Risk of cancer of the breast after legal abortion during first trimester: a Swedish register study

An increase in induced abortions in Sweden has been accompanied by an increase in the incidence of breast cancer of about 40% in women aged 20-44. To assess whether the apparent risk is real the risk of breast cancer was investigated in practically all Swedish women with a history of a legal abortion in the first trimester before the age of 30 during 1966-74 (n = 49,000). The cohort was followed up in the Swedish cancer register to identify cases of breast cancer diagnosed more than five years after the abortion until the end of 1984. The number of observed cases of breast cancer was 65 compared with an expected number of 84.5, estimated from the contemporary Swedish population with due consideration to age, giving a relative risk of 0.8 (95% confidence interval 0.58 to 0.99). Contrary to most earlier reports, this study did not indicate any overall increased risk of breast cancer after an induced abortion in the first trimester in young women.

Risk of cancer in pesticide applicators in Swedish agriculture

The risk of cancer was analysed in a cohort of 20,245 licensed pesticide applicators in agriculture who had licences issued between 1965 and 1976. Most were men (99%) and about 50% had been born in 1935 or later. The cohort was followed up in the Swedish Cancer Register from date of licence until death or 31 December 1982. The mean follow up time was 12.2 years. Average time since first exposure was longer, however, since one fifth of the cohort was exposed in the 1950s. A total of 558 malignant tumours was found compared with 649.8 expected, which resulted in a statistically significantly decreased standardised incidence ratio (SIR) of 0.86 (95% confidence interval (CI): 0.79-0.93). Significantly decreased risks of cancer were also found for liver (SIR = 0.45, 95% CI: 0.18-0.93), pancreas (SIR = 0.50, 95% CI: 0.26-0.87), lung (SIR = 0.50, 95% CI: 0.35-0.68), and kidney (SIR = 0.53, 95% CI: 0.32-0.84). No statistically significantly increased risks or any time trends were observed. SIR for testicular cancer was increased (SIR = 1.55, 95% CI: 0.92-2.45) and increased with period since licence. Eighteen cases with testicular cancer were found. For those born in 1935 or later a non-significant increased overall risk of cancer was observed (SIR = 1.07, 95% CI: 0.82-1.37). Comparisons were made with agricultural workers in general since pesticide applicators are mainly farmers that use or have used pesticides to a greater extent. Higher risks for pesticide applicators were found for testicular cancer, tumours of the nervous system and endocrine glands, and Hodgkin's disease.

Additional value of fine-needle aspiration biopsy in a mammographic screening trial

The Stockholm breast cancer screening trial used single-view mammography as the sole screening method. A majority (63 per cent) of the mammographic selected cases from the first two screening rounds had uncertain mammograms, coded as 3 on an ordinal scale from 1 to 5, where 1 and 2 are dismissed as normal mammograms and 5 stands for a typical cancer. In this group of uncertain mammograms 30 cases were malignant and 431 were non-malignant. The aim of this study was to examine whether surgical biopsy in this group could be replaced by fine-needle aspiration (FNA) biopsy, combined with the information from the mammogram and clinical examination, and whether this diagnostic strategy could select the malignant cases with a high sensitivity. FNA biopsy selected 25 of the 30 mammary carcinomas as definite malignancy or atypia, with a sensitivity of 83 per cent (95 per cent confidence interval: 69-96 per cent), and combined with the information from the mammogram and clinical examination 29 of the malignancies were selected with a sensitivity of 97 per cent (95 per cent confidence interval: 83-100 per cent). In 398 of 431 non-malignant cases the diagnosis was established with the triple diagnostic approach without needing a surgical biopsy. In a clinical follow-up study, up to 64 months after the first screening round, only one false negative case was found, included in the group of 30 malignancies described above. With this strategy the rate of negative surgical biopsies was reduced by 90 per cent in the group with uncertain mammograms and without considerably impairing the reliability of the results.

The Stockholm breast cancer screening trial--5-year results and stage at discovery

In screening programmes it is important to assess a preliminary effectiveness of the screening method as soon as possible in order to forecast survival figures. In March 1981 a controlled single-view mammographic screening trial for breast cancer was started in the south of Stockholm. The population invited for screening mammography consisted of 40,000 women aged 40-64 years, and 20,000 women served as a well-defined control group. The main aim of the trial was to determine whether repeated mammographic screening could reduce the mortality in the study population (SP) compared to the control population (CP). The cumulative number of advanced mammary carcinomas in the screening and the control populations from the first five years of screening have shown a tendency towards more favourable stages in the screened population aged 40-64 years. A breakdown by age suggests an effect in age group 50-59 years, but not yet in age groups 40-49 and 60-64 years. When comparing the rates of stage II+ cancer, an increased number is found in the study group. As the total rate of breast cancer is higher in SP than in CP, there ought to be a concealed group of stage II+ cancers in the CP which makes the comparison biased. A new approach has been designed, where an estimation of the 'hidden' number of stage II+ cancers in CP is added to the clinically detected cases, and in this respect a comparison has shown a decrease in the cumulative number of advanced cancers in the SP in relation to the CP (p less than 0.05).(ABSTRACT TRUNCATED AT 250 WORDS)

Time trends in occupational risks of lung cancer among Swedish men from 1961-1979

Using data from the Swedish Cancer-Environment Register, time trends in the standardized incidence ratio (SIR) for lung cancer 1961-1979 were studied in different occupations. After adjustments for differences in the SIR with respect to year of birth, only the decreasing trends for blacksmiths and members of the armed forces as well as increasing trends for foundry workers and construction machine operators were significant (p less than 0.05). For bakers and pastry cooks, there was a significant interaction between year of birth and observation period in relation to SIR. Data on smoking habits, obtained from a sample of the population, did not seem to explain the trends.

The prevalence of cancer in Sweden 1984

A total of 772,492 (99.3%) of all patients with a newly diagnosed malignant disease notified to the National Swedish Cancer Registry during 1958 through 1984 could be followed up with respect to survival or emigration by means of computerized record linkages. The number of cancer patients still alive on December 31, 1984, totalling 194,389, was divided by the appropriate population denominator. The crude prevalence rate in Sweden of individuals who have or have had any cancer was 1,840 per 10(5) in males and 2,808 per 10(5) in females. At ages 40 through 59, the rates in females were 2.2 to 2.5 times higher than those in males, whereas after the age of 75 cancer was more prevalent in males. Prostate cancer was the most common tumour in males, 24.5% of the crude prevalence rate (451 per 10(5), followed by colorectal cancer, cancer of the bladder and malignant melanoma. In females, the breast was the dominating cancer site, accounting for 32.7% (917 per 10(5), followed by cancer of the large bowel, uterine corpus and uterine cervix. We conclude that prevalence rates provide important information about the magnitude of the cancer problem over and above that revealed by incidence and mortality statistics. The high, and probably increasing, prevalence rates over time emphasize that important savings in economic and other resources can be achieved by strictly evaluated and cost-effective regimens for follow-up.

Smoking-adjusted incidence of lung cancer among Swedish men in different occupations

The Swedish Cancer-Environment Register was used to study the relation between occupation and lung cancer risk during the period 1961-79 in 1.6 million men aged 30-64 years in 1960. By adding information concerning smoking habits from a sample of 1% of the Swedish population, smoking-adjusted standardized incidence ratios (SIR) were estimated for different occupational categories according to the population census of 1960. Smoking-adjusted excess risks (p less than 0.01) were found in assemblers and machine erectors, drivers, miners, packers and longshoremen as well as in sheetmetal workers. Significantly fewer lung cancer cases than expected were seen in artists and writers, chemical and cellulose workers, farmers, farm workers, forestry workers, public administrators and in teachers. As a result of a high prevalence of smoking, the smoking-adjusted SIR was markedly lower than the unadjusted SIR in artists and writers, drivers, mechanics and repairmen, members of the armed forces and painters. The opposite situation was seen for clergy, farmers and forestry workers.

Effects of routine one-stage ultrasound screening in pregnancy: a randomised controlled trial

4997 of 7354 pregnant women had no clinical indication for an elective ultrasound examination at 12 weeks' gestation. 2482 of these women were randomly selected for ultrasound screening at 15 weeks and the remainder received the same standard antenatal care without the scan. Labour was less often induced among screened women both for all reasons (5.9% vs 9.1%, p less than 0.0001) and for suspected post-term pregnancy (1.7% vs 3.7%, p less than 0.0001). Earlier detection of twins had no effect on neonatal outcome. Among babies born to screened women, fewer were of birthweight less than 2500 g (59 vs 95, p = 0.005) and mean birthweight was 42 g higher (p 0.008). For babies born to screened women who smoked it was 75 g higher (p 0.012) and for those of non-smokers 26 g (not significant). The reason for the differences in mean birthweight could be that screened women reduced smoking in response to watching their fetus on the scan.

Lung cancer incidence among Swedish bakers and pastrycooks: geographical variation

In a cohort of 14,352 Swedish male bakers and pastrycooks, the standardized incidence ratio (SIR) for lung cancer 1961-79 varied significantly between geographical regions. In the three largest towns, the risk in bakers and pastrycooks was at the same level as in all men. When these three towns were excluded, there was a considerable excess risk, even after adjustment for smoking (SIR = 1.6, CI = 1.2-2.1). The SIR for lung cancer in bakers and pastrycooks were significantly lower in regions where the percentages of employed in big bakeries and confectioneries were high. The result of a case-control study, done within the cohort, suggested a somewhat higher lung cancer risk in bakers compared with pastrycooks. These results support the hypothesis that the excess risk may be due to exposure to carcinogens especially prevalent in small bakeries.

Lung cancer incidence among Swedish bakers and pastrycooks: temporal variation

In a cohort of Swedish bakers and pastrycooks, based on the census of 1960, 188 male lung cancer cases, were reported to the national Cancer Registry 1961-79. The risk of lung cancer exceeded that of all men with 43% (confidence interval 23-65%). After adjustment for smoking habits, using data from a sample of one percent of the Swedish population, the excess risk was reduced. There was a temporal variation in the relative risk, which decreased during the follow-up period in the younger birth cohorts but not in the older ones. Changes in smoking habits did not seem to explain the decreasing trend. The lung cancer risk did not differ significantly between employees and those self-employed in the cohort. To some extent these results confirm earlier findings concerning excess risks of lung cancer in bakers. The lowered risk in Sweden towards the end of the seventies, suggests that the problem is now of less importance.

Bambuterol: clinical effects of different doses of a long-acting bronchodilator prodrug

Sixty-eight asthmatics participated in a dose-finding study on bambuterol, a terbutaline prodrug, administered once every evening. Bambuterol administrations of 0.185, 0.270 and 0.400 mg/kg gave effective and long-lasting bronchodilation, for at least 24 h, with the two higher doses probably close to the maximal effect of the drug. Bambuterol 0.400 mg/kg was associated with more adverse effects than bambuterol 0.185 mg/kg. The side effects were those expected in oral beta 2-agonist treatment and mainly experienced by patients who had not been on oral beta 2-agonists before. The most favourable of the investigated doses was found to be 0.270 mg/kg. It can not be excluded, however, that a somewhat lower dose may still be as beneficial. This will be investigated in forthcoming studies.

Obstetric pain medication and eventual adult amphetamine addiction in offspring

Our purpose was to investigate whether obstetric analgesia, particularly by nitrous oxide, constitutes a risk that the infant might develop amphetamine addiction in later life. Of 200 current amphetamine addicts born between 1945 and 1966 in Stockholm, proportionately more were born at hospitals where pain medication had been administered in large doses (p less than 0.05). A blind matched comparison was made between 73 addicts and 109 non-addicted siblings by logistic regression, in which nitrous oxide administration was tested in competition with 12 other natal variables as possible confounders. The risk for amphetamine drug addiction in offspring was found to increase with duration of intermittent administration of pure nitrous oxide, i.e. it was estimated to be 5.6 times greater (95% confidence intervals 1.6-16.9, p = 0.005) when nitrous oxide had been given for greater than or equal to 4.5 h vis-à-vis less than or equal to 0.25 h. Calculated risks are probably underestimates. Results can be explained as an effect of imprinting. It is concluded that local or regional anesthesia are preferable to general anesthesia which allows substantial amounts of drugs to cross the placenta.

Solid tumours and chromosome aberrations as late side effects of melphalan therapy in ovarian carcinoma

Fifty-five ovarian cancer patients treated with melphalan during 1968-1978 were followed during 309 person years and studied with cytogenetic analyses. During the clinical follow-up 7 patients developed a new primary solid tumour. The excess risk of developing new primary solid tumours in patients treated with melphalan was statistically significant (p less than 0.05) and the relative risk corresponded to 3.0. Patients developing a new solid tumour showed a similar pattern of chromosome aberrations in the peripheral lymphocytes to that previously shown for the whole cohort.

Smoking and the increased risk of contracting spontaneous pneumothorax

The relation between smoking habits and the occurrence of spontaneous pneumothorax (SP) was studied in a Swedish population, predominantly urban. The study group consisted of a consecutive series of 138 patients admitted to Huddinge University Hospital over ten years for treatment of their first spontaneous pneumothorax. Their smoking habits were routinely analyzed. The sample consisted of 15,204 persons domiciled in the same circumscribed area (County of Stockholm). The annual incidence of first SP in the admission area is 6/100,000 for women and 18/100,000 for men. The study showed that smoking increased the relative risk of contracting a first spontaneous pneumothorax approximately ninefold among women and 22-fold among men and that there is a striking, statistically significant (p less than 0.001) dose-response relationship between smoking and the occurrence of SP. The life span risk of contracting SP among lifelong heavily smoking men is roughly estimated to be 12 percent but only 1/1,000 among never smokers.

Photosensitive psoriasis. An epidemiologic study

In this study of photosensitivity among psoriasis patients, a questionnaire was mailed to 2000 psoriasis patients living within the service area of Karolinska Hospital, Stockholm. Of the 88% patients who replied, 4.4% stated that their psoriasis always worsened after sun exposure, and 7.3% stated that this was sometimes so. After telephone interviews with an 80% sample of these allegedly photosensitive patients, half of them were considered nonphotosensitive. Thus an estimated prevalence of 5.5% photosensitivity was obtained. Forty-three percent of the light-sensitive patients had a history of polymorphous light eruption with secondary exacerbation of psoriasis lesions. Comparison between the photosensitive and the nonphotosensitive patients concerning background factors and symptoms showed a statistically significant increase (p less than or equal to 0.001) in the photosensitive group concerning skin type I, psoriasis affecting hands, heredity for photosensitivity, and advanced age.

Analysis of interval breast carcinomas in a randomized screening trial in Stockholm

In the interval between screening examinations, some cases of breast cancer are invariably detected clinically in patients whose mammogram was considered to be normal at the earlier screening. During the first interval in the Stockholm study, 60 interval cancers were detected, giving a rate of 1.8 cases/1000 examinations/24 months. About half of these interval cases (31/60) were true interval tumours in that no sign of them could be found on the first mammogram; the other half, non-true, were possible to trace on the first mammogram. It is mainly women under 50 who feature in the interval group, above all in the sub-group of true interval cancers (p less than 0.05). The incidence of interval cancer rises, as expected, with the length of the interval (Fig. 1). In the final six months of the 2-year interval the incidence of interval cancers had risen to 88 per cent of the cancers detected in the control group in the same period of time. The cumulative incidence of interval cancers supports the hypothesis that the distribution of sojourn time in the interval 0-2 years is approximately rectangular. This means that shortening the interval by one-half would halve the number of interval cases. If mammography becomes a wide spread screening method for early detection of breast cancer, the number of non-true interval cancers could be a feed back on the effectiveness of the screening.(ABSTRACT TRUNCATED AT 250 WORDS)

Perinatal origin of adult self-destructive behavior

The study was undertaken to test whether obstetric procedures are of importance for eventual adult behavior of the newborn, as ecological data from the United States seem to indicate. Birth record data were gathered for 412 forensic victims comprising suicides, alcoholics and drug addicts born in Stockholm after 1940, and who died there in 1978-1984. The births of the victims were unevenly distributed among six hospitals. Comparison with 2,901 controls, and mutual comparison of categories, showed that suicides involving asphyxiation were closely associated with asphyxia at birth, suicides by violent mechanical means were associated with mechanical birth trauma and drug addiction was associated with opiate and/or barbiturate administration to mothers during labor. Irrespective of the mechanism transferring the birth trauma to adulthood--which might be analogous to imprinting--the results show that obstetric procedures should be carefully evaluated and possibly modified to prevent eventual self-destructive behavior.

Increased risk of developing acute leukemia after employment as a painter

A case-control interview study of 125 adult patients with acute leukemia and 125 controls matched with respect to age (+/- four years), sex, and residence was carried out in central Sweden during the period from September 1980 to May 1983. Their history of organic solvent exposure is described. A significant overrisk of developing acute leukemia was found when comparison between patients and controls revealed a difference in the solvent exposure rate, which was significantly higher in patients than in controls, with an estimated odds ratio (OR) of 4.9, 95% CI (2.2 to 12.1). The most frequently exposed profession, painters, exhibit a relative risk of 13 (2.0 to 554). These results suggest that an etiologic relationship exists between organic solvent exposure and the development of acute leukemia in man.

S-phase rate as a predictor of early recurrences in carcinoma of the uterine cervix

Flow cytometric measurements of ploidy level and S-phase rate were performed in a prospective study of 165 patients with cervical squamous cell carcinoma. Patients were followed-up for 24 months after initial treatment. There was no significant difference in recurrence rate between patients with peri-diploid tumors (1.8c-2.2c) and aneuploid tumors. The S-phase rate (evaluable in 133 cases), which previously has been studied only occasionally in cervical carcinomas, was correlated with early relapses. Significantly more relapses were found in tumors with S-phase rates greater than or equal to 20% than among tumors with S-phase rates less than 20% (chi 2 = 9.54, p less than 0.01). A higher relapse rate among tumors with S-phase rates greater than or equal to 20% was found even after taking staging into consideration (Cochran-Mantel-Haenszel test, p less than 0.01). Thus, besides staging, evaluation of the S-phase rate yielded additional prognostic information.

Mortality in relation to cigarette and pipe smoking: 16 years' observation of 25,000 Swedish men

In a random sample of 25,129 Swedish men who responded to a questionnaire on smoking habits in 1963 the cause specific mortality was followed through 1979. In the cohort, 32% smoked cigarettes, 27% a pipe, and 5% cigars. There were clear covariations (p less than 0.001) between the amount of tobacco smoked and the risk of death due to cancer of the oral cavity and larynx, oesophagus, liver, pancreas, lung, and bladder as well as due to bronchitis and emphysema, ischaemic heart disease, aortic aneurysm, and peptic ulcer. Pipe smokers showed similar risk levels to cigarette smokers. There was a close to linear increase in lung cancer risk in relation to the amount of tobacco smoked for cigarette, pipe, and cigar smokers, respectively. An increasing risk of ischaemic heart disease with amount smoked was seen among both cigarette and pipe smokers. A similar fraction of inhalers in Swedish cigarette and pipe smokers may explain the similarity in risks.

Indoor exposure to radon from the ground and bronchial cancer in women

A case-referent study on the possible association between radon emanating from the ground and bronchial cancer was carried out on 292 female lung cancer cases and 584 matched population referents. Both groups had lived for at least 30 years in the city of Stockholm, Sweden. The cases were diagnosed during 1972 to 1980 with oat-cell and other types of anaplastic pulmonary carcinomas. A sample of about 10% of the dwellings where cases and referents had lived was selected for measurements of radon and radon daughters. There was a relative risk of 2.2 (P = 0.01) for lung cancer associated with living in dwellings close to the ground in areas with an increased risk of radon emanation. Smoking habits did not appear to be a major confounding factor for this association, although a detailed evaluation was not possible. The measurements indicated increased radon daughter concentrations in ground level dwellings within radon risk areas where lung cancer cases had lived, suggesting that this exposure was of etiologic importance.

Incidence of malignant skin tumors in 14,140 patients after grenz-ray treatment for benign skin disorders

During the years 1949 to 1975, 14,237 patients received therapeutic doses of grenz rays for the treatment of benign skin disorders such as chronic eczema, psoriasis, and warts. The records of 14,140 of these patients (99.3%) formed the basis for an epidemiologic study of the incidence of skin malignancies in this population. Information about the patients, diagnoses, doses, and sites of treatment was obtained from separate records. The follow-up time was 15 years on the average. We searched the Swedish Cancer Registry, Stockholm, for records reporting the incidence of malignant skin tumors in the study population (incidences of basal cell carcinoma are not registered). The expected number of malignancies was calculated on the basis of age- and sex-standardized incidence data from the Swedish Cancer Registry. In 58 patients, a malignant skin tumor was diagnosed more than five years after grenz-ray therapy had first been administered. Nineteen patients had malignant melanomas, and 39 patients had other malignant skin tumors. The expected number of melanomas was 17.8, and that of other malignant skin tumors was 26.9. None of the patients with melanomas, and only eight of the patients with other malignant skin tumors, had received grenz-ray therapy at the site of the tumor. Six of these eight patients had also been exposed to other known carcinogens. Four hundred eighty-one patients had received an accumulated high dose of grenz rays (greater than or equal to 10 000 rad [greater than or equal to 100 Gy]) on one and the same area. No malignancies were found on those areas. Although we cannot exclude grenz-ray therapy as a risk factor in the development of nonmelanoma skin malignancies, this risk, if any, is small, if recommendations for therapy are followed.

Measures of continuity of care. A register-based correlation study

In an empirical study using data from a health center in Sweden, correlation coefficients were computed among nine different measures of continuity of care, five of them visit-based and four individual-based. Generally, the correlations were high. This may be due, in part, to the similar behavior of the measures for people making few visits. The correlations were also quite high, however, when the sample was restricted to people with many visits. Several measures display a significant dependence on utilization level. The results suggest that, for general purposes, the measure COC should be preferred among the individual-based measures and fraction-of-care continuity among the visit-based measures. On grounds of flexibility and ease of interpretation, the authors recommend fraction-of-care measures.