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Cancer remains one of the most serious long‐term complications after liver transplantation (LT). Data for all adult LTpatients between 1982 and 2013 were extracted from the Nordic Liver Transplant Registry. Through linkage with respective national cancer‐registry data, we calculated standardized incidence ratios (SIRs) based on country, sex, calendar time, and age‐specific incidence rates. Altogether 461 cancers were observed in 424 individuals of the 4246 LTpatients during a mean 6.6‐year follow‐up. The overall SIRwas 2.22 (95% confidence interval [CI], 2.02‐2.43). SIRs were especially increased for colorectal cancer in recipients with primary sclerosing cholangitis (4.04) and for lung cancer in recipients with alcoholic liver disease (4.96). A decrease in the SIRfor cancers occurring within 10 years post‐LTwas observed from the 1980s: 4.53 (95%CI, 2.47‐7.60), the 1990s: 3.17 (95%CI, 2.70‐3.71), to the 2000s: 1.76 (95%CI, 1.51‐2.05). This was observed across age‐ and indication‐groups. The sequential decrease for the SIRof non‐Hodgkin lymphoma was 25.0‐12.9‐7.53, and for nonmelanoma skin cancer 80.0‐29.7‐10.4. Cancer risk after LTwas found to be decreasing over time, especially for those cancers that are strongly associated with immunosuppression. Whether immunosuppression minimization contributed to this decrease merits further study. This multicenter study from four countries finds that overall cancer incidence after liver transplantation has decreased over time relative to the general population, especially for immunosuppression‐related cancer types.

Cancer remains one of the most serious long-term complications after liver transplantation (LT). Data for all adult LT patients between 1982 and 2013 were extracted from the Nordic Liver Transplant Registry. Through linkage with respective national cancer-registry data, we calculated standardized incidence ratios (SIRs) based on country, sex, calendar time, and age-specific incidence rates. Altogether 461 cancers were observed in 424 individuals of the 4246 LT patients during a mean 6.6-year follow-up. The overall SIR was 2.22 (95% confidence interval [CI], 2.02-2.43). SIRs were especially increased for colorectal cancer in recipients with primary sclerosing cholangitis (4.04) and for lung cancer in recipients with alcoholic liver disease (4.96). A decrease in the SIR for cancers occurring within 10 years post-LT was observed from the 1980s: 4.53 (95%CI, 2.47-7.60), the 1990s: 3.17 (95%CI, 2.70-3.71), to the 2000s: 1.76 (95%CI, 1.51-2.05). This was observed across age- and indication-groups. The sequential decrease for the SIR of non-Hodgkin lymphoma was 25.0-12.9-7.53, and for nonmelanoma skin cancer 80.0-29.7-10.4. Cancer risk after LT was found to be decreasing over time, especially for those cancers that are strongly associated with immunosuppression. Whether immunosuppression minimization contributed to this decrease merits further study.

We aimed to estimate stratified absolute (cumulative) and relative (standardized incidence ratios; SIRs) risks of non-Hodgkin lymphoma (NHL) in relatives of NHL patients. A cohort of 169?830 first-degree relatives of 45?406 NHL patients who were diagnosed between 1955 and 2010 in five European countries was followed for cancer incidence. The lifetime (0–79 year) cumulative risk of NHL in siblings of a patient with NHL was 1.6%, which represents a 1.6-fold increased risk (SIR=1.6, 95% confidence interval (CI)=1.2–1.9) over the general population risk. NHL risk among parent-offspring pairs was increased up to 1.4-fold (95% CI=1.3–1.5; lifetime risk 1.4%). The lifetime risk was higher when NHL was diagnosed in a sister (2.5% in her brothers and 1.9% in her sisters) or a father (1.7% in his son). When there were ?2 NHL patients diagnosed in a family, the lifetime NHL risk for relatives was 2.1%. Depending on sex and age at diagnosis, twins had a 3.1–12.9% lifetime risk of NHL. Family history of most of the histological subtypes of NHL increased the risk of concordant and some discordant subtypes. Familial risk did not significantly change by age at diagnosis of NHL in relatives. Familial risk of NHL was not limited to early onset cases.

Background and Aims: In a randomized trial the effect of short-term preoperative radio therapy and postoperative chemotherapy was studied in patients undergoing total mesorectal excision (TME) for clinically resectable rectal cancer. The primary endpoint was overall survival. The secondary endpoints published herein were the incidence of postoperative complications and adverse events with perioperative adjuvant therapy.Material and Methods: In 1995–2002, 278 eligible patients with stage II and stage III rectal cancer were randomly assigned to TME alone (surgery group) or to preoperative 25Gy radiotherapy in 5 fractions and postoperative 5-fluorouracil and leucovorin chemotherapy in addition (RT+CTgroup).Results: Anastomotic leakage rate did not significantly differ between the surgery and the RT + CT group, 20.6% vs. 27.4%. Postoperative infections (15.5 vs. 26.2%, p = 0.037) and perineal wound dehiscence (15.9 vs. 38.5%, p = 0.045) were more common after radiotherapy. Grade 3–5 adverse events were uncommon with preoperative radiotherapy (one, 0.7% with reversible lumbar plexopathy) and postoperative chemotherapy (hematologic in 10.8%, with one septic death, and gastrointestinal in 4.8%).Conclusions: Perioperative adjuvant therapy was generally well tolerated and did not lead to an increase in serious surgical complications. Wound infections and perineal wound dehiscence were more common in irradiated patients.

Cancer treatment may affect school performance. Scholastic achievements after childhood brain tumors have not been previously reported on the level of actual grades.

Abstract. Background: A lowering of colorectal cancer risk for the birth cohorts born around World War II (WWII) has previously been observed in Norway, a country which suffered some 20% caloric restriction during the war. The purpose of the study was to conduct a similar kind of analysis in the other Nordic countries and Estonia, which were also subjected to various degrees of energy restriction during WWII.

Cosmic radiation is an occupational risk factor for commercial aircrews. In this large European cohort study (ESCAPE) its association with cancer mortality was investigated on the basis of individual effective dose estimates for 19,184 male pilots. Mean annual doses were in the range of 2–5 mSv and cumulative lifetime doses did not exceed 80 mSv. All-cause and all-cancer mortality was low for all exposure categories. A significant negative risk trend for all-cause mortality was seen with increasing dose. Neither external and internal comparisons nor nested case-control analyses showed any substantially increased risks for cancer mortality due to ionizing radiation. However, the number of deaths for specific types of cancer was low and the confidence intervals of the risk estimates were rather wide. Difficulties in interpreting mortality risk estimates for time-dependent exposures are discussed.

Time trends and geographical variation of Helicobacter pylori antibodies in Finland were investigated by enzyme immunoassay in 20- to 34-year-old randomly selected females from six localities during 1969–73 (n = 375), and 15- to 45-year-old females representing nine communities and four geographical areas in 1983 (n = 882) and 1995 (n = 842). In the six communities investigated at three different time points, the overall prevalence declined from 38 to 12%, with an emphasis on the latter 12 years. The regionally varying rate of decrease in helicobacter prevalence changed the pre-existing geographical variation, leaving northern Finland with the highest rate. A 10%-units higher local helicobacter prevalence seemed to predict a 23% (95% CI 3–44%) higher gastric cancer incidence 20 years later. The overall decline in helicobacter seropositivity is consistent with earlier reports from Finland and other developed countries, and supports the cohort theory as an explanation for the age-related increase in H. pylori seroprevalence.

Background: In epidemiological studies abundant physical activity has been related to decreased breast cancer risk, though the results have been inconsistent. The purpose of this paper was to study the association of physical activity at leisure and commuting to work and incidence of breast cancer. Methods: The study cohort consisted of 30,548 female participants of the Finnish adult health behaviour survey, based on annual random samples of Finns aged 15–64, collected in 1978–1993. By the end of 1995, 332 breast cancer cases had been diagnosed in the cohort. Relative risks of breast cancer were adjusted for age at survey, body mass index (BMI), education, length of follow-up, parity and age at first birth using Poisson regression models. Results: Compared to women exercising less than once a week, the adjusted relative risk of breast cancer for women exercising once a week was 0.80 (95% confidence interval (CI): 0.58–1.10), for women exercising 2–3 times per week 0.92 (95% CI: 0.78–1.22) and for women exercising daily 1.01 (95% CI: 0.72–1.42). Women who reported commuting, walking or bicycling to work 30 min or more daily had slightly lower adjusted risk of breast cancer (RR: 0.87, 95% CI: 0.62–1.24) than women working at home, being unemployed or driving a car to working place. Conclusion: Although a small protective effect of regular physical activity for breast cancer incidence was found in physical activity when commuting to work, the role of the physical activity in breast cancer prevention is still an open question.

AbstractA study on cancer incidence after kidney transplantation was performed using data of national transplant and cancer registries. Since 1964 up to 30 June 1997, 3440 kidney transplantations were performed on 2890 patients. From 1967 to 1997, 230 posttransplantation malignancies were found in 20 817 patient‐years of follow up. The standardised incidence ratio (SIR) was 3.33 compared to the general population. The SIR was highest in skin cancer (39.2). The SIRs were high in cancers of the lip (23.0), thyroid (8.08), kidney (8.0), lower urinary tract (3.2), non‐Hodgkin lymphoma (4.8), ovary (3.9) and colon (3.9). Skin cancer and lymphomas had much higher SIRs in men than in women whereas lower urinary tract cancer had a higher SIR in women. During the first 10 follow up years, life‐table analysis indicates a higher cancer risk in cyclosporine‐treated patients, but this may be biased by their shorter follow up as the overall SIR was equal in both groups. This population study shows the increased incidence of cancer in the transplant population and points out the importance of cancer surveillance in the years following kidney transplantation.

Background:Identification of human papillomavirus type 16 (HPV16) as the major risk factor for cervical neoplasia, and mass production of DNA free HPV capsids have paved the way to preventive vaccination trials. Design of such trials requires reliable attack rate data.Objective:Determination of (1) HPV16 and (2) cervical neoplasia attack rates in primiparous women. Estimation of actuarial sample sizes for HPV16 vaccination phase IV trials.Design:A longitudinal cohort study.Methods:Population based Finnish Maternity Cohort (FMC) and Finnish Cancer Registry (FCR) were linked for the identification of two cohorts of primiparous women: (1) a random subsample of the FMC: 1656 women with two pregnancies between 1983-9 or 1990-6 and living in the Helsinki metropolitan area, and (2) all 72 791 primiparous women living in the same area during 1983-94. Attack rate for persistent HPV16 infection (1) was estimated in 1279 seronegative women by proportion of seroconversions between the first and the second pregnancy. Comparable 10 year cumulative incidence rate (CR) of cervical intraepithelial neoplasia grade III and cervical cancer (CIN III+) (2) was estimated based on cases registered at the FCR during 1991-4.Results:The HPV16 attack rates were 13.8% (<18 years), 7.0% (18-19 years), 2.3% (21 years), 2.4% (23 years), and 4.5% (<25 years). Number of vaccinees required for a 5 year efficacy trial with persistent HPV16 infection as the end point ranged between 1000 and 3900, assuming 80% power, 90%-70% vaccine efficacy (VE), and misclassification. The CRs of CIN III+ were 0.33% (<18 years), 0.44% (18-19 years), 0.21% (20-24 years), and 0.28% (<25 years). Number of vaccinees required for a 10 year efficacy trial with HPV16 positive CIN III+ as the end point was 15 000 assuming 80% power, 90% VE, and 75% aetiological fraction of CIN III+ for HPV16.Conclusions:The attack rates of HPV16 and CIN III+ identify primiparous women under 25 years of age among target populations for postnatal HPV vaccination at phase II/III trials.

Summary: ¶ The aim was to assess the frequency of von Hippel-Lindau disease (VHL) and the long-term prognosis of VHL and non-VHL patients among 110 consecutive patients with haemangioblastoma (HB) of the CNS treated between 1953 and 1993 at one neurosurgical unit.  To reveal VHL manifestations we performed a detailed clinical and radiological examination (neuraxis and abdomen) (61/110), VHL-gene mutation analysis (40/110), and collection of all available clinical, imaging, operative and autopsy data from the hospitals involved. All patients were followed-up with a median of 14 years (excluding 14 operative deaths), and no patient was lost to follow-up. Altogether 49 patients died during the follow-up.  In the 14 VHL patients (13%), HB(s) of the CNS were detected at a median age of 33 years, retinal HB(s) at 39 years, and renal cell carcinoma (RCC) at 43 years. The frequency of VHL in patients operated on for HB(s) was 29% before the age of 25 years, 19% between 25 and 45 years, and only 2% after 45 years. HB patients not meeting the VHL criteria had internal organ cysts in 14%. One non-VHL patient (4%) had two adjacent HBs in the same cyst wall. The growth rates of non-VHL and VHL-related HBs were similar as indicated by the median time to recurrence and the proliferation indices (MIB-1). Recurrence of the HB in patients whose primary operation was considered radical developed in four of the 10 VHL patients at a median of 19 years, and in nine of the 74 non-VHL patients at a median of 11 years. The median length of life of all VHL and non-VHL patients was 46 and 63 years, respectively. In VHL, RCC and HBs were equal causes of death.

Using data taken from the organised mass screening system in Finland, risk indicators of cervical cancer were identified in order to define a high-risk group which could then be used for selective screening of cervical cancer. Single risk factors classified at best 39% of the cases into a high-risk group of 8%. A combination of risk factors by different statistical methods was applied, but the results were essentially the same. In order to find a high-risk group small enough to yield a reduction in costs, the number of cases originating from the low-risk group was increased. Theoretical calculations showed that for selective screening to be effective, the risk of disease in the high-risk group relative to that in the low-risk group must be greater than that implied by current knowledge of cervical cancer epidemiology. It was concluded that selective screening has only a limited applicability.

The aim of the study was to create a rapid method for estimating cancer risk in areas defined by exact map coordinates and to test it using as an example incidence of leukemia near an oil refinery. The method can be used to investigate possible local excesses of cancer of suspected environmental origin in Finland. Map coordinates with an accuracy of 10 m for the place of residence of each Finn were obtained from national registers. Based on this data set, numbers of inhabitants and expected number of cancer cases by sex and age in squares of 500 × 500 m were calculated for all of Finland. Observed number of cancer cases in each square were obtained based on record Linkage of the map coordinates with the Finnish Cancer Registry. The ratio of observed and expected number of cancer cases was modeled using Poisson regression. The example analysis included all 23 leukemia and 531 any cancer cases registered in an area around an oil refinery in 1983-1986. There was no significant association between distance from the oil refinery and risk of leukemia or any cancer. The method proved fast and efficient in comparing areal differences in cancer incidence in Finland. In cases of environmental concern, geographical analyses of existing registers is a rapid method to perform first analyses when evaluating the need for further studies.

The relation between the intake of retinoids, carotenoids, vitamin E, vitamin C, and selenium and the subsequent risk of lung cancer was studied among 4,538 initially cancer-free Finnish men aged 20-69 years. During a follow-up of 20 years beginning in 1966-1972, 117 lung cancer cases were diagnosed. Inverse gradients were observed between the intake of carotenoids, vitamin E, and vitamin C and the incidence of lung cancer among nonsmokers, for whom the age-adjusted relative risks of lung cancer in the lowest tertile of intake compared with that in the highest tertile were 2.5 (p value for trend = 0.04), 3.1 (p = 0.12), and 3.1 (p less than 0.01) for the three intakes, respectively. Adjustment for various potential confounding factors did not materially alter the results, and the associations did not seem to be due to preclinical cancer. In the total cohort, there was an inverse association between intake of margarine and fruits and risk of lung cancer. The relative risk of lung cancer for the lowest compared with the highest tertile of margarine intake was 4.0 (p less than 0.001), and that for fruits was 1.8 (p = 0.01). These associations persisted after adjustment for the micronutrient intakes and were stronger among nonsmokers. The results suggest that carotenoids, vitamin E, and vitamin C may be protective against lung cancer among nonsmokers. Food sources rich in these micronutrients may also have other constituents with independent protective effects against lung cancer.

A number of chemicals encountered predominantly in occupational settings have been causally linked with cancer in humans; furthermore, several industrial processes and occupations have been associated convincingly with increased rates of cancer, although the specific carcinogens remain to be identified. The tissues affected are mainly the epithelial lining of the respiratory organs (nasal cavity, paranasal sinuses, larynx and lung), and urinary tract (renal parenchyma, renal pelvis and urinary bladder), the mesothelial linings, the bone marrow and the liver. During the period 1970–84, almost 4 million people (3.7 million men and 0.2 million women) in the Nordic countries were potentially exposed to above‐average levels of one or more verified industrial carcinogens. It is expected that these exposures will result in a total of about 1,900 new cases of cancer every year in the Nordic countries around the year 2000, with 1,890 among men and fewer than 25 among women. The proportions that could be avoided if industrial carcinogens were eliminated would be 70% of mesotheliomas, 20% of cancers of the nasal cavity and sinuses, 12% of lung cancers, 5% of laryngeal cancers, 2% of urinary bladder cancers, 1% of the leukaemias, and 1% of renal cancers. Overall, it is estimated that verified industrial carcinogens will account for approximately 3% of all cancers in men and less than 0.1% of all cancers in women in the Nordic countries around the year 2000. No attempt was made to estimate the potential effects of suspected carcinogens in the workplace.

Alcohol intake is causally associated with cancers of the larynx, oral cavity, pharynx, oesophagus and liver. In all five Nordic countries, alcohol consumption increased substantially between 1965 (6.5 litres per adult per year) and 1975 (10 litres), but remained at about 10 litres between 1975 and 1985. The daily consumption of men during the period was substantially higher than that of women, and that of both men and women was higher in Denmark than in the other Nordic countries. In about 2000, an annual total of almost 1,300 cancer cases (1,000 in men and 300 in women) would be avoided if alcohol drinking were eliminated. This corresponds to about 29% of all alcohol‐related cancers, i.e. in the oesophagus (37%), oral cavity and pharynx (33%), larynx (29%) and liver (15%). About 2% of all cancers in men and 1% in women in the Nordic countries around the year 2000 will be caused by the drinking habits of the respective populations.

Active smoking is causally associated with cancers of the lung, larynx, oral cavity, pharynx, oesophagus, pancreas, renal parenchyma, renal pelvis and urinary bladder, and passive smoking appears to be causally associated with cancer of the lung. Information on smoking habits for the years 1965, 1975 and 1985 shows that more men than women in the Nordic countries were current smokers. The rates of women were stable over time and those of men were decreasing, approaching those of women. Lung cancer, in particular, is strongly associated with active smoking: by increasing the number of cigarettes smoked per day (lifelong) to 5, 10, 20 and 40 or more, the risk increases by five‐, eight‐, 16‐ and 30‐fold, respectively, over that of people who have never smoked. Thus, with approximately 35% current smokers and 25% former smokers among Nordic men in 1985 and approximately 30% current smokers and 15% former smokers among Nordic women in that year, by the year 2000 10,000 cases of lung cancer (6,500 in men and 3,500 in women) will be caused by active smoking; this is equivalent to 82% of all cases of lung cancer in these populations. Another 6,000 cancers of other types (4,000 in men and 2,000 in women) are caused annually by active smoking, yielding a total of 16,000 new cases each year around the turn of the century. This implies that 14% (19% in men and 9% in women) of all incident cancers in the Nordic countries around the year 2000 will be caused by active tobacco smoking. In comparison, passive smoking is a minor cause of lung cancer, responsible for approximately 0.6% of all new cases (approximately 70 cases annually) in this area around the turn of the century.

An overview is given of the most important known causes of cancer in the five Nordic countries and the resulting number of cancers that are potentially avoidable. The main causes include active and passive smoking, alcohol consumption, exposure to asbestos and other occupational carcinogens, solar and ionizing radiation, obesity, human papillomavirus infection in the female genital tract and infection with Helicobacter pylori.The organs most commonly affected are those of the respiratory system, the upper digestive tract and stomach, skin, the lower urinary tract and the uterine cervix. Annually, more than 18,000 cancers in men and 11,000 in women in the Nordic populations could be avoided by eliminating exposure to known carcinogens which is equivalent to 33% and 20% of all cancers arising in men and women, respectively, around the year 2000. Smoking habits account for a little more than half of these avoidable cases. Estimates of avoidable cancers are given for each Nordic country, separately.

Exposure to solar and ionizing radiation increases the risk for cancer in humans. Some 5% of solar radiation is within the ultraviolet spectrum and may cause both malignant melanoma and nonmelanocytic skin cancer; the latter is regarded as a benign disease and is accordingly not included in our estimation of avoidable cancers. Under the assumption that the rate of occurrence of malignant melanoma of the buttocks of both men and women and of the scalp of women would apply to all parts of the body in people completely unexposed to solar radiation, it was estimated that approximately 95% of all malignant melanomas arising in the Nordic populations around the year 2000 will be due to exposure to natural ultraviolet radiation, equivalent to an annual number of about 4700 cases, with 2100 in men and 2600 in women, or some 4% of all cancers notified. Exposure to ionizing radiation in the Nordic countries occurs at an average effective dose per capitaper year of about 3 mSv (Iceland, 1.1 mSv) from natural sources, and about 1 mSv from man‐made sources. While the natural sources are primarily radon in indoor air, natural radionuclides in food, cosmic radiation and gamma radiation from soil and building materials, the man‐made sources are dominated by the diagnostic and therapeutic use of ionizing radiation. On the basis of measured levels of radon in Nordic dwellings and associated risk estimates for lung cancer derived from well‐conducted epidemiological studies, we estimated that about 180 cases of lung cancer (1% of all lung cancer cases) per year could be avoided in the Nordic countries around the year 2000 if indoor exposure to radon were eliminated, and that an additional 720 cases (6%) could be avoided annually if either radon or tobacco smoking were eliminated. Similarly, it was estimated that the exposure of the Nordic populations to natural sources of ionizing radiation other than radon and to medical sources will each give rise to an annual total of 2120 cancers at various sites. For all types of ionizing radiation, the annual total will be 4420 cancer cases, or 3.9% of all cancers arising in the Nordic populations, with 3.4% in men and 4.4% in women.

Tobacco smoking was studied in relation to colorectal cancer in 56 973 Finnish men and women initially free from cancer. Smoking status was determined by a health questionnaire. During a follow-up period of 28 years, from the baseline in 1966-72 to the end of 1994, 457 cases of colorectal cancer occurred. There was no significant association between baseline smoking status and colorectal cancer risk over the total follow-up period. The sex- and age-adjusted relative risk of colorectal cancer between smokers and non-smokers was 1.06 (95% confidence interval 0.84-1.33). For follow-up periods of 11-20 years, however, the relative risk was 1.57 (95% confidence interval 1.09-2.24). In a subgroup in which smoking habits were assessed twice, the relative risk of colorectal cancer among persistent smokers was 1.71 (95% confidence interval 1.09-2.68) compared with others. The results of the present prospective study are consistent with the possibility that smoking increases the risk of colorectal cancer after a relatively long induction period. To clarify the role of smoking in colorectal cancer development, further cohort studies are needed with long follow-up periods and allowing for control of dietary and other potential confounding factors.

The European Childhood Leukaemia - Lymphoma Incidence Study (ECLIS) is designed to address concerns about a possible increase in the risk of cancer in Europe following the nuclear accident in Chernobyle in 1986. This paper reports results of surveillance of childhood leukaemia in cancer registry populations from 1980 up to the end of 1991. There was a slight increase in the incidence of childhood leukaemia in Europe during this period, but the overall geographical pattern of change bears no relation to estimated exposure to radiation resulting from the accident. We conclude that at this stage of follow-up any changes in incidence consequent upon the Chernobyl accident remain undetectable against the usual background rates. Our results are consistent with current estimates of the leukaemogenic risk of radiation exposure, which, outside the immediate vicinity of the accident, was small.

Previous job-exposure matrices (JEM) have usually cross-tabulated classified exposure information by chemical agent and occupational class. A new Finnish job-exposure matrix (FINJEM) was constructed for exposure assessment in large register-based studies. Unlike most other JEMs, FINJEM was designed to contain definitions, inferences, exposure data, and references. This documentation enables FINJEM to be applied also as a general exposure information system for hazard control, risk quantification and hazard surveillance. The system includes, e.g., workforce data, and it provides information on the numbers of exposed workers in Finland by agent, occupation, and level of exposure. The exposures of FINJEM cover major physical, chemical, microbiological, ergonomic, and psychosocial factors. The assessment period is 1945–1997, divided into several subperiods. Exposure is described by the prevalence of exposure and the level of exposure among the exposed, both estimated mainly on continuous scales. The user may also define the final criteria of exposure, and thereby influence the magnitude of misclassification. Am. J. Ind. Med. 33:409–417, 1998. © 1998 Wiley-Liss, Inc.

The risk of smoking-related secondary cancers developing in bladder cancer patients was studied. The study population consisted of 10,014 bladder cancer patients reported to the Finnish Cancer Registry between 1953 and 1989. The risk of contracting a new primary cancer was estimated as a standardized incidence ratio, defined as the ratio of the observed and expected numbers of cases. Of 660 secondary cancers (6.6%) observed (standardized incidence ratio 0.96) 44% were considered to be smoking-related. Lung cancer was the most common secondary cancer (30% overall), and it occurred significantly more often than expected (standardized incidence ratio 1.31, 95% confidence interval 1.13 to 1.50). Also, larynx cancer among men (standardized incidence ratio 1.67, 95% confidence interval 0.95 to 2.79) and kidney cancer among women (standardized incidence ratio 3.55, 95% confidence interval 1.84 to 6.20) were found more often than expected. These excess risks were observed up to 20 years after diagnosis of bladder cancer. Therefore, bladder cancer patients experience an excess risk of smoking-related new tumors, which must be acknowledged during the initial evaluation and regular followup of such patients.

The effect of social class on survival was assessed in a cohort of cancer patients identified from the nationwide population-based Finnish Cancer Registry. The cohort consisted of all reported cases of the 12 most common types of cancer occurring in Finland between 1971 and 1985 among persons born in 1906-1945 (n = 106,661). Social class information based on occupation was obtained individually for each patient from the population census of 1970. Both observed and corrected (i.e., cause of death-specific) 5-year survival rates were used in the analyses. A statistically significant linear effect of social class on age-adjusted relative risk of cancer death was observed in six of 12 cancer types among men and in nine of 12 among women; and the risk was highest for those in the lowest social class. The relative risk of death due to cancer for social class I (highest) relative to social class IV (lowest) was lowest in bladder cancer (relative risk (RR) = 0.46, 95% confidence interval (CI) 0.34-0.61) and kidney cancer (RR = 0.61, 95% CI 0.48-0.78) among men and in corpus uteri (RR = 0.51, 95% CI 0.36-0.72) and rectum cancer (RR = 0.56, 95% CI 0.42-0.74) among women. The differences between results obtained using corrected and observed survival rates were small. These findings indicate that social class is an important determinant of cancer patient survival. Additional research is required to clarify the etiology of the social class differences and to identify factors that could be used for developing strategies to diminish such inequalities.

Ecologic and individual risk indicators were derived from the population censuses of Finland Cancer Registry. The years covered in the study were 1955-1974 for the ecologic analysis and 1971-1975 for the analysis on individuals. The incidence of both diseases was high in an urban environment with high standard of living. The individuals with high risk of breast cancer were of high socioeconomic status and were well educated, whereas cervical cancer was common among women of low socioeconomic status and with less education. Conceptually similar indicators used on both the ecologic and individual levels characterize different aspects of risk; for example, a woman with a low standard of living in a well-to-do environment has a high risk of cervical cancer.

The objective of this retrospective cohort study was to assess the effect of hysterectomy on subsequent risk of cancer among 25,382 hysterectomized and a similar number of non-hysterectomized control women, registered in 1963-1976 in the Mass Screening Registry (MSR).

Cancer incidence was studied among 3072 first-degree relatives of 559 unselected ovarian cancer patients. Among cohort members there were 306 cancer cases. The overall cancer incidence was not increased: the standardised incidence ratio (SIR) in males was 0.9 (95% confidence interval 0.8-1.1) and in females 1.0 (0.8-1.1). The female relatives had a significantly increased risk for ovarian cancer (SIR 2.8, 1.8-4.2). The excess was attributable to sisters only (SIR 3.7, 2.3-5.7). The relative risk for ovarian cancer among sisters decreased both by increasing age of the sister and by increasing age at diagnosis of the index patient: the SIRs were 7.3 (1.5-21.4), 4.5 (1.6-9.8) and 3.1 (1.7-5.4) for sisters of index patients diagnosed in age < 45, 45-54 and 55-75 years respectively. The age dependency of the risk supports the role of genetic factors in familial ovarian cancer. Although the risk of ovarian cancer among sisters from families with breast cancer (SIR 9.2, 3.7-19.0) was significantly higher than among sisters from families with no breast cancer patients (SIR 2.9, 1.6-4.8, rate ratio 3.1, P < 0.05), the excess was not solely attributable to coaggregation of breast and ovarian cancer. Among the 27 families with two or more ovarian cancers, only sisters were affected in 24 families, which might implicate recessive inheritance or shared environmental factors influencing ovarian cancer risk in sisters.

Based on data from the Nordic cancer registries, time-related trends in incidence of Kaposi's sarcoma (KS) were analysed in four ethnically similar populations before the AIDS epidemic. Data were available for different time periods in Denmark (1970-79), Sweden (1958-79), Finland (1953-79) and Norway (1953-79). KS was more common among men than among women aged 60 years or more, whereas no differences were observed for younger persons. The incidence of KS differed significantly between the four countries (P = 0.0001); Sweden having the highest and Denmark the lowest rates. Similarly, regional differences in incidence were observed within Sweden, rates being higher in the northern than in the southern areas (Ptrend = 0.002). Overall, in Nordic men the world standardised incidence rose from 0.5/1,000,000 person-years in the period 1953-57 to 1.8/1,000,000 person-years in 1978-79; in Nordic women, the corresponding rates were 0.2/1,000,000 person-years and 0.8/1,000,000 person-years respectively. The rate of increase was similar in Sweden, Finland and Norway (P = 0.14), whereas the short period of observation in Denmark precluded precise assessment of time-related incidence trends. These observations cannot be explained by registrational procedures or known risk factors for KS, and argue that environmental factors play an important role in the development of the disease.

The relative risk of subsequent cancers was evaluated for a total of 9,092 patients with lip and oropharyngeal cancer recorded between 1953 and 1989 in the nationwide Finnish Cancer Registry. The observed numbers of patients were compared with those expected on the basis of the incidence rates in the Finnish population. There were 1,130 patients (12%) with a new cancer. The standardised incidence ratio (SIR) of contracting a new primary cancer was 1.2 for lip cancer patients (95% CI 1.1-1.3) and 1.4 for patients with oropharyngeal cancer (95% CI 1.2-1.4). Among lip cancer patients, a statistically significant excess risk was found for subsequent cancers in the oropharyngeal area (SIR 1.9, 95% CI 1.1-3.1), larynx (SIR 2.0, 95% CI 1.2-2.9) and lung (SIR 1.4, 95% CI 1.3-1.6), i.e. for cancers with tobacco aetiology. Among patients with oropharyngeal cancer there was an excess of lip cancer (SIR, 3.5, 95% CI 1.5-6.9), lung cancer (SIR 1.8, 95% CI 1.3-2.3) and leukaemia (SIR 2.3, 95% CI 1.0-4.3). Radiotherapy for the first primary did not increase the risk of new cancer.

Some earlier studies based on relatively small data sets have suggested that the month of diagnosis affects survival of breast cancer patients. This phenomenon has been suggested to be attributable to daylight-related hormonal factors. Factors related to the holidays of both the medical personnel and the women themselves might also provide the explanation. In this study we assessed the effect of the month of diagnosis on the survival of 32,807 female breast cancer patients diagnosed in Finland in 1956-1985. Our results indicate that the month of diagnosis is a significant prognostic factor after adjusting for age at diagnosis, period of diagnosis, and stage at diagnosis. The adjusted relative excess risk of death was highest among those diagnosed in July and August, and lowest in March and November, the difference between the lowest and highest risk being 18%. Since colorectal cancer should not have any daylight-related hormone dependent risk determinants, a control cohort of 12,950 women with a diagnosis of colorectal cancer in the same calendar period was studied in a similar way. The survival pattern by month of diagnosis among the colorectal cancer patients was similar to that among breast cancer patients, indicating that general factors associated with the health behaviour of women and the health services (such as holidays) rather than biological factors may cause seasonal variations in survival of cancer patients.

The relationship between intake of dairy products and risk of breast cancer was studied in 4697 initially cancer-free women, aged 15 years or over. During a 25 year follow-up period after the collection of food consumption data, 88 breast cancers were diagnosed. Intakes of foods were calculated from dietary history interviews covering the habitual diet of examinees over the preceding year. There was a significant inverse gradient between milk intake and incidence of breast cancer, the age-adjusted relative risk of breast cancer being 0.42 (95% confidence interval=0.24-0.74) between the highest and lowest tertiles of milk consumption. The associations with respect to other dairy products were not significant. Adjustment for potential confounding factors, i.e. smoking, body mass index, number of childbirths, occupation and geographic area, resulted in only a minor change in the milk intake-breast cancer relation. Nor did adjustment for intake of other foodstuffs and nutrients, e.g. energy, carbohydrates, protein, fat, vitamins and trace elements, alter the results. No significant interactions between milk intake and demographic or dietary variables or time of cancer diagnosis were observed. Our data suggest that there is a protective effect, dietary or habitual, associated with consumption of milk that overwhelms the associations between different other factors and risk of breast cancer.

Previous job‐exposure matrices (JEM) have usually cross‐tabulated classified exposure information by chemical agent and occupational class. A new Finnish job‐exposure matrix (FINJEM) was constructed for exposure assessment in large register‐based studies. Unlike most other JEMs, FINJEM was designed to contain definitions, inferences, exposure data, and references. This documentation enables FINJEM to be applied also as a general exposure information system for hazard control, risk quantification and hazard surveillance. The system includes, e.g., workforce data, and it provides information on the numbers of exposed workers in Finland by agent, occupation, and level of exposure. The exposures of FINJEM cover major physical, chemical, microbiological, ergonomic, and psychosocial factors. The assessment period is 1945–1997, divided into several subperiods. Exposure is described by the prevalence of exposure and the level of exposure among the exposed, both estimated mainly on continuous scales. The user may also define the final criteria of exposure, and thereby influence the magnitude of misclassification. Am. J. Ind. Med. 33:409–417, 1998. © 1998 Wiley‐Liss, Inc.

The interpretation of reports of clusters of childhood leukaemia is difficult, first because little is known about the causes of the disease, and second because there is insufficient information on whether cases show a generalized tendency to cluster geographically. The EUROCLUS project is a European collaborative study whose primary objective is to determine whether the residence locations of cases at diagnosis show a general tendency towards spatial clustering. The second objective is to interpret any patterns observed and, in particular, to see if clustering can be explained in terms of either infectious agents or environmental hazards as aetiological agents. The spatial distribution of 13351 cases of childhood leukaemia diagnosed in 17 countries between 1980 and 1989 has been analysed using the Potthoff-Whittinghill method. The overall results show statistically significant evidence of clustering of total childhood leukaemia within small census areas (P=0.03) but the magnitude of the clustering is small (extra-Poisson component of variance (%) = 1.7 with 90% confidence interval 0.2-3.1). The clustering is most marked in areas that have intermediate population density (150-499 persons km[-2]). It cannot be attributed to any specific age group at diagnosis or cell type and involves spatial aggregation of cases of different ages and cell types. The results indicate that intense clusters are a rare phenomenon that merit careful investigation, although aetiological insights are more likely to come from investigation of large numbers of cases. We present a method for detecting clustering that is simple and readily available to cancer registries and similar groups.

The EUROCLUS project included information on residence at diagnosis for 13351 cases of childhood leukaemia diagnosed in the period 1980-89 in defined geographical regions in 17 countries. A formal algorithm permits identification of small census areas as containing case excesses. The present analysis examines spatial-temporal patterns of the cases (n = 970) within these clustered areas. The objectives were, first, to compare these results with those from an analysis conducted for UK data for the period 1966-83, and, second, to extend them to consider infant leukaemias. A modification of the Knox test investigates, within the small areas, temporal overlap between cases in a subgroup of interest at a putative critical time and all other cases at any time between birth and diagnosis. Critical times were specified in advance as follows: for cases of acute lymphoblastic leukaemia aged 2-4 years, the 18-month period preceding diagnosis; for cases of total leukaemia aged 5-14 years, 1 year before to 1 year after birth; and for infant cases (diagnosed < 1 year), 1 year before to 6 months after birth. Each of the analyses found evidence of excess space-time overlap compared with that expected; these were 10% (P = 0.005), 15% (P= 0.0002) and 26% (P= 0.03) respectively. The results are interpreted in terms of an infectious origin of childhood leukaemia.

Background: Long-term oral 8-methoxypsoralen (8-MOP) and UVA (PUVA) therapy increases the risk of nonmelanoma skin cancer and possibly also of cutaneous malignant melanoma. Topical application of 8-MOP PUVA induces malignant tumors in rodent skin, but little is known about its carcinogenicity in human skin. Objective: Our purpose was to investigate the carcinogenicity of 8-MOP bath PUVA in humans. Methods: This was a cohort study of 158 patients with psoriasis, for whom 8-MOP bath PUVA had been initiated during 1979 to 1992. The average number of 8-MOP bath PUVA treatments was 36 (range, 6 to 204) and the mean cumulative UVA dose was 92 J/cm^2 (range, 3 to 884 J/cm^2) by the end of 1995. The patients were not treated with any other forms of PUVA. Cancer incidence subsequent to 8-MOP bath PUVA up to the end of 1995 was determined by linking the cohort with the records of the Finnish Cancer Registry. The standardized incidence ratios (SIR) were calculated for skin cancer and some common internal cancers, using the expected numbers of cases based on the regional cancer incidence rates. Results: There was one case of basal cell carcinoma, but no cases of other types of skin cancer. A total of 6 noncutaneous cancers were observed (SIR, 1.3; 95% confidence interval, 0.5 to 2.8). Conclusion: No association between cutaneous cancer and 8-MOP bath PUVA was found, but the statistical power of this study alone is not adequate to warrant definite conclusions. The results can be used in a meta-analysis as soon as other studies on the carcinogenicity of 8-MOP bath PUVA are published.(J Am Acad Dermatol 1999;40:694-6.)

Air pollutants arising from traffic clustering and industrial production include a number of chemical compounds that at high doses are carcinogenic in animal models and in some instances also in humans. Direct epidemiological evidence for a carcinogenic effect of air pollution in humans is, however, weak, and most of the available studies are limited by lack of adequate control of confounding factors and other methodological drawbacks. Limited evidence exists for a link between urban air pollution and lung cancer, with reported relative risks of 1.0–1.5. About one‐third of the population of the Nordic countries, corresponding to 7.3 million people, lives in urban areas. If there is an excess risk associated with air pollution, the annual number of lung cancer cases around the year 2000 in the Nordic countries would range from 0 (no excess risk) to 1,800 (relative risk, 1.5). As the existence of a causal link between air pollution and cancer is not uncorroborated, measures for avoiding cancer from this source cannot be recommended.

Several epidemiological studies suggested a correlation between occupational exposure to electromagnetic fields and cancer (leukemia, brain tumors). Also, living close to high voltage powerlines has been reported to be associated with increased risk of cancer. Our studies with chick embryos suggested that low-frequency magnetic fields (LFMFs) had an adverse effect on embryonal development (1). The effects of LFMFs on growth and cell division could be the basis of both teratogenic effects and promotion of cancer.