Undescended testis and the risk of testicular cancer: importance of source and classification of exposure information.

BACKGROUND: The strength of the association between undescended testis and testicular cancer varies considerably across studies. Here we report the effect of various classifications of self-reported history of undescended testis and different data sources on the estimates of the risk of testicular cancer from a case-control study. METHODS: We performed a population-based case-control study including 269 testicular cancer cases and 797 controls matched on age and region. Medical history was assessed by interviews (index persons) and mailed questionnaires (mothers). We used conditional logistic regression to calculate odds ratios (OR) and kappa coefficients to assess agreement between different sources of information. RESULTS: Odds ratios for testicular cancer ranged between 2.4 and 5.4 based on the sons' self-reports and between 1.1 and 1.9 based on the mothers' reports. The agreement between the sons and mothers on undescended, gliding or retractile testis was fair (kappa 0.53) and was good when these conditions were treated by surgery (kappa 0.89). The rating of a history of undescended testis by two urologists was fair (kappa 0.54). CONCLUSIONS: The questionnaire design, the classifications of undescended testis and data sources have an important impact on the OR for the association of undescended testis and testicular cancer. These factors may partially explain the heterogeneity of the OR for this association in case-control studies relying on self-reports.

Sorting the hype from the facts in testicular cancer: is testicular cancer related to trauma?

PURPOSE: The rate of testicular cancer is increasing. Trauma severe enough to cause testicular atrophy is a putative risk factor for testicular cancer but the epidemiological evidence is not conclusive. A population based, multicenter case-control study was performed from 1995 to 1997 to investigate potential risk factors for gonadal and extragonadal germ cell cancer. MATERIALS AND METHODS: The study was done in 5 German regions. Interviews were performed with 269 eligible male patients with a histologically verified diagnosis and 797 controls. Detailed information on medical and family history was collected at personal interviews. RESULTS: We identified a significantly elevated risk for testicular cancer in relation to testis and/or groin trauma (odds ratio 2.5, 95% confidence interval [CI] 1.51 to 4.20). After introducing a lag time by excluding reports of trauma within the last 12 months before diagnosis or interview the corresponding odds ratio was 2.1 (95% CI 1.24 to 3.61). Analysis of the circumstances and the reported types of injury allowed us to restrict the study to testis trauma specifically, which had an odds ratio of 3.49 (95% CI 1.78 to 6.81). To account for a potential reporting bias analysis was restricted to traumatic episodes for which medical attention was sought. This restriction resulted in an odds ratio of 0.70 (95% CI 0.19 to 2.63) after excluding from study trauma reports within the last 12 months. CONCLUSIONS: The results of our study do not support the hypothesis that testicular trauma is an important risk factor for testicular cancer. The possibility of recall bias should be considered.

Cancer registration in Germany: current status, perspectives and trends in cancer incidence 1973-93.

BACKGROUND: A federal law effective in 1995 makes it mandatory for all German States to build up population-based cancer registries. Although the law provides a model of cancer registration, each State may modify this by State-specific regulations, as long as they ensure data exchange between the registries and between registries and scientific institutions. The 'Network of German Population-Based Cancer Registries' constitutes the basis for cooperation among the German cancer registries. In order to improve the cooperation between physicians and epidemiologists, and to demonstrate the benefits of cancer registration, the network published a booklet containing facts on time-trends in cancer incidence during the last two decades. METHODS: Information on cancer incidence and mortality was derived from the population-based cancer registries of Saarland, the former German Democratic Republic (until 1989), the City of Hamburg and the region of Münster. Altogether these registries cover a population of about 23 million. Sixteen types of cancer were selected for the analyses. RESULTS: Major increases in cancer incidence were observed for female lung cancer, testicular cancer, cancer of the oral cavity, malignant melanoma of the skin and non-Hodgkin's lymphoma. Incidence rates also increased for cancer of the female breast, prostate cancer and colorectal cancer. A decrease was observed for stomach and cervical cancer. DISCUSSION: In 1998, only a small fraction of all German adults were monitored by a population-based cancer registry, making it impossible to work out accurate incidence rates for the whole of Germany. Several new cancer registries have been built up recently. Data summaries of existing German population-based cancer registries assist in enhancing the completeness of new cancer registries.

[Risk factors and surgery rates in gallstones. Results of a population-based study]. / Risikofaktoren und Operationsraten des Gallensteinleidens. Ergebnisse einer bevölkerungsbezogenen Studie.

STUDY OBJECTIVE: The prevalence of gallstone disease, time trends in the frequency of cholecystectomies and risk factors for the occurrence of cholelithiasis were examined in a cross-sectional population study. METHODS: The survey was based on a random sample from the populations of 4 regions in Germany, stratified by region, age and sex. Information on the frequency of gallstone disease and on potential risk factors were collected by standardized interviews. For the statistical analysis, multiple logistic regression was used. RESULTS: Overall, 1,085 persons were interviewed. The age-standardized prevalence of known gallstones was 4.2% for men and 14.5% for women. The frequency of cholecystectomy almost tripled in women from 1985 to 1994 as compared to 1975 to 1984 despite a decreasing trend in gallstone diagnoses in the same time period. No such trend was apparent in men. In men, age, body weight, changes in body weight, diabetes and use of corticosteroids were identified as risk factors for gallstone disease. In women, gallstone disease was also associated with body weight, changes in body weight and age, and, in addition, the number of births. An inverse association with gallstone disease was found for use of oral contraceptives and level of education in women.

[Lymphomas and leukemias in population-related cancer registries in Germany]. / Lymphome und Leukämien in bevölkerungsbezogenen Krebsregistern in Deutschland.

BACKGROUND: A German Federal law enacted in 1995 aims at nation-wide cancer registration, the details of realization based on local regulations being left to the individual Federal states. The impact of different approaches and regulations on the results of registration was investigated at three well-established records in the Saarland, Hamburg and North-Rhine Westphalia, taking the group of lymphoma and leukaemia (ICD 200-208) taken as an example. MATERIAL AND METHODS: Incidence and mortality rates calculated by the record files for the period from 1987 to 1994 were compared. The resulting mortality/incidence ratios were compared as well as the percentage of cases in each register with death certificates (DCO) as the only information source. RESULTS: There was a distinct increase of incidence rates visible in Hamburg and Münster. As far as the male patients was concerned, both records attained the level of Saarland at the end of the period. However, the leukaemia and lymphoma mortality figures for males and females was about 10% lower for Saarland than in the comparative regions. The male mortality incidence ratio was 0.55 for Saarland versus 0.60 average in Hamburg and Münster at the end of the period. In Saarland and Hamburg there was a decrease of DCO-cases from 14% to less than 6% in 1994. More constant values around 11% could be observed in the Münster registry. The distribution of diagnosis within the group as well as age-specific incidence rates for the selected diagnosis "lymphatic leukaemia" (ICD 204) and "Hodgkin's disease" (ICD 201) yielded only slight differences. CONCLUSION: The increase of incidence rates in Münster and Hamburg indicates more complete reporting. Assuming that the survival rates are the same in the three regions, the lower mortality in Saarland points to lower morbidity. Hence in spite of a definite approximation the cancer registries in Hamburg and Münster do not reach the level of completeness of the Saarland cancer registry. This may be due to the informed patient consent required by regional law for reports to the registry. To achieve completeness a special reporting procedure for pathological and haematological Institutes is mandatory. Simple indicators should be available in each registry for continuous estimation of completeness. Standardised case definitions and rules for the coding of diagnosis in cancer registries will improve national and international comparability and feasibility of data exchange.