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Study Question: Is there an association between premature ovarian insufficiency (POI) and severe autoimmune diseases before and after POI diagnosis?, Summary Answer: Women with POI had at least one hospital-treated autoimmune disorder preceding POI diagnosis 2.6 times more often compared with matched female controls, and a 2- to 3-fold risk for these diseases for several years after POI diagnosis., What Is Known Already: It has been suggested that autoimmunity is an important factor in the pathogenesis of POI. Estimations of the prevalence of POI cases with autoimmune origin have ranged from 4% to 50%., Study Design, Size, Duration: This population-based registry study included 3972 women diagnosed with spontaneous POI between 1988 and 2017 and 15 708 female population controls and used both case-control and cohort analysis. Autoimmune disease diagnoses were evaluated from childhood until the end of the year 2017., Participants/materials, Setting, Methods: Women with POI were identified from the reimbursement registry of the Finnish Social Insurance Institution by their right to hormone replacement therapy (HRT). Four female population controls matched by age and municipality of residence were searched for each POI case to form a reference cohort. Women with a history of cancer or bilateral oophorectomy were excluded. Severe autoimmune disorder diagnoses for the years 1970-2017 were identified from the Hospital Discharge Registry. Odds ratios (ORs) with 95% confidence intervals (CI) were calculated using binary logistic regression for cases of having any, or one or more, specific autoimmune diseases preceding the index date (the date when reimbursement for HRT was granted for the POI) among women with POI as compared to controls. Standardized incidence ratios (SIR) with 95% CIs for getting diagnosed with an autoimmune disease after the index date in 3-year follow-up periods among women with POI (who did not have these diseases prior to the index date) were also calculated. The expected numbers of autoimmune disease cases were based on the incidence of first-onset severe autoimmune disease among the controls., Main Results and the Role of Chance: The prevalence of having at least one severe autoimmune disease in women with POI was 5.6% (n = 233), with an OR of 2.6 (95% CI 2.2, 3.1) when compared to population controls. Women with POI had an increased prevalence of several specific autoimmune diseases prior to the index date compared to controls: polyglandular autoimmune diseases (OR 25.8, 95% CI 9.0, 74.1), Addison's disease (OR 22.9, 95% CI 7.9, 66.1), vasculitis (OR 10.2, 95% 4.3, 24.5), systemic lupus erythematosus (OR 6.3 95% CI 4.2, 20.3), rheumatoid arthritis (OR 2.3, 95% CI 1.7, 3.2), sarcoidosis (OR 2.3, 95% CI 1.2, 4.5), inflammatory bowel diseases (OR 2.2, 95% CI 1.5, 3.3), and hyperthyroidism (OR 1.9, 95% CI 1.2, 3.1); whereas the prevalence of diabetes type 1 and ankylosing spondylitis did not differ between the women with POI and the reference cohort. The SIRs for being diagnosed for the first time with a severe autoimmune disease after POI diagnosis was 2.8 (95% CI 2.3, 3.4), during the first three years after POI diagnosis, decreasing gradually to 1.3 (1.1, 1.6) after 12 years., Limitations, Reasons for Caution: This study only included autoimmune disorders diagnosed in specialized health care; hence, the overall prevalence of autoimmune disorders in women with POI may be higher., Wider Implications of the Findings: Severe autoimmune diseases have a strong association with POI, suggesting that immunological mechanisms play a pivotal role in POI. Future studies should focus on specific autoimmune mechanisms behind POI, from both preventive and curative perspectives., Study Funding/competing Interest(s): This work was financially supported by Oulu University Hospital. S.M.S. received grants from the Finnish Menopause Society, the Finnish Medical Foundation, and the Juho Vainio Foundation. H.S. received grants from the Finnish Menopause Society, the Oulu Medical Research Foundation, the Finnish Research Foundation of Gynecology and Obstetrics, UniOGS graduate school, The Finnish Medical Society Duodecim, Orion Research Foundation, and the University of Oulu Scholarship Fund. M.-M.O. received a grant from the Sakari Alhopuro Foundation and the Finnish Diabetes Research Foundation. None of the funders had any involvement in the study design or its execution or reporting. The authors do not have any competing interests to report., Trial Registration Number: N/A., (© The Author(s) 2024. Published by Oxford University Press on behalf of European Society of Human Reproduction and Embryology.)

Numerous studies have reported lower overall cancer mortality rates among immigrants compared to native populations. However, limited information exists regarding cancer mortality among immigrants based on specific birth countries and cancer types. We used population-based registries and followed 10 million individuals aged 20 years or older in Sweden between 1992 and 2016. The Cox proportional hazard model was used to explore the disparities in cancer mortality by country of birth and cancer type, stratified by gender. Age-standardized mortality rates were also computed using the world standard population. Hazard ratio (HR) of all-site cancer was slightly lower among immigrants (males: HR m  = 0.97: 95% confidence interval: 0.95, 0.98; females: HR f  = 0.93: 0.91, 0.94) than Swedish-born population. However, the immigrants showed higher mortality for infection-related cancers, including liver (HR f  = 1.10: 1.01, 1.19; HR m  = 1.10: 1.02, 1.17), stomach (HR f  = 1.39: 1.31, 1.49; HR m  = 1.33: 1.26, 1.41) cancers, and tobacco-related cancers, including lung (HR m  = 1.44: 1.40, 1.49), and laryngeal cancers (HR m  = 1.47: 1.24, 1.75). The HR of mesothelioma was also significantly higher in immigrants (HR f  = 1.44: 1.10, 1.90). Mortality from lung cancer was specifically higher in men from Nordic (HR m  = 1.41: 1.27, 1.55) and non-Nordic Europe (HR m  = 1.49: 1.43, 1.55) countries and lower in Asian (HR m  = 0.78: 0.66, 0.93) and South American men (HR m  = 0.70: 0.57, 0.87). In conclusion, there are large variations in cancer mortality by country of birth, and cancer type and require regular surveillance. Our detailed analyses lead to some novel findings such as excess mortality rate of mesothelioma and laryngeal cancers in Immigrants in Sweden. A targeted cancer prevention program among immigrants in Sweden is needed., (© 2024 The Author(s). Cancer Medicine published by John Wiley & Sons Ltd.)

Background: Endometriosis is associated with increased risk of clear cell ovarian cancer and has even suggested being an etiological factor for this cancer. Association between endometriosis and extraovarian clear cell cancers is unclear. This study aimed to assess the association between surgically diagnosed endometriosis and risk of extraovarian clear cell cancers according to the type of endometriosis (i.e., ovarian, peritoneal, and other endometriosis) and the site of clear cell cancer., Methods: In this register-based historic cohort study we identified all women with surgically diagnosed endometriosis from the Finnish Hospital Discharge Registry 1987-2012. Data on extraovarian clear cell cancers of these women were obtained from the Finnish Cancer Registry. The follow-up started January 1st, 2007 or at endometriosis diagnosis (if later), and ended at emigration, death or on the December 31st, 2014. Standardized incidence ratios were calculated for each site of clear cell carcinoma (intestine, kidney, urinary tract, gynecological organs other than ovary), using the Finnish female population as reference., Results: The endometriosis cohort consisted of 48,996 women, including 22,745 women with ovarian and 19,809 women with peritoneal endometriosis. Altogether 23 extraovarian clear cell cancers were observed during 367,386 person-years of follow-up. The risk of extraovarian clear cell cancer was not increased among all women with surgically diagnosed endometriosis (standardized incidence ratio 0.89, 95% confidence interval 0.56-1.33) nor in different types of endometriosis. The incidence of clear cell cancer in any specific site was not increased either., Conclusions: The risk of extraovarian clear cell cancers in women with surgically diagnosed endometriosis is similar to that in the general population in Finland., Competing Interests: The authors have declared that no competing interests exist.

Even 30 years after the accident, an association between breast cancer incidence and ionizing radiation exposure from Chernobyl fallout remains uncertain. We studied breast cancer incidence in the most contaminated regions of Belarus (Gomel and Mogilev) and Ukraine (Kyiv, Zhytomyr and Chernihiv) before (1978-1986) and after (1987-2016) the accident. Breast cancer cases and female population size data were received from the national cancer registries and the state departments of statistics. The study included 85 132 breast cancers with 150 million person-years at risk. We estimated annual rayon (district)-average absorbed doses to the breast from external and internal irradiation of the adult female population over the period of 1986-2016. We studied an association between rayon-average cumulative absorbed breast dose with 5-year lag, that is, excluding the exposure in 5 years prior to breast cancer diagnosis, and breast cancer incidence using negative binomial regression models. Mean (median) cumulative breast dose in 2016 was 12.3 (5.0) milligray (mGy) in Belarus and 5.7 (2.3) mGy in Ukraine, with the maximum dose of 55 mGy and 54 mGy, respectively. Breast cancer incidence rates statistically significantly increased with calendar year and attained age, and were higher in urban than in rural residents. Adjusting for time, age and urbanicity effects, we found no evidence of increasing incidence with rayon-average 5-year lagged cumulative breast dose. Owing to ecological study design limitations, a case-control study covering this area with individually reconstructed absorbed breast doses is needed testing for association between low-dose protracted radiation exposure and breast cancer risk after Chernobyl., (© 2021 Union for International Cancer Control.)

Purpose: Published epidemiological studies on the association between finasteride use and the risk of male breast cancer have been inconclusive due to methodological limitations including a few male breast cancer cases included. Determinants of male breast cancer have been studied, but it remains unexplored whether these are also related to finasteride use and thereby constitute potential confounders. This study aimed to assess whether there are differences between finasteride users and nonusers with regard to numerous potential confounders., Methods: In total, 246 508 finasteride users (≥35 years) were identified in the prescription registries of Denmark (1995-2014), Finland (1997-2013), and Sweden (2005-2014). An equal number of nonusers were sampled. The directed acyclic graph (DAG) methodology was used to identify potential confounders for the association between finasteride and male breast cancer. A logistic regression model compared finasteride users and nonusers with regard to potential confounders that were measurable in registries and population surveys., Results: Finasteride users had higher odds of testicular abnormalities (odds ratio [OR] 1.40; 95% confidence interval [CI] 1.36-1.44), obesity (1.31; 1.23-1.39), exogenous testosterone (1.61; 1.48-1.74), radiation exposure (1.22; 1.18-1.27), and diabetes (1.07; 1.04-1.10) and lower odds of occupational exposure in perfume industry or in high temperature environments (0.93; 0.87-0.99), living alone (0.89; 0.88-0.91), living in urban/suburban areas (0.97; 0.95-0.99), and physical inactivity (0.70; 0.50-0.99) compared to nonusers., Conclusions: Systematic differences between finasteride users and nonusers were found emphasizing the importance of confounder adjustment of associations between finasteride and male breast cancer., (© 2020 John Wiley & Sons Ltd.)

Background: Cancer is currently one of the most important factors affecting the long-term health and survival of heart transplant patients. Material and methods: We calculated the standardized incidence ratios (SIR) for different cancer sites and the cancer-specific standardized mortality ratio (SMR) by linking a cohort of 479 adult heart transplant recipients transplanted in 1985-2014 (4491.6 person-years of follow-up) with data from the national Finnish Cancer Registry until the end of 2015, and with the data from the Statistics Finland's national registry of causes of death. Results: A total of 267 cancers occurred in 143 patients (SIR 6.0; 95% confidence interval (CI) 5.3-6.7). The SIR for overall cancer was considerably higher for men (SIR 6.7; 95% CI 5.9-7.5) than for women (1.4; 95% CI 0.6-2.6). Most frequent cancers were non-melanoma skin cancers (basal cell carcinoma 83 cases, squamous cell skin cancer (SCC) 56 cases), followed by Non-Hodgkin lymphoma (NHL) (36 cases), lung cancer (17), cancer of prostate (16) and cancer of kidney (12). SIRs were highest for SCC (51.9; 95% CI 39.2-67.4), lip cancer (47.4; 95% CI 19.1-97.7), cancer of tongue (26.3; 95% CI 7.2-67.4), and NHL (25.7; 95% CI 18.0-35.6). For most cancers, SIRs increased steadily by time since transplantation. Cancer mortality was three times higher for heart transplant recipients than for the population (SMR 3.1; 95% CI 2.1-4.1). Conclusions: Both cancer incidence and mortality are remarkably increased after heart transplantation, with the relative incidence most elevated for SCC, lip and other oral cancers, and for NHL.

Purpose: A history of anorexia nervosa has been associated with a reduced risk of developing breast cancer. We investigated survival after breast cancer among women with a prior anorexia nervosa diagnosis compared with women in a population comparison group., Methods: This register-based study included combined data from Sweden, Denmark and Finland. A total of 76 and 1462 breast cancer cases identified among 22,654 women with anorexia nervosa and 224,619 women in a population comparison group, respectively, were included in the study. Hazard ratios (HR) for overall and breast cancer-specific mortality after breast cancer diagnosis were estimated using Cox regression. Cause of death was available only for Swedish and Danish women; therefore, the analysis on breast cancer-specific mortality was restricted to these women., Results: We observed 23 deaths after breast cancer among anorexia nervosa patients and 247 among population comparisons. The overall mortality after the breast cancer diagnosis was increased in women with a history of anorexia nervosa compared with population comparisons (HR 2.5, 95% CI 1.6-3.9) after adjustment for age, period and extent of disease. Results were similar for overall (HR 2.3, 95% CI 1.4-3.6) and breast cancer-specific mortality (HR 2.1, 95% CI 1.3-3.6) among Swedish and Danish women., Conclusions: We found that female breast cancer patients with a prior diagnosis of anorexia nervosa have a worse survival compared with other breast cancer patients.

Cancer remains one of the most serious long-term complications after liver transplantation (LT). Data for all adult LT patients between 1982 and 2013 were extracted from the Nordic Liver Transplant Registry. Through linkage with respective national cancer-registry data, we calculated standardized incidence ratios (SIRs) based on country, sex, calendar time, and age-specific incidence rates. Altogether 461 cancers were observed in 424 individuals of the 4246 LT patients during a mean 6.6-year follow-up. The overall SIR was 2.22 (95% confidence interval [CI], 2.02-2.43). SIRs were especially increased for colorectal cancer in recipients with primary sclerosing cholangitis (4.04) and for lung cancer in recipients with alcoholic liver disease (4.96). A decrease in the SIR for cancers occurring within 10 years post-LT was observed from the 1980s: 4.53 (95%CI, 2.47-7.60), the 1990s: 3.17 (95%CI, 2.70-3.71), to the 2000s: 1.76 (95%CI, 1.51-2.05). This was observed across age- and indication-groups. The sequential decrease for the SIR of non-Hodgkin lymphoma was 25.0-12.9-7.53, and for nonmelanoma skin cancer 80.0-29.7-10.4. Cancer risk after LT was found to be decreasing over time, especially for those cancers that are strongly associated with immunosuppression. Whether immunosuppression minimization contributed to this decrease merits further study., (© 2017 The American Society of Transplantation and the American Society of Transplant Surgeons.)

Background: The Nordic Cancer Registries are among the oldest population-based registries in the world, with more than 60 years of complete coverage of what is now a combined population of 26 million. However, despite being the source of a substantial number of studies, there is no published paper comparing the different registries. Therefore, we did a systematic review to identify similarities and dissimilarities of the Nordic Cancer Registries, which could possibly explain some of the differences in cancer incidence rates across these countries., Methods: We describe and compare here the core characteristics of each of the Nordic Cancer Registries: (i) data sources; (ii) registered disease entities and deviations from IARC multiple cancer coding rules; (iii) variables and related coding systems. Major changes over time are described and discussed., Results: All Nordic Cancer Registries represent a high quality standard in terms of completeness and accuracy of the registered data., Conclusions: Even though the information in the Nordic Cancer Registries in general can be considered more similar than any other collection of data from five different countries, there are numerous differences in registration routines, classification systems and inclusion of some tumors. These differences are important to be aware of when comparing time trends in the Nordic countries.

A potential link has been suggested between dispensed finasteride and increased risk of male breast cancer (MBC). Due to the rare occurrence of MBC, it remains to be established if such a relationship exists. The purpose of this study was to combine nationwide registers in four countries to assess the potential association between dispensed finasteride and MBC. A cohort of all males with dispensed finasteride in Denmark, Finland, Norway, and Sweden (1,365,088 person years) was followed up for up to 15 years for breast cancer, and compared to a cohort of males unexposed to finasteride. Individual-level register data included country, dates of dispensed finasteride, MBC diagnosis, and death. Incidence rate ratios (IRRs) were estimated using a generalized linear model with a Poisson distribution. An increased risk of MBC was found among finasteride users (IRR = 1.44, 95% confidence interval [95% CI] = 1.11-1.88) compared to nonusers. The IRR increased to 1.60 (95% CI = 1.20-2.13) when users in Norway and Sweden with short follow-up time were excluded. The highest IRR was seen among men with medium duration of dispensed finasteride, medium accumulated consumption of finasteride, and among men with first dispensed finasteride prescription 1-3 years prior to diagnosis. The analyses suggested possible ascertainment bias and did not support a clear relationship between dispensed finasteride and MBC. In conclusion, a significant association between dispensed finasteride and MBC was identified. However, due to limited data for adjustment of potential confounding and surveillance bias in the present study, further research is needed to confirm these results., (© 2017 The Authors. Cancer Medicine published by John Wiley & Sons Ltd.)

Population-based Finnish Maternity Cohort (FMC) comprises 2M first trimester sera collected from 1M women during 33 years. Informed consent is by the opt-out principle, and linkages with cancer and population registries provide a base for over time and over generation studies. Follow-up for 17M person-years by the end of 2014 can identify 39,700 cases of invasive cancer and 18,900 cases of premalignant breast and cervix lesions, and basal cell carcinoma diagnosed after serum sampling. For women with multiple pregnancies, serial samples taken before cancer diagnosis are available. Offspring of the women have developed more than 4000 cancers. For 100,000 individuals, samples taken during the pregnancies of both their mothers and grandmothers enable familial cancer studies. FMC continues to collect samples, and surveillance of exposures or interventions like vaccination programs is feasible. In summary, the FMC is a unique, accessible biobank for epidemiological, biomarker, and surveillance studies on cancer., (© 2017 The Authors. Cancer Medicine published by John Wiley & Sons Ltd.)

Background Earlier research suggests poorer outcome of cancer care among people with severe mental illness (SMI). Aims To assess the effect of stage at presentation, comorbidities and treatment on differences in survival among cancer patients with and without a history of SMI in Finland. Method The total population with a first cancer diagnosis in 1990-2013 was drawn from the Finnish Cancer Registry. Hospital admissions because of SMI and deaths were obtained from administrative registers. We calculated Kaplan-Meier estimates and Cox regression models to examine survival differences. Results We found excess mortality in people with a history of psychotic and substance use disorders. Cancer stage and comorbidity did not explain mortality differences. Controlling for cancer treatment decreased the differences. The mortality gap between patients with psychosis and cancer patients without SMI increased over time. Conclusions Integrated medical and psychiatric care is needed to improve outcomes of cancer care among patients with SMI., Competing Interests: Declaration of interestNone., (© The Royal College of Psychiatrists 2017.)

Background: The age-adjusted incidence of cutaneous squamous cell carcinoma (cSCC) in the Nordic countries has increased during the last 60 years, and the identification of occupational variation in the relative risk of cSCC may have preventive implications., Objective: We sought to describe variation in the relative risk of cSCC between occupational categories in Finland, Iceland, Norway, and Sweden., Methods: This is a historical prospective cohort study based on record linkages between census data for 12.9 million people and cancer registry data from 1961 to 2005. Standardized incidence ratios for cSCC were estimated for 53 occupational categories with the cSCC incidence rates for the national population of each country used as reference., Results: During follow-up, 87,619 incident cases of cSCC were reported to the national cancer registries. In all countries combined, significant increased standardized incidence ratios were observed among seamen, military personnel, public safety workers, technical workers, teachers, transport workers, physicians, dentists, nurses, other health workers, religious workers, clerical workers, administrators, and sale agents (standardized incidence ratios between 1.08 and 1.77)., Limitations: Information on occupation was based on 1 point in time only., Conclusion: The occupational variation of the relative risk of cSCC might be associated with socioeconomic factors, and to some extent to occupational exposures., (Copyright © 2016 American Academy of Dermatology, Inc. Published by Elsevier Inc. All rights reserved.)

Background and Aim: Increased mortality has been reported in Crohn's disease (CD) but mostly not in ulcerative colitis (UC). We evaluated the overall and cause-specific mortality in a nationwide cohort of patients with inflammatory bowel disease (IBD) in Finland., Methods: A total of 21,964 patients with IBD (16,649 with UC and 5315 with CD) from the Special Reimbursement register were diagnosed 1987-1993 and 2000-2007 and followed up to the end of 2010 by collating these figures with the national computerized Cause-of-Death Register of Statistics Finland. In each cause-of-death category, the number of deaths reported was compared to that expected in general population, and expressed as a standardized mortality ratio (SMR)., Results: Overall mortality was increased among patients with CD (SMR 1.33, 95% confidence interval 1.21-1.46) and UC (1.10, 1.05-1.15). SMR was significantly increased for gastrointestinal causes in CD (6.53, 4.91-8.52) and UC (2.81, 2.32-3.34). Patients with UC were found also to have increased SMR from pulmonary (1.24, 1.02-1.46) and cardiovascular disease (1.14, 1.06-1.22) and cancers of the colon (1.90, 1.38-2.55), rectum (1.79, 1.14-2.69) and biliary tract (5.65, 3.54-8.54), whereas SMR from alcohol-related deaths was decreased (0.54, 0.39-0.71). Patients with CD had a significantly increased SMR for pulmonary diseases (2.01, 1.39-2.80), infections (4.27, 2.13-7.63) and cancers of the biliary tract (4.51, 1.23-11.5) and lymphoid and hematopoietic tissue (2.95, 1.85-4.45)., Conclusions: In this Finnish nationwide study increased overall mortality in both CD and UC was observed. The excess mortality of 14% in IBD is mainly due to deaths related to inflammation in the gut., (Copyright © 2014 European Crohn's and Colitis Organisation. Published by Elsevier B.V. All rights reserved.)

Many cancer predisposition syndromes are rare or have incomplete penetrance, and traditional epidemiological tools are not well suited for their detection. Here we have used an approach that employs the entire population based data in the Finnish Cancer Registry (FCR) for analyzing familial aggregation of all types of cancer, in order to find evidence for previously unrecognized cancer susceptibility conditions. We performed a systematic clustering of 878,593 patients in FCR based on family name at birth, municipality of birth, and tumor type, diagnosed between years 1952 and 2011. We also estimated the familial occurrence of the tumor types using cluster score that reflects the proportion of patients belonging to the most significant clusters compared to all patients in Finland. The clustering effort identified 25,910 birth name-municipality based clusters representing 183 different tumor types characterized by topography and morphology. We produced information about familial occurrence of hundreds of tumor types, and many of the tumor types with high cluster score represented known cancer syndromes. Unexpectedly, Kaposi sarcoma (KS) also produced a very high score (cluster score 1.91, p-value <0.0001). We verified from population records that many of the KS patients forming the clusters were indeed close relatives, and identified one family with five affected individuals in two generations and several families with two first degree relatives. Our approach is unique in enabling systematic examination of a national epidemiological database to derive evidence of aberrant familial aggregation of all tumor types, both common and rare. It allowed effortless identification of families displaying features of both known as well as potentially novel cancer predisposition conditions, including striking familial aggregation of KS. Further work with high-throughput methods should elucidate the molecular basis of the potentially novel predisposition conditions found in this study.

Personality traits have been studied extensively as risk and prognostic factors for cancer; however, the association remains unclear. This prospective, population-based cohort study comprised 59,548 Swedish (1974-1999) and Finnish (1976-2004) participants who completed a questionnaire eliciting information for the Eysenck Personality Inventory and on health behavior at baseline. To analyze the association of personality traits extraversion and neuroticism with risk of cancer, the authors identified 4,631 cancer cases for a maximum 30 years of follow-up. To assess the association with cancer survival among the Finnish participants, they identified 2,733 cancer cases and, later, 1,548 deaths for a maximum 29 years of follow-up. Hazard ratios were estimated by treating the personality scales as continuous variables and are presented per one increase in score on each scale. In multivariate analyses, extraversion and neuroticism were not significantly associated with risk of cancers at all sites (extraversion: hazard ratio = 0.99, 95% confidence interval: 0.98, 1.01; neuroticism: hazard ratio = 1.00, 95% confidence interval: 0.99, 1.02). Results showed no significant association between these traits and the hazard ratio for death after cancers at all sites, and they do not support the hypothesis that extraversion and neuroticism are direct risk factors for cancer or survival after cancer.

Objectives: The purpose of this study was to utilize the variation in the level and timing of the change in postmenopausal hormone therapy (HT) use between the Nordic countries to assess the population-level impact of decline in HT use on the breast and colon cancer incidences., Methods: Nationwide HT-sales data in defined daily doses (DDDs) per 1000 inhabitant in 1995-2005 in Finland, Iceland, Norway and Sweden were obtained from drug control authorities. Breast and colon cancer incidence data by 5-year age-groups were obtained from the National Cancer Registers. By time series analysis we estimated in each age-group and country how much a change in HT-sales changes cancer incidence., Results: The decline of HT-sales varied; the decline from the highest sales was 61% in Sweden, 51% in Norway, 43% in Iceland and 25% in Finland. With the exception of Finland, the breast cancer incidence increased from 1995 to the year following the year with maximum HT-sales and decreased after that year. In the model combining countries and years, changes in HT-sales predicted the change in breast cancer incidence, an average 7% for each 10 DDD units of HT-sales. No clear association between HT-sales and colon cancer incidence was found., Conclusions: The time and country specific data suggest, that on the population level, a notable drop from high level of HT use somewhat decreases breast cancer incidence or breaks its increasing trends. The suggested protective effect of HT for colon cancer was not seen.

The objective of the study was to assess the risk of second primary cancers (SPCs) following a primary head and neck cancer (oral cavity, pharynx and larynx) and the risk of head and neck cancer as a SPC. The present investigation is a multicenter study from 13 population-based cancer registries. The study population involved 99,257 patients with a first primary head and neck cancer and contributed 489,855 person-years of follow-up. To assess the excess risk of SPCs following head and neck cancers, we calculated standardized incidence ratios (SIRs) by dividing the observed numbers of SPCs by the expected number of cancers calculated from accumulated person-years and the age-, sex- and calendar period-specific first primary cancer incidence rates in each of the cancer registries. During the observation period, there were 10,826 cases of SPCs after head and neck cancer. For all cancer sites combined, the SIR of SPCs was 1.86 (95% CI = 1.83-1.90) and the 20-year cumulative risk was 36%. Lung cancer contributed to the highest proportion of the SPCs with a 20-year cumulative risk of 13%. Excess second head and neck cancer risk was observed 10 years after diagnosis with lymphohaematopoietic cancers. The most common SPC following a first primary head and neck cancer was lung cancer. However, the highest excess of SPCs was in the head and neck region. These patterns were consistent with the notion that the pattern of cancer in survivors of head and neck cancer is dominated by the effect of tobacco smoking and alcohol drinking., ((c) 2008 Wiley-Liss, Inc.)

Cancer treatment may affect school performance. School report grades after childhood lymphomas and Wilms tumor have not been previously reported. All Finnish patients with Wilms tumor (N = 74), Hodgkin lymphoma (HL) (N = 99) and non-Hodgkin lymphoma (NHL) (N = 94) who were born in 1974-1986 and had achieved the age of 16 years were identified from the Finnish cancer registry. Population controls (N = 1329) were matched for age, gender and residence. Their 9th grade school reports were obtained from Statistics Finland. The overall average and grades for mother tongue, first foreign language, mathematics and physical education were compared between the patients and their controls. Almost all the patients (>98%) had finished their comprehensive school. NHL patients had lower overall averages than their controls (difference -0.27 grade units; 95% CI -0.39, -0.15). Irradiation or age at diagnosis did not explain this difference in NHL patients. The grades of NHL patients were significantly lower than those of their controls in each academic school subject, especially in mathematics (-0.45; 95% CI -0.63, -0.27). In mother tongue, girls with irradiation had greatest difference (-0.66, 95% CI -0.99, -0.34) to their controls. Patients with HL and Wilms tumor performed similarly or even better than their controls in all academic subjects. Grades for physical education were impaired in Wilms tumor patients (-0.20; 95% CI -0.33, -0.06). Impairment of school report grades was observed in patients with NHL. The difference to controls was greatest in mathematics. The patients with HL and Wilms tumor, who had not received any central nervous system directed therapy, achieved equally good grades as their controls in all the academic subjects., ((c) 2008 Wiley-Liss, Inc.)

Cartilage-hair hypoplasia (CHH) is an autosomal recessive chondrodysplasia with short stature, sparse hair and defective cell-mediated immunity. It is caused by mutations in the RMRP (ribonuclease mitochondrial RNA processing) gene, encoding the RNA component of the ribonuclease complex RNase MRP. The aim of this study was to further elucidate the risk and spectrum of cancer in CHH. A cohort of 123 Finnish patients with CHH (51 males) was followed for malignancy through the Finnish Cancer Registry. The number of identified cancers was compared with expected numbers of cancer using population-based data to obtain standardized incidence ratios (SIR). Hospital records were reviewed for clinical data related to the malignancies. During the follow-up (2,365 person-years; mean 19.2 years), 14 cases of cancer were diagnosed in the CHH cohort (expected number 2.0; SIR 7.0, CI 3.8-12). Non-Hodgkin lymphoma was the most frequent cancer type (n = 9; SIR 90.2, CI 39.0-180) followed by squamous cell carcinoma (3), leukemia (1) and Hodgkin lymphoma (1). One tumor was not histologically classified. Nine of the 14 cancers were diagnosed in patients less than 45 years of age. In addition, ten patients had basal cell carcinoma of the skin (expected number 0.3; SIR 33.2, CI 16-61). Patients with CHH have significantly increased risk for developing non-Hodgkin lymphoma or basal cell carcinoma at early age; the overall prognosis is poor. The underlying pathogenetic mechanisms remain to be elucidated in future studies. Careful follow-up, extending beyond pediatric age, is warranted for early diagnosis of malignancies., (Copyright 2008 Wiley-Liss, Inc.)

Background: The objective of this study is to assess the risk of second primary cancers following a first primary esophageal cancer as well as the risk of esophageal cancer as a second primary, following first primary cancers of other sites., Methods: The present investigation is a multicenter study of 13 population-based cancer registries in Europe, Australia, Canada, and Singapore. To assess excess occurrence of second cancers after esophageal cancers, we calculated standardized incidence ratios (SIR) by dividing the observed numbers of second cancers by the expected number of cancers calculated from the accumulated person-years and the age-, sex-, calendar period-, and registry-specific first primary cancer incidence rates., Results: During the study period, 959 cases of second primary cancers occurred after an initial esophageal cancer, resulting in a SIR of 1.15 (95% confidence interval, 1.08-1.22). Second primary stomach cancers were associated with first primary esophageal adenocarcinomas (SIR, 2.13; 95% confidence interval, 1.26-3.37) and second primary cancers of the oral cavity and pharynx (6.68; 5.33-8.26), stomach (1.53; 1.14-2.01), larynx (3.24; 1.88-5.18), lung (1.55; 1.28-1.87), kidney (1.88; 1.18-2.85), and thyroid (2.92; 1.18-6.02) were associated with first primary squamous cell carcinomas of the esophagus. An excess of esophageal cancer as a second primary were observed following first primary cancers of the aerodigestive tract, female breast, cervix, testis, bladder, Hodgkin's lymphoma, and non-Hodgkin lymphoma., Conclusion: We observed associations of esophageal cancer with second primary head and neck cancers and lung cancer regardless of years of follow-up, which may suggest that common risk factors play a role in multiple tumor development.

Objectives: The objective of this study was to evaluate the performance and effectiveness of a register of employees exposed to carcinogens (the ASA Register) which has been in operation in Finland since 1979, and to study cancer risks among the notified workers., Methods: The impact of ASA at workplaces was studied by questionnaires mailed to 1448 work departments, which were notified to ASA in 1996, and to 1033 departments, which departed ASA in 1991-1996. The mailing was responded by 69% of departments. The cancer incidence of 35,138 workers notified to ASA in 1979-1988 was followed up through the files of the Finnish Cancer Register for the period 1980-2003., Results: Changes eliminating or substantially reducing exposure to carcinogens were reported by 73% of departments notified to ASA in 1996. The ASA notification process had directly prompted measures to reduce exposure (8% of cases) or contributed to them (24% of cases). Estimations based on responses of the workplaces suggested that the ASA registration had decreased exposure of 600 workers year(-1) (out of approximately 15,000 notified workers, which is <1% of the employed in Finland), preventing thereby an unknown number of occupational cancers. Other benefits of ASA included the saving of the treatment costs of prevented cancers, the prevention of other health outcomes of carcinogens, improved safety behaviour of exposed workers and avoidance of human suffering among cancer patients and their families. The labour safety authorities had better possibilities to direct their activities against carcinogen exposure. These benefits should be considered against the annual costs, mainly due to 7-8 person-years of work required by tasks related to ASA. The results of the cancer incidence study among notified workers were based on a relatively short follow-up (on average 19 years). The incidence of mesothelioma was significantly increased in the ASA cohort, probably due to exposure to asbestos., Conclusions: These results suggest that a national exposure register may stimulate preventive measures at workplaces. Partially based on the results of the present study the Finnish Ministry of Social Affairs and Health continues ASA registration.

We investigated the risk of second malignancies among 29,511 survivors of germ-cell testicular cancer recorded in 13 cancer registries. Standardized incidence ratios (SIRs) were estimated comparing the observed numbers of second malignancies with the expected numbers obtained from sex-, age-, period- and population-specific incidence rates. Seminomas and nonseminomas, the 2 main histological groups of testicular cancer, were analyzed separately. During a median follow-up period of 8.3 years (0-35 years), we observed 1,811 second tumors, with a corresponding SIR of 1.65 (95% confidence interval (CI): 1.57-1.73). Statistically significant increased risks were found for fifteen cancer types, including SIRs of 2.0 or higher for cancers of the stomach, gallbladder and bile ducts, pancreas, bladder, kidney, thyroid, and for soft-tissue sarcoma, nonmelanoma skin cancer and myeloid leukemia. The SIR for myeloid leukemia was 2.39 (95% CI: 1.41-3.77) after seminomas, and 6.77 (95% CI: 4.14-10.5) after nonseminomas. It increased to 37.9 (95% CI: 18.9-67.8; based on 11 observed cases of leukemia) among nonseminoma patients diagnosed since 1990. SIRs for most solid cancers increased with follow-up duration, whereas they did not change with year of testicular cancer diagnosis. Among subjects diagnosed before 1980, 20 year survivors of seminoma had a cumulative risk of solid cancer of 9.6% (95% CI: 8.7-10.5%) vs. 6.5% expected, whereas 20 years survivors of nonseminoma had a risk of 5.0% (95% CI: 4.2-6.0%) vs. 3.1% expected. In conclusion, survivors of testicular cancers have an increased risk of several second primaries, where the effect of the treatment seems to play a major role.

A total of 29,133 male smokers, aged 50-69 years, were recruited into the Alpha-Tocopherol, Beta-Carotene Cancer Prevention (ATBC) Study in 1984-1988. The nationwide Finnish Cancer Registry (FCR) recorded 5944 incident cases of cancer in this cohort through the end of 1999. Compared with the FCR data of the entire Finnish male population of same age the standardized incidence ratio (SIR) of total cancer in the ATBC cohort was 1.55 [95% confidence interval (CI) 1.51-1.59]. There was a significant excess of established smoking-related malignancies, such as lung cancer (SIR 2.45, 95% CI 2.35-2.56), and cancers of the tongue, mouth, pharynx, larynx, oesophagus, pancreas, stomach, liver, urinary bladder and kidney. In addition to these sites, cancers of the prostate and colon were slightly more common in the ATBC cohort than in the total Finnish male population (SIR 1.10, 95% CI 1.04-1.18 and SIR 1.14, 95% CI 1.00-1.30, respectively). In conclusion, the risk of many cancers was significantly higher in the ATBC Study cohort compared with the total Finnish male population of same age. In addition to the well known smoking-related cancers, cigarette smoking may increase slightly the risk of colon and prostate cancer, too.

All patients with total hip arthroplasty (THA) are exposed to soluble or particulate forms of Co and Cr. Adverse effects of these wear products are not known. Data from Nordic registries is used to estimate adverse effects on a large scale, based mostly on metal-on-polyethylene bearings. Cancer incidence was in line with the general population when the patients were operated on for all indications and significantly decreased when the indication was primary osteoarthritis. Stomach cancer and colorectal cancers were significantly reduced and prostate cancer and skin melanoma significantly increased. There was no significant excess of cancer in target organs, i.e. liver, kidney, or haematopoietic cancers. THA patients had reduced mortality and extended life expectancy compared with standard Nordic populations. All-site cancer incidence of the first-generation metal-on-metal McKee-Farrar patients operated on for primary osteoarthritis was in line with the general population after follow-up for up to 28 years. General mortality of these patients was also reduced and they also had an extended life expectancy. Temporary increases in haematopoietic cancers at different follow-up periods were seen in some cohorts. This malignancy deserves a special record linkage monitoring while large numbers of young patients are provided with the second generation of metal-on-metal prostheses.

An international multicentre study of first and second primary neoplasms associated with male breast cancer was carried out by pooling data from 13 cancer registries. Among a total of 3409 men with primary breast cancer, 426 (12.5%) developed a second neoplasia; other than breast cancer, a 34% overall excess risk of second primary neoplasia, affecting the small intestine (standardised incidence ratio, 4.95, 95% confidence interval, 1.35-12.7), rectum (1.78, 1.20-2.54), pancreas (1.93, 1.14-3.05), skin (nonmelanoma, 1.65, 1.16-2.29), prostate (1.61, 1.34-1.93) and lymphohaematopoietic system (1.63, 1.12-2.29). A total of 225 male breast cancers was recorded after cancers other than breast cancer, but an increase was found only after lymphohaematopoietic neoplasms. BRCA2 (and to some extent BRCA1) mutations may explain the findings for pancreatic and prostate cancers. Increases at other sites may be related to unknown factors or to chance. This large study shows that the risks for second discordant tumours after male breast cancer pose only a moderate excess risk.

Background: A lowering of colorectal cancer risk for the birth cohorts born around World War II (WWII) has previously been observed in Norway, a country which suffered some 20% caloric restriction during the war. The purpose of the study was to conduct a similar kind of analysis in the other Nordic countries and Estonia, which were also subjected to various degrees of energy restriction during WWII., Methods: All new cases of colorectal cancer in the Nordic countries and Estonia diagnosed between 40 and 84 years of age and born between 1874 and 1953, were collected from the national cancer registries. The incidence data were fitted to an age-period-cohort model., Results: A transient drop in the estimated colorectal cancer incidence rate was observed for the birth cohorts born around WWII in Estonia, together with a tendency of decreased risk in Sweden and Denmark., Conclusion: The previously observed lowering of colorectal cancer risk for persons born during WWII in Norway also prevails in Estonia. Energy restriction is a possible explanation for these findings, since the countries suffered from varying nutritional conditions during the war. Exogenous factors acting during periods early in life may have an impact on later colorectal cancer risk.

Occupational exposure to diesel exhaust has been classified as probably carcinogenic and that to gasoline engine exhaust as possibly carcinogenic to humans. Earlier results concerning cancers other than lung cancer are scarce and inconsistent, and exposure-response relations have seldom been reported. We followed up a cohort of all economically active Finns born between 1906 and 1945 for 30 million person-years during 1971-1995. Incident cases of esophageal cancer (n = 2,198), ovarian cancer (5,082), testicular cancer (387), kidney cancer (7,366), bladder cancer (8,110) and leukemia (4,562) were identified through a record linkage with the Finnish Cancer Registry. Occupations from the population census in 1970 were converted to exposures to diesel and gasoline engine exhausts with a job-exposure matrix (FINJEM). Cumulative exposure (CE) was calculated as product of prevalence, level and estimated duration of exposure. The relative risk (RR) of cancer for exposure categories in relation to the unexposed group was calculated using the Poisson regression model and adjusted for confounders. An increasing RR for ovarian cancer was observed with the increasing CE of diesel exhaust (p for trend = 0.006). The RR in the highest CE category was 3.69 (95% CI = 1.38-9.86). For gasoline engine exhaust, the RR was significantly increased only in the middle CE category (1.70; 95% CI = 1.11-2.62). Slight elevations of RR for bladder and kidney cancers were found at the lowest exposure level of engine exhausts, largely attributable to drivers. No effect of the exposures was observed for the other cancers. This study suggests an exposure-response relation between diesel exhaust and ovarian cancer., (Copyright 2004 Wiley-Liss, Inc.)

The River Kymijoki in southern Finland is heavily polluted with polychlorinated dibenzo-p-dioxins and dibenzofurans and may pose a health threat to local residents, especially farmers. In this study we investigated cancer risk in people living near the river (less than 20.0 km) in 1980. We used a geographic information system, which stores registry data, in 500 m times 500 m grid squares, from the Population Register Centre, Statistics Finland, and Finnish Cancer Registry. From 1981 to 2000, cancer incidence in all people (N = 188884) and in farmers (n = 11132) residing in the study area was at the level expected based on national rates. Relative risks for total cancer and 27 cancer subtypes were calculated by distance of individuals to the river in 1980 (reference: 5.0-19.9 km, 1.0-4.9 km, less than 1.0 km), adjusting for sex, age, time period, socioeconomic status, and distance of individuals to the sea. The respective relative risks for total cancer were 1.00, 1.09 [95% confidence interval (CI), 1.04-1.13], and 1.04 (95% CI, 0.99-1.09) among all residents, and 1.00, 0.99 (95% CI, 0.85-1.15), and 1.13 (95% CI, 0.97-1.32) among farmers. A statistically significant increase was observed for basal cell carcinoma of the skin (not included in total cancers) in all residents less than 5.0 km. Several other common cancers, including cancers of the breast, uterine cervix, gallbladder, and nervous system, showed slightly elevated risk estimates at less than 5.0 km from the river. Despite the limitations of exposure assessment, we cannot exclude the possibility that residence near the river may have contributed to a small increase in cancer risk, especially among farmers.

Human papillomavirus has emerged as the leading infectious cause of cervical and other anogenital cancers. We have studied the relation between human papillomavirus infection and the subsequent risk of anal and perianal skin cancer. A case-cohort study within two large Nordic serum banks to which about 760 000 individuals had donated serum samples was performed. Subjects who developed anal and perianal skin cancer during follow up (median time of 10 years) were identified by registry linkage with the nationwide cancer registries in Finland and Norway. Twenty-eight cases and 1500 controls were analysed for the presence of IgG antibodies to HPV 16, 18, 33 or 73, and odds ratios of developing anal and perianal skin cancer were calculated. There was an increased risk of developing anal and perianal skin cancer among subjects seropositive for HPV 16 (OR=3.0; 95%CI=1.1-8.2) and HPV 18 (OR=4.4; 95%CI=1.1-17). The highest risks were seen for HPV 16 seropositive patients above the age of 45 years at serum sampling and for patients with a lag time of less than 10 years. This study provides prospective epidemiological evidence of an association between infection with HPV 16 and 18 and anal and perianal skin cancer., (Copyright 2002 Cancer Research UK)

We evaluated the accuracy and time to reporting of cancer diagnoses obtained through the Finnish Cancer Registry (FCR) for the Alpha-Tocopherol Beta-Carotene Cancer Prevention (ATBC) Study in 1985-1997. In the ATBC Study suspect neoplasms were centrally reviewed through medical records and pathology specimens. The FCR data were compared against the reviewed data for 3600 cancers of eight sites. For most sites, 95% of the cases were reported to the FCR within 0.9 years with longer delays for lung and pancreatic cancers. Ninety-six percent of all FCR cases received the same primary site diagnosis in the ATBC review, and in 1.4% no malignancy was found. Conversely, 97% of cancers ascertained in the ATBC review had the same primary site in the FCR and 0.8% were unknown to the Registry. The accuracy of the FCR data is high but the delay in case notification should be considered in epidemiological studies.

Twelve blockhouses were built in Helsinki in the 1970s on a former dump area containing industrial and household waste. We investigated whether the exposure to landfill caused cancer or other chronic diseases in the inhabitants of these houses. From the Population Register, we identified 2,000 persons who had ever lived in houses built on the dump area and a similar reference cohort from similar houses elsewhere in Helsinki. We identified their cancer cases from the Cancer Registry, and the other chronic diseases eligible for free medication from the Finnish Social Insurance Institution. At the end of 1998, 88 cases of cancer had been diagnosed, whereas the expected number based on the incidence rates among all inhabitants of Helsinki was 76.1. The excess cases were entirely attributable to males and to follow-up >or= 5 years after moving into the dump area [standardized incidence ratio (SIR) in this category, 1.61; 95% confidence interval (CI), 1.11-2.24], and they were distributed evenly over primary sites. The relative risk increased slightly with the number of years lived in the area. The relative risk of cancer between the dump area and reference houses was 1.50 (1.08-2.09), similar in both sexes. Of the other chronic diseases, the SIRs for asthma (1.63; CI, 1.27-2.07) and chronic pancreatitis (19.3; CI, 2.34-69.7) were significantly increased. The possibility of a causal association between dump exposure and incidence of cancer and asthma cannot be fully excluded. The Helsinki City Council decided to demolish the houses in the dump area, and most houses have already been destroyed.

The decreasing incidence rate and improvement in survival of laryngeal cancer patients in Finland are exceptions among western countries. A descriptive study of these trends was conducted including both nationwide population-based cancer registry data with 5 766 patients diagnosed in 1956-1995 and regional hospital-based data from Northern Finland, allowing classification into supraglottic and glottic cancers, with 353 patients diagnosed in 1976-1995. In Finland, the age-adjusted incidence rate among males decreased from 6.5 per 100 000 in 1956-1965 to 3.5 in 1986-1995, while in females the rate remained around 0.3 per 100 000. The rates in Northern Finland were slightly higher and the supraglottic to glottic incidence ratio diminished from 1.4:1 in 1976-1985 to 0.5:1 in 1986-1995. The 5-year relative survival rate improved in both Northern Finland and the whole country, most noticeably among males and the elderly. In the data from Northern Finland, the survival rate was more favourable in glottic (80%) than in supraglottic cancer (64%). Considering the marked decrease in the incidence of the less favourable supraglottic disease, the observed improvement in survival was small.

Identification of predisposition loci to complex diseases, such as prostate cancer, requires high-quality family material, the ascertainment of which is often laborious, time-consuming and inaccurate with conventional methods. Here, we describe a new method for rapid, nationwide cancer family ascertainment using Finnish Cancer Registry data on 35,761 prostate cancer cases over a 40-year period. As members of a prostate cancer family are likely to share the same family name and place of birth, we stratified all prostate cancer cases by these 2 parameters (10,721 different names and 596 municipalities). Data were compared with the distribution of family names and places of birth for all 3.3 million Finnish men to derive standardized prevalence ratios (SPRs). A significantly elevated SPR of prostate cancer was detected for 468 (1.6%) of the 28,459 evaluable combinations of family name and place of birth. Of the 20 highest SPR values, 19 corresponded to true nuclear families, most of these having 3 or more affected cases. Two-thirds of our 50 previously established Finnish prostate cancer families were classified among this 1.6% fraction of the highest SPR values. Finally, many of the highest SPR values originated from municipalities in southern and south-western Finland. To explore whether such clusters could highlight local founder effects, we applied genealogical research to link together several families with elevated SPRs and identified an extended family with 20 prostate cancer cases with common ancestors in the early seventeenth century. In summary, a rapid novel method was developed and validated for identification of prostate cancer families from nationwide cancer registry data and for the identification of putative regional founder effects., (Copyright 2000 Wiley-Liss, Inc.)

Introduction: The study of survival of cancer patients is essential for monitoring the effectiveness of cancer control. The previous monograph describing cancer patient survival in Finland was published by the Finnish Cancer Registry in 1981 and covered patients diagnosed in 1953-1974. This new supplement assesses cancer patient survival up to the year 1995., Material and Methods: The study includes over 560000 tumours registered at the Finnish Cancer Registry with a date of diagnosis between 1955 and 1994. Patients were followed up to the end of 1995. Trends in relative survival rates are studied over four 10-year diagnostic periods from 1955 to 1994. In addition, detailed results are presented for patients diagnosed during 1985-1994, including relative survival rates tabulated by stage, sex, and age. Additional sections describe differences in cancer patient survival according to social class and region of residence and a comparison of cancer patient survival in Finland to other European countries., Results: Patient survival improved over time for almost all anatomical sites. The main exception is in cancer of the cervix uteri, where patient survival has decreased slightly from 1965-1974 to 1985-1994 due to the selective prevention of less aggressive tumours through cytologic screening. Very few differences in patient survival are observed between males and females. A substantial improvement in survival can be seen for childhood cancers., Conclusion: The increasing survival rates reflect improvements that have taken place in various areas of cancer control, from health education and early diagnosis to treatment and aftercare. This study provides valuable reference information for both clinicians and health administrators, as well as a baseline for more detailed studies of patient survival for individual anatomical sites.

Cancer registries should pay great attention to the quality of their data, both in terms of completeness (all cancer patients in the population are registered) and accuracy (data on individual cancer patients must be correct). In addition to technical measures in the data processing, different types of checks and comparisons should be routine practice. Active research policy and ambitious, research-oriented staff with competence in medicine, biostatistics and computer science are essential in terms of maintaining good data quality.

The first cancer maps of Finland based on small geographical areas, municipalities (mean population 5000 inhabitants), were drawn by the Finnish Cancer Registry in late 1950s. Since then several cancer maps based on larger administrative units, such as counties or central hospital districts, have been produced. Because of the heterogeneity of large administrative areas in terms of way of life and possible cancer risk determinants, different methods were tried to portray the geographical pattern of cancer incidence by municipality. Two major problems were encountered: (1) because of the small numbers of cases per municipality the random variation was disturbingly large when single municipality-specific rates were presented and (2) the areas of municipalities with largest populations (cities) were so small that these most important points were hardly visible on the map. After the development of computerized mapping programs, a method based on smoothed averages of municipality-based cancer incidences was selected for the Atlas of Cancer Incidence in Finland 1953-82. These maps are combinations of municipality-specific observation and the background illustrating the average cancer incidence in different parts of the country. Because of the weighting by population, a large town whose rate deviates from the level of the surrounding areas is more visible on the map than a small municipality which differs from its background in the same way. The maps show the present situation for total cancer and for the 20 most interesting specific cancer sites using a 21-color scale. In addition some comparisons are illustrated, for example geographical time trends, male/female differences, and urban/rural variations.(ABSTRACT TRUNCATED AT 250 WORDS)