Lyly Teppo

Data quality and quality control of a population-based cancer registry. Experience in Finland.

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.

Prostate cancer risk and prediagnostic serum 25-hydroxyvitamin D levels (Finland).

AbstractObjectives:The aim was to evaluate the association between serum vitamin D (25-hydroxyvitamin D) level and risk of prostate cancer. Methods:The nested case–control study was based on a 13-year follow-up of about 19,000 middle-aged men who attended the first screening visit within the Helsinki Heart Study and were free of clinically verified prostate cancer at baseline. Through record linkage with the files of the Finnish Cancer Registry, 149 prostate cancer cases were identified in the cohort. They were matched (1:4) to probability density sampled controls for age, time of sample retrieval, and residence. Serum levels of 25-hydroxyvitamin D (25-VD) at entry were measured for cases and controls. The relative risks of prostate cancer were derived using conditional logistic regression analysis. Results:Prostate cancer risk, analyzed by quartiles of the 25-VD levels, was inversely related to 25-VD. Men with 25-VD concentration below the median had an adjusted relative risk (OR) of 1.7 compared to men with 25-VD level above the median. The prostate cancer risk was highest among younger men (<52 years) at entry and low serum 25-VD (OR 3.1 nonadjusted and 3.5 adjusted). Among those younger men (<52 years), low 25-VD entailed a higher risk of non-localized cancers (OR 6.3). The mean age at diagnosis of the patients with 25-VD concentration above the median was 1.8 years higher than that of patients with vitamin D below the median (63.1 vs 61.3 years). Conclusions: We conclude that low levels of 25-VD associated with an increased risk for subsequent earlier exposure and more aggressive development of prostate cancer, especially before the andropause.

Survival of Cancer Patients in Finland 1955-1994

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.

Diet and breast cancer risk in a cohort of Finnish women

The associations between dietary antioxidant vitamins, dietary fiber, and selected foods and risk of breast cancer were studied in 4697 initially cancer-free women, aged 15 years or older. At baseline (1967-1972) the women were interviewed for total habitual diet over the preceding year. During a 25-year follow-up period 88 breast cancer cases were diagnosed. There was a significant inverse gradient between milk consumption and occurrence of breast cancer, whereas higher consumption of fried meat was associated with increased risk of breast cancer. No significant relationships were found between the intakes of vitamin E, vitamin C, beta-carotene, lycopene, lutein or dietary fiber and the occurrence of breast cancer.

Circulating enterolactone and prostate cancer risk: A Nordic nested case‐control study

Enterolactone, a phytoestrogen belonging to the class of lignans, is produced by the intestinal microflora from precursors in plant foods and has been implicated in protection against cancer. We study the effect of enterolactone on the risk of a subsequent diagnosis of prostate cancer. We conducted a longitudinal, nested case‐control study by linkage of 3 biobanks to the cancer registries in Finland, Norway and Sweden, respectively. Enterolactone concentrations were measured by time‐resolved fluoroimmunoassay in serum from 794 men who had a diagnosis of prostate cancer at a mean follow‐up time of 14.2 years after blood collection and among 2,550 control men matched within each cohort for age (±2 years), date of blood collection (±2 months) and county. The median enterolactone concentrations did not differ between case and control subjects in the full study group (8.4 nmol/L [25th–75th percentile = 4.5–15.0] vs. 8.5 nmol/L [25th–75th percentile = 4.3–15.9]), nor in the national groups. Odds ratios of prostate cancer risk estimated by conditional logistic regression for increasing concentrations of enterolactone in quartiles in the full study group were 1.00 (referent), 1.21 (95% confidence interval [CI] = 0.96–1.52), 1.16 (95% CI = 0.91–1.47) and 1.08 (95% CI = 0.83–1.39). The OR estimate for the highest vs. the lowest quartile of enterolactone in separate analyses of the Norwegian, Finnish and Swedish cohort was 1.21 (95% CI = 0.91–1.60), 1.02 (95% CI = 0.59–1.76) and 0.87 (95% CI = 0.45–1.67), respectively. No support for the hypothesis that high circulating enterolactone is protective against prostate cancer was found.

The Helsinki Heart Study: an 8.5-year safety and mortality follow-up

Abstract. Objectives. Earlier monitoring of all symptoms, hospital admissions, cancer diagnoses and causes of death during gemfibrozil treatment had raised some suspicions which called for further follow‐up.

Sunlight as a risk factor of malignant melanoma of the skin.

The series of cutaneous melanoma compiled by the Finnish Cancer Registry, a total of 2501 cases covering all tumors diagnosed in Finland in 1953–1973, was analysed. The age adjusted incidence was equal in both sexes (about 3.5/105 in the 1970s). The risk more than doubled during the study period. The most common locations of melanoma in males were the trunk (48%) and lower limbs (17%), and in females the lower limbs (36%) and the trunk (28%).

Subsequent primary cancers after basal-cell carcinoma: A nationwide study in Finland from 1953 to 1995

The aim of this study was to investigate whether patients with basal‐cell carcinoma (BCC) of the skin have an increased risk of developing other cancers. A total of 71,924 patients diagnosed with BCC between 1953 and 1995 were identified from the Finnish Cancer Registry. They were followed up for subsequent primary cancers from the date of the first BCC diagnosis to the end of 1995. Standardized incidence ratios (SIR) with 95% confidence intervals (CI) were calculated based on national rates. Altogether 11,042 subsequent primary cancers occurred among the study cohort during 625,000 person‐years of follow‐up. Risk increases were observed for non‐melanoma skin cancer (SIR 3.79, 95% CI 3.59–4.00) and skin melanoma (SIR 2.34, 95% CI 2.08–2.61). The five other primary sites presenting the highest SIRs were salivary glands (SIR 3.30), lip (2.19), small intestine (1.85), nose (1.73) and pharynx (1.71). Patients who were less than 40 years of age at the time of BCC diagnosis had a significantly higher relative risk for a subsequent new cancer than the older patients (ratio of the SIRs 1.29, 95% CI 1.10–1.51). Time since BCC diagnosis did not materially influence the overall relative risk of subsequent cancers. Part of the increase in the risk of skin cancer is likely to be due to enhanced diagnostic activity after an initial diagnosis of BCC. However, the increases in the risk of several non‐cutaneous cancers suggest a generalized carcinogenic role of some factors in the BCC pathogenic pathways. Int. J. Cancer 87:283–288, 2000.

Cancer Incidence Following Chlorophenol Exposure in a Community in Southern Finland

Chlorophenols have contaminated the drinking water system and the local lake in the village of Järvelä in southern Finland. Local geology, ground water streams, and chemical analyses incriminated a local sawmill as the only plausible source of exposure. Cancer incidence in the municipality of Kärkölä (half of the population lives in Järvelä), compared with the rest of the local health-care district and with the greater cancer control region, indicated an excess of soft-tissue sarcomas and non-Hodgkins lymphomas. A case-control study, which focused on cancers of the colon, bladder and soft tissues, lymphomas, and leukemia, demonstrated a significantly elevated risk ratio for non-Hodgkins lymphomas among persons who consumed fish from the local lake, which was contaminated with chlorophenols. Probable exposure to chlorophenol-contaminated drinking water played a role in the increased incidence of non-Hodgkins lymphomas and possibly was a factor in the development of soft-tissue sarcoma.

Stress of daily activities and risk of breast cancer: A prospective cohort study in Finland

The belief that life stress enhances breast cancer is common, but there are few prospective epidemiological studies on the relationship of life stress and breast cancer. We have investigated the association between stress of daily activities (SDA) and breast‐cancer risk in a prospective cohort study of 10,519 Finnish women aged 18 years or more. SDA measures a subjects own appraisal of daily stress. It was assessed in 1975 and 1981 by a self‐administered questionnaire, which also provided information on subject characteristics and other known breast‐cancer risk factors. Follow‐up data for breast cancer from 1976 to 1996 were attained through record linkage to the Finnish Cancer Registry. Study subjects were divided into 3 groups based on their SDA scores in 1975: no stress (23% of subjects), some stress (68%) and severe stress (9%). Hazard ratios (HRs) and respective 95% confidence intervals (CIs) for incidence of breast cancer by level of SDA were obtained from the Cox proportional hazards model. We identified 205 incident breast cancers in the cohort. Multivariable‐adjusted HRs for breast‐cancer risk were 1.00 (reference), 1.11 (95% CI 0.78–1.57) and 0.96 (95% CI 0.53–1.73) by increasing level of stress. Neither shifting of the SDA cut‐off points nor restricting the analysis to women who reported the same level of SDA in 1975 and 1981 materially altered the results. We found no evidence of an association between self‐perceived daily stress and breast‐cancer risk.