Data quality at the Cancer Registry of Norway: An overview of comparability, completeness, validity and timeliness

Sexual health in long-term breast cancer survivors: a comparison with female population controls from the HUNT study

PURPOSE

Sexual health is an important aspect of quality of life. Knowledge concerning sexual health in long-term breast cancer survivors (BCSs) is limited. This study compared sexual health in BCSs 8 years after diagnosis with similarly aged controls and examined the impact of menopausal status at diagnosis and systemic breast cancer treatments on sexual health.

METHODS

Women aged 20-65 years when diagnosed with stage I-III breast cancer in 2011-2012 were identified by the Cancer Registry of Norway (n = 2803) and invited to participate in a nationwide survey. Controls were women from the Trøndelag Health Study (HUNT4). Sexual functioning and sexual enjoyment were measured by the EORTC QLQ-BR23 subscales scored from 0 to 100, and sexual discomfort by the Sexual Activity Questionnaire scored from 0 to 6. Linear regression analyses with adjustments for sociodemographic and health-related variables were performed to compare groups. Differences of ≥ 10% of range score were considered clinically significant.

RESULTS

The study samples consisted of 1241 BCSs and 17,751 controls. Sexual enjoyment was poorer (B - 13.1, 95%CI - 15.0, - 11.2) and discomfort higher (B 0.9, 95%CI 0.8, 1.0) among BCSs compared to controls, and larger differences were evident between premenopausal BCSs and controls (B - 17.3, 95%CI - 19.6, - 14.9 and B 1.2, 95%CI 1.0, 1.3, respectively). BCSs treated with both endocrine- and chemotherapy had lower sexual functioning (B - 11.9, 95%CI - 13.8, - 10.1), poorer sexual enjoyment (B - 18.1, 95%CI - 20.7, - 15.5), and more sexual discomfort (B 1.4, 95% 1.3, 1.6) than controls.

CONCLUSION

Sexual health impairments are more common in BCSs 8 years after diagnosis compared to similar aged population controls. During follow-up, attention to such impairments, especially among women diagnosed at premenopausal age and treated with heavy systemic treatment, is warranted.

Pre-diagnostic intake of vitamin D and incidence of colorectal cancer by anatomical subsites: the Norwegian Women and Cancer Cohort Study (NOWAC)

According to the World Cancer Research Fund International, vitamin D might decrease the risk of colorectal cancer (CRC). However, less is known about the association with cancers in different subsites of the colon and in the rectum. The aim of this study was to examine associations between pre-diagnostic intake of vitamin D and risk of CRC by anatomical subsites. Data from 95 416 participants in the Norwegian Women and Cancer Cohort Study was included, and vitamin D intake was estimated from two repeated FFQ. Associations between vitamin D intake and incidence of CRC were assessed using multivariable Cox regression. During follow-up, there were 1774 incident cases of CRC. A small but borderline significant inverse association was found for a 5-µg increase in vitamin D intake and risk of CRC (hazard ratio (HR) = 0·97; 95 % CI 0·93, 1·01) and colon cancer (HR = 0·96; 95 % CI 0·91, 1·01). High (≥ 20 µg) compared with low (< 10 µg) vitamin D intake was associated with 17 % borderline significant reduced risk of CRC (HR = 0·83; 95 % CI 0·68, 1·02). Medium (10-19 µg) v. low intake (< 10 µg) was associated with 27 % reduced risk of proximal colon cancer (HR = 0·73; 95 % CI 0·57, 0·94). No significant associations were observed between vitamin D intake and risk of distal colon or rectal cancer. Our study indicates that vitamin D may be differently associated with subsites of the colon. The association between vitamin D intake and proximal colon cancer is novel.

Lifelong differences in cancer incidence and mortality between subgroups of similar socioeconomic status in the Royal Norwegian Navy

OBJECTIVES

In a previous cohort study of 28 300 Navy servicemen, vessel crews showed higher cancer incidence and mortality than did land-based personnel. We have extended the follow-up to look for changes in cancer risk, and to explore temporal trends in cancer incidence and cancer mortality during more than six decades of follow-up.

METHODS

Cancer incidence and total cancer mortality were compared with the general population by calculating standardised ratios (standardised incidence ratios (SIRs), standardised mortality ratios) for the entire follow-up, with temporal trends through seven consecutive 10-year time spans from individual entry to follow-up. Rates were compared between the subgroups using Poisson regression, expressed as rate ratios (RRs).

RESULTS

Cancer incidence in Navy servicemen suggested a healthy soldier effect limited to the first three decades of follow-up and confined to land-based personnel. Overall, vessel crews showed 13% higher cancer incidence and 36% higher cancer mortality than other Navy servicemen. Some of the differences may be explained by a higher risk in vessel crews of cancers known to have less than 25% 5-year relative survival (RR=1.71), such as cancers of the lung, liver, pancreas and mesothelioma.

CONCLUSION

Through most of the observation time, vessel crews had an overall cancer SIR that was higher than that of land-based personnel. Much of this excess involved cancers with a generally poor prognosis, linked to lifestyle and work environment. The contrasts in cancer incidence and mortality between the two subgroups of Navy servicemen persisted through more than six decades.

Improving communication of cancer survival statistics-feasibility of implementing model-based algorithms in routine publications

BACKGROUND

Routine reporting of cancer patient survival is important, both to monitor the effectiveness of health care and to inform about prognosis following a cancer diagnosis. A range of different survival measures exist, each serving different purposes and targeting different audiences. It is important that routine publications expand on current practice and provide estimates on a wider range of survival measures. We examine the feasibility of automated production of such statistics.

METHODS

We used data on 23 cancer sites obtained from the Cancer Registry of Norway (CRN). We propose an automated way of estimating flexible parametric relative survival models and calculating estimates of net survival, crude probabilities, and loss in life expectancy across many cancer sites and subgroups of patients.

RESULTS

For 21 of 23 cancer sites, we were able to estimate survival models without assuming proportional hazards. Reliable estimates of all desired measures were obtained for all cancer sites.

DISCUSSION

It may be challenging to implement new survival measures in routine publications as it can require the application of modeling techniques. We propose a way of automating the production of such statistics and show that we can obtain reliable estimates across a range of measures and subgroups of patients.

Exposure to benzene and other hydrocarbons and risk of bladder cancer among male offshore petroleum workers

BACKGROUND

Occupational exposures constitute the second leading cause of urinary bladder cancer after tobacco smoking. Increased risks have been found in the petroleum industry, but high-quality exposure data are needed to explain these observations.

METHODS

Using a prospective case-cohort design, we analysed 189 bladder cancer cases (1999-2017) and 2065 randomly drawn non-cases from the Norwegian Offshore Petroleum Workers cohort. Cases were identified in the Cancer Registry of Norway, while work histories (1965-1998) and lifestyle factors were recorded by questionnaire at baseline (1998). Occupational petroleum-related hydrocarbon exposures were assessed by expert-developed job-exposure matrices. Hazard ratios were estimated by weighted Cox-regressions, adjusted for age, tobacco smoking, education, and year of first employment, and with lagged exposures.

RESULTS

Increased risks were found in benzene-exposed workers, either long-term exposure (≥18.8 years, HR = 1.89, 95% CI: 1.14-3.13; p-trend = 0.044) or high-level cumulative benzene exposure (HR = 1.60, 95% CI: 0.97-2.63; p-trend = 0.065), compared with the unexposed. Associations persisted with 20-year exposure lag. No associations were found with skin or inhalation exposure to crude oil, mineral oil (lubrication, hydraulics, turbines, drilling), or diesel exhaust.

CONCLUSIONS

The results suggest that exposures in the benzene fraction of the petroleum stream may be associated with increased bladder cancer risk.

Increased magnetic resonance imaging in prostate cancer management-What are the outcomes?

RATIONALE

Increased attention to cancer care has instigated altered systems for screening, diagnosis, and management of various types of cancer, such as in the prostate. While such systems very likely have improved the quality of cancer care, they also result in the altered use of specific services, such as magnetic resonance imaging (MRI).

AIMS AND OBJECTIVE

To study the change in the use of prostate MRI in the Norwegian health care system from 2013 to 2021 and to investigate some reasons for and potential implications of this change.

METHOD

Data from the Norwegian Health Economics Administration (HELFO), The Cancer Registry of Norway and Cause-of-death registry at the Norwegian Institute of public health and the health registry of Vestfold Hospital Trust were used for descriptive statistical analysis.

RESULTS

The number of MRIs of the prostate increased threefold from 2013 to 2021, representing an extra cost of 2 million USD in 2020. The incidence of prostate cancer was stable at about 5000 cases per year, corresponding to 178 per 100,000 men, indicating no increased overdiagnosis. However, the clinical staging has changed substantially during this period, indicating stage and grade migration. The number of negative biopsies was reduced, and there are three MRIs per reduced negative biopsy. The number of persons on active surveillance increased during the period. However, these changes are partly independent of the increase in the number of MRIs.

CONCLUSION

There was a substantial increase in the number of prostate MRIs and thus an increase in costs. This appears to have contributed to the reduction of negative biopsies, improved staging and increased active surveillance. However, as these effects are partly independent of the increase in MRIs, we need to document the outcomes for patients from prostate MRIs as their opportunity costs are substantial.

Rates of Second Tumor, Metastasis, and Death From Cutaneous Squamous Cell Carcinoma in Patients With and Without Transplant-Associated Immunosuppression

Importance

Cutaneous squamous cell carcinoma (cSCC) may occur with multiple primary tumors, metastasize, and cause death both in immunocompetent and immunosuppressed patients.

Objective

To study the rates of second cSCC, metastasis, and death from cSCC in patients with and without organ transplant-associated immunosuppressive treatment.

Design, Setting, and Participants

This population-based, nationwide cohort study used Cancer Registry of Norway data from 47 992 individuals diagnosed with cSCC at 18 years or older between January 1, 1968, and December 31, 2020. Data were analyzed between November 24, 2021, and November 15, 2022.

Exposures

Receipt of a solid organ transplant at Oslo University Hospital between 1968 and 2012 followed by long-term immunosuppressive treatment.

Main Outcomes and Measures

Absolute rates of second cSCC, metastasis, and death from cSCC were calculated per 1000 person-years with 95% CIs. Hazard ratios (HRs) estimated using Cox proportional hazard regression were adjusted for age, sex, and year of first cSCC diagnosis.

Results

The study cohort comprised 1208 organ transplant recipients (OTRs) (median age, 66 years [range, 27-89 years]; 882 men [73.0%] and 326 women [27.0%]) and 46 784 non-OTRs (median age, 79 years [range, 18-106 years]; 25 406 men [54.3%] and 21 378 women [45.7%]). The rate of a second cSCC per 1000 person-years was 30.9 (95% CI, 30.2-31.6) in non-OTRs and 250.6 (95% CI, 232.2-270.1) in OTRs, with OTRs having a 4.3-fold increased rate in the adjusted analysis. The metastasis rate per 1000 person-years was 2.8 (95% CI, 2.6-3.0) in non-OTRs and 4.8 (95% CI, 3.4-6.7) in OTRs, with OTRs having a 1.5-fold increased rate in the adjusted analysis. A total of 30 451 deaths were observed, of which 29 895 (98.2%) were from causes other than cSCC. Death from cSCC was observed in 516 non-OTRs (1.1%) and 40 OTRs (3.3%). The rate of death from cSCC per 1000 person-years was 1.7 (95% CI, 1.5-1.8) in non-OTRs and 5.4 (95% CI, 3.9-7.4) in OTRs, with OTRs having a 5.5-fold increased rate in the adjusted analysis.

Conclusions and Relevance

In this cohort study, OTRs with cSCC had significantly higher rates of second cSCC, metastasis, and death from cSCC than non-OTRs with cSCC, although most patients with cSCC in both groups died from causes other than cSCC. These findings are relevant for the planning of follow-up of patients with cSCC and for skin cancer services.

Night shift work and risk of aggressive prostate cancer in the Norwegian Offshore Petroleum Workers (NOPW) cohort

BACKGROUND

Night shift work may acutely disrupt the circadian rhythm, with possible carcinogenic effects. Prostate cancer has few established risk factors though night shift work, a probable human carcinogen, may increase the risk. We aimed to study the association between night shift work and chlorinated degreasing agents (CDAs) as possible endocrine disrupters in relation to aggressive prostate cancer as verified malignancies.

METHODS

We conducted a case-cohort study on 299 aggressive prostate cancer cases and 2056 randomly drawn non-cases in the Norwegian Offshore Petroleum Workers cohort (1965-98) with linkage to the Cancer Registry of Norway (1953-2019). Work history was recorded as years with day, night, and rollover (rotating) shift work, and CDA exposure was assessed with expert-made job-exposure matrices. Weighted Cox regression was used to estimate hazard ratios (HRs) and 95% confidence intervals (CIs) for aggressive prostate cancer, adjusted for education and year of first employment, stratified by 10-year birth cohorts, and with 10, 15, and 20 years of exposure lag periods.

RESULTS

Compared with day work only, an increased hazard of aggressive prostate cancer (HR = 1.86, 95% CI 1.18-2.91; P-trend = 0.046) was found in workers exposed to ≥19.5 years of rollover shift work. This persisted with longer lag periods (HR = 1.90, 95% CI 0.92-3.95; P-trend = 0.007). The exposure-hazard curve for a non-linear model increased linearly (HRs ≥1.00) for 18-26 years of rollover shift work. No association was found with CDA exposure.

CONCLUSIONS

Long-term exposure to rollover shift work may increase the hazard of aggressive prostate cancer in offshore petroleum workers.

Validation of the Swedish Trauma Registry (SweTrau)

PURPOSE

Validation of registries is important to ensure accuracy of data and registry-based research. This is often done by comparisons of the original registry data with other sources, e.g. another registry or a re-registration of data. Founded in 2011, the Swedish Trauma Registry (SweTrau) consists of variables based on international consensus (the Utstein Template of Trauma). This project aimed to perform the first validation of SweTrau.

METHODS

On-site re-registration was performed on randomly selected trauma patients and compared to the registration in SweTrau. Accuracy (exact agreement), correctness (exact agreement plus data within acceptable range), comparability (similarity with other registries), data completeness (1-missing data) and case completeness (1-missing cases) were deemed as either good ([Formula: see text] 85%), adequate (70-84%) or poor (< 70%). Correlation was determined as either excellent ([Formula: see text] 0.8), strong (0.6-0.79), moderate (0.4-0.59) or weak (< 0.4).

RESULTS

The data in SweTrau had good accuracy (85.8%), correctness (89.7%) and data completeness (88.5%), as well as strong or excellent correlation (87.5%). Case completeness was 44.3%, however, for NISS > 15 case completeness was 100%. Median time to registration was 4.5 months, with 84.2% registered one year after the trauma. The comparability showed an accordance with the Utstein Template of Trauma of almost 90%.

CONCLUSIONS

The validity of SweTrau is good, with high accuracy, correctness, data completeness and correlation. The data are comparable to other trauma registries using the Utstein Template of Trauma; however, timeliness and case completeness are areas of improvement.

A Comparison of Risk Classification Systems of Colorectal Adenomas: A Case-Cohort Study

BACKGROUND & AIMS

Because post-polypectomy surveillance uses a growing proportion of colonoscopy capacity, more targeted surveillance is warranted. We therefore compared surveillance burden and cancer detection using 3 different adenoma classification systems.

METHODS

In a case-cohort study among individuals who had adenomas removed between 1993 and 2007, we included 675 individuals with colorectal cancer (cases) diagnosed a median of 5.6 years after adenoma removal and 906 randomly selected individuals (subcohort). We compared colorectal cancer incidence among high- and low-risk individuals defined according to the traditional (high-risk: diameter ≥10 mm, high-grade dysplasia, villous growth pattern, or 3 or more adenomas), European Society of Gastrointestinal Endoscopy (ESGE) 2020 (high-risk: diameter ≥10 mm, high-grade dysplasia, or 5 or more adenomas), and novel (high-risk: diameter ≥20 mm or high-grade dysplasia) classification systems. For the different classification systems, we calculated the number of individuals recommended frequent surveillance colonoscopy and estimated number of delayed cancer diagnoses.

RESULTS

Four hundred and thirty individuals with adenomas (52.7%) were high risk based on the traditional classification, 369 (45.2%) were high risk based on the ESGE 2020 classification, and 220 (27.0%) were high risk based on the novel classification. Using the traditional, ESGE 2020, and novel classifications, the colorectal cancer incidences per 100,000 person-years were 479, 552, and 690 among high-risk individuals, and 123, 124, and 179 among low-risk individuals, respectively. Compared with the traditional classification, the number of individuals who needed frequent surveillance was reduced by 13.9% and 44.2%, respectively, and 1 (3.4%) and 7 (24.1%) cancer diagnoses were delayed using the ESGE 2020 and novel classifications.

CONCLUSIONS

Using the ESGE 2020 and novel risk classifications will substantially reduce resources needed for colonoscopy surveillance after adenoma removal.

Quality indicators: completeness, validity and timeliness of cancer registry data contributing to the European Cancer Information System

Population-based Cancer Registries (PBCRs) are tasked with collecting high-quality data, important for monitoring cancer burden and its trends, planning and evaluating cancer control activities, clinical and epidemiological research and development of health policies. The main indicators to measure data quality are validity, completeness, comparability and timeliness. The aim of this article is to evaluate the quality of PBCRs data collected in the first ENCR-JRC data call, dated 2015.

Methods

All malignant tumours, except skin non-melanoma, and in situ and uncertain behaviour of bladder were obtained from 130 European general PBCRs for patients older than 19 years. Proportion of cases with death certificate only (DCO%), proportion of cases with unknown primary site (PSU%), proportion of microscopically verified cases (MV%), mortality to incidence (M:I) ratio, proportion of cases with unspecified morphology (UM%) and the median of the difference between the registration date and the incidence date were computed by sex, age group, cancer site, period and PBCR.

Results

A total of 28,776,562 cases from 130 PBCRs, operating in 30 European countries were included in the analysis. The quality of incidence data reported by PBCRs has been improving across the study period. Data quality is worse for the oldest age groups and for cancer sites with poor survival. No differences were found between males and females. High variability in data quality was detected across European PBCRs.

Conclusion

the results reported in this paper are to be interpreted as the baseline for monitoring PBCRs data quality indicators in Europe along time.

S100A8 gene copy number and protein expression in breast cancer: associations with proliferation, histopathological grade and molecular subtypes

BACKGROUND AND AIMS

Amplification of S100A8 occurs in 10-30% of all breast cancers and has been linked to poorer prognosis. Similarly, the protein S100A8 is overexpressed in a roughly comparable proportion of breast cancers and is also found in infiltrating myeloid-lineage cells, again linked to poorer prognosis. We explore the relationship between these findings.

METHODS

We examined S100A8 copy number (CN) alterations using fluorescence in situ hybridization in 475 primary breast cancers and 117 corresponding lymph nodes. In addition, we studied S100A8 protein expression using immunohistochemistry in 498 primary breast cancers from the same cohort.

RESULTS

We found increased S100A8 CN (≥ 4) in tumor epithelial cells in 20% of the tumors, increased S100A8 protein expression in 15%, and ≥ 10 infiltrating S100A8 + polymorphonuclear cells in 19%. Both increased S100A8 CN and protein expression in cancer cells were associated with high Ki67 status, high mitotic count and high histopathological grade. We observed no association between increased S100A8 CN and S100A8 protein expression, and only a weak association (p = 0.09) between increased CN and number of infiltrating S100A8 + immune cells. Only S100A8 protein expression in cancer cells was associated with significantly worse prognosis.

CONCLUSIONS

Amplification of S100A8 does not appear to be associated with S100A8 protein expression in breast cancer. S100A8 protein expression in tumor epithelial cells identifies a subgroup of predominantly non-luminal tumors with a high mean age at diagnosis and significantly worse prognosis. Finally, S100A8 alone is not a sufficient marker to identify infiltrating immune cells linked to worse prognosis.

Non-progressive breast carcinomas detected at mammography screening: a population study

BACKGROUND

Some breast carcinomas detected at screening, especially ductal carcinoma in situ, may have limited potential for progression to symptomatic disease. To determine non-progression is a challenge, but if all screening-detected breast tumors eventually reach a clinical stage, the cumulative incidence at a reasonably high age would be similar for women with or without screening, conditional on the women being alive.

METHODS

Using high-quality population data with 24 years of follow-up from the gradually introduced BreastScreen Norway program, we studied whether all breast carcinomas detected at mammography screening 50-69 years of age would progress to clinical symptoms within 85 years of age. First, we estimated the incidence rates of breast carcinomas by age in scenarios with or without screening, based on an extended age-period-cohort incidence model. Next, we estimated the frequency of non-progressive tumors among screening-detected cases, by calculating the difference in the cumulative rate of breast carcinomas between the screening and non-screening scenarios at 85 years of age.

RESULTS

Among women who attended BreastScreen Norway from the age of 50 to 69 years, we estimated that 1.1% of the participants were diagnosed with a breast carcinoma without the potential to progress to symptomatic disease by 85 years of age. This proportion of potentially non-progressive tumors corresponded to 15.7% [95% CI 3.3, 27.1] of breast carcinomas detected at screening.

CONCLUSIONS

Our findings suggest that nearly one in six breast carcinomas detected at screening may be non-progressive.

Development and evaluation of a customized checklist to assess the quality control of disease registry systems of Tehran, the capital of Iran in 2021

BACKGROUND

Clinical registries facilitate medical research by providing 'real data'. In the past decade, an increasing number of disease registry systems (DRS) have been initiated in Iran. Here, we assessed the quality control (QC) of the data recorded in the DRS established by Shahid Beheshti University of Medical Sciences in Tehran, the capital city of Iran, in 2021.

METHODS

The present study was conducted in two consecutive qualitative and quantitative phases and employed a mixed-method design. A checklist containing 23 questions was developed based on a consensus reached following several panel group discussions, whose face content and construct validities were confirmed. Cronbach's alpha was calculated to verify the tool's internal consistency. Overall, the QC of 49 DRS was assessed in six dimensions, including completeness, timeliness, accessibility, validity, comparability, and interpretability. The seventy percent of the mean score was considered a cut-point for desirable domains.

RESULTS

The total content validity index (CVI) was obtained as 0.79, which is a reasonable level. Cronbach's alpha coefficients obtained showed acceptable internal consistency for all of the six QC domains. The data recorded in the registries included different aspects of diagnosis/treatment (81.6%) and treatment quality requirements outcomes (12.2%). According to the acceptable quality cut-point, out of 49 evaluated registries, 48(98%), 46(94%), 41(84%), and 38(77.5%), fulfilled desirable quality scores in terms of interpretability, accessibility, completeness, and comparability, however, 36(73.5%) and 32(65.3%) of registries obtained the quality requirement for timeliness and validity, respectively.

CONCLUSION

The checklist developed here, containing customized questions to assess six QC domains of DRSs, provided a valid and reliable tool that could be considered as a proof-of-concept for future investigations. The clinical data available in the studied DRSs fulfilled desirable levels in terms of interpretability, accessibility, comparability, and completeness; however, timeliness and validity of these registries needed to be improved.

Tracheal cancer: a rare and deadly but potentially curable disease that also affects younger people

OBJECTIVES

The incidence of tracheal cancer is low, few clinicians get much experience and the awareness may be low. Recent data on the treatment and outcome are limited. The aim of the present study was to present updated, national data on the incidence, characteristics, treatment and outcome for patients with tracheal cancer.

METHODS

All tracheal cancers registered at the Cancer Registry of Norway in 2000-2020 were extracted. The patient and tumour characteristics age, sex, stage, histology and treatment modality (surgery and radiotherapy) were examined. Overall, median and relative survival were estimated. Cox regression models were used to identify independent prognostic factors.

RESULTS

The 77 patients diagnosed with tracheal cancer equals a crude incidence rate and an age-standardized incidence rate of 0.075 and 0.046 per 100,000 per year respectively. The mean age was 63.8 years (range: 26-94). The numerical preponderance of men (n = 41) is not statistically significant. Eighteen patients (23.4%) were diagnosed in the localized stage. The 5-year overall survival was 31.7% [95% confidence interval (CI): 21.0-42.9], and in those treated with surgical resection or curative radiotherapy, it was 53.7% (95% CI: 26.1-75.0) and 37.8% (95% CI: 18.8-56.7), respectively. Age, histological type and treatment modality were identified as independent prognostic factors.

CONCLUSIONS

Despite improved survival, the prognosis for patients with tracheal cancer is still poor. Few are diagnosed in the early stage and thus most are not eligible for curative treatment, mainly surgery. An increased awareness and diagnosis in the earlier stage is crucial.

Age at Menarche, age at Natural Menopause, and Risk of Lung and Colorectal Cancers: A Mendelian Randomization Study

Background

The roles of age at menarche and age at menopause in the etiology of lung and colorectal cancers are unclear.

Objective

We aimed to investigate potential causal associations between age at menarche, age at natural menopause, and risk of lung and colorectal cancers using a Mendelian randomization (MR) approach.

Methods

From the Trøndelag Health Study in Norway, we defined two cohorts of 35 477 and 17 118 women to study the effects of age at menarche and age at natural menopause, respectively. We ran univariable MR to evaluate the potential causal associations. We performed multivariable MR adjusting for genetic variants of adult body mass index (BMI) to estimate the direct effect of age at menarche.

Results

Genetically predicted 1-year increase in age at menarche was associated with a lower risk of lung cancer overall (hazard ratio [HR, 0.64; 95% CI, 0.48-0.86), lung adenocarcinoma (HR, 0.61; 95% CI, 0.38-0.99), and lung non-adenocarcinoma (HR, 0.66; 95% CI, 0.45-0.95). After adjusting for adult BMI using a multivariable MR model, the direct effect estimates reduced to HR 0.72 (95% CI, 0.54-0.95) for lung cancer overall, HR 0.67 (95% CI, 0.43-1.03) for lung adenocarcinoma, and HR 0.77 (95% CI, 0.54-1.09) for lung non-adenocarcinoma. Age at menarche was not associated with colorectal cancer. Moreover, genetically predicted age at natural menopause was not associated with lung and colorectal cancers.

Conclusion

Our MR study suggested that later age at menarche was causally associated with a decreased risk of lung cancer overall and its subtypes, and adult BMI might be a mediator.

Incidence of cancer in patients with ulcerative colitis 30 years after diagnosis (the IBSEN study)

OBJECTIVES

Patients with ulcerative colitis (UC) have shown an increased risk for colorectal cancer, hepatobiliary, hematologic, and skin cancers, but updated long-term data is needed. This study aimed to estimate the risk of cancer in patients with UC compared to the general Norwegian population, in a population-based cohort (the IBSEN study), 30 years after diagnosis; and to identify possible risk factors associated with cancer.

METHODS

The IBSEN cohort prospectively included all incident patients between 1990 and 1993. Cancer incidence data were obtained from the Cancer Registry of Norway. The overall and cancer-specific hazard ratios (HR) were modelled using Cox regression. Standardized incidence ratios were estimated compared to the general population.

RESULTS

In total, the cohort included 519 patients, and 83 cases were diagnosed with cancer. There was no statistically significant difference in the overall cancer risk (HR = 1.01, 95% CI: [0.79-1.29]) and colorectal cancer risk (HR = 1.37, 95% CI: [0.75-2.47]) between patients and controls. The incidence of biliary tract cancer was higher than expected (SIR = 9.84, 95%CI: [3.19-20.15]), especially when UC patients suffered from primary sclerosing cholangitis. Male UC patients were also more at risk of being diagnosed with hematologic malignancies (HR = 3.48, 95% CI: [1.55-7.82]). Being prescribed thiopurines was associated with a higher risk of cancer (HR = 2.03, 95% CI: [1.02-4.01]).

CONCLUSIONS

At 30 years after diagnosis, the risk of all cancer in patients with UC was not significantly increased compared with the general population. However, the risks of biliary tract cancer and hematologic cancers were increased, particularly in male patients.

Hospital surgical volume and colorectal cancer survival in Norway: A nationwide cohort study

BACKGROUND

Studies of hospital surgical volume and colorectal cancer survival are inconclusive. We investigated whether surgical volume was associated with survival of patients operated for colorectal cancer in Norway.

METHODS

Using Cancer Registry of Norway data, we compared excess mortality from colorectal cancer by hospital surgical volume among 26,989 colon and 9779 rectal cancer patients diagnosed 2009-2020 and followed-up to 31.12.2021. Hospitals were divided into terciles according to their three-year average annual surgical volume; colon: low (< 22), middle (22-73), high (> 73); rectal: low (< 17), middle (17-38), high (> 38). We estimated excess hazard ratios (EHR) with flexible parametric models adjusted for age, year, stage, surgical urgency and surgery location (within/outside patient's residential health trust).

RESULTS

Low-volume hospitals had the highest proportion of late-stage or acutely operated colon cancer patients. Colon cancer patients operated at low- versus high-volume hospitals had significantly increased crude excess mortality (EHR = 1.30; 95 % CI = 1.14-1.48) but no difference after adjustment for age, year, and stage (EHR = 0.97; 0.85-1.11). High-volume hospitals had the highest proportion of late-stage rectal cancer patients and patients operated outside their residential area. Rectal cancer patients operated at low- versus high-volume hospitals did not have significantly different excess mortality before (EHR = 0.84; 0.64-1.10) or after (EHR = 1.03; 0.79-1.35) adjustment for age, year, stage, surgical urgency and surgery location. After accounting for case-mix, hospital surgical volume was not associated with excess mortality from colon (P = 0.40) or rectal cancer (P = 0.22).

CONCLUSION

Low hospital surgical volume was not associated with poorer colorectal cancer survival.

Use of antihypertensive drugs and risk of cutaneous melanoma: a nationwide nested case-control study

BACKGROUND

Most antihypertensives can induce dermal photosensitivity, which may increase melanoma risk. However, corroborating evidence is limited. We examined the associations between use of antihypertensives and melanoma risk.

METHODS

A nationwide nested case-control study was conducted using data from the Cancer Registry of Norway, the National Registry and the Norwegian Prescription Database in 2004-15. Ten controls were randomly selected for each melanoma case, matched on sex and birth year. The study included 12 048 cases and 117 895 controls. We estimated rate ratios (RRs) with 95% confidence intervals (CIs). All analyses were adjusted for ambient ultraviolet radiation (UVR). We additionally performed active comparator analyses, and sensitivity analyses by only including new users, distinguishing between exclusive and mixed users, allowing for different latency periods, and subgroup analyses by melanoma subtype and clinical stage.

RESULTS

Compared with non-use, we observed a slightly increased melanoma risk in users of diuretics (RR 1.08, CI 1.01-1.15), calcium-channel blockers (RR 1.10, CI 1.04-1.18) and drugs affecting the renin-angiotensin system (RR 1.10, CI 1.04-1.16), but not for beta blockers (RR 0.97, CI 0.92-1.03). We found no heterogeneity of associations by melanoma subtype or clinical stage and no dose-response relationship between the cumulative defined daily doses (DDDs) and melanoma. No interaction was found between cumulative DDDs and ambient UVR.

CONCLUSIONS

Weak associations, with lack of a dose-response relationship and lack of interactions with ambient UVR, in the DDD analysis in this nationwide study do not support a causal relationship between antihypertensives and melanoma risk.

Mammographic density and interval cancers in mammographic screening: Moving towards more personalized screening

PURPOSE

The European Society on Breast Imaging has recommended supplemental magnetic resonance imaging (MRI) every two to four years for women with mammographically dense breasts. This may not be feasible in many screening programs. Also, the European Commission Initiative on Breast Cancer suggests not implementing screening with MRI. By analyzing interval cancers and time from screening to diagnosis by density, we present alternative screening strategies for women with dense breasts.

METHODS

Our BreastScreen Norway cohort included 508 536 screening examinations, including 3125 screen-detected and 945 interval breast cancers. Time from screening to interval cancer was stratified by density measured by an automated software and classified into Volpara Density Grades (VDGs) 1-4. Examinations with volumetric density ≤3.4% were categorized as VDG1, 3.5%-7.4% as VDG2, 7.5%-15.4% as VDG3, and ≥15.5% as VDG4. Interval cancer rates were also determined by continuous density measures.

RESULTS

Median time from screening to interval cancer was 496 (IQR: 391-587) days for VDG1, 500 (IQR: 350-616) for VDG2, 482 (IQR: 309-595) for VDG3 and 427 (IQR: 266-577) for VDG4. A total of 35.9% of the interval cancers among VDG4 were detected within the first year of the biennial screening interval. For VDG2, 26.3% were detected within the first year. The highest annual interval cancer rate (2.7 per 1000 examinations) was observed for VDG4 in the second year of the biennial interval.

CONCLUSIONS

Annual screening of women with extremely dense breasts may reduce the interval cancer rate and increase program-wide sensitivity, especially in settings where supplemental MRI screening is not feasible.

Trends in the incidence of urothelial carcinoma in Taiwan after the ban on aristolochic acid-containing Chinese herbal preparations, 2001-2018: a national population-based cohort study

PURPOSE

Urothelial carcinoma (UC) of the bladder (BUC) and the upper urinary tract (UTUC) are the two most common UCs. The incidence of UTUC in Taiwan is the highest worldwide. Aristolochic acid (AA) was identified as the main cause of UTUC in Taiwan. To explore trends in the incidence of UC in Taiwan after the ban on Chinese herbal preparations containing AA in 2003.

METHODS

We used data from the Taiwanese National Health Insurance Research Database-linked Taiwanese National Cancer Registry for 2001-2018. UC was defined in accordance with the International Classification of Disease for Oncology. The age-standardized incidence was calculated on the basis of the World Health Organization standard population. Trends in the incidence were calculated as the annual percent change (APC) by using the Joinpoint regression program.

RESULTS

Over the investigated period, the incidence of UC decreased at an average annual percent change (AAPC) of - 1.19% (95% CI - 1.47 ~ - 0.91, P < 0.001). However, the incidence in UTUC significantly increased, with the AAPC being 1.47% (95% CI 1.03 ~ 1.90, P < 0.001). In contrast, the incidence of BUC significantly decreased, with the overall AAPC being - 1.92% (95% CI - 2.3 ~ - 1.54, P < 0. 001). From 2001 to 2018, the overall incidence of UCs and BUC decreased in Taiwan, but the incidence of UTUC significantly increased.

CONCLUSION

We suggest to apply the same review standards of new drug development process to herbal preparations and incorporate them into the adverse drug reaction or poison surveillance system. Most importantly, raise public awareness of the potential toxicity of phytotherapy.

Antimuscarinics and lung cancer survival: a Norwegian population-based cohort study

OBJECTIVES

Epidemiological studies have reported an association between antimuscarinics and reduced risk of cancer, including lung cancer (LC). However, the potential association between antimuscarinic use and LC prognosis has not previously been assessed. In a large population-based cohort, we aimed to investigate the association between the use of antimuscarinics and LC-specific survival.

MATERIALS AND METHODS

Norwegian residents, aged ≥ 50 years, and diagnosed with LC between 2005 and 2018, were identified in the Cancer Registry of Norway, and information on filled prescriptions was obtained from the Norwegian Prescription Database. We used Cox proportional hazard models to estimate hazard ratios (HR) and 95 % confidence intervals (CI) for the association between peri-diagnostic and post-diagnostic use of antimuscarinics and LC-specific survival.

RESULTS

We included 26,693 patients with incident primary invasive LC. Of these, 466 (1.7 %) were peri-diagnostic users, and 877 (3.3 %) were post-diagnostic users of antimuscarinics, respectively. During a median follow-up of nine months, 18,088 (67.8 %) patients died due to LC. In the overall LC population, the HRs for the association between the use of antimuscarinics, compared to no use, were estimated at 1.01 (95 %CI: 0.90-1.12) for peri-diagnostic use, and 0.84 (95 %CI: 0.77-0.92) for post-diagnostic use. The association with post-diagnostic use was observed in many subgroups defined by sex, age, smoking status, histopathology, and stage, except for patients with unspecified or other histopathology than small cell LC and non-small cell LC, and for patients with local disease. The association was observed in patients treated with chemotherapy (HR = 0.75, 95 %CI: 0.64-0.88), but not in those not treated with chemotherapy (HR = 1.00, 95 %CI: 0.86-1.17; p for interaction: 0.007).

CONCLUSION

Our results suggest a possible association between use of antimuscarinics and longer LC-specific survival. More studies are warranted to investigate the use of antimuscarinics to possibly prolong LC prognosis.

Low-dose aspirin and risk of breast cancer: a Norwegian population-based cohort study of one million women

Several studies evaluated the association between aspirin use and risk of breast cancer (BC), with inconsistent results. We identified women aged ≥ 50 years residing in Norway between 2004 and 2018, and linked data from nationwide registries; including the Cancer Registry of Norway, the Norwegian Prescription Database, and national health surveys. We used Cox regression models to estimate the association between low-dose aspirin use and BC risk, overall and by BC characteristics, women's age and body mass index (BMI), adjusting for sociodemographic factors and use of other medications. We included 1,083,629 women. During a median follow-up of 11.6 years, 257,442 (24%) women used aspirin, and 29,533 (3%) BCs occurred. For current use of aspirin, compared to never use, we found an indication of a reduced risk of oestrogen receptor-positive (ER +) BC (hazard ratio [HR] = 0.96, 95% confidence interval [CI]: 0.92-1.00), but not ER-negative BC (HR = 1.01, 95%CI: 0.90-1.13). The association with ER + BC was only found in women aged ≥ 65 years (HR = 0.95, 95%CI: 0.90-0.99), and became stronger as the duration of use increased (use of ≥ 4 years HR = 0.91, 95%CI: 0.85-0.98). BMI was available for 450,080 (42%) women. Current use of aspirin was associated with a reduced risk of ER + BC in women with BMI ≥ 25 (HR = 0.91, 95%CI: 0.83-0.99; HR = 0.86, 95%CI: 0.75-0.97 for use of ≥ 4 years), but not in women with BMI < 25.Use of low-dose aspirin was associated with reduced risk of ER + BC, in particular in women aged ≥ 65 years and overweight women.

Incidence and prevalence of neuroendocrine neoplasms in Norway 1993-2021

The incidence of neuroendocrine neoplasms (NENs) has increased over the last decades. The prevalence of NENs has to a lesser extent been previously reported. We wanted to study the trends in incidence and prevalence of NEN in Norway from 1993 to 2021 through the Cancer Registry of Norway. This registry, which covers the whole population, has been found to be 99% complete. The neoplasms were classified as neuroendocrine tumors (NETs) and neuroendocrine carcinomas (NECs). From 1993 to 2021 altogether 10.288 NETs and 13,982 (1.756 outside the lungs) NECs were diagnosed. The incidence of NETs increased from 3.72 to 9.97 per 100,000 per year, corresponding to a 268% increase, p < .001. The largest increase in incidence for NETs was found for pancreas (338%), lung (330%) and small intestine (303%). For NECs there was no change in the incidence, from 9.74 to 9.95 per 100,000 per year, p = .4, but there was an increase in the incidence of NECs originating from the skin (Merkel cell carcinoma) (287%), p < .001, and the GI tract (200%), p = .03. There were no changes in stage distribution at diagnosis for NETs and NECs. The prevalence for NENs increased 666% during the study period, NETs increased from 10.77 to 99.37 per 100.000 (927%), p < .001. For NECs the increase was from 7.4 to 21.56 per 100.000 (291%), p < .001. GI-NECs increased the most from 0.005 to 0.94 (1880%), p = .002. In conclusion, there was a substantial increase in incidence and prevalence of neuroendocrine neoplasms in Norway from 1993 to 2021. This is the first study to report complete prevalence of NENs for a whole nation.

Additional malignancies and mortality in uveal melanoma: A 20-year follow-up of a Norwegian patient cohort

PURPOSE

The purpose of this study is to explore the frequency of additional primary malignancies in uveal melanoma (UM) patients and cause-specific mortality, to help guide surveillance strategies after UM.

METHODS

All patients diagnosed with UM at Oslo University Hospital during 1990-2017 were eligible for inclusion. Linkage to the Cancer Registry of Norway obtained information on additional malignancies and cause of death throughout 2019. UM patients were categorized according to timing of additional malignancy (prior/simultaneously or after UM) or no additional cancer, and by UM stage at diagnosis. Age-adjusted mortality rates were presented per 1000 person-years with 95% confidence intervals (CI).

RESULTS

The study population included 960 UM patients: 77% were diagnosed in stage and I/II and 56% were men. Mean age at diagnosis was 63 years. Additional malignancies were observed in 152 patients prior/simultaneous to UM, and in 120 patients >1 year after UM. Overall, mortality per 1000 person-years was 3.5 (95% CI 3.1-3.9) for UM and 3.0 (2.6-3.4) for other causes. Lowest UM mortality [1.3 (0.60-2.1)] was seen in patients with a second malignancy after UM, regardless of stage. Highest UM mortality was seen for UM patients in stage III/IV, both without [16.1 (13.2-19.1)] and with any additional malignancy [16.9 (6.6-27.3)].

CONCLUSION

Our results support that UM patients frequently have additional malignancies, both before and after UM. Low-UM mortality in patients with a primary malignancy after UM, might indicate less aggressive UM. The cumulative UM mortality flattens about 10 years after diagnosis and annual follow-up of patients for 10 years seems adequate.

Artificial intelligence in BreastScreen Norway: a retrospective analysis of a cancer-enriched sample including 1254 breast cancer cases

OBJECTIVES

To compare results of selected performance measures in mammographic screening for an artificial intelligence (AI) system versus independent double reading by radiologists.

METHODS

In this retrospective study, we analyzed data from 949 screen-detected breast cancers, 305 interval cancers, and 13,646 negative examinations performed in BreastScreen Norway during the period from 2010 to 2018. An AI system scored the examinations from 1 to 10, based on the risk of malignancy. Results from the AI system were compared to screening results after independent double reading. AI score 10 was set as the threshold. The results were stratified by mammographic density.

RESULTS

A total of 92.7% of the screen-detected and 40.0% of the interval cancers had an AI score of 10. Among women with a negative screening outcome, 9.1% had an AI score of 10. For women with the highest breast density, the AI system scored 100% of the screen-detected cancers and 48.6% of the interval cancers with an AI score of 10, which resulted in a sensitivity of 80.9% for women with the highest breast density for the AI system, compared to 62.8% for independent double reading. For women with screen-detected cancers who had prior mammograms available, 41.9% had an AI score of 10 at the prior screening round.

CONCLUSIONS

The high proportion of cancers with an AI score of 10 indicates a promising performance of the AI system, particularly for women with dense breasts. Results on prior mammograms with AI score 10 illustrate the potential for earlier detection of breast cancers by using AI in screen-reading.

KEY POINTS

• The AI system scored 93% of the screen-detected cancers and 40% of the interval cancers with AI score 10. • The AI system scored all screen-detected cancers and almost 50% of interval cancers among women with the highest breast density with AI score 10. • About 40% of the screen-detected cancers had an AI score of 10 on the prior mammograms, indicating a potential for earlier detection by using AI in screen-reading.

Clinical associations for traditional and complementary medicine use among norwegian cancer survivors in the seventh survey of the Tromsø study: a cross-sectional study

BACKGROUND

Cancer survivors are a diverse group with varying needs that are patient-, disease-, and/or treatment-specific. Cancer survivors have reported supplementing conventional anti-cancer treatment with Traditional and Complementary Medicine (T&CM). Although female cancer survivors are reported to have more severe anticancer adverse effects, little is known about the association between anticancer treatment and T&CM use among Norwegian cancer survivors. The aims of this study are therefore to investigate (1) associations between cancer diagnosis characteristics and T&CM utilization and (2) associations between anticancer treatment and T&CM utilization among cancer survivors in the seventh survey of the Tromsø study.

METHODS

Data was collected from the seventh survey of the Tromsø Study conducted in 2015-16 among all inhabitants of Tromsø municipality aged 40 and above (response rate 65%), where inhabitants received online and paper form questionnaires. Data from the data linkage to the Cancer Registry of Norway for cancer diagnosis characteristics was also used. The final study sample was made up of 1307 participants with a cancer diagnosis. Categorical variables were compared using Pearson's Chi-square test or Fisher's exact test while independent sample t-test was used to compare continuous variables.

RESULTS

The use of T&CM the preceding 12 months was reported by 31.2% of the participants with natural remedies as the most reported modality of T&CM (18.2%, n = 238), followed by self-help practices of meditation, yoga, qigong, or tai chi, which was reported by 8.7% (n = 114). Users of T&CM were significantly younger (p = .001) and more likely to be female (p < .001) than the non-users, with higher use of T&CM among female survivors with poor self-reported health and being 1-5 years post-diagnosis. Lower use of T&CM was found among female survivors who received a combination of surgery with hormone therapy and those who received a combination of surgery with hormone therapy and radiotherapy. Similar usage was seen in male survivors, but not at a significant level. For both male and female survivors, T&CM was most frequently used by those with only one cancer diagnosis (p = .046).

CONCLUSION

Our results indicate that the profile of the Norwegian cancer survivor who uses T&M is slightly changing compared to previous findings. Additionally, compared to male survivors, more clinical factors are associated with use of T&CM among female cancer survivors. These results should serve as a reminder to conventional health care providers to discuss the use of T&CM with patients across the entire cancer survivorship continuum to promote safe use, especially among female survivors.

Oncological outcomes after simple and skin-sparing mastectomy of ductal carcinoma in situ: A register-based cohort study of 576 Norwegian women

BACKGROUND

For Ductal Carcinoma in Situ (DCIS), recurrence is shown to be higher after skin-sparing (SSM) versus simple (SM) mastectomy. This study aimed to compare the two groups recurrence rates, disease-free survival (DFS), and overall (OS) survival.

METHODS

We conducted a retrospective register-based cohort study of women operated with SSM (n = 338) or SM (n = 238) for DCIS between 2007 and 2017. Data from the Norwegian Breast Cancer Registry was used to estimate recurrences rates, DFS and OS.

RESULTS

Mean age was 51 and 61 years in the SSM and SM groups, respectively. Median follow-up time was 77 months for SSM (range: 21-152 months) vs 84 months for SM (range: 7-171 months). After five years of follow-up, the overall recurrence rate (OR) was 2.1%; 3.9% for SSM and 0.9% for SM. After ten years, the rates were 3.0%, 6.2% for SSM and still 0.9% for SM. DFS was after ten years 92.2%; 91.8% for SSM, and 92.4% for SM. OS was 95.0%; 97.5% for SSM and 93.3% for SM at ten years. For SSM, involved margins represented a significant risk for recurrence.

CONCLUSION

The recurrence rate was higher in the SSM versus the SM group. Whether the difference is due to the operating procedures or underlying risk factors remains unknown. When stratifying for the difference in age, there was no statistical difference in DFS or OS. Involved margins in the SSM group were associated with an increased risk of recurrence.

Risk and survival in colorectal cancer with increasing body mass index: A nationwide population-based cohort study

AIM

The aim was to explore potential associations between the body mass index (BMI) and the risk of colorectal cancer (CRC), including subsites of the colon, and cancer-specific death.

METHODS

A registry-based cohort study was conducted with baseline data gathered from the Norwegian Tuberculosis Screening Programme, collected between 1963 and 1975, and linked to follow-up data from the Cancer Registry of Norway and the Norwegian Cause of Death Registry. Cox regression models were used to explore associations between BMI and CRC risk and cancer-specific death.

RESULTS

Of 1 723 692 included individuals, 76 616 developed CRC during 55 370 707 person-years of follow-up. In men, a 5 kg/m² increase in BMI was associated with an increased risk of colon cancer, including both right and left subsites, and rectal cancer. Allowing for nonlinearities, we found a U-shaped association for the right colon and an inverse U-shape for the left colon and rectum cancer. In women, a 5 kg/m² increase in BMI in early adulthood was associated with increased risk of colon cancer, including both subsites. In women, an increased risk of CRC death with increasing BMI was found for colon cancer.

CONCLUSIONS

Men of all ages have an increased risk of CRC with increasing BMI, with the highest risk for right-sided colon cancer. An increased risk for colon cancer was also found in women with high BMI in early adulthood. Furthermore, women of all age groups appeared to have an increased risk of CRC death with higher BMI.

Body mass index and pancreatic adenocarcinoma: A nationwide registry-based cohort study

BACKGROUND AND OBJECTIVE

An association between body mass index (BMI) and pancreatic cancer is suggested in observational studies. However, further studies are required to substantiate available evidence. The aim of this study was to explore the association between BMI and pancreatic ductal adenocarcinoma (PDAC) risk, treatment, and mortality.

METHODS

A registry-based cohort study was performed by combining data from four registries in Norway. Baseline data were collected between 1963 and 1975 with follow-up data collected until 2018. Kaplan-Meier curves and multivariable Cox regressions were estimated. Chi-square tests were used to analyze differences between groups.

RESULTS

The study cohort consisted of 1,723,692 individuals. A total of 8973 PDAC cases were identified during 55,744,749 person-years of follow-up. A 5 kg/m² increase in BMI was associated with an increased risk of PDAC if high BMI at young age (16-29 years) (hazard ratio (HR): 1.21, 95% confidence interval (CI): 1.13-1.31), both for men (HR: 1.30, 95% CI: 1.15-1.46) and women (HR: 1.16, 95% CI: 1.05-1.28). In men, there was a 52% increase in risk of early-onset PDAC (<age 50) (HR: 1.52, 95% CI: 1.13-2.03) with 5 kg/m² increase in BMI. A total of 2645 individuals were diagnosed with stage 1-3 disease, of whom 1131 underwent curative surgery. In all, 49% of normal weight, 38% overweight, and 30% obese individuals with stage 1-3 PDAC underwent surgery with curative intent (p < 0.001). Cancer survival was lower in overweight and obese individuals for both sexes. Analysis adjusted for sex, age, and period of diagnosis confirmed increased risk of cancer death in obese individuals.

CONCLUSION

This study suggests that increased BMI in young adults may increase the risk of PDAC, and higher BMI in men is associated with an increased risk of early onset PDAC (<age 50). Overweight and obese individuals were less likely to undergo curative surgery and obese individuals had a higher risk of cancer-related death.

The national incidence of chondrosarcoma of bone; a review

BACKGROUND

Chondrosarcoma (CS) epidemiology has been studied by a number of authors using national cancer registry cohorts. Many reports share the common findings of a slight increase in incidence, but not all. The patterns and causes for these changes are divergent while reflection concerning methodological challenges are often missing.

METHOD

We have performed a structured literature review to find national analyses of CS incidence published from 2010 to 2020. We included eight studies of national incidence of CS, summarise their findings and patterns of change. We further discuss explanations given for these changes to better understand the real patterns and raise awareness in their interpretation.

RESULTS

Reported crude incidence ranges from 0.27 per million per year overall in Saudi Arabia to 5.4 in the Netherlands. Four studies from the USA, England, Switzerland and France report age standardised rates of 2.0-4.1 per million per year overall. While some countries report stable patterns, most report a slight increase. The Netherlands is the only country reporting a large increase, driven by a 10-fold increase in the incidence of ACT/grade 1 CS during the study period. We challenge the explanations given for this and suggest that this most likely is a result of variable interpretation and definition of CS at the lower levels of disease aggressiveness. This should raise awareness to possible over-treatment of CS in the Netherlands.

CONCLUSION

The most likely national incidence of CS of bone is between 2-4 per million per year. Three modern reports present an incidence of 3.4-4.1 per million per year.

Real-World Data on EGFR and ALK Testing and TKI Usage in Norway-A Nation-Wide Population Study

Clinical studies have shown the efficacy of EGFR- and ALK-directed therapies in non-small cell lung cancer (NSCLC). Real-world data on, e.g., testing patterns, uptake, and duration of treatment are scarce. Reflex EGFR and ALK testing of non-squamous NSCLCs were implemented in Norwegian guidelines in 2010 and 2013, respectively. We present a complete national registry data on incidence, pathology procedures, and drug prescription in the period of 2013 to 2020. Test rates for both EGFR and ALK increased over time and were 85% and 89%, respectively, at the end of the study period, independent of age up to 85 years. The positivity rate for EGFR was higher among females and young patients, whereas no sex difference was observed for ALK. EGFR-treated patients were older than ALK-treated patients (71 vs. 63 years at start, p < 0.001). Male ALK-treated patients were significantly younger than females at the start of treatment (58 vs. 65 years, p = 0.019). The time from the first dispensation to the last dispensation of TKI (as a surrogate for progression-free survival) was shorter for EGFR- than for ALK-TKI, and survival for both EGFR- and ALK-positive patients was substantially longer than for non-mutated patients. We found a high adherence to molecular testing guidelines, good concordance of mutation positivity and treatment, and the real-world replication of findings in clinical trials, indicating that the relevant patients are provided substantially life-prolonging therapy.

Evaluation of data quality at the Hungarian National Cancer Registry, 2000-2019

BACKGROUND

The Hungarian National Cancer Registry (HNCR) was legally established as a population-based cancer registry in 1999, and its operation started in 2000 supporting the planning and development of the Hungarian oncology network as well as informing national cancer control policies. Ensuring comparable, accurate, and complete data on malignant and in situ neoplasms is critical in determining the applicability of the database. The aim of this study was to perform a comprehensive evaluation of the data quality at the HNCR.

METHODS

Based on qualitative and semiquantitative methods from current international guidelines, we assess the comparability, completeness, validity, and timeliness of the collected data over the diagnostic period 2000-2019, with a focus on the year 2018.

RESULTS

Coding practices and the classification system used at the HNCR are based on the International Classification of Diseases (ICD-10), which differs from the internationally recommended ICD-O. The annual trends in incidence did not indicate major fluctuations, that may have resulted from data collection discrepancies, while comparisons of the mortality-to-incidence ratio (M:I) compared with 1 minus 5-year observed survival indicated some systematic differences requiring further exploration. The age-standardized (European standard) incidence rate per 100 000 measured by the HNCR in 2018 was very high: 647.9 for men and 501.6 for women, 11.6% and 14.6% higher than the International Agency for Research on Cancer (IARC) estimates respectively. Behind the overall differences between the two data sources, we identified that the vast majority were due to ill-defined ICD codes: malignant neoplasm of other and ill-defined sites (C76), and malignant neoplasm without specification of site (C80). Otherwise, there were no major discrepancies by localization. The proportion of morphologically verified cancer cases was 57.8% overall, that of death certificates was 2.3%, and that of unknown primary tumors was 1.4%.

CONCLUSION

Further implementations and interventions are required to ensure that the operations, coding practices, and the classification system used at the national registry are in accordance with international standards, and to increase the completeness and validity of the collected cancer data. In particular, the low morphologically verified proportion questions the overall accuracy of the stated diagnoses within the database. Nevertheless, our examination implies that the data of the HNCR are reasonably comparable, and without doubt fulfill the requirements to support national oncology services and cancer planning. However, most importantly, a review of registry personnel and resource requirements to run the national population-based cancer registry should be an essential part of Hungary's national cancer strategy.

Incidence and prevalence of drugs used for chronic diseases in survivors of adult-onset gynaecological cancer - A nationwide cohort study

OBJECTIVES

To evaluate both incidence and prevalence of drugs used for chronic diseases in survivors of adult-onset gynaecological cancer.

DESIGN

A prospective study.

SETTING

Population-based registries.

POPULATION

1.76 million women, including 17 500 women with gynaecological cancers.

METHODS

Data from the Cancer Registry of Norway was linked to the Norwegian Prescription Database and other national databases.

MAIN OUTCOME MEASURES

Prevalence ratios (PRs) and hazard ratios (HRs), with 95% confidence intervals (CIs), of dispensed drugs in gynaecological cancer patients (up to 15 years after diagnosis) were estimated by log-binomial and Cox regression, respectively, with cancer-free women as reference.

RESULTS

For gynaecological cancer patients, the incidence of drugs used for pain control was higher than in cancer-free women, especially the first 5 years after diagnosis, and the prevalence was high at least 10 years after. The prevalence of sex hormones was high in women with gynaecological cancer at least 10 years after diagnosis (cervical and ovarian cancer PR = 23, 95% CI 18-30 and PR = 29, 95% CI 15-38, respectively), but low in cancer-free women (0.3%). Patients with uterine corpus cancer had a higher prevalence of antidiabetics before and at least 10 years after diagnosis, most pronounced in women diagnosed before age 50 (PR = 10, 95% CI 5.0-21). The prevalence of antidepressants was moderately elevated in women with gynaecological cancers.

CONCLUSIONS

Gynaecological cancer survivors, particularly cervical and ovarian cancer survivors, had an increased long-term use of drugs for pain control and sex hormones. Survivors of uterine corpus cancer used antidiabetics more often, both before and after diagnosis.

The burden of colon cancer attributable to modifiable factors-The Norwegian Women and Cancer Study

Colon cancer is the second most frequently diagnosed cancer in women in Norway, where incidence rates of colon cancer increased 3-fold between 1955 and 2014, for unknown reasons. We aimed to assess the burden of colon cancer attributable to modifiable risk factors in Norwegian women using the data from the Norwegian Women and Cancer (NOWAC) study. Self-reported information from 35 525 women from the NOWAC study were available. These included the following exposures: smoking status, alcohol consumption, body mass index, physical activity, intake of calcium, fibers, and red and processed meat. Colon cancer cases were identified from the Cancer Registry of Norway. A parametric piecewise constant hazards model was used to estimate the strength of exposure-cancer associations. Population attributable fractions with 95% confidence intervals (CIs) were calculated considering competing risk of death. The fraction of incident colon cancer attributable to ever smoking was 18.7% (95% CI 4.7%-30.6%), low physical activity 10.8% (95% CI -0.7% to 21.0%), alcohol consumption 14.5% (95% CI -2.8% to 28.9%), and low intake of calcium 10.0% (95% CI -7.8% to 24.8%). A small proportion of colon cancer cases was attributable to combined intake of red and processed meat over 500 g/week, overweight/obesity, and low intake of fibers. Jointly, these seven risk factors could explain 46.0% (95% CI 23.0%-62.4%) of the colon cancer incidence burden. Between 23% and 62% of the colon cancer burden among women in Norway was attributable to modifiable risk factors, indicating an important preventive potential of a healthy lifestyle.

Impact of prebiopsy MRI on prostate cancer staging: Results from the Norwegian Prostate Cancer Registry

Objectives

The aim of this study is to evaluate the 2015 introduction of prebiopsy magnetic resonance imaging of the prostate (MRI-P) as the standard of care for diagnosing prostate cancer (PCa) by the Norwegian public health care authorities. There were three specific objectives of this study: first, to evaluate the consequences of using different TNM manuals for clinical T-staging (cT-staging) in a national setting; second, to determine if the data reveals that MRI-P based cT-staging is superior to digital rectal examination (DRE)-based cT-staging compared with pathological T-stage (pT-stage) post radical prostatectomy; and third, to assess whether treatment allocations have changed over time.

Materials and Methods

All patients registered in the Norwegian Prostate Cancer Registry between 2004 and 2021 were retrieved and 5538 were eligible for inclusion. Concordance between clinical T-stage (cT-stage) and pT-stage was assessed by percentage agreement, Cohen's kappa and Gwet's agreement.

Results

MR visualisation of lesions influences reporting of tumour extension beyond DRE findings. Agreement between cT-stage and pT-stage declined from 2004 to 2009, which coincided with an increase in the percentage being pT3. From 2010, agreement increased, which aligned with changes in cT-staging and the introduction of MRI-P. From 2017, regarding the reporting of cT-DRE and cT-Total (overall cT-stage), agreement diminished for cT-DRE but remained relatively stable (>60%) for cT-Total. Regarding treatment allocation, the study suggests that staging with MRI-P has shifted treatment towards radiotherapy in locally advanced high-risk disease.

Conclusion

Introduction of MRI-P has affected cT-stage reporting. Agreement between cT-stage and pT-stage appears to have improved. This study suggests that use of MRI-P influences treatment decisions in certain patient subgroups.

Lung cancer registries in Denmark, Finland, Norway and Sweden: a comparison and proposal for harmonization

BACKGROUND

Lung cancer is the leading cause of cancer-related death in all Nordic countries which, though similar in demographics and healthcare systems, have noticeable differences in lung cancer survival. Historically, Denmark and Finland have had higher lung cancer incidences and lower survival than Norway and Sweden. All four countries have national cancer registries. Data in these registries are often compared, but their full potential as a source of learning across the Nordic countries is impeded by differences between the registries. In this paper, we describe and compare the Nordic registries on lung cancer-specific data and discuss how a more harmonized registration practice could increase their usefulness as a source for mutual learning and quality improvements.

METHODS

We describe and compare the characteristics of data on lung cancer cases from registries in Denmark, Finland, Norway and Sweden. Moreover, we compare the results from the latest annual reports and specify how data may be acquired from the registries for research.

RESULTS

Denmark has a separate clinical lung cancer registry with more detailed data than the other Nordic countries. Finland and Norway report lung cancer survival as relative survival, whereas Denmark and Sweden report overall survival. The Danish Lung Cancer Registry and the Swedish Cancer Registry do not receive data from the Cause of Death registries in contrast to the Finnish Cancer Registry and the Cancer Registry of Norway.

CONCLUSION

The lung cancer registries in Denmark, Finland, Norway and Sweden have high level of completeness. However, several important differences between the registries may bias comparative analyses.

Applying recommended definition of aggressive prostate cancer: a validation study using high-quality data from the Cancer Registry of Norway

BACKGROUND

The Prostate Cancer Cohort Consortium (PC3) Working Group proposed a definition for aggressive prostate cancer (PC) for aetiologic epidemiologic research. We aimed to validate this definition as well as a second approach utilising only information on stage at diagnosis.

METHODS

First primary PCs diagnosed 2004 - 2009 in the population-based Janus Serum Bank (JSB) cohort were identified by linkage to the population-based Cancer Registry of Norway (CRN) (n = 3568). The CRN and Norwegian Prostate Cancer Registry provided clinicopathological data for these cases. Approach 1 classified PC as aggressive if it was clinically T4, or N1, or M1, or had a Gleason score ≥8 at diagnosis (as proposed). Approach 2 classified PC as aggressive if CRN stage at diagnosis was 'regional spread' or 'distant metastases'. Both approaches were validated by calculating the sensitivity and positive predictive value (PPV) against PC-death within 10 years of diagnosis.

RESULTS

Overall, 555 died from PC within 10 years. Approach 1 classified 24.7% of cases as aggressive and 13.6% were unclassified due to missing information. Approach 2 classified 19.6% as aggressive and 29% were unclassified. Sensitivity was highest for Approach 1 (0.76, 95% CI: 0.72 - 0.80 vs 0.69, 95% CI: 0.64 - 0.73), while PPVs were similar for both approaches (0.43, 95% CI: 0.40 - 0.46 and 0.40, 95% CI: 0.36 - 0.44). We observed similarly high sensitivity and higher PPVs than those reported by the PC3 Working Group.

CONCLUSIONS

The proposed definition of aggressive PC was applicable and valid in the JSB cohort. Stage at diagnosis can be useful if data on cTNM or Gleason score is unavailable.

Cancer related mortality in multiple sclerosis. A population based cohort study

BACKGROUND

Cancer is a major cause of death, but how cancer influences mortality risk in Multiple Sclerosis (MS) is unclear.

OBJECTIVES

Determine all-cause mortality and mortality following a cancer diagnosis among MS patients compared with matched population controls.

METHODS

Norwegian MS patients born 1930 - 1979 (n= 6950) followed-up 1953 - 2016, were matched with 37 922 controls. We compared incident cancer diagnosis from the Cancer Registry of Norway, date of death from the Cause of Death Registry, education from the National Education Database, by multivariate Cox proportional hazard regression.

RESULTS

Hazard ratio (HR) and 95% confidence interval (CI) for all-cause mortality among MS patients was 4.97 (4.64 - 5.33), and 2.61 (2.29 - 2.98) for mortality following a cancer diagnosis. Mortality in MS was highest following urinary- (2.53: 1.55 - 4.14), colorectal- (2.14: 1.47 - 3.11), hematological- (1.76: 1.08 - 2.88), ovarian - 2.30 (1.73-3.06) and breast cancer diagnosis (2.61: 1.85 - 3.68), compared to controls. High education was inversely associated with mortality among MS patients.

CONCLUSIONS

All-cause mortality was five- fold and mortality following a cancer diagnosis was two- fold increased among MS patients. Mortality following specific cancers raises the possibility of diagnostic neglect.

Haematological malignancies in patients with psoriatic arthritis overall and treated with TNF inhibitors: a Nordic cohort study

OBJECTIVES

To evaluate the risk of haematological malignancies in patients with psoriatic arthritis (PsA) overall, and in relation to treatment with tumour necrosis factor inhibitors (TNFi).

METHODS

We identified that patients with PsA starting a first TNFi from the clinical rheumatology registers (CRR) in the five Nordic countries (n=10 621) and biologics-naïve PsA patients from (1) the CRR (n=18 705) and (2) the national patient registers (NPR, n=27 286, Sweden and Denmark) from 2006 through 2019. For Sweden and Denmark, general population comparators were matched 5:1 to PsA patients on birth year, year at start of follow-up and sex. By linkage to the national cancer registers in all countries, we collected information on haematological malignancies overall, and categorised into lymphoid or myeloid types. We estimated incidence rate ratios (IRRs) with 95% CIs using modified Poisson regression for TNFi-treated versus biologics-naïve PsA patients and versus the general population adjusted for age, sex, calendar period and country.

RESULTS

During 59 827 person-years, 40 haematological malignancies occurred among TNFi-treated patients with PsA resulting in a pooled IRR of 0.96 (0.68-1.35) versus biologics-naïve PsA from CRR and an IRR of 0.84 (0.64-1.10) versus biologics-naïve PsA from NPR. The IRR of haematological malignancies in PsA overall versus general population comparators was 1.35 (1.17-1.55). The estimates were largely similar for lymphoid and myeloid malignancies.

CONCLUSIONS

Treatment with TNFi in patients with PsA was not associated with an increased incidence of haematological malignancies. Conversely, a moderately increased underlying risk was seen in patients with PsA compared with the general population.

Life-Course Trajectories of Physical Activity and Melanoma Risk in a Large Cohort of Norwegian Women

Purpose

Physical activity (PA) is a cornerstone in disease prevention and varies throughout life. A pooled analysis of cohort studies and a meta-analysis of cohort studies found positive associations between PA and melanoma risk. However, previous studies focused on PA at specific ages and often lacked information on ultraviolet radiation (UVR) exposure. Using the population-based Norwegian Women and Cancer (NOWAC) cohort, including information on PA and UVR exposure, we estimated life-course PA trajectories from adolescence to adulthood and their associations with melanoma.

Methods

Total PA across different domains (recreation, occupation, transport, household) was reported for ages 14 and 30 years, and when responding to the questionnaire (31-76 years) using a 10-point scale, validated to rank PA levels in Norwegian females. We estimated life-course PA trajectories using a latent class mixed model in 152,248 women divided into three subcohorts depending on age at questionnaire completion: 31-39 (n = 27,098), 40-49 (n = 52,515) and ≥50 years (n = 72,635). The unique 11-digit identity number of Norwegian citizens was used to link NOWAC to the Cancer Registry of Norway for information on cancer diagnoses, emigration and death. Associations between PA trajectories and melanoma risk were estimated in each subcohort using multivariable Cox regression.

Results

Five classes of individual life-course PA trajectories were identified in subcohort 31-39 years (low, moderate, high, decreasing, increasing PA) and four in subcohorts 40-49 and ≥50 years (low, moderate, high, decreasing PA). No significant association was found between life-course PA trajectories and melanoma risk in any subcohort. Hazard ratios (95% confidence intervals) for the high versus moderate trajectory were 0.92 (0.66-1.29), 1.15 (0.97-1.37) and 0.90 (0.78-1.05) for subcohorts 31-39, 40-49 and ≥50 years, respectively.

Conclusion

Our results do not support a positive association between PA and melanoma risk found in previous studies, which is important for public health guidelines promoting regular PA.

Downstaging and survival after Neoadjuvant chemotherapy for bladder cancer in Norway; a population-based study

BACKGROUND

Neoadjuvant chemotherapy (NAC) before radical cystectomy is associated with pathological downstaging (DS) and improved overall survival (OS) in patients with muscle-invasive bladder cancer (MIBC). Population-based studies have not unequivocally shown improved survival. The aim of this population-based study was to evaluate the effect of NAC on DS and OS in Norwegian patients with MIBC.

METHODS

Patients in the Cancer Registry of Norway undergoing radical cystectomy (2008-2015) with or without NAC diagnosed with MIBC between 2008 and 2012 were included. Follow-up data were available until 31 December 2019. Logistic regression estimated the odds of DS with NAC, and a Cox model investigated the effect of DS on OS. Cox models, a mediator analysis and an instrumental variable approach were used to investigate the effect of NAC on OS.

RESULTS

A total of 575 patients were included. NAC was administered to 82 (14%) patients. Compared to cystectomy only, NAC increased the proportion (43% vs. 22%) and the odds of DS (OR 2.51, CI 1.37-4.60, p = 0.003). Independent of NAC, the proportion of pN0 was higher in patients with DS (89% vs. 60%) and DS yielded a 78% mortality risk reduction (HR 0.22, CI 0.15-0.34, p = 1.9∙10-12), compared to patients without DS. We did not find an association between NAC and OS, neither by Cox regression (HR 1.16, CI 0.80-1.68, p = 0.417) nor by an instrumental variable approach (HR = 0.56, CI = 0.07-4.57, p = 0.586). The mediation analysis (p = 0.026) confirmed an indirect effect of NAC on OS through DS. Limitations include limited information of the primary tumour, details of NAC treatment and treatment indications.

CONCLUSIONS

NAC increases the probability of DS and is indirectly associated to OS. DS is related to the absence of regional lymph node metastases and is associated with an OS benefit. Improved staging and biomarkers are needed to identify patients most likely to achieve DS and to benefit from NAC.

Cohort Description: Preventing an Opioid Epidemic in Norway - Focusing on Treatment of Chronic Pain (POINT) - A National Registry-Based Study

AIM

The POINT project aims to provide evidence to optimise chronic pain management, prevent adverse consequences of opioids, and improve chronic pain patients' pain relief, functional capacity, and quality of life. We describe the outline of the project and its work packages. More specifically, we describe a cohort of persons with chronic pain and a cohort of long-term opioid users identified from a national registry linkage.

DATA SOURCES

The project utilises data from nationwide healthcare and population registers in Norway. Using the Norwegian Prescription Database, we identified a cohort of persons who have been dispensed drugs reimbursed for chronic pain and a cohort of persons who used opioids long term from 2010 to 2019. Data from the Norwegian Registry for Primary Health Care and the Norwegian Patient Registry (2008-2019), Cancer Registry (1990-2018) Cause of Death Registry (2010-2019) and demographic and socioeconomic registers from Statistics Norway (2010-2019) were linked to the cohorts.

STUDY POPULATION

There were 568,869 participants with chronic pain. Sixty-three percent of the cohort was women, and the mean age was 57.1 years. There were 336,712 long-term opioid users (58.6% women; 60.9 years). In chronic pain and long-term opioid user cohorts, the most frequent musculoskeletal diagnosis was back pain diagnosed in primary care (27.6% and 30.7%). Psychiatric diagnoses were also common.

MAIN VARIABLES

Upcoming studies will utilise psychiatric and somatic diagnoses from the patient registers, drug use from the prescription register, causes of death, demographics, and socioeconomic status (eg, education, income, workability, immigrant status) as exposures or outcomes.

CONCLUSION AND FUTURE PLANS

The two cohorts have numerous pain-related diagnoses, especially in the musculoskeletal system, and noticeably frequent somatic and psychiatric morbidity. The POINT project also includes later work packages that explore prescriber and patient perspectives around safe and effective treatment of chronic pain.

Improvements in survival for patients with stage IV adenocarcinoma in the lung, diagnosed between 2010 - 2020 - A population-based registry study from Norway

OBJECTIVES

We investigated how the prognosis for Norwegian patients with stage IV, adenocarcinoma (NSCLC) has developed during the last decade, to observe if increased survival coincides with the introduction of immunotherapy at a population level.

MATERIALS AND METHODS

Incidence data from the Cancer Registry of Norway are virtually complete and includes information about histological subtypes and biomarkers. The data was used to analyze median and relative survival for females and males diagnosed with stage IV NSCLC, divided by histological subgroups and age-groups.

RESULTS

During 2010 - 2020, 14472 patients were diagnosed with lung cancer in stage IV, in Norway. Among them 6351 patients (43%) were classified with adenocarcinoma. The median survival has increased for both sexes, but the largest increase is seen in females. From 2010 to 2020, median survival for females in the 0-69 group increased from 6.7 months to 12 months and from 3.7 months to 10 months for the 70+ age group. For the equivalent male age groups, we see an increase from 6.1 months to 7.7 months for the 0-69 group, and an increase from 3.8 months to 4.5 months for the 70+ group. When excluding patients with EGFR/ALK mutations from the survival analysis, the groups continue to display an increased survival from 2010 to 2020, although modest in the male 70+ group. The 1-year relative survival (RS) has increased for both sexes, from 32.4% to 51.2 in females and 25.4% to 44.5% in males. When EGFR/ALK positive patients were excluded from the analysis 1-year RS in females rose from 32.4% to 47.4% and for males from 25.4% to 41.8%.

CONCLUSION

A real-world patient population of stage IV, NSCLC adenocarcinoma have had a clinically meaningful increase in both median and relative survival from 2010 - 2020. The steepest survival increase has taken place after 2016, the time point where immunotherapy was implemented as a treatment option for the stage IV, adenocarcinoma population not harboring targetable mutations (EGFR/ALK).

Cohort profile: Nordic Helicobacter Pylori eradication project (NordHePEP)

PURPOSE

This cohort description presents the Nordic Helicobacter Pylori Eradication Project (NordHePEP), a population-based cohort of patients having received eradication treatment for Helicobacter pylori (HP). The cohort is created with the main purpose of examining whether and to what extent HP eradication treatment influences the risk of gastrointestinal cancer.

PARTICIPANTS

NordHePEP includes all adults (aged ≥18 years) having been prescribed and dispensed HP eradication treatment according to the nationwide complete drug registries in any of the five Nordic countries (Denmark, Finland, Iceland, Norway, or Sweden) between 1994 and 2020 (start and end year varies between countries). We have retrieved and merged individual-level data from multiple national registries, including drug, patient, cancer, population, and death registries.

FINDINGS

The cohort includes 674,771 patients having received HP eradication treatment. During up to 23 years of follow-up, 59,292 (8.8%) participants were diagnosed with cancer (non-melanoma skin cancer excluded), whereof 15,496 (2.3%) in the gastrointestinal tract.

FUTURE PLANS

We will analyse HP eradication treatment in relation to gastrointestinal cancer risk. Standardised incidence ratios will be calculated as the observed cancer incidence in the cohort divided by the expected cancer incidence, derived from the background population of the corresponding age, sex, and calendar year.

Body mass index and incidence of lung cancer in the HUNT study: using observational and Mendelian randomization approaches

Background

Traditional observational studies have shown an inverse association between body mass index (BMI) and lung cancer risk. Mendelian randomization (MR) analysis using genetic variants as instruments for BMI may clarify the nature of the association.

Aims

We studied the causal association between BMI and lung cancer incidence using observational and MR approaches.

Methods

We followed up 62,453 cancer-free Norwegian adults from 1995–97 (HUNT2) until 2017. BMI at baseline in HUNT2 was classified as < 25.0, 25.0–29.9 and ≥ 30.0 kg/m2. BMI change over ten years between HUNT1 (1984–86) and HUNT2 was calculated and classified into quartiles. Seventy-five genetic variants were included as instruments for BMI (among which 14 also associated with smoking behavior). Incident lung cancer cases were ascertained from the Cancer Registry of Norway. Cox regression models were used to estimate hazard ratios (HRs) with 95% confidence intervals (CIs). Multivariable MR was used to examine the effect of BMI after genetically controlling for smoking.

Results

During a median follow-up of 21.1 years, 1009 participants developed lung cancer including 327 with lung adenocarcinoma. The HRs and 95% CIs for incidence of adenocarcinoma were 0.73 (0.58–0.92) for BMI 25.0–29.9 kg/m2 and 0.53 (0.37–0.76) for BMI ≥ 30 kg/m2 compared with BMI < 25.0 kg/m2 in HUNT2 (P for trend < 0.001). However, there was little evidence of a dose–response relationship between the BMI change from HUNT1 to HUNT2 in quartiles and the incidence of adenocarcinoma (P for trend = 0.08). Furthermore, multivariable MR approach suggested a positive association between genetically determined 1 kg/m2 increase in BMI and the incidence of adenocarcinoma (HR 1.25, 95% CI 1.02–1.53). No associations were found with other lung cancer histologic types.

Conclusions

Our study suggests that the inverse association between baseline BMI and lung adenocarcinoma in observational analysis may not be causal. More MR studies are needed to confirm our finding of a positive association between BMI and lung adenocarcinoma.

Interpreting Breast Cancer Mortality Trends Related to Introduction of Mammography Screening: A Simulation Study

Background. Several studies have evaluated the effect of mammography screening on breast cancer mortality based on overall breast cancer mortality trends, with varied conclusions. The statistical power of such trend analyses is, however, not carefully studied. Methods. We estimated how the effect of screening on overall breast cancer mortality is likely to unfold. Because a screening effect is based on earlier treatment, screening can affect only new incident cases after screening introduction. To evaluate the likelihood of detecting screening effects on overall breast cancer mortality time trends, we calculated the statistical power of joinpoint regression analysis on breast cancer mortality trends around screening introduction using simulations. Results. We found that a very gradual increase in population-level screening effect is expected due to prescreening incident cases. Assuming 25% effectiveness of a biennial screening program in reducing breast cancer mortality among women 50 to 69 y of age, the expected reduction in overall breast cancer mortality was 3% after 2 y and reached a long-term effect of 18% after 20 y. In common settings, the statistical power to detect any screening effects using joinpoint regression analysis is very low (<50%), even in an artificial setting of constant risk of baseline breast cancer mortality over time. Conclusions. Population effects of screening on breast cancer mortality emerge very gradually and are expected to be considerably lower than the effects reported in trials excluding women diagnosed before screening. Studies of overall breast cancer mortality time trends have too low statistical power to reliably detect screening effects in most populations. Implications. Researchers and policy makers evaluating mammography screening should avoid using breast cancer mortality trend analysis that does not separate pre- and postscreening incident cases.

HIGHLIGHTS

Population-level mammography screening effects on breast cancer mortality emerge gradually following screening introduction, resulting in very low statistical power of trend analysis.Researchers and policy makers evaluating mammography screening should avoid relying on population-wide breast cancer mortality trends.Expected mammography screening effects at population level are lower than those from screening trials, as many cases of breast cancer fall outside the screening age range.

Time trends in mobile phone use and glioma incidence among males in the Nordic Countries, 1979-2016

INTRODUCTION

In the Nordic countries, the use of mobile phones increased sharply in the mid-1990s especially among middle-aged men. We investigated time trends in glioma incidence rates (IR) with the perspective to inform about the plausibility of brain tumour risks from mobile phone use reported in some case-control studies.

METHODS

We analysed IR of glioma in Denmark, Finland, Norway, and Sweden among men aged 40-69 years, using data from national cancer registries and population statistics during 1979-2016, using log-linear joinpoint analysis. Information on regular mobile phone use and amount of call-time was obtained from major studies of mobile phones in these countries. We compared annual observed incidence with that expected under various risk scenarios to assess which of the reported effect sizes are compatible with the observed IR. The expected numbers of cases were computed accounting for an impact of other factors besides mobile phone use, such as improved cancer registration.

RESULTS

Based on 18,232 glioma cases, IR increased slightly but steadily with a change of 0.1% (95 %CI 0.0%; 0.3%) per year during 1979-2016 among 40-59-year-old men and for ages 60-69, by 0.6 % (95 %CI 0.4; 0.9) annually. The observed IR trends among men aged 40-59 years were incompatible with risk ratios (RR) 1.08 or higher with a 10-year lag, RR ≥ 1.2 with 15-year lag and RR ≥ 1.5 with 20-year lag. For the age group 60-69 years, corresponding effect sizes RR ≥ 1.4, ≥2 and ≥ 2.5 could be rejected for lag times 10, 15 and 20 years.

DISCUSSION

This study confirms and reinforces the conclusions that no changes in glioma incidence in the Nordic countries have occurred that are consistent with a substantial risk attributable to mobile phone use. This particularly applies to virtually all reported risk increases reported by previous case-control studies with positive findings.

Sex differences in childhood cancer risk among children with major birth defects: a Nordic population-based nested case-control study

BACKGROUND

Childhood cancer is more common among children with birth defects, suggesting a common aetiology. Whether this association differs by sex is unclear.

METHODS

We performed a population-based nested case-control study using nationwide health registries in four Nordic countries. We included 21 898 cancer cases (0-19 years) and 218 980 matched population controls, born 1967-2014. Associations between childhood cancer and major birth defects were calculated as odds ratios (ORs) with 95% confidence intervals (CIs) using logistic regression models. Effect modification was evaluated using a counterfactual framework to estimate confidence intervals and P-values for the natural indirect effects.

RESULTS

Birth defects were present for 5.1% (1117/21 898) of childhood cancer cases and 2.2% (4873/218 980) of controls; OR of cancer was higher for chromosomal (OR = 10, 95% CI = 8.6-12) than for non-chromosomal defects (OR = 1.9, 95% CI = 1.8-2.1), strongest between genetic syndromes/microdeletion and renal tumours, Down syndrome and leukaemia, and nervous system defects and central nervous system tumours. The association between birth defects and cancer was stronger among females (OR = 2.8, 95% CI = 2.6-3.1) than males (OR = 2.1, 95% CI = 1.9-2.2, Pinteraction <0.001). Male sex was an independent risk factor for childhood cancer, but very little of the overall association between sex and childhood cancer was mediated through birth defects (4.8%, PNIE <0.001), although more at younger ages (10% below years and 28% below 1 year).

CONCLUSIONS

The birth defect-cancer associations were generally stronger among females than males. Birth defects did not act as a strong mediator for the modest differences in childhood cancer risk by sex, suggesting that other biological pathways are involved.