Showing papers by "Timo Hakulinen published in 2004"

Regression models for relative survival.

Abstract: Four approaches to estimating a regression model for relative survival using the method of maximum likelihood are described and compared. The underlying model is an additive hazards model where the total hazard is written as the sum of the known baseline hazard and the excess hazard associated with a diagnosis of cancer. The excess hazards are assumed to be constant within pre-specified bands of follow-up. The likelihood can be maximized directly or in the framework of generalized linear models. Minor differences exist due to, for example, the way the data are presented (individual, aggregated or grouped), and in some assumptions (e.g. distributional assumptions). The four approaches are applied to two real data sets and produce very similar estimates even when the assumption of proportional excess hazards is violated. The choice of approach to use in practice can, therefore, be guided by ease of use and availability of software. We recommend using a generalized linear model with a Poisson error structure based on collapsed data using exact survival times. The model can be estimated in any software package that estimates GLMs with user-defined link functions (including SAS, Stata, S-plus, and R) and utilizes the theory of generalized linear models for assessing goodness-of-fit and studying regression diagnostics.

Testicular cancer incidence in eight northern European countries: secular and recent trends.

Abstract: Objective: Striking geographic variation and marked increasing secular trends characterize the incidence of testicular cancer. However, it is not known whether these patterns have attenuated in recent years and whether they are similar for seminomas and nonseminomas, the two main histologic groups of testicular cancer. Method: Cancer registry data, including 27,030 testicular cancer cases, were obtained from Denmark, Estonia, Finland, Latvia, Lithuania, Norway, Poland, and Sweden. Between 57 (Denmark) and 9 (Poland) years of registration were covered. Country-specific temporal trends were estimated, with focus on the last decade and seminomas and nonseminomas. Data from the Nordic countries were further analyzed using an age-period-cohort approach. Results: Age-standardized incidence rates increased annually by 2.6% to 4.9% during the study period, with marginal differences between seminomas and nonseminomas. In the last decade, the increasing trend attenuated only in Denmark (annual change, −0.3%; 95% confidence interval, −1.5 to 0.9). In 1995, the highest and the lowest age-standardized incidence rates (per 105) were 15.2 in Denmark and 2.1 in Lithuania. Incidence rates (i.e., for all cancers and for seminomas and nonseminomas, separately) depended chiefly on birth cohort rather than on calendar period of diagnosis (although both birth cohort and period determined the Danish incidence rates). Conclusions: Testicular cancer incidence is still increasing, with the exception of Denmark, and a large geographic difference exists. The increasing trend is mainly a birth cohort phenomenon also in recent cohorts. Temporal trends for seminomas and nonseminomas are similar, which suggests that they share important causal factors.

Are Patients Diagnosed With Breast Cancer Before Age 50 Years Ever Cured

Abstract: Purpose Breast cancer diagnosed before the age of 50 years has become a common disease in many developed countries. Although average remaining life expectancy in the affected age groups is usually several decades, data regarding survival perspectives beyond 10 to 20 years after diagnosis are sparse. The aim of this study was to assess long-term survival in a large population-based sample of patients diagnosed with breast cancer before age 50 years. Patients and Methods Relative survival within up to 40 years after diagnosis was assessed for cohorts of women diagnosed with breast cancer before age 50 years and notified to the nationwide Finnish Cancer Registry within various time intervals since 1953. In addition, up-to-date estimates of 40-year relative survival were obtained by exclusively looking at the survival experience of breast cancer patients in recent years (1993 to 1999) using period analysis, a new method of survival analysis. Results Prognosis of patients diagnosed with breast cancer before ag...

Survival of in situ carcinoma of cervix uteri: a 50-year follow-up in Finland.

Abstract: Preinvasive lesions of cervix uteri are regarded a curable disease despite some progression to invasive cancer. The ultimate outcome is not known. We estimated the 45-year survival of 12,655 patients with carcinoma in situ lesions diagnosed in 1953–2000 and reported to the Finnish Cancer Registry. Up to 30 years of follow-up there was about 1% decrease in cumulative relative survival per 5 years of follow-up. After that the excess mortality increased and the survival at 45 years was 84%. The 15-year survival was 100% in the patients under 30 at diagnosis and became the poorer the older the patient. Survival was 89% in the patients 60–74 at diagnosis. Women with carcinoma in situ are at substantial increased risk of death (>10%) only at high ages and independent of age at diagnosis. © 2004 Wiley-Liss, Inc.

Class I and II HLA genes are associated with susceptibility and age at onset in Finnish families with type 1 diabetes.

Abstract: Objectives: We explored the properties of the long-term survivor model (LTS) in the genetic association studies and studied allelic and haplotypic associations between the age at on

Blood biochemistry and the risk of cancer.

Abstract: A longitudinal study based on a serum sample bank was carried out in Finland to find out the association between biochemical substances and the subsequent risk of cancer. The objective was to evaluate the consistency between means of individually estimated levels of these compounds and levels based on pooling. Levels of alpha-tocopherol, beta-carotene, retinol, retinol-binding protein, and ceruloplasmin were estimated by primary site and sex and partly by age and morphology. The concentrations in pooled samples were consistently lower than the averages of the individual samples. On the basis of individual samples, all the five biochemical compounds had a rather consistent protective effect on the risk of cancers at most primary sites. This protective effect disappeared in the pool analyses, and more than half of exposure contrasts showed an opposite sign. For ceruloplasmin, the effect of pooling was smaller but not negligible. The results of this study emphasize the demand to standardize the collecting, handling, and analysing of samples in serum banks. They are, furthermore, consistent with the hypothesis that pooling of biochemical samples affects the levels of the substances and may affect the conclusions of epidemiological studies on causes of diseases.

Metabolism of 25‐hydroxyvitamin D3 may explain the u‐shaped risk curve for prostate cancer

Abstract: Metabolism of 25-hydroxyvitamin D3 may explain the U-shaped risk curve for prostate cancer : Letter to the Editor