Danish Cancer Registry Research Articles

Factors behind favorable long-term lung cancer survival in Norway compared to Denmark: a retrospective cohort study

ABSTRACT Background Long-term survival of patients with non-small cell lung cancer (NSCLC) is considerably higher in Norway compared to Denmark, even though diagnostic work-up, treatment, and follow-up are comparable. We aim to explore factors behind favorable long-term survival for lung cancer patients in Norway compared to Denmark. Method A retrospective cohort study of patients with NSCLC diagnosed between 2014 and 2016. From the Danish Lung Cancer Registry, 1000 patients were randomly selected, and 974 patients were included. From the Norwegian Vestfold Hospital Trust, 220 patients were randomly selected, and 218 were included. Data from medical records were obtained for all patients. The Danish and Norwegian cohorts were compared using the Pearson chi squared test and multivariate logistic regression analysis. Results The two cohorts were comparable in terms of age, sex, and smoking history. However, the Danish patients had a higher number of pack-years (43.5 vs 34.5 p < 0.001) and more comorbidities. The Norwegian patients had less advanced disease stage (p < 0.001), and a larger proportion was treated with curative intent (90 (41.3%) vs 343 (35.2%), p = 0.063). One-year survival was similar, but the 5-year survival was superior in the Norwegian cohort (58 (26.6%) vs 177 (18.2%), p = 0.005). In a multivariate logistic regression model, adjusted for sex, smoking history, performance status, TNM stage and comorbidity, the odds ratio of being a five-year survivor in Norway was 1.81 (95% CI: 1.11–2.94) compared to Denmark. Conclusions We found a higher proportion of Norwegian patients diagnosed at potential curable stage and fewer heavy smokers compared to Danish patients. This could contribute to the superior long-term survival found in Norwegian NSCLC patients.

Is Cancer Associated With Frailty? Results From a Longitudinal Study of Old Danish Twins.

Although age is an important risk factor for both cancer and frailty, it is unclear whether cancer itself increases the risk of frailty. We aimed to assess the association between cancer and frailty in a longitudinal cohort of older Danish twins, taking familial effect into account. Using the Danish Cancer Registry, cancer cases were identified among participants aged 70 and over in the Longitudinal Study of Aging Danish Twins (LSADT). Frailty was evaluated over 10 years of follow-up using the frailty index (FI) and defined as FI > 0.21. Stratified Cox regressions were performed on discordant twin pairs (pairs where one twin had incident cancer and the other was cancer-free) and on all LSADT individual twins (twin pairs and singletons) with no history of cancer. Among the 72 discordant pairs (n = 144, median age at inclusion = 75) included in the study, the median FI at inclusion was 0.08 for both cancer twins and cancer-free co-twins. From the stratified Cox regression, twins with cancer had an increased hazard of developing frailty (hazard ratio [HR] = 3.67, 95% confidence interval [CI] = 1.02-13.14) compared with their cancer-free co-twins. The analyses on individual twins (n = 4 027) provided similar results, showing an increased hazard of frailty in individuals with cancer (HR = 2.57, 95% CI = 1.77-3.74) compared with those without cancer. We showed a higher risk of becoming frail following a cancer diagnosis in both discordant twin pairs and individual twins. These findings support the importance of monitoring frailty in older adults with cancer through geriatric assessments and the implementation of frailty interventions.

Trends in papillary thyroid cancer mortality in Denmark according to stage and education.

Few studies exist on trends in papillary thyroid cancer (PTC) survival and mortality according to stage and level of socioeconomic status. Nationwide cohort study. Patients diagnosed with PTC during 2000-2015 in Denmark were identified from the Danish Cancer Registry and followed until the end of 2020. We evaluated 5-year all-cause mortality and relative survival according to stage and 5-year mortality rates with corresponding average annual percentage changes (AAPCs) according to stage and education. Finally, we assessed the association between several factors and mortality of PTC using Cox regression. For the 2006 cases of PTC diagnosed during 2000-2015, relative survival tended to increaseand mortality rates tended to decrease for all stages. For localized PTC, mortality rates tended to decrease among individuals with medium education (AAPC = -7.0, 95% confidence interval [CI]: -14.7 to 1.5), but showed an increasing pattern among individuals with long education (AAPC = 19.8, 95%CI: -4.2 to 50.0). For nonlocalized PTC, mortality rates showed a decreasing tendency among individuals with medium and long education (AAPC = -5.5, 95%CI: -13.2 to 2.9, and AAPC = -10.4, 95%CI: -20.8 to 1.4, respectively). Being diagnosed with PTC in a more recent calendar period and long education were associated with a lower mortality rate in the Cox regression analysis. A pattern of an increasing relative survival and decreasing mortality rates of PTC across all stages was seen in Denmark during 2000-2015. The decreasing pattern in mortality rates was most evident in individuals with localized stage and medium education, and in individuals with nonlocalized stage and medium or long education.

Survival improvements in esophageal and gastric cancers in the Nordic countries favor younger patients.

Esophageal cancer (EC) and gastric cancer (GC) are fatal cancers with a relatively late age of onset. Age is a negative risk factor for survival in many cancers and our aim was to analyze age-specific survival in EC and GC using the recently updated NORDCAN database. NORDCAN data originate from the Danish, Finnish, Norwegian, and Swedish nationwide cancer registries covering years 1972 through 2021 inviting for comparison of 50-year survival trends between the countries. Relative 1- and 5-year survival and 5/1-year conditional survival (i.e., survival in those who were alive in Year 1 to survive additional 4 years) were analyzed. Survival in EC showed large gains for patients below age 80 years, 5-year survival in Norwegian men reaching 30% and in women over 30% but for 80-89 year old survival remained at 10%. In contrast, hardly any gain was seen among the 80-89 year patients for 1-year survival and small gains in 5 year and 5/1-year survival. Survival gaps between age-groups increased over time. For GC there was also a clear age-related negative survival gradient but the survival gaps between the age groups did not widen over time; Norwegian male and female 5-year survival for 80-89 year old was about 20%. The age-specific survival difference in GC arose in Year 1 and did not essentially increase in 5-year survival. While there were differences in survival improvements between the countries, poor survival of the 80-89 year old patients was shared by all of them. To conclude, survival has improved steadily in younger GC and EC patients in most Nordic countries. While the 80-89 year old population accounts for nearly a quarter of all patients and their poor survival depressed overall survival, which can therefore be increased further by improving diagnostics, treatment and care of elderly EC and GC patients.

Biopsy-verified vulvar lichen sclerosus and the risk of non-vulvar cancer: A nationwide cohort study.

Vulvar lichen sclerosus (VLS) is a chronic inflammatory mucocutaneous disease known to be associated with human papillomavirus-independent vulvar squamous cell carcinoma. Evidence on the association with other types of cancer, however, is sparce. We conducted a large nationwide cohort study examining the incidence of non-vulvar cancers among women with biopsy-verified VLS compared with the general female population. By using the nationwide Pathology Registry, we identified all women in Denmark with a biopsy-verified VLS diagnosis during 1978-2019 (n = 16,921). The cohort was followed up in the Danish Cancer Registry until 2022 for a subsequent non-vulvar cancer diagnosis. Standardized incidence ratios (SIRs) were computed with 95% confidence intervals (CIs) as relative risk estimates of all specific non-vulvar cancer sites. Compared with general female population rates, women with biopsy-verified VLS had decreased rates of several non-vulvar cancers, including HPV-related cancers (combined estimate: SIR = 0.5; 95% CI: 0.3-0.7), and lung (SIR = 0.6; 95% CI: 0.5-0.7), liver (SIR = 0.5; 95% CI: 0.2-0.9), and thyroid cancer (SIR = 0.5; 95% CI: 0.3-0.9). The decreased SIRs tended to sustain throughout the follow-up period following the VLS diagnosis. This large nationwide cohort study shows that women with biopsy-verified VLS may have a long-term reduced risk of developing HPV-related (cervical, vaginal, oropharyngeal, and anal) and smoking-associated cancers (lung, liver, and cervical) as well as thyroid cancer. Future studies focusing on the mechanisms behind the decreased cancer risk are needed.

Cervical cancer incidence in Denmark: Disentangling determinants of time trend.

Cervical cancer is a preventable disease. Nevertheless, stagnation has been seen in incidence rates also in countries with well-functioning healthcare. On this basis, we investigated associations between control interventions and changes in cervical cancer incidence in Denmark from 2009 to 2022. Data on human papillomavirus (HPV)-vaccination were retrieved from Staten's Serum Institute; on screening recommendations from Danish Health Authority, on screening performance from Danish Quality Database for Cervical Screening; and on cervical cancer incidence from Nordcan and Danish Cancer Register. We reported coverage with HPV vaccination (1+ dose); coverage with cervical cell samples; number of women with primary HPV tests; proportion of non-normal cell samples without timely follow-up; number of conizations; and cervical cancer incidence rates. In 2022, all women aged ≤29 had been offered childhood HPV vaccination with coverage of 80%-90%. By 2020-2022, the cervical cancer incidence rate in women aged 20-29 was 3 per 100,000; at level of disease elimination. In 2017, women aged 70+ were offered a one-time HPV screening, and by 2020-2022, the old-age peak in cervical cancer incidence had largely disappeared. From 2009 to 2022, proportion of non-normal cell samples without timely follow-up decreased from 20% to 10%, and conventional cytology was largely replaced by SurePath liquid-based cytology; these factors could explain the steady decrease in cervical cancer incidence rate. Implementation of primary HPV screening in women aged 30-59 in 2021 was reflected in a, probably temporary, increase in the 2022 cervical cancer incidence rate. In conclusion, combined interventions with childhood HPV vaccination; one-time HPV screening of elderly women; and better management of screening broke previous stagnation in cervical cancer incidence rate.

Regional cancer incidence and survival in Denmark

BackgroundPotential regional differences in cancer incidence and survival would demand targeted interventions to decrease cancer related death. MethodsThis descriptive cohort study provides an overview of regional cancer incidence and relative survival (RS) in Denmark during 2007–2021. National cancer incidence and RS estimates were calculated similar to the official statistics for the Danish Cancer Registry. Specifically, we estimated age-standardized (World) cancer incidence rates (ASR), and RS in 3-year periods by sex, and the five regions of Denmark (i.e., Region of Northern Denmark, Central Denmark Region, Region of Southern Denmark, Region Zealand, and Capital Region). ResultsWe identified 578,107 incident cancers in Denmark during 2007–2021, of which 124 123 were diagnosed in 2019–2021. Small fluctuations were seen in ASR for cancer overall in all five regions during 2007–2018, followed by decreasing trends in 2019–2021. Men exhibited higher ASRs than women. Consistent improvements in 1- and 5-year RS were seen during the study period in all regions. However, for patients diagnosed in 2019–2021, the 5-year RS levelled off. These patients experienced 1-year RS of 83 % among men and 84 % among women, and the 5-year RS was also similar between sexes (men: 67 %, women: 70 %, overall: 68 %). Region Zealand generally presented lower RS estimates for both sexes combined. ConclusionCancer survival improved between 2007 and 2021 in all Danish regions for both sexes. However, the improvements in cancer survival appeared to have levelled off in the most recent period, 2019–2021. For both sexes, the lowest survival was suggested for Region Zealand.

Incidence and geographic differences in keratinocyte carcinoma and Bowen's disease in office‐based dermatological practice between 2013 and 2022: A nationwide Danish registry‐based study

AbstractBackgroundRates of keratinocyte carcinoma (KC) across Europe are impacted by population demographics and geography. Regional differences in KC occurrence exist, but few European studies investigate incidences of specific subtypes in the secondary healthcare sector on a national level.ObjectivesTo determine geographical differences in incidence rate and lifetime risk of KC subtypes across Denmark, including nodular and superficial basal cell carcinoma (BCC), squamous cell carcinoma (SCC) and the KC precursor, Bowen's disease (BD), identified in office‐based dermatological practice.MethodsBased on a nationwide registry (The Danish Skin Cancer Registry), all patients in Denmark's five regions with a histologically‐ or clinically verified KC or BD registered in a state‐funded office‐based dermatology practice between 2013 and 2022 were included. Trends in national‐ and region‐specific age and sex standardised tumour incidence rates (STIR) were calculated. Further, national lifetime risk of each tumour subtype was estimated.ResultsBetween 2013 and 2022, the combined STIR for KC/BD rose 172% nationally from 180 to 489 per 100,000 person‐years (PY). This increase reflected rising rates of nodular BCC, SCC, and BD, while superficial BCC incidence was relatively stable. Regional differences in STIR for combined KC/BD were observed, with the Capital Region and North Jutland generally demonstrating higher rates than Zealand, Southern‐ and Central Denmark (e.g., North Jutland vs. Southern Denmark: 714 vs. 405/100,000PY). While the estimated lifetime risk of developing at least one KC or BD tumour was 21.8%, risk varied with tumour subtype, resulting in subtype‐specific risks of 16.4%, 5.1%, 1.9% and 1.3% for nodular BCC, superficial BCC, SCC, and BD, respectively.ConclusionsIn Denmark's secondary dermatological care sector, incidence of nodular BCC, SCC and BD continues to rise with an overall lifetime risk nearing 22%. While KC incidence is increasing in Denmark, the study detected differences in geographical trends and rate increases of specific tumour subtypes.

Progress against lung cancer, Denmark, 2008-2022.

There has been marked progress against lung cancer in Denmark. To gain further insight into the different aspects of the improvement, we examined the stage-specific incidence rates, stage-specific survival and mortality rates. We used information from the Danish Lung Cancer Registry on date of diagnosis and clinical stage to calculate age-standardised incidence rates and patient survival by sex, period and stage. Information about age-standardised lung cancer-specific mortality rates by sex and period was extracted from The Danish Health Data Authority. Firstly, the decrease in incidence rates was due to a reduction in the rates of advanced stages. Secondly, there was a gradual increase in survival across all stages, and thirdly, the mortality rates gradually decreased over time. The improvements in survival and mortality from lung cancer were due to decreasing incidence rates of advanced cancer and improvement in survival at all stages of the disease.

Risk of Venous Thromboembolism in Patients With Stage III and IV Non–Small-Cell Lung Cancer: Nationwide Descriptive Cohort Study

BackgroundVenous thromboembolism (VTE) is a common complication in patients starting cancer therapies for non–small-cell lung cancer (NSCLC). We examined the risk and timing of VTE in patients with stage IIIA, IIIB to C, and stage IV NSCLC according to received cancer treatments. Materials and MethodsA nationwide registry-based cohort study of patients recorded in the Danish Lung Cancer Registry (2010-2021) followed for 1 year after entry into the registry to assess the incidence of VTE. The Aalen–Johansen estimator was used to calculate the risk of VTE after treatment commencement with chemotherapy, radiotherapy, chemoradiation, immunotherapy, and targeted therapy. ResultsAmong the 3475 patients with stage IIIA, 4047 with stage IIIB to C, and 18,082 patients with stage IV cancer, the 1-year risk of VTE was highest in the first 6 months and varied markedly by cancer stage and cancer treatment. In stage IIIA, VTE risk was highest with chemotherapy (3.9%) and chemoradiation (4.1%). In stage IIIB to C, risks increased with chemotherapy (5.2%), immunotherapy (9.4%), and targeted therapy (6.0%). Stage IV NSCLC showed high risk with targeted therapy (12.5%) and immunotherapy (12.2%). The risk was consistently higher for pulmonary embolism than deep vein thrombosis. ConclusionVTE risks vary substantially according to cancer treatments and cancer stages. The highest risk was observed in the initial 6 months of therapy initiation. These insights emphasize the need for tailored risk assessment and vigilance in managing VTE complications in patients with NSCLC. Further research is needed to optimize individual thromboprophylaxis strategies for patients with unresectable and metastatic NSCLC.

Association of cancer with functional decline at old age: a longitudinal study in Danish twins.

There is evidence that older adults with cancer have a higher risk of functional decline than cancer-free older adults. However, few studies are longitudinal, and none are twin studies. Thus, we aimed to investigate the relationship between cancer and functional decline in older adult (aged 70+ years) twins. Cancer cases in the Longitudinal Study of Aging Danish Twins were identified through the Danish Cancer Registry. Functional status was assessed using hand grip strength (6 years follow-up), and self-reported questions on mobility (10 years follow-up), and cut-offs were defined to assess functional decline. Cox regression models were performed for all the individual twins. In addition, we extended the analysis to discordant twin pairs (twin pairs with one having cancer and the other being cancer-free), to control to a certain extent for (unmeasured) shared confounders (genetic and environmental factors). The analysis based on individual twins showed that individual twins with cancer are at increased hazard of worsening hand grip strength (hazard ratio (HR) 1.37, 95% confidence interval (CI) 1.04, 1.80) than cancer-free twins. Among the discordant twin pairs, twins with cancer had a higher hazard of worsening hand grip strength (HR 3.50, 95% CI 1.15, 10.63) than cancer-free cotwins. In contrast, there was no evidence of a difference between the hazard of experiencing mobility decline for twins with cancer compared with cancer-free twins, in both individual twins and discordant twin pairs analyses. Cancer was associated with hand grip strength functional decline in old individual twins and discordant pairs. Our results strengthen the importance of comprehensive geriatric assessment in older adults with cancer, as well as the importance of routine assessment of functional status. Promoting physical activity through exercise training programmes could enable the prevention of functional decline in older adults with cancer.

Lung cancer among the Elderly in Denmark – A comprehensive population-based cohort study

ObjectiveLung cancer primarily occurs in the elderly with a median age at diagnosis in Denmark of 73 years. However, elderly patients are under-represented in clinical trials as well as in screening studies. In this study, we aim to characterize elderly patients with lung cancer and explore the diagnostic intensity, treatment patterns, and survival. MethodPatients diagnosed with lung cancer between 2014 and 2017 according to the Danish Cancer Registry, and with clinical information in the Danish Lung Cancer Registry were included. Patient information was linked by the unique social identification number to information from Statistics Denmark. ResultsWe included n = 17,835 patients in this study, of whom 2,871 (16.1 %) were 80 years or older. Fewer elderly patients had lung biopsies (47 % vs 53 %) or mediastinal procedures (34 % vs 26 %), compared to the younger patients (p < 0.001). Fewer elderly patients had treatment registration (60 % vs 85 %), and fewer received treatment with curative intent (23 % vs 42 %) compared to patients younger than 80 years (p < 0.001). The elderly patients had 2.1 (CI 95 % 1.9 – 2.2) times higher odds of dying within 12 months after diagnosis than younger patients. ConclusionThe diagnostic intensity among lung cancer patients aged eighty years or above is lower compared to younger patients. Being elderly is associated with not undergoing surgical treatment or treatment with curative intent. Across all treatment groups, being older than eighty years of age was associated with an adverse prognosis.

Abstract 3441: Application of a maternal comorbidity index to predict childhood cancer risk: A population-based case-control study in Denmark

Abstract Background: Maternal health has been found to be an indicator of children’s health and has also been found to affect the risk of childhood diseases. Children are especially susceptible to in-utero exposures. A mother’s health conditions before and during pregnancy could have important consequences for her child's health, including cancer development, as was observed in some prior studies. Objectives: This study aimed to identify the impact of varying maternal comorbidities on the development of childhood cancers. This study applied an Obstetric Comorbidity Index (Bateman et al, 2013) to examine maternal comorbid conditions in childhood cancer risk. Methods: Using maternal and birth records, and cancer records from the Danish Cancer Registry, we conducted a population-based case-control study with two population groups- the first population included cases (n=2578) and controls (n=64450) with ICD-10 diagnoses from 1994-2013, and the second population included cases (n=8339) and controls (n=208475) with ICD-8 and 10 diagnoses from 1977-2013. Maternal comorbidities were ascertained from the National Patient Register using the Obstetric Comorbidity Index. We estimated the risk of childhood cancer using conditional logistic regression. Results: Multiple gestation pregnancy (OR=1.17, 95% CI 1.05, 1.30), maternal pre-existing diabetes (OR=1.68, 95% CI 1.14, 2.48), congenital heart disease (OR=2.62, 95% CI 1.13, 6.09) and previous cesarean delivery (OR=1.35, 95% CI 1.03, 1.75) showed an increased risk of childhood cancers (all types combined). Children born to mothers between the ages of 35 and 39 also had a higher risk of cancer as compared to those born before. In the 1977-2013 population, there was an increased risk of acute lymphocytic leukemia (ALL; OR=1.08, 95% CI 1.04, 1.13) and rhabdomyosarcoma (OR=1.13, 95% CI 1.01, 1.27) for each unit of increase on the Obstetric Comorbidity Index. There was also an increased risk of retinoblastoma (OR=1.16, 95% CI 1.01, 1.32) for each unit of increase on the maternal comorbidities index in the 1994-2013 population. Examining mothers that had a score of one or more in the Obstetric Comorbidity Index, there was a higher risk of ALL (OR=1.43, 95% CI 1.26, 1.62), non-Hodgkin lymphoma (OR=1.50, 95% CI 1.17, 1.91), Burkitt lymphoma (OR=1.71, 95% CI 1.12, 2.61), and rhabdomyosarcoma (OR=1.58, 95% CI 1.10, 2.26) for children whose mothers with at least one maternal comorbidity. A similar trend was observed in the 1994-2013 population for ALL, non-Hodgkin lymphoma, and Burkitt lymphoma. Conclusion: The results of the study show varying effects of exposure to one or more maternal comorbidities on individual pediatric cancer types, and an overall increased risk of most cancers development in children with exposure of mothers to 1 or more maternal comorbidities. Citation Format: Tobiloba Adanma Adenekan, Julia E. Heck, Cheng Yin, Johnni Hansen. Application of a maternal comorbidity index to predict childhood cancer risk: A population-based case-control study in Denmark [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 3441.

Congenital Tooth Agenesis and Risk of Early-Onset Cancer

There is some evidence that tooth agenesis (congenital absence of 1 or more teeth) is associated with cancer risk, especially carcinomas of the colon and ovaries, but results of previous studies are conflicting, and associations have not yet been evaluated in a population-based setting. To examine the association between tooth agenesis and specific cancer types before 40 years of age. This population-based cohort study used linking data from nationwide registries in Denmark to assess all Danish live-born singletons born from January 1, 1977, to December 31, 2018, and followed up for up to 40 years. Data were analyzed from January through June 2023. Tooth agenesis as documented by the Danish Central Registry of Odontology (Danish municipal pediatric dental care) from January 1, 1988, to December 31, 2018, and from hospital encounters in the Danish National Patient Registry within the entire study period. The primary outcome was first cancer diagnosis before 40 years of age obtained from the Danish Cancer Registry. Associations between tooth agenesis and specific cancers were estimated by Cox proportional hazards regression as hazard ratios (HRs) with 95% CIs. Analyses were split into age groups: younger than 1 year, 1 to younger than 3 years, 3 to younger than 10 years, 10 to younger than 20 years, 20 to younger than 30 years, and 30 to younger than 40 years. Associations with nonsyndromic tooth agenesis were evaluated after exclusion of individuals with known syndromes. Among 2 501 715 included individuals (1 284 292 [51.3%] male), 70 288 (2.8%) had a diagnosis of tooth agenesis (mean [SD] age at diagnosis, 13.2 [4.1] years) and 26 308 (1.1%) had a diagnosis of early-onset cancer within the study period; 778 individuals had co-occurrence of tooth agenesis and cancer. Overall, tooth agenesis was positively associated with several cancer types, including neuroblastoma (age 1 to <3 years; HR, 4.20; 95% CI, 2.24-7.88), nephroblastoma (age 1 to <3 years; HR, 4.59; 95% CI, 2.37-8.91), hepatoblastoma (age 1 to <3 years; HR, 7.10; 95% CI, 2.70-18.68), osteosarcoma (age 10 to <20 years; HR, 2.19; 95% CI, 1.11-4.32), colorectal carcinomas (age 30 to <40 years; HR, 2.81; 95% CI, 1.38-5.71), and carcinomas of bladder (age 20 to <30 years; HR, 3.35; 95% CI, 1.35-8.30). This cohort study found associations between congenital tooth agenesis and several cancer types, from childhood to early adulthood. Further evaluation of these associations is needed to assess possible clinical implications.

Social factors and age play a significant role in cervical cancer and advanced-stage disease among Danish women

BackgroundFor cervical cancer (CC), the implementation of preventive strategies has the potential to make cervical cancer occurrence and death largely avoidable. To better understand the factors possibly responsible for cervical cancer, we aimed to examine possible differences in age and social parameters as well as screening status between women with low- or high-stage cervical cancer and matched controls.MethodsThrough the Danish Cancer Registry (DCR), women diagnosed with cervical cancer in Denmark between 1987 and 2016 were included. These were age- and residence-matched in a 1:5 ratio with controls from the general female population. The study population was sub grouped into a low-stage subpopulation with women with early-stage cervical cancer and matched controls and a high-stage subpopulation with women with late-stage cervical cancer and matched controls. Age and social parameters were compared within the subpopulations as well as between low- and high-stage cases. For part of the study population, screening attendance was examined to compare differences in adherence.ResultsOverall, we found that the risk of cervical cancer is significantly increased in socially disadvantaged women and not least non-attenders in screening. Interestingly, the high-stage subpopulation was significantly older than the low-stage subpopulation (p < 0.001), and when examining the impact of age further, we found that for cervical cancer cases, the risk of having low-stage disease decreases significantly with increasing age, whereas the risk of having high-stage disease increases significantly with increasing age. In the screening cohort, significantly less cases than controls were attenders in screening with the most pronounced differences seen in the old subpopulation (women aged 50–64 years) and in the high-stage subpopulation (p-values all < 0.001). Interestingly, when examining the risk of CC for attenders and non-attenders, we demonstrated that many social parameters continue to influence the risk of cervical cancer, even in women attending screening.ConclusionsOlder women, socially disadvantaged women, and non-attenders in screening are particularly vulnerable in terms of developing cervical cancer, especially high-stage disease. Therefore, improvements in the participating rate in screening as well as a revision of the current screening guidelines are needed.

Introduction of the Danish Lung Nodule Registry: A part of the Danish Lung Cancer Registry

BackgroundThe majority of lung cancer cases are diagnosed late, resulting in poor prognosis and high mortality rates. Early detection and management of lung cancer can improve patient outcomes and reduce mortality rates. Pulmonary nodules are key factors in the early detection of lung cancer, they are common in high-risk populations and require correct classification to determine whether they are benign or malignant. Over the last decade a steep increase in the number of thoracic CT scans has been seen in Denmark, resulting in substantial resources allocated to CT follow-up of incidentally detected pulmonary nodules. The implementation of a nationwide Danish prospective pulmonary nodule registry is to methodically record pulmonary nodules and thereby evaluate the scope of pulmonary nodule follow-up, the nature of the nodules, and the clinical progression of patients with pulmonary nodules. MethodsA prospective pulmonary nodule registry (Danish Lung Nodule Registry) will be a natural appendix to the Danish Lung Cancer Registry. Three new ICD-10 classification codes will be introduced, defining the type of nodule: /DR91.1/ Solid nodule /DR91.2/ Part-solid nodule; /DR91.3/ Non-solid nodule. Furthermore, an additional letter will describe whether the imaging exam is performed on suspicion of lung cancer (A), or the finding is incidental (B). Registration of the nodules will be performed by the departments of respiratory medicine who manage follow-up of pulmonary nodules. It is estimated that around 7000 nodules will be registered annually. DiscussionThe registration of patients in the lung nodule registry complies with current Danish legislation. The registry will be seamlessly integrated with other nationwide Danish registries, including the Danish Lung Cancer Registry, to collect additional patient data and improve the quality and scope of the data acquired. The results from these comprehensive epidemiological studies will be of significant interest and offer valuable research opportunities.

Validity of self-reported night shift work among women with and without breast cancer.

This study aimed to estimate the validity of self-reported information on ever-night shift work among women with and without breast cancer and illustrate the consequences for breast cancer risk estimates. During 2015-2016, 225 women diagnosed with breast cancer and 1800 matched controls without breast cancer employed within the Danish hospital regions during 2007-2016 participated in a questionnaire-based survey. Their reported night shift work status was linked with objective payroll register day-by-day working hour data from the Danish Working Hour Database and the Danish Cancer Registry. For the breast cancer patients and their matched controls, we estimated sensitivity and specificity for ever-working night shifts using the payroll data as the gold standard. We also used quantitative bias analysis to estimate the impact on relative risk estimates for a hypothetical population. For breast cancer patients, we observed a sensitivity of ever-night shifts of 86.2% and a specificity of never-night shifts of 82.6%. For controls, the sensitivity was 80.6% and the specificity 83.7%. Odds ratio for breast cancer in a hypothetical population decreased from 1.12 [95% confidence interval (CI) 1.03-1.21] to 1.05 (95% CI 0.95-1.16) when corrected by the sensitivity and specificity estimates. This study shows that female breast cancer patients had slightly better recall of previous night shift work than controls. Additionally, both breast cancer patients and controls recalled previous never-night shift work with low specificity. The net effect of this misclassification is a small over-estimation of the relative breast cancer risk due to night shift work.

Association of vaginal oestradiol and the rate of breast cancer in Denmark: registry based, case-control study, nested in a nationwide cohort

ObjectiveTo estimate the rate of breast cancer associated with use of vaginal oestradiol tablets according to duration and intensity of their use.DesignRegistry based, case-control study, nested in a nationwide cohort.SettingBased...

Use of [18F]Fluorodeoxyglucose Positron Emission Tomography/Computed Tomography after Curative Treatment of Non-Small-Cell Lung Cancer Patients: A Nationwide Cohort Study.

[¹⁸F]Fluorodeoxyglucose positron emission tomography/computed tomography ([¹⁸F]FDG PET/CT) is a valuable imaging tool in the post-treatment management of non-small-cell lung cancer (NSCLC). This study aimed to investigate the trends in utilization and factors associated with the use of [¹⁸F]FDG PET/CT after curative-intent treatment. Data from 13,758 NSCLC patients diagnosed between 2007 and 2020 identified in the Danish Lung Cancer Registry, who underwent curative-intent treatment, were analyzed using multivariable regression. The results showed a significant increase in the use of [¹⁸F]FDG PET/CT scans, from 10.4 per 100 patients per year in 2007 to 39.6 in 2013, followed by a period of stability. Higher utilization rates were observed in patients who received radiotherapy (22% increase compared to surgical resection) and in patients with stage II-III disease (14% and 20% increase compared to stage I, respectively). Additionally, utilization was increased when other diagnostic procedures were performed, such as MRI, ultrasound, endoscopy, and biopsy. These findings highlight an increasing reliance on [¹⁸F]FDG PET/CT in post-treatment NSCLC, especially after radiotherapy and in patients with locally advanced disease, where treatment-induced radiographic changes and an increased risk of recurrence present a significant diagnostic challenge.

Risk of cancer in relatives of patients with myelodysplastic neoplasia and acute leukemias

BackgroundThe risk of cancer among relatives of patients with either myelodysplastic neoplasia (MDS), acute myeloid leukemia (AML) or acute lymphoblastic leukemia (ALL) has not been thoroughly examined. MethodsWe linked the Danish Civil Registration System with the Danish Cancer Registry, the Danish National Acute Leukemia Registry, and the Danish Myelodysplastic Syndrome Database to estimate the relative risk of cancer among relatives of patients with MDS/AML/ALL. We used standardized incidence ratios (SIRs), i.e., the ratio of observed to expected number of cancers among the relatives as a measure of relative risk. ResultsWe identified 13010 first-degree (FDR) and 22051 second‐degree (SDR) relatives of 8386 patients with MDS/ALL/AML. Disregarding basal cell carcinoma (BCC), the relative risk for cancer overall was increased in both FDR (SIR=1.3; 95% confidence interval (CI) 1.1–1.4) and SDR (SIR=1.5; 95% CI 1.2–1.8). SIRs among FDRs were statistically significantly increased for malignant melanoma, BCC and for the combined groups of cancers of the male genital organs, urinary tract, and MDS/AML/ALL. Among SDRs, SIRs were statistically significantly increased for malignant melanoma, BCC, and cancers in the digestive organs and peritoneum. ConclusionsWe observed an increased risk of cancer among FDR and SDR of patients with MDS/AML/ALL.