Background: Population-based studies using patient-reported outcomes provide important insights into health-related quality of life (HRQoL) and the long-term impact of cancer and its treatment. Declining response rates and potential non-response bias have presented methodological challenges, particularly in registry-based surveys including both cancer survivors and population controls. The SURV-ICE study was established to assess HRQoL and health literacy among cancer survivors in Iceland while evaluating recruitment processes and participation patterns in a nationwide mixed-mode survey. Methods: SURV-ICE is a nationwide, population-based cross-sectional survey conducted in Iceland in 2025. Adults diagnosed with invasive cancer between 2014 and 2024 were identified through the Icelandic Cancer Registry and invited alongside an age- and gender-matched control group sampled from national registers. Participants completed validated EORTC instruments. Recruitment used a mixed-mode strategy including postal invitations, web-based and paper questionnaires, electronic reminders via the national health portal, and targeted telephone follow-up. Results: Among 10,005 cancer survivors 5489 (54.9%) responded to the questionnaires and among 5663 controls 2297 (40.6%) responded to the questionnaires. In both groups participation peaked among individuals aged 60-79 years and was lowest among the youngest and oldest groups. Cancer survivors had higher odds of participation than controls (OR 1.84; 95% CI 1.72-1.97). Most responses followed the initial postal invitation and first electronic reminder. Data completeness was high (≥80% item completion in 95.7% of instruments). Conclusions: Nationwide registry-based recruitment for large-scale PRO research is feasible in Iceland and can achieve competitive response rates without incentives. SURV-ICE provides an infrastructure for future research on cancer survivorship, HRQoL, and health literacy.
Importance:Esophageal squamous cell carcinoma (ESCC) carries a poor prognosis, stressing the need for preventive measures. A decreased risk of ESCC among metformin users has been suggested, but evidence is limited. Objective:To assess whether metformin use, given its potential anticancer properties, is associated with risk of ESCC. Design, Setting, and Participants:This population-based case-control study set between 1994 and 2023 looked at data from all 5 Nordic countries (ie, Denmark, Finland, Iceland, Norway, and Sweden). Participants were patients newly diagnosed with ESCC during the study period, and each was compared with 10 times as many control participants randomly selected from the general population (matched by age, sex, calendar year, and country). Exposures:Use of metformin vs nonuse. Main Outcomes and Measures:Conditional logistic regression provided odds ratios (OR) with 95% CIs for the association between metformin use and the development of ESCC. In addition to the matching, the ORs were adjusted for tobacco smoking, alcohol overconsumption, use of nonsteroidal anti-inflammatory drugs or aspirin, and use of statins. A dose-response analysis was conducted among participants with at least 5 years of observation time, based on the defined daily dose during the 5-year period. Results:This study included 13 050 case patients with ESCC (8030 men [61.5%] and 5020 women [38.5%], diagnosed at a median age of 70 years [IQR, 62-77 years]), and 130 500 age- and sex-matched control participants. Metformin use was associated with a 36% lower odds of ESCC compared with nonuse (OR, 0.64; 95% CI, 0.59-0.69). The odds were especially lower in participants with a higher dosage of metformin (>1278 defined daily dose in 5 years: OR, 0.52; 95% CI, 0.44-0.61). Conclusions and Relevance:In this case-control study, metformin use was associated with substantially lower odds of ESCC. This finding should prompt investigations of metformin as a preventive option in high-risk individuals and as a potential future therapeutic agent for ESCC.
INTRODUCTION:While comparison studies are common in the Nordic countries, important differences need to be illuminated to understand the comparability of future studies within colorectal cancer (CRC) screening research. Therefore, a systematic overview of similarities and differences in the CRC screening programmes in Denmark, Finland, Iceland, Norway, and Sweden was conducted METHODS: Information from each country was gathered through the Nordic CRC screening network, which includes experts in CRC screening from the participating countries. A timeline describing preceding pilot studies and national roll-outs in all countries was established. Furthermore, the screening flow in each country and the quality indicator monitoring including performance standards were presented. RESULTS:During 2014-2024, all five Nordic countries implemented CRC screening using faecal immunochemical testing (FIT) but with different implementation strategies and cut-off values. Taking colonoscopy resources into account, gradual implementation strategies were used in all countries, but with different paces. Quality monitoring follows the European recommendations with some variation; however key performance indicators such as adenoma detection rates (ADR), colonoscopy complication rates, serrated polyp detection, post-colonoscopy CRC (PCCRC) rates, and interval cancer rates, are monitored by all countries. CONCLUSION:This paper may serve as a key reference for future research and comparison studies across the Nordic countries. The variation found in countries with similar health care systems might serve as natural experiments in future studies. Furthermore, this overview shows that there might be room for improvements in the monitoring of certain quality indicators to facilitate quality improvement efforts in all Nordic countries.
BACKGROUND:Prostate cancer survival varies across Nordic countries, potentially reflecting variation in stage distribution at diagnosis. To highlight the variation in the diagnostic intensity of prostate cancer, we outlined the differences in stage distributions at diagnosis across these countries. Specifically, we evaluated whether the variation in cancer survival could be attributed to differences in stage at diagnosis. METHODS:In this population-based cohort study, we identified 243 893 men diagnosed with prostate cancer from 2004 to 2016 in Denmark, Iceland, Norway, and Sweden. Country-specific stage distributions at diagnosis were obtained from individual cancer registry records provided by the NORDCAN collaboration. Relative survival and 95% confidence intervals (CIs) were estimated by using the Pohar Perme estimator. Stage-standardized relative survival was estimated by applying pre-weighting based on the stage distribution of the entire Nordic cohort. RESULTS:The stage distribution of prostate cancer varied between the Nordic countries, with the highest proportion of early-stage (0-I) cases in Sweden and the highest proportion of advanced-stage (IV) cases in Denmark. When adjusting for differences in stage distribution (i.e. stage standardization), the 5-year relative survival improved in Denmark and Norway within the study period (2004-17), increasing from 83.9% (95% CI, 83.2-84.6) and 91.4% (95% CI, 90.8-92.0) to 87.3 (95% CI, 86.5-88.2) and 93.4% (95% CI, 92.8-94.1). Conversely, the 5-year relative survival declined in Sweden from 90.6% (95% CI, 90.3-91.0) to 88.5% (95% CI, 88.0-89.1). CONCLUSION:The distinct differences in stage distributions between the Nordic countries substantially contributed to the variation in prostate cancer survival.
Abstract Purpose Almost 200,000 tongue cancers were diagnosed worldwide in 2020. The aim of this study was to describe occupational risk variation in this malignancy. Methods The data are based on the Nordic Occupational Cancer (NOCCA) study containing 14.9 million people from the Nordic countries with 9020 tongue cancers diagnosed during 1961–2005. The standardized incidence ratio (SIR) of tongue cancer in each occupational category was calculated using national incidence rates as the reference. Results Among men, the incidence was statistically significantly elevated in waiters (SIR 4.36, 95% confidence interval (CI) 3.13-–5.92), beverage workers (SIR 3.42, 95% CI 2.02-5.40), cooks and stewards (SIR 2.55, 95% CI 1.82-3.48), seamen (SIR 1.66, 95% CI 1.36-2.00), journalists (SIR 1.85, 95% CI 1.18-2.75), artistic workers (SIR 2.05, 95% CI 1.54-2.66), hairdressers (SIR 2.17, 95% CI 1.39-3.22), and economically inactive persons (SIR 1.57, 95% CI 1.42-1.73). Among women, the SIR was statistically significantly elevated only in waitresses (SIR 1.39, 95% CI 1.05-1.81). Statistically significant SIRs ≤ 0.63 were observed in male farmers, gardeners, forestry workers and teachers, and in female launderers. Conclusions These findings may be related to consumption of alcohol and tobacco, but the effect of carcinogenic exposure from work cannot be excluded.
