 1.82, 95% CI 1.66-1.99). A sixfold increased incidence hazard of EOCRC (HR 5.98, 95% CI 4.78-7.48) was seen in those with inflammatory bowel disease (IBD), but the risk increment decreased in presence of concomitant metabolic disease (HR 3.65, 95% CI 2.57-5.19). Non-IBD autoimmune disease was not statistically significantly associated with EOCRC. IBD and metabolic disease are risk factors for EOCRC and should be considered in screening guidelines.