Showing papers by "Timo Hakulinen published in 2008"

Cancer survival in five continents: a worldwide population-based study (CONCORD)

Abstract: Summary Background Cancer survival varies widely between countries. The CONCORD study provides survival estimates for 1·9 million adults (aged 15–99 years) diagnosed with a first, primary, invasive cancer of the breast (women), colon, rectum, or prostate during 1990–94 and followed up to 1999, by use of individual tumour records from 101 population-based cancer registries in 31 countries on five continents. This is, to our knowledge, the first worldwide analysis of cancer survival, with standard quality-control procedures and identical analytic methods for all datasets. Methods To compensate for wide international differences in general population (background) mortality by age, sex, country, region, calendar period, and (in the USA) ethnic origin, we estimated relative survival, the ratio of survival noted in the patients with cancer, and the survival that would have been expected had they been subject only to the background mortality rates. 2800 life tables were constructed. Survival estimates were also adjusted for differences in the age structure of populations of patients with cancer. Findings Global variation in cancer survival was very wide. 5-year relative survival for breast, colorectal, and prostate cancer was generally higher in North America, Australia, Japan, and northern, western, and southern Europe, and lower in Algeria, Brazil, and eastern Europe. CONCORD has provided the first opportunity to estimate cancer survival in 11 states in USA covered by the National Program of Cancer Registries (NPCR), and the study covers 42% of the US population, four-fold more than previously available. Cancer survival in black men and women was systematically and substantially lower than in white men and women in all 16 states and six metropolitan areas included. Relative survival for all ethnicities combined was 2–4% lower in states covered by NPCR than in areas covered by the Surveillance Epidemiology and End Results (SEER) Program. Age-standardised relative survival by use of the appropriate race-specific and state-specific life tables was up to 2% lower for breast cancer and up to 5% lower for prostate cancer than with the census-derived national life tables used by the SEER Program. These differences in population coverage and analytical method have both contributed to the survival deficit noted between Europe and the USA, from which only SEER data have been available until now. Interpretation Until now, direct comparisons of cancer survival between high-income and low-income countries have not generally been available. The information provided here might therefore be a useful stimulus for change. The findings should eventually facilitate joint assessment of international trends in incidence, survival, and mortality as indicators of cancer control. Funding Centers for Disease Control and Prevention (Atlanta, GA, USA), Department of Health (London, UK), Cancer Research UK (London, UK).

Probability of parenthood after early onset cancer: a population-based study.

Abstract: We evaluated in a population-based setting the postdiagnosis parenthood among survivors compared with the fertility patterns of siblings. Cancer patients aged 0-34 years at diagnosis were identified from the Finnish Cancer Registry (N = 25,784), and their siblings (N = 44,611) by registry linkage. Further linkage identified the offspring of the patient and sibling cohorts. The relative probabilities of parenthood for first and second births separately were estimated for male and female survivors in different diagnostic age-groups and subsites using a Cox proportional hazards model, with age as the time variable and adjusting for the birth cohort of parents. In addition, estimates were calculated for 5 diagnostic eras in all subsites combined. Compared to siblings, both female and male cancer survivors were less likely to parent at least 1 child (RR 0.46, 95% CI 0.44-0.48 and RR 0.57, 95% CI 0.54-0.60, respectively). The relative probability of parenthood was especially low in male childhood cancer survivors and female young adult cancer survivors. However, cancer patients were only slightly less likely than siblings to parent a second child, with RR 0.91, 95% CI 0.86-0.97 and RR 0.95, 95% CI 0.89-1.01 for females and males, respectively. The relative probability of parenthood increased over calendar time among young adult cancer patients. The relative probability of parenthood following early onset cancer was overall significantly reduced by approximately 50%. Parenting a second child, however, was not reduced among pediatric and adolescent survivors, and only slightly reduced among early adulthood cancer survivors compared to siblings.

Vitamin D Status and the Risk of Lung Cancer: A Cohort Study in Finland

Abstract: Experimental data support the suppressing effect of vitamin D on lung carcinogenesis, but epidemiologic evidence is limited. The aim of the present study was to evaluate whether serum 25-hydroxyvitamin D [25(OH)D] level is associated with the risk of lung cancer in a prospective cohort study in Finland. 25(OH)D levels were measured by RIA from serum collected at baseline (1978--1980) from 6,937 men and women. During a maximum follow-up of 24 years, 122 lung cancers were identified. After adjustment for potential confounders, no overall significant association between vitamin D and lung cancer risk was observed [relative risk (RR) for the highest versus lowest tertile, 0.72; 95% confidence interval (95% CI), 0.43-1.19; Ptrend = 0.22]. There was a statistically significant interaction between vitamin D and sex (P = 0.02) and age (P = 0.02): serum 25(OH)D level was inversely associated with lung cancer incidence for women (RR, 0.16; 95% CI, 0.04-0.59; Ptrend < 0.001) and younger participants (RR, 0.34; 95% CI, 0.13-0.90; Ptrend = 0.04) but not for men (RR, 1.03; 95% CI, 0.59-1.82; Ptrend = 0.81) or older individuals (RR, 0.92; 95% CI, 0.50-1.70; Ptrend = 0.79). In conclusion, although there was no overall association between vitamin D and lung cancer risk, women and young participants with a higher level of vitamin D were observed to have a lower lung cancer risk. Although experimental data support the suppressing effect of vitamin D on the development of lung cancer, large epidemiologic studies from different populations with repeated measurements of vitamin D are warranted to confirm this finding.

Life tables for world-wide comparison of relative survival for cancer (CONCORD study).

Abstract: BACKGROUND: The CONCORD study compares population-based relative survival from cancer using data from cancer registries in five continents. To estimate relative survival, general mortality life tables are required. Available statistics are incomplete, so various approaches are used to construct complete life tables. This article outlines how the life tables were constructed for CONCORD; it compares life expectancy at birth between 101 populations covered by cancer registries in 31 countries and compares the impact of two approaches to the deployment of life tables in relative survival analysis. METHODS: The CONCORD approach, using specific mathematical methods, produced complete (single-year-of-age) life tables by sex, cancer registry area, calendar year (1990-1999) and race (only in the USA). In order to study the impact of different approaches, we compared relative survival in the USA using the US national life table, centered on the relevant census years, and the CONCORD approach. We estimated relative survival in each American participating cancer registry for patients diagnosed with breast (women), colorectal or prostate cancer during 1990-1994 and followed up to 1999. RESULTS: Average life expectancy at birth during 1990-1999 varied in CONCORD cancer registry areas from 64 to 78 years in males and from 71 to 84 years in females. It increased during the 1990s more in men than in women. In the USA, it was lower in blacks than in whites. Relative survival in American populations was lower with the CONCORD approach, which incorporates trends and geographic variation in background mortality, than with the USA census life tables. CONCLUSIONS: International variation in background mortality by geographic area, calendar time, race, age and sex is wide. We suggest that in international comparisons of cancer relative survival, complete life tables that are specific for cancer registry area, calendar year and race should be used.

Impacts of the Finnish service screening programme on breast cancer rates

Abstract: The aim of the current study was to examine impacts of the Finnish breast cancer (BC) screening programme on the population-based incidence and mortality rates. The programme has been historically targeted to a rather narrow age band, mainly women of ages 50–59 years. The study was based on the information on breast cancer during 1971–2003 from the files of the Finnish Cancer Registry. Incidence, cause-specific mortality as well as incidence-based (refined) mortality from BC were analysed with Poisson regression. Age-specific incidence and routine cause-specific mortality were estimated for the most recent five-year period available; incidence-based mortality, respectively, for the whole steady state of the programme, 1992–2003. There was excess BC incidence with actual screening ages; incidence in ages 50–69 was increased 8% (95 CI 2.9–13.4). There was an increasing temporal tendency in the incidence of localised BC; and, respectively, a decrease in that of non-localised BC. The latter was most consistent in age groups where screening had been on-going several years or eventually after the last screen. The refined mortality rate from BC diagnosed in ages 50–69 was decreased with -11.1% (95% CI -19.4, -2.1). The current study demonstrates that BC screening in Finland is effective in reducing mortality rates from breast cancers, even though the impact on the population level is smaller than expected based on the results from randomised trials among women screened in age 50 to 69. This may be explained by the rather young age group targeted in our country. Consideration whether to targeted screening up to age 69 is warranted.

Period versus cohort modeling of up-to-date cancer survival.

Abstract: Recently, 2 modeling strategies have been proposed and shown to be useful to increase precision of up-to-date cancer survival estimates and to predict cancer patient survival: modeled period analysis and modeled cohort analysis. We aimed to compare the performance of both types of modeling for providing up-to-date and precise cancer survival estimates. Data from the nationwide Finnish Cancer Registry were used to assess how well both approaches would have been able to predict 5-year relative survival of concurrently diagnosed patients if they had been applied for that purpose throughout the past decades. Analyses were carried out for 20 common forms of cancer. For each cancer, 5-year relative survival was modeled with either approach for each single calendar year from 1962 to 1997. Mean differences and mean squared differences from 5-year relative survival later observed for patients diagnosed in the 5-year period around those calendar years were calculated. Survival estimates obtained by period modeling had much lower standard errors than those obtained by cohort modeling. Furthermore, for a clear majority of cancers, period modeling on average also provided better prediction of 5-year relative survival than cohort modeling. We conclude that, although both modeling strategies have their merits and specific indications, period modeling of survival has distinct advantages for up-to-date and precise estimation of cancer survival in population-based cancer survival studies.

Follow-up study of cancer incidence after chlorophenol exposure in a community in southern Finland.

Abstract: Objectives In the 1970s and 1980s, people in a village in southern Finland had been exposed to high concentrations of chlorophenols in the drinking water and in fish from a nearby lake. An ecological analysis and a case–control study conducted around 1990 indicated significant excess in the incidence of non-Hodgkin’s lymphoma and soft-tissue cancer in the municipality and a relationship between the chlorophenol exposure and the incidence of these cancers. The present article reports a follow-up of cancer risk in the same study area during a 20-year period after the closing of the old water intake plant, which was contaminated by chlorophenols. Methods The observed and expected numbers of cancer were obtained for three periods, 1953–1971 (before exposure), 1972–1986 (during exposure) and 1987–2006 (after exposure), for all cancers combined and separately for cancers potentially related to chlorophenols. Results The present study demonstrates that all of the cancer risks returned to the average population level during the 20-year period after the old water intake plant was closed and chlorophenol exposure stopped. Conclusions The rapid changes in cancer risk after changes in chlorophenol exposure suggest that chlorophenols may have a promotion effect in the carcinogenic process.

Comparison of cancer registry and clinical data as predictors for breast cancer survival.

Abstract: In spite of the increasing amount of clinically relevant information for survival from breast cancer, the amount of data recorded in a population-based cancer registry is limited and the registry-based survival predictions are routinely made without clinical details. To find out how important is the role of screening and clinical tumor characteristics in addition to cancer registry information in describing the breast cancer survival. A representative clinical database on 483 breast cancer patients diagnosed during 1996–1997 in Tampere University Hospital Area was linked with Finnish Cancer Registry data and a survival model including the available registry variables was compared to models including screen-detection information and clinical tumor characteristics also. Estimates of registry stage and age act as surrogates for clinical variables and mammography-detection. The surrogacy was found to be almost complete indicating that clinical variables are not necessarily needed when making breast cancer mortality predictions based on a population-based cancer registry. In cases with dissimilar staging cancer registry stage gave a better picture of the breast cancer survival than the clinical stage.

Predicting impacts of mass-screening policy changes on breast cancer mortality.

Abstract: The aim of this study is to present a methodology for taking into account the mass-screening invitation data in breast cancer mortality predictions, particularly in assessing impacts of screening policy changes on the short-term predictions. The methodology is applied to a database that includes observed year- and age-specific screening invitation schemes in Finnish municipalities from the time period 1987-2001. The target year for predictions is 2012. To predict mortality, breast cancer incidence and patients' survival from breast cancer are modelled with the screening data included. The knowledge of breast cancer survival together with the other cause survival is then used to calculate the number of breast cancer deaths caused by observed (1987-2001) and predicted (2002-2012) incident cases in Finland. Survival from breast cancer was estimated with a parametric mixture model where the patient population is assumed to be a combination of cured and uncured patients. This approach provides a way of modelling the hazard of fatal cases and the proportion of cured cases simultaneously. In other cause survival, the patients' hazard was allowed to differ from that of the general population. Breast cancer mortality predictions are presented according to three alternative future scenarios of screening policy. The results show no major differences between predictions yielded by alternative scenarios: Any policy change would have at the most a 3.0 per cent impact on breast cancer mortality in the near future.