| 1. |
- Folkesson, Joakim, et al.
(author)
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Rectal cancer survival in the Nordic countries and Scotland
- 2009
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In: International Journal of Cancer. - : Wiley. - 0020-7136 .- 1097-0215. ; 125:10, s. 2406-12
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Journal article (peer-reviewed)abstract
- The aim of this study was to present detailed population-based survival estimates for patients with a rectal adenocarcinoma, using cancer register data supplemented with clinical data. Based on cancer register data, differences in rectal cancer survival have been reported between countries in Europe. Variation in the distribution of stage at diagnosis, initial therapy including surgical technique, and comorbidity are possible explanatory factors. Adenocarcinomas in the rectum, diagnosed in 1997 and identified in the national cancer registries in the Nordic countries and Scotland were included. Age standardized 5-year relative survival and multiplicative regression models for the relative excess mortality were calculated. 3888 patients were included in the survival study. Men in Denmark, Finland and Iceland had lower 5-year relative survival and poorer stage distribution compared to Norway, Sweden and Scotland. Danish men had the highest rate of excess deaths in the first six months after diagnosis. Stage adjusted, the elevated relative excess mortality decreased and after six months the excess mortality rates were the same in all countries. The poor 5-year relative survival in Danish men was mainly due to a high excess rate of death during the first six months after diagnosis. The low survival in Finland and Iceland was not in accordance with other periods. For both countries this may be explained by random variation due to small numbers. The study emphasizes the need for high quality and detailed data in order to understand international survival differences, and cautions comparisons between large national samples and those of smaller areas.
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| 2. |
- Kapeu, Aline Simen, et al.
(author)
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Is Smoking an Independent Risk Factor for Invasive Cervical Cancer? A Nested Case-Control Study Within Nordic Biobanks
- 2009
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In: American Journal of Epidemiology. - Baltimore, Md. : Oxford University Press (OUP). - 0002-9262 .- 1476-6256. ; 169:4, s. 480-488
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Journal article (peer-reviewed)abstract
- The strong correlation between smoking and exposure to oncogenic human papillomaviruses (HPVs) has made it difficult to verify the independent role of smoking in cervical carcinogenesis. Thus, the authors evaluated this role. Five large Nordic serum banks containing samples from more than 1,000,000 subjects were linked with nationwide cancer registries (1973-2003). Serum samples were retrieved from 588 women who developed invasive cervical cancer and 2,861 matched controls. The samples were analyzed for cotinine (a biomarker of tobacco exposure) and antibodies to HPV types 16 and 18, herpes simplex virus type 2, and Chlamydia trachomatis. Smoking was associated with the risk of squamous cell carcinoma (SCC) among HPV16- and/or HPV18-seropositive heavy smokers (odds ratio = 2.7, 95% confidence interval: 1.7, 4.3). A similar risk of SCC (odds ratio = 3.2, 95% confidence interval: 2.6, 4.0) was found in heavy smokers after adjustment for HPV16/18 antibodies. The point estimates increased with increasing age at diagnosis and increasing cotinine level. This study confirms that smoking is an independent risk factor for cervical cancer/SCC in women infected with oncogenic HPVs. These findings emphasize the importance of cervical cancer prevention among women exposed to tobacco smoke.
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| 3. |
- Olsen, Jørgen H, et al.
(author)
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Lifelong Cancer Incidence in 47 697 Patients Treated for Childhood Cancer in the Nordic Countries.
- 2009
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In: Journal of the National Cancer Institute. - : Oxford University Press (OUP). - 1460-2105 .- 0027-8874. ; 101, s. 806-813
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Journal article (peer-reviewed)abstract
- Background The pattern of cancer in long-term survivors from childhood cancer has not been investigated comprehensively. Methods We obtained a cohort of 47 697 children and adolescents aged 0-19 years with cancer as defined by the country-wide cancer registries of Denmark, Finland, Iceland, Norway, and Sweden during 1943-2005. Cohort members were followed through age 79 years for subsequent primary cancers notified to the registries, and the age-specific risk pattern of the survivors was compared with that of the national populations using country and sex standardized incidence ratios (SIRs). We used a multiplicative Poisson regression model to estimate relative risk of cancer for attained age, with adjustment for calendar period and age at diagnosis of primary cancer. We also calculated excess absolute risk (EAR) attributable to status as childhood cancer survivor and determined the cumulative incidence of second primary cancer as a function of attained age for three subcohorts defined by period of treatment for childhood cancer. Results A total of 1180 asynchronous second primary cancers were observed in 1088 persons, yielding an overall SIR of 3.3 (95% confidence interval = 3.1 to 3.5). The relative risk was statistically significantly increased in all age groups, even for cohort members approaching 70 years of age. The EAR for second primary cancer among survivors increased gradually from one additional case per 1000 person-years of observation in early life to six additional cases per 1000 person-years in the age group 60-69 years. For children treated in the prechemotherapy era (1943-1959), the cumulative risk for a second primary cancer reached 18%, 34%, and 48% at ages 60, 70, and 80 years, respectively. The age-specific incidence rates were highest for cohort members treated in the era of intensive, multiple-agent chemotherapy (1975-2005). Conclusion Survivors of childhood cancer have a persistent excess risk for a second primary cancer throughout their lives, accompanied by continuous changes in the risk of cancers at specific sites.
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| 4. |
- Pukkala, Eero, et al.
(author)
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Nordic biological specimen banks as basis for studies of cancer causes and control - more than 2 million sample donors, 25 million person years and 100 000 prospective cancers
- 2007
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In: Acta Oncologica. - : Informa UK Limited. - 1651-226X .- 0284-186X. ; 46:3, s. 286-307
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Journal article (peer-reviewed)abstract
- The Nordic countries have a long tradition of large-scale biobanking and comprehensive, population-based health data registries linkable on unique personal identifiers, enabling follow-up studies spanning many decades. Joint Nordic biobank-based studies provide unique opportunities for longitudinal molecular epidemiological research. The purpose of the present paper is to describe the possibilities for such joint studies, by describing some of the major Nordic biobank cohorts with a standardised calculation of the cancer incidence in these cohorts. Altogether two million donors have since 1966 donated more than four million biological samples, stored at -20 degrees C to -135 degrees C, to 17 biobank cohorts in Finland, Iceland, Norway and Sweden. As a result of joint database handling principles, the accuracy of personal identifiers and completeness of follow-up for vital status in all participating biobanks was improved. Thereafter, the cancer incidence was determined using follow-up through the national cancer registries. Biobanks based on random samples of population typically showed slightly lower cancer incidence rates than the general population, presumably due to better participation rates among health-conscious subjects. On the other hand, biobanks including samples for viral screening or clinical testing showed 1.5 to 2.1 fold increased incidence of cancer. This excess was very high immediately after sampling, but for some cancer sites remained elevated for years after clinical sampling. So far, more than 100 000 malignant neoplasms have occurred after sample donation, and the annual increase of the cancer cases in these cohorts is about 10 000. The estimates on the population-representativity of the biobanks will assist in interpretation of generalizability of results of future studies based on these samples, and the systematic tabulations of numbers of cancer cases will serve in study power estimations. The present paper summarizes optimal study designs of biobank-based studies of cancer.
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