Colorectal Cancer Survival in German-Danish Border Regions-A Registry-Based Cohort Study.

The aim of this study was (i) to update the reporting of colorectal cancer survival differences over time in the German-Danish border region (Schleswig-Holstein, Southern Denmark, and Zealand) and (ii) to assess the extent to which it can be explained by stage and primary treatment. Incident invasive colorectal cancer cases diagnosed from 2004 to 2016 with a follow-up of vital status through 31 December 2017 were extracted from cancer registries. Analyses were conducted by anatomical subsite and for four consecutive periods. Kaplan-Meier curves and log-rank tests were computed. Cox regression models using data from Schleswig-Holstein from 2004 to 2007 as the reference category were run while controlling for age, sex, stage, and treatment. The cox regression models showed decreasing hazard ratios of death for all three regions over time for both anatomical subsites. The improvement was stronger in the Danish regions, and adjustment for age, sex, stage, and treatment attenuated the results only slightly. In 2014-2016, colon cancer survival was similar across regions, while rectal cancer survival was significantly superior in the Danish regions. Regional survival differences can only partially be explained by differing stage distribution and treatment and may be linked additionally to healthcare system reforms and screening efforts.

Nordcan.R: a new tool for federated analysis and quality assurance of cancer registry data.

Aim of the article: We present our new GDPR-compliant federated analysis programme (nordcan.R), how it is used to compute statistics for the Nordic cancer statistics web platform NORDCAN, and demonstrate that it works also with non-Nordic data. Materials and methods: We chose R and Stata programming languages for writing nordcan.R. Additionally, the internationally used CRG Tools programme by International Agency for Research on Cancer (IARC/WHO) was employed. A formal assessment of (GDPR-compliant) anonymity of all nordcan.R outputs was performed. In order to demonstrate that nordcan.R also works with non-Nordic data, we used data from the Netherlands Cancer Registry. Results: nordcan.R, publicly available on Github, takes as input cancer and general population data and produces tables of statistics. Each NORDCAN participant runs nordcan.R locally and delivers its results to IARC for publication. According to our anonymity assessment the data can be shared with international organizations, including IARC. nordcan.R incidence results on Norwegian and Dutch data are highly similar to those produced by two other independent methods. Conclusion: nordcan.R produces accurate cancer statistics where all personal and sensitive data are kept within each cancer registry. In the age of strict data protection policies, we have shown that international collaboration in cancer registry research and statistics reporting is achievable with the federated analysis approach. Undertakings similar to NORDCAN should consider using nordcan.R.

Survival of breast cancer patients in German-Danish border regions - A registry-based cohort study.

BACKGROUND AND AIM: Denmark reports slightly lower breast cancer survival before 2010 than its neighbouring country Germany. Previous research is limited by lacking stage and treatment information. This study aims to investigate differences in breast cancer survival between the bordering regions Schleswig-Holstein (Germany), Southern Denmark and Zealand (Denmark) using registry data including stage and treatment information. METHOD: Invasive female breast cancer cases diagnosed during 2004-2013 with follow up through 31st December 2014 were extracted from cancer registries. Cases notified by death certificates only and those aged 90+ years were excluded. Kaplan-Meier curves and log-rank tests were computed. Cox regression analysis was conducted with adjustment for year of diagnosis, age, stage, and treatment. RESULTS: The analytical sample included 42,966 cases. Kaplan-Meier curves and log-rank tests show significant survival differences between the regions. The Cox regression model adjusted for year of diagnosis and age shows significantly worse overall survival of breast cancer patients in both Danish regions compared to Schleswig-Holstein with hazard ratios (HR) of 1.09 (95 % CI: 1.04; 1.15) for patients from Southern Denmark (SD) and 1.25 (95 % CI: 1.18; 1.32) for residents of Zealand (ZL). This effect diminished after adjustment for stage and treatment (HR: 1.05 (SD), 1.09 (ZL) 95 % CI: 0.99; 1.10 (SD), 1.03; 1.15 (ZL)). CONCLUSION: Survival differences can be explained by differing stage distribution and treatment administration, which formerly were more favourable in Schleswig-Holstein. The survival gap will probably close due to Denmark's national screening program and increased use of adjuvant cancer therapy.

The histology of brain tumors for 67 331 children and 671 085 adults diagnosed in 60 countries during 2000-2014: a global, population-based study (CONCORD-3).

BACKGROUND: Global variations in survival for brain tumors are very wide when all histological types are considered together. Appraisal of international differences should be informed by the distribution of histology, but little is known beyond Europe and North America. METHODS: The source for the analysis was the CONCORD database, a program of global surveillance of cancer survival trends, which includes the tumor records of individual patients from more than 300 population-based cancer registries. We considered all patients aged 0-99 years who were diagnosed with a primary brain tumor during 2000-2014, whether malignant or nonmalignant. We presented the histology distribution of these tumors, for patients diagnosed during 2000-2004, 2005-2009, and 2010-2014. RESULTS: Records were submitted from 60 countries on 5 continents, 67 331 for children and 671 085 for adults. After exclusion of irrelevant morphology codes, the final study population comprised 60 783 children and 602 112 adults. Only 59 of 60 countries covered in CONCORD-3 were included because none of the Mexican records were eligible. We defined 12 histology groups for children, and 11 for adults. In children (0-14 years), the proportion of low-grade astrocytomas ranged between 6% and 50%. Medulloblastoma was the most common subtype in countries where low-grade astrocytoma was less commonly reported. In adults (15-99 years), the proportion of glioblastomas varied between 9% and 69%. International comparisons were made difficult by wide differences in the proportion of tumors with unspecified histology, which accounted for up to 52% of diagnoses in children and up to 65% in adults. CONCLUSIONS: To our knowledge, this is the first account of the global histology distribution of brain tumors, in children and adults. Our findings provide insights into the practices and the quality of cancer registration worldwide.

Tobacco-related cancers in Europe: The scale of the epidemic in 2018.

BACKGROUND: Tobacco smoking is the major preventable cause of cancer. Despite the longstanding decline in smoking prevalence, lung cancer remains one of the most frequently diagnosed cancers in both sexes. We aimed to estimate the current cancer burden attributable to smoking in Europe. METHODS: Smoking-related cancer incidence by country, cancer type, sex and age in Europe was estimated from GLOBOCAN 2018. We applied a modified version of the indirect method to estimate the population attributable fraction (PAF) for lung cancer and applied Levin's formula to estimate the PAF for other smoking-related cancer sites. RESULTS: In Europe in 2018, 572,000 and 186,000 cancer cases were attributable to tobacco smoking in males and females respectively, accounting for 28% (males) and 10% (females) of all cancer cases. By region, the largest and the lowest PAF due to smoking in males occurred in Eastern Europe (35% of all cancer cases) and Northern Europe (21%), respectively. Among women, this pattern was reversed (16% in Northern Europe and 6% in Eastern Europe). Lung cancer accounted for more than half of the total cancer burden attributable to smoking (382,000). Other major contributors to the total PAF were lip, oral cavity and pharynx, bladder and laryngeal cancers in men (27% out of total PAF) and colorectal, pancreatic, oral cavity and pharyngeal cancers (21%) in women. CONCLUSIONS: Tobacco smoking was responsible for one in five cancer cases in Europe in 2018. The introduction and robust implementation of tobacco control programmes are critical to reduce this cancer burden in the future.

Risk of primary brain tumour after breast cancer.

INTRODUCTION: Cancer registry data in the USA indicated that women diagnosed with breast cancer before the age of 40 were at increased risk of a new primary tumour within the brain and women aged 50 years or above were at lower risk than expected. Our aim was to investigate if similar results could be found in Danish population-based data, considering an explanatory role of hormonal status. METHODS: Our study cohort included all women diagnosed with breast cancer below the age of 60 between 1978 and 2013 in Denmark. A total of 47,920 women were followed up in the Danish Cancer Registry for primary brain cancer. Standardized incidence ratios (observed/expected cases (O/E)) were used to estimate the risk of getting a primary brain tumour in the breast cancer cohort. RESULTS: Data indicated an increased tendency of brain cancer following breast cancer at ages below 60 years (O/E = 1.24). For premenopausal women (age <49 at the diagnosis of breast cancer) the O/E was 1.25. Stratifying by time of breast cancer diagnosis, we observed an increased risk of being diagnosed with a brain tumour among women aged 49 years or younger at breast cancer diagnosis between 2004 and 2013. CONCLUSION: The results indicate an increased tendency of developing a primary brain tumour in women with previous breast cancer history. Whereas the finding in premenopausal women is in line with the SEER data, the finding among postmenopausal is not. Primary brain tumours in breast cancer patients call for research in genetics and hormones to establish common risk factors.

Cancer After Liver Transplantation in Children and Young Adults: A Population-Based Study From 4 Nordic Countries.

Cancer after liver transplantation (LT) constitutes a threat also for young recipients, but cancer risk factors are usually absent in children and large studies on the cancer risk profile in young LT recipients are scarce. Data of patients younger than 30 years who underwent LT during the period 1982-2013 in the Nordic countries were linked with respective national cancer registries to calculate standardized incidence ratios (SIRs). A total of 37 cancer cases were observed in 923 patients with 7846 person-years of follow-up. The SIR for all cancer types, compared with the matched general population, was 9.8 (12.4 for males and 7.8 for females). Cumulative incidence of cancer adjusted for the competing risk of death was 2% at 10 years, 6% at 20 years, and 22% at 25 years after LT. Non-Hodgkin lymphoma was the most common cancer type (n = 14) followed by colorectal (n = 4) and hepatocellular cancer (n = 4). Age was a significant risk factor for cancer, and the absolute risk of most cancers (except for lymphoma) increased considerably in young adults older than 20 years. The cancer risk pattern is different in pediatric and young LT patients compared with adult recipients. The striking increase in cancer incidence in young adulthood after the second decade of life deserves further consideration in transition programs.

Stomach Cancer Following Hodgkin Lymphoma, Testicular Cancer and Cervical Cancer: A Pooled Analysis of Three International Studies with a Focus on Radiation Effects.

To further understand the risk of stomach cancer after fractionated high-dose radiotherapy, we pooled individual-level data from three recent stomach cancer case-control studies. These studies were nested in cohorts of five-year survivors of first primary Hodgkin lymphoma (HL), testicular cancer (TC) or cervical cancer (CX) from seven countries. Detailed data were abstracted from patient records and radiation doses were reconstructed to the site of the stomach cancer for cases and to the corresponding sites for matched controls. Among 327 cases and 678 controls, mean doses to the stomach were 15.3 Gy, 24.7 Gy and 1.9 Gy, respectively, for Hodgkin lymphoma, testicular cancer and cervical cancer survivors, with an overall mean dose of 10.3 Gy. Risk increased with increasing radiation dose to the stomach cancer site (P < 0.001) with no evidence of nonlinearity or of a downturn at the highest doses (≥35 Gy). The pooled excess odds ratio per Gy (EOR/Gy) was 0.091 [95% confidence interval (CI): 0.036-0.20] with estimates of 0.049 (95% CI: 0.007-0.16) for Hodgkin lymphoma, 0.27 (95% CI: 0.054-1.44) for testicular cancer and 0.096 (95% CI: -0.002-0.39) for cervical cancer (P homogeneity = 0.25). The EOR/Gy increased with time since exposure (P trend = 0.004), with an EOR/Gy of 0.38 (95% CI: 0.12-1.04) for stomach cancer occurring ≥20 years postirradiation corresponding to odds ratios of 4.8 and 10.5 at radiation doses to the stomach of 10 and 25 Gy, respectively. Of 111 stomach cancers occurring ≥20 years after radiotherapy, 63.8 (57%) could be attributed to radiotherapy. Our findings differ from those based on Japanese atomic-bomb survivors, where the overall EOR/Gy was higher and where there was no evidence of an increase with time since exposure. By pooling data from three studies, we demonstrated a clear increase in stomach cancer risk over a wide range of doses from fractionated radiotherapy with the highest risks occurring many years after exposure. These findings highlight the need to directly evaluate the health effects of high-dose fractionated radiotherapy rather than relying on the data of persons exposed at low and moderate acute doses.

Increased pancreatic cancer risk following radiotherapy for testicular cancer.

BACKGROUND: Pancreatic cancer risk is elevated among testicular cancer (TC) survivors. However, the roles of specific treatments are unclear. METHODS: Among 23 982 5-year TC survivors diagnosed during 1947-1991, doses from radiotherapy to the pancreas were estimated for 80 pancreatic cancer patients and 145 matched controls. Chemotherapy details were recorded. Logistic regression was used to estimate odds ratios (ORs). RESULTS: Cumulative incidence of second primary pancreatic cancer was 1.1% at 30 years after TC diagnosis. Radiotherapy (72 (90%) cases and 115 (80%) controls) was associated with a 2.9-fold (95% confidence interval (CI) 1.0-7.8) increased risk. The OR increased linearly by 0.12 per Gy to the pancreas (P-trend<0.001), with an OR of 4.6 (95% CI 1.9-11.0) for ⩾25 Gy vs <25 Gy. Radiation-related risks remained elevated ⩾20 years after TC diagnosis (P=0.020). The risk increased with the number of cycles of chemotherapy with alkylating or platinum agents (P=0.057), although only one case was exposed to platinum. CONCLUSIONS: A dose-response relationship exists between radiation to the pancreas and subsequent cancer risk, and persists for over 20 years. These excesses, although small, should be considered when radiotherapy with exposure to the pancreas is considered for newly diagnosed patients. Additional data are needed on the role of chemotherapy.

Trends in cancer in the elderly population in Denmark, 1980-2012.

BACKGROUND: Age is the strongest risk factor for developing cancer. The aim of the present analysis is to give an overview of the trends in cancer incidence, mortality, prevalence, and relative survival in Denmark from 1980 to 2012 focusing on age, comparing persons aged 70 years or more with those aged less than 70 years. MATERIAL AND METHODS: Data derived from the NORDCAN database with comparable data on cancer incidence, mortality, prevalence and relative survival in the Nordic countries. The Danish data originate from the Danish Cancer Registry and the Danish Cause of Death Registry with follow-up for death or emigration until the end of 2013. RESULTS: Incidence and mortality rates of all sites, but non-melanoma skin cancer, were higher and relative survival was lower among persons aged 70 years or more than those aged less than 70 years. The age distribution (age group-specific percentages of total number of incident cases) remained constant over time while the percentage of persons dying from cancer decreased with time up to the age of 79 years but increased for those aged 80 years or more, in whom about a third of all cancer deaths occurred in 2012. In 2003-2007, the five-year relative survival was 48% for men aged 70-79 years, 38% for men aged 80-89 years, and 29% for men aged 90 years or more and the corresponding figures for women were 46%, 39%, and 36%, respectively. There was a substantial increase in the number of prevalent cancer cases aged 70 years or older, especially among those aged 90 years or more. CONCLUSION: An increase in elderly cancer patients is expected over the coming 20 years due to an increasing elderly population. Healthcare providers need to focus on developing specific strategies for treatment of elderly cancer patients in the future.

Quality assessment of prostate cancer reports to the Danish Cancer Registry.

BACKGROUND: The Danish Cancer Registry (DCR) is the oldest nationwide population-based cancer registry in the Nordic countries. At the time of the study the DCR recorded date of diagnosis, tumor stage and initial treatment. The validity of the clinical information reported to the DCR has never been analyzed. MATERIAL AND METHODS: Patients diagnosed with prostate cancer from 1 May to 31 December 1997 and living in eight Danish counties were identified through the DCR. Clinical data was retrieved from hospital records where date of diagnosis, stage at diagnosis and treatment received were registered. RESULTS: The mean age at diagnosis was 74.6 years (s.d. 8.6 years). Diagnosis was verified histologically for 87% of cases. Overall 95% of the patients had a difference less than three months between the reported date of diagnosis and the date found in hospital records. Correction of dates of diagnosis had no impact on survival. Hospital records identified 86 patients with T1-2 disease without distant metastases (M0), but only 56 of these patients (65%) were reported to the DCR as having localized disease. According to hospital records a total of 242 patients were confirmed having distant metastases (M1) at diagnosis but only 139 of these cases (57%) were reported to the DCR as such. Considerable "over reporting" of curative treatment was observed. CONCLUSION: The DCR has been shown to be reliable in terms of new cases being reported. For the majority of cases there were insignificant differences concerning the date of diagnosis. However, the DCR information on stage and treatment was found to be inaccurate. Since 2004 the DCR registration process, including staging according to the TNM classification, has been carried out electronically from several registers. Future comparison between cohorts of different time intervals or international comparison should be interpreted with caution when clinical information is included.

Incidence and survival in patients with cutaneous melanoma by morphology, anatomical site and TNM stage: a Danish Population-based Register Study 1989-2011.

INTRODUCTION: The incidence of melanoma of the skin has risen in Denmark in recent decades, the increase being steeper from 2004. It is unclear whether this represents a true rise in incidence or whether it is caused by an increased awareness of the condition. METHODS: To assess whether the increase was characterised by early-stage melanomas and a higher proportion of melanomas with superficial spreading morphology, we studied all skin melanoma patients registered in the Danish Cancer Register 1989-2011 (n=27,010) and followed up for death through 2013. Trends in age-standardised incidence by sex, subsite and morphology, relative survival, TNM stage distribution and stage-specific relative survival from 2004 were analysed. RESULTS: The incidence of melanoma more than doubled over 23 years. A steeper increase from 2004 was driven mainly by superficial spreading tumours, but the proportion of nodular melanomas in patients 50 years of age and over also increased significantly. The largest increase occurred for stage I tumours and for tumours on the trunk. From 1989-1993 to 2009-2011 the 5-year relative survival increased at 12% and 6% points for male and female patients, respectively. INTERPRETATION: Greater awareness, and thus lower stage at diagnosis (mediated by a large skin cancer prevention campaign from 2007), might explain part of the increase, but the increase in nodular melanoma also points to a genuine increase in the risk of melanoma.

Less pitfalls and variation in population based cancer survival comparisons within the European Union: Lessons from colorectal cancer patients in neighbouring regions in Denmark and Germany - The Fehmarn Belt project.

BACKGROUND: International comparisons of cancer registry based survival are often used as a marker of the performance of health care services on cancer. These are debated for comparability, validity and lack of detail with respect to prognostic factors. With a view to cross border collaborative cancer research and care in the European Union (EU), we used the established routine registration systems for cancer in the neighbouring regions Zealand, Denmark, and Schleswig-Holstein, Germany, to study if available routine registration suffices for the study of diagnosis, treatment and follow-up for colorectal cancer patients. The aim was to assess to which extent differences in survival between the regions could be explained. METHODS: Colorectal cancer patients recorded 2004-2010 in Schleswig-Holstein (colon: 10,631; rectum 5683) and region Zealand (colon: 3205; rectum 1747) were studied. Excluding cases aged 90+ or only known from death certificates, one- and four-year relative survival by stage for the periods 2004-2006 and 2007-2009 (one-year) were calculated. FINDINGS: A high proportion of patients in Schleswig-Holstein were known only from death certificates (colon 11%; rectum 6.9%) compared to <0.3% in region Zealand. Colon cancer incidence (asr-e) (men 36; women 28) and mortality (men 12; women 8.7) in Schleswig-Holstein were 10 per 100,000 lower than in Zealand; minor differences were seen for rectum cancer. One and four-year overall survival increased in both regions but was superior in Schleswig-Holstein. For patients with reported stage I-III, negligible differences in survival were seen; with further restriction to patients with treatment reported, even so in stage IV patients 2007-2009. INTERPRETATION: Improved data quality and comparability than presently used in the large international survival studies is needed. If stage and treatment is taken into account, more valid international comparisons of cancer survival are possible. Reporting and follow-up must be improved and cases only known from death certificates (DCO) minimised. A high proportion DCO (excluded from analyses) may produce higher survival, whereas a low the opposite. Co-morbidity and socio-economic status should be included alongside other prognostic variables in survival studies. Barriers towards proper follow-up and monitoring of outcome e.g. privacy legislation must be considered with a view to future patient mobility.

Cancer registration, public health and the reform of the European data protection framework: Abandoning or improving European public health research?

The importance of cancer- and other disease registries for planning, management and evaluation of healthcare systems has been shown repeatedly during the last 50 years. Complete and unbiased population-level analyses on routinely collected, individual data concerning health and personal characteristics can address significant concerns about risk factors for cancer and provide sound evidence about public health and the effectiveness of healthcare systems. The existence of quality controlled and comprehensive data in registries, allowed to be used for quality control, research and public health purposes are taken as granted by most health professionals and researchers. However, the current revision of the European Union (EU) data protection framework suggests a harmonisation of requirements for confidentiality and individual consent to data processing, likely at the expense of proper use of registry data in the health sector. Consequences of excessive confidentiality rules that may lead to missed data linkages have been simulated. The simulations provide one possible explanation for observed heterogeneity among some cancer incidence data. Further, public health, quality control and epidemiological research on large populations can no longer provide evidence for health interventions, if requirements for consent renders research impossible or where attempts to obtain consent from each data subject generates biased results. Health professionals should engage in the on-going debate on the Commission's proposal for a General Data Protection Regulation. The nature and use of registry data in public health research must be explained and known to policy-makers and the public. Use of cancer registry data and other epidemiological activity will terminate abruptly if an unnecessarily strict EU data protection regulation is adopted. Research based interventions, as well as the international recognised standing of cancer registries and register-based research institutions in Europe are at stake.

Mortality from cancer and other causes in commercial airline crews: a joint analysis of cohorts from 10 countries.

BACKGROUND: Commercial airline crew is one of the occupational groups with the highest exposures to ionising radiation. Crew members are also exposed to other physical risk factors and subject to potential disruption of circadian rhythms. METHODS: This study analyses mortality in a pooled cohort of 93 771 crew members from 10 countries. The cohort was followed for a mean of 21.7 years (2.0 million person-years), during which 5508 deaths occurred. RESULTS: The overall mortality was strongly reduced in male cockpit (SMR 0.56) and female cabin crews (SMR 0.73). The mortality from radiation-related cancers was also reduced in male cockpit crew (SMR 0.73), but not in female or male cabin crews (SMR 1.01 and 1.00, respectively). The mortality from female breast cancer (SMR 1.06), leukaemia and brain cancer was similar to that of the general population. The mortality from malignant melanoma was elevated, and significantly so in male cockpit crew (SMR 1.57). The mortality from cardiovascular diseases was strongly reduced (SMR 0.46). On the other hand, the mortality from aircraft accidents was exceedingly high (SMR 33.9), as was that from AIDS in male cabin crew (SMR 14.0). CONCLUSIONS: This large study with highly complete follow-up shows a reduced overall mortality in male cockpit and female cabin crews, an increased mortality of aircraft accidents and an increased mortality in malignant skin melanoma in cockpit crew. Further analysis after longer follow-up is recommended.