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M Thörn

Publications and source records attributed to M Thörn.

At least 37 records · Page 2Linked to original sources
PubMed1998

Rapid increase in diagnosis of cutaneous melanoma in situ in Sweden, 1968-1992.

We analyzed incidence trends of cutaneous melanoma in situ in Sweden in 1968-1992. Among men, age-standardized rates increased from 0.1/100,000 in 1968 to 2.9/100,000 in 1992, which corresponds to an average annual increase of 15.0%. Among women, rates increased from 0.3 to 3.7, and the annual increase was 12.8%. Age-specific rates increased since 1978, predominantly in men aged 45 years and older, whereas in women rates increased in all ages. Multivariate analysis showed that incidence rates could be explained by both cohort effects and period effects in addition to age. However, cohort effects seemed more important among men than among women, in whom period effects dominated. Thus, factors associated with the development of melanoma in situ may differ between the sexes. Melanoma in situ is an immediate precursor of invasive melanoma, and the increased detection and surgical excision of these tumors will prevent the occurrence of invasive melanoma.

Adolescent↗
PubMed1997

Trends in urinary bladder cancer incidence in Sweden 1960-93 with special reference to histopathology, time period, birth cohort, and smoking.

This study investigates the incidence trends of urinary bladder cancer in Sweden from 1960 through 1993 (a total of 46,211 cases). Age-standardized incidence rates increased among men from 14.6 per 10(5) in 1960 to 33.5 in 1993 and among women from 4.8 to 8.8, corresponding to an average annual increase of 2.4 percent (95 percent confidence interval [CI]) = 2.0-2.7 percent) and 1.1 percent (CI = 0.9-1.4 percent), respectively. The largest increase occurred in the oldest age-groups. The proportion of patients with transitional cell carcinoma increased in men from 66.0 percent in 1960-64 to 93.6 percent in 1990-93 and in women from 61.0 percent to 89.4 percent. The proportion of patients with papillomas decreased, whereas those with adenocarcinoma and squamous cell carcinoma were stable. Regression modeling (based on the period 1960-89) showed a strong linear effect due to either period and/or cohort. Among men, additional non-linear effects by both period and cohort were obtained. The cohort effects were more important. Cohort data on having smoked daily showed considerable similarities with the estimated cohort-effects. Our findings suggest that the increase of tobacco smoking in successive generations can explain the increase in incidence rates of bladder cancer in Sweden, whereas improved diagnostic activities and registration are less likely to explain fully the changes in incidence rates.

Adult↗
PubMed1996

Predictors of late mortality in cutaneous malignant melanoma--a population-based study in Sweden.

We determined risk factors for late deaths from cutaneous malignant melanoma (CMM) based on clinical characteristics at diagnosis, initial surgical treatment, histopathologic features of the primary tumor and type of eventual recurrences during follow-up. We examined deaths from CMM 8 or more completed years after the initial diagnosis in a case-control study nested in a nationwide cohort comprising all 8,838 patients with CMM diagnosed in Sweden during 1960-1978 with complete follow-up through 1986. There were 285 case patients and 285 control patients, individually matched by sex, age and follow-up time. Conditional logistic regression was used to obtain odds ratios (OR) as estimates of the relative risk. The risk of late mortality increased stepwise, almost 19-fold, with increasing tumor thickness from < or = 0.75 to > or = 7.00 mm. Besides the thickest tumors (> or = 7.00 mm), those of intermediate thickness (1.50-2.49 mm) had the highest risk (OR 8.5). After adjustment for tumor thickness, non-radical primary surgical treatment increased the risk of late mortality almost 3-fold while prophylactic lymph node dissection entailed a significantly reduced risk of late mortality (OR 0.5); the histopathologic features increasing level of invasion and vertical growth phase also remained significantly associated with a poor outcome. In a multivariate model, non-radical primary surgical treatment, prophylactic lymph node dissection, vertical growth phase, level of invasion and lymphocyte reaction were independent predictors of late mortality.

Adult↗
PubMed1996

Second primary cancers in patients with cutaneous malignant melanoma: a population-based study in Sweden.

To quantify the risk of second primary cancers among patients with cutaneous malignant melanoma, we studied 20,354 patients in the Swedish Cancer Register during 1958-88. A second primary cancer was reported in 1605 patients, compared with an expected number of 1109.5 [standardised incidence ratio (SIR) = 1.45, 95% confidence interval (CI) = 1.38-1.52]. The highest risk was found among patients younger than 60 years. The greatest risk was seen during the first year after diagnosis (SIR = 1.91, CI = 1.69-2.14), but even after long-term follow-up--15 years or more--the risk was still significantly elevated (SIR = 1.56, CI = 1.35-1.79). The strongest association was found for a second primary malignant melanoma (men, SIR = 10.0, CI = 8.26-12.00; women, SIR = 8.66, CI = 7.22-10.30) and non-melanoma skin cancer (men, SIR = 3.58, CI = 2.85-4.44; women, SIR = 2.41, CI = 1.71-3.29). The risk of second cancers associated with tissues of neuroectodermal origin was increased, especially tumours of the nervous system (men, SIR = 1.73, CI = 1.10-2.60; women, SIR = 2.03, CI = 1.45-2.78). The SIR of second cancers involving the immune system was also increased. An excess risk of endometrial cancer was seen (SIR = 1.41, CI = 1.03-1.88), but no significant associations existed for cancers of the breast, ovary, testis or other endocrine glands. Among tumours of the digestive tract, only colon cancer in men had a significantly increased SIR (1.33, CI = 1.00-1.74).

Age Factors↗
PubMed1996

The accuracy of skin self-examination for atypical nevi.

We conducted a validation study to assess laypersons' ability to self-report atypical nevi. Study subjects were drawn from a large population-based cohort of middle-aged Swedish women who had responded to a previous health survey. The health survey questionnaire included color photographs of atypical nevi. Respondents were asked to examine their lower extremities for similar lesions. We invited 500 survey respondents to participate in a physician-conducted skin examination; 400 (80%) subjects agreed. We compared the results of skin self-examination for atypical nevi to the results of the physician-conducted skin examination. Using methods developed for this study, we estimated sensitivity as 29% and specificity as 85%. Positive predictive value was 20%; negative predictive value was 90%. We estimated that 12% of Swedish women have atypical nevi on the lower extremities. Although these findings suggest poor accuracy of skin self-examination for atypical nevi, our results may have been adversely affected by limiting self-examination to the legs and by the severity of atypical nevi shown in the comparison photographs used by survey respondents.

Adult↗
PubMed1996

Malignant melanoma: reduced risk associated with early childbearing and multiparity.

Pigmentary changes during pregnancy and sex-specific differences in incidence patterns of cutaneous malignant melanoma (CMM) suggest that sex hormones may be involved in the development of CMM. We explored possible associations between childbearing and the risk of CMM in a case-control study "nested' in a nation-wide cohort. A total of 4,779 incident cases of CMM in women aged 24-65 were compared with 23,888 individually age-matched controls. Delayed childbearing was associated with an increased risk of CMM, corresponding to approximately 16% per 5 years. Parous women had a significantly lower risk of CMM compared with nulliparous women; in univariate analysis there was an 8% reduction in risk for each additional birth (odds ratio = 0.92; 95% confidence interval = 0.89-0.95). In multivariate analyses the risk of CMM was best explained by a model including both age at first birth and parity. Age at first birth was the most important variable. Time since most recent birth was unrelated to risk of CMM. These findings indicate that early childbearing and multiparity reduce the risk of CMM. Conceivable explanations are hormonal changes induced by childbearing, enhanced immunologic activity via exposure to fetal antigens during pregnancy, or long-lasting effects of pregnancy-associated hyperpigmentation. Our results need confirmation in studies with proper adjustment for confounding; less sun exposure in young mothers and high parity women may represent an alternative explanation but is unlikely to explain entirely the twofold difference in risk found between extreme categories of age at first birth and parity.

Adult↗
PubMed1994

Clinical and histopathologic predictors of survival in patients with malignant melanoma: a population-based study in Sweden.

BACKGROUND: Previous malignant melanoma studies regarding prognostic factors have often selected their patients from hospitals. Unfortunately, most of these studies have had small numbers of patients, consisted of short-term data sets, omitted important factors, did not optimize histopathologic classification, had too short or inadequate follow-up, and did not test their predictive models. PURPOSE: Our study goals were to identify independent clinical and histopathologic determinants of survival in malignant melanoma, to analyze changes in prognostic value over follow-up time, and, finally to construct a prognostic index. METHODS: A random sample from the Swedish Cancer Registry of the records of 498 (246 men and 252 women) patients defined by gender, five 5-year time periods of diagnosis from 1960 through 1984, and five anatomic sites formed the cohort on whom data were analyzed by univariate analyses. Multivariate analyses were based on data on 476 patients with complete information about all variables. All patients in the cohort had complete follow-up through December 31, 1989. Clinical information was abstracted and recorded as: date of diagnosis, stage at diagnosis, sex, age, anatomic site of primary tumor, date of death, and cause of death. Histopathologic slides were re-examined and classified with regard to histogenetic type, level of invasion, tumor thickness, ulceration, vascular invasion, regression, lymphocytic reaction, pre-existing nevus, and cell type. RESULTS: All variables, except pre-existing nevus and cell type, were significant predictors of survival. In the multivariate analyses including all variables, women still had a significant, 33% lower relative hazard than men. The prognosis was poor in the youngest age group. Patients with external ear, scalp-neck, and trunk-located melanoma had increasing relative hazard when all variables were included. Regional metastases and tumor thickness remained independent prognostic factors. No significant association between histogenetic type or level of invasion persisted. Patients whose tumors showed ulceration or vascular invasion had lower relative hazard when all variables were included. Level of invasion, tumor thickness, ulceration, and vascular invasion were significantly associated with the prognosis during both short- and long-term follow-up. The patients were subgrouped according to percentage fractions of their score on the prognostic index. Survival curves for these groups of patients were well separated, thus identifying patients with a low or high risk of death from malignant melanoma. CONCLUSION: The present population-based study identifies independent clinical and histopathologic predictors of survival in cutaneous malignant melanoma and emphasizes the role of histopathologic characteristics such as tumor thickness, ulceration, and vascular invasion besides anatomic site.

Adult↗
PubMed1994

Methodological aspects on measurements of temporal trends in melanoma survival.

We compared measurements of temporal trends in cancer survival either based on observed survival or relative survival. Survival rates for cutaneous malignant melanoma diagnosed in Sweden 1960-1982 were used as an example. In a proportional hazards model based on observed survival, the hazard ratio for patients diagnosed during the period 1975-1979 was 0.56 (95% confidence limits 0.49-0.64) in men and 0.45 (0.38-0.53) in women when the period 1960-1964 was the reference. When relative survival was the outcome measure, during the same period, the hazard ratio decreased to 0.47 (0.39-0.56) in men and 0.36 (0.29-0.44) in women. Thus, the effect of period of diagnosis was larger when the analysis was based on relative survival rates. The reasons for the differences between these two alternative measurements are explained in the article and advantages/disadvantages of the two approaches are discussed.

Adult↗
PubMed1994

Trends in tumour characteristics and survival of malignant melanoma 1960-84: a population-based study in Sweden.

In Sweden, improvement in survival rates of patients with cutaneous malignant melanoma has counteracted the increase in incidence to produce a moderate rise in mortality. Our aim was to determine the possible impact of drift in diagnostic criteria, earlier diagnosis and changing biological features of the tumours upon trends in survival. We studied a stratified sample of 528 patients diagnosed between 1960 and 1984 in a strictly defined geographical region. No evidence of drift in diagnostic criteria was found. The proportion of patients with invasion level Clark II increased from 3.2% in 1960-64 to 22.5% in 1980-84, the proportion of thin melanomas (< or = 0.75 mm) increased from 9.4% to 31.5% and the tumour thickness decreased significantly between each 5 year period of diagnosis. These changes are most likely the results of earlier diagnosis. However, changes in tumour characteristics have occurred, since the proportion of superficially spreading malignant melanoma increased from 35% in 1960-64 to 51% in 1980-84 and the proportion of acral lentiginous melanoma decreased from 11% to 2%. The proportion of nodular melanomas remained fairly constant. The proportion of tumours with lymphocytic reaction did not change, whereas those with histological regression increased slightly. Proportional hazards analyses showed a significantly lower survival in patients diagnosed in 1960-64 but no apparent trend after 1965. This finding remained after adjustment for all studied clinical and histopathological factors which point towards changes in unmeasured biological features of the disease.

Cohort Studies↗
PubMed1993

Increasing survival of patients with urinary bladder cancer. A nationwide study in Sweden 1960-1986.

Survival rates were analysed in 29,055 patients with urinary bladder cancer diagnosed in Sweden from 1960 to 1986 and followed up until 1987. The 2-, 5- and 10-year relative survival rates were 79, 70 and 64% for men and 75, 68 and 63% for women, respectively. Patients with a history of bladder cancer for at least 15 years ran a negligible risk of dying from their disease. Prognosis was consistently better in younger than in older patients; below 50 years of age the 5-year relative survival rate was 90%, as compared with 60% in patients aged 70-79 years. Patients diagnosed between 1960 and 1964 had a 60% 5-year relative survival, as compared to 71% in those diagnosed between 1980 and 1984. Multivariate analyses further confirmed that age but not sex is an important prognostic factor in bladder cancer and, further, that a substantial improvement in survival rates took place during the 1960-1986 period. Compared with 1960-1964 the risk of dying of bladder cancer within 5 years in patients diagnosed between 1980 and 1984 was 51% lower in men [relative risk (RR) = 0.49; 95% confidence interval (C.I.) 0.42-0.57] and 44% lower in women (RR = 0.56; 95% C.I. 0.45-0.70).

Age Distribution↗
PubMed1993

Trends in breast cancer incidence in Sweden 1958-1988 by time period and birth cohort.

Statistics from the Swedish National Cancer Registry based on all 110,658 cases of invasive breast cancer during the 31-year period 1958-1988 were analysed. Age-specific incidence rates increased over successive calendar periods. The average annual increase in the age-standardised incidence rate was 1.3%, with the greatest percentage changes among the youngest age groups. During the latter half of the study period, the rates of increase tended to diminish in the youngest age groups and even reversed significantly among women from 75 years of age. In analyses using age-period-cohort models, the best fit of the cancer incidence data was found for the full model which simultaneously considered the effects of age, period and cohort. Cohort effects were found to be more important than period effects, in terms of model fit. These effects emerged as a seemingly consistent, and in a logarithmic scale, fairly linear increase in the relative risk of breast cancer incidence with a 3-fold elevation in women born in the 1950's relative to those born in the 1880's. It is concluded that the rising breast cancer incidence in Sweden is explained chiefly by birth cohort effects, which indicate persistent secular changes in largely unknown risk factors associated with life style. We could not in the present data see any clear evidence for an adverse effect of contraceptive or replacement sex steroids on breast cancer incidence.

Adult↗
PubMed1992

Trends in mortality rates from malignant melanoma in Sweden 1953-1987 and forecasts up to 2007.

To monitor mortality rates from malignant melanoma we analysed all patients in Sweden (6,324) who died of malignant melanoma in 1953 through 1987. Age-standardised rates per 10(5) increased from 1.1 to 4.0 in men and from 1.0 to 2.6 in women. The average annual increase levelled off in men from 4.6% during 1953-1967 to 2.0% in 1978-1987; and in women from 3.7% to 0%. Multivariate analyses showed that the change in rates for men was mainly due to a birth-cohort effect, whereas in women the rates changed similarly in all age-groups in accordance with a time-period effect. The risk of dying of malignant melanoma increased in men for birth cohorts up to 1932, whereas in women the rise continued for cohorts born as late as 1947. The best-fitted multivariate models were extrapolated to the year 2007, among men a slight increase in mortality rates seemed likely, whereas among women the rates will probably remain unchanged.

Adult↗
PubMed1991

Early detection and prevention of cutaneous malignant melanoma: emphasis on Swedish activities.

The incidence of cutaneous malignant melanoma has increased more than the incidence of any other malignant tumour disease in Sweden the last three decades. Parallel to the almost 6% annual increase in incidence there has been a 3% annual increase in mortality. The knowledge of significant risk factors for melanoma (intermittent sun exposure and phenotypic traits related to skin pigmentation and propensity for dysplastic nevi) as well as the relationship between thin tumours and a good prognosis has been used to develop strategies for primary and secondary prevention. In this paper the Swedish programs for education of physicians, nurses and the general population are presented. A nationwide program for the identification and follow-up of individuals with dysplastic nevus syndrome has been initiated. The effects of the programs are followed by population-based melanoma registries.

Humans↗
PubMed1990

Trends in the incidence of malignant melanoma in Sweden, by anatomic site, 1960-1984.

This study was based on 15,376 patients in Sweden with cutaneous malignant melanoma diagnosed during the 25-year period 1960-1984. Trunk melanoma increased substantially during that period among men, with age-standardized rates rising from 1.1 to 7.0 per 10(5). Among women, the greatest increases occurred in melanoma of the upper extremity (rising from 0.4 to 2.3), lower extremity (rising from 1.6 to 4.4), and trunk (rising form 0.6 to 3.1), but the rates for the latter two sites seemed to level off after 1978. Multivariate analyses showed that models based on a common parameter ("drift"), including linear birth cohort and/or time periods effects, were significantly superior to simple age models for explaining incidence trends for each separate site. Further, in men with melanoma of the trunk and upper and lower extremities, birth cohort effects had significant effects compared with drift. In contrast, in women, time period effects were a significant improvement on drift for melanoma of the trunk and lower extremity. The relative risk of malignant melanoma among men leveled off in later-born cohorts for all separate sites. A similar trend was found in women, except for melanomas of the trunk, in which the increase in relative risk persisted. The results indicate sex-specific differences in temporal trends of exposure to factors causing malignant melanoma.

Adult↗
PubMed1989

Trends in survival from malignant melanoma: remarkable improvement in 23 years.

Trends in incidence of and mortality and survival from malignant melanoma in Sweden for 1960 through 1982 were analyzed. Incidence rates increased annually by 5.4% for females and by 5.8% for males, whereas mortality rates increased annually by 2.7% for females and 3.3% for males. For females, the 5-year relative survival (RS) rates increased by approximately 15 percentage points before 1970. In contrast, males before 1970 had a successive improvement in RS rates of 4.6-8.2 percentage points for each 5-year period of diagnosis. Multivariate analyses revealed that during the study period the malignant melanoma-specific hazard decreased by 71% [95% confidence interval (CI) = 59%-79%] for females and by 64% (95% CI = 54%-73%) for males during the first 5 years of follow-up.

Aged↗
PubMed1989

The association between anatomic site and survival in malignant melanoma. An analysis of 12,353 cases from the Swedish Cancer Registry.

The relationship between site and survival in cutaneous malignant melanoma was investigated by a follow-up of 12,353 Swedish patients diagnosed in 1960-1982. In males, the poorest prognosis was found for tumors located on the scalp-neck region (5-year relative survival rate, RS51%), followed by the lower extremity (RS66%) and trunk (RS68%). Among females, the poorest prognosis was noted for tumors located on the external ear (5-year RS 71%), trunk (RS 78%) and scalp-neck (RS 78%). The prognosis varied considerably between the sites of the head-neck region--for eyelid and facial lesions the prognosis was good, but for external ear and scalp-neck tumors it was poor. Multivariate analysis taking into account age and year of diagnosis showed the highest relative hazards (RH) for female lesions of the trunk (1.40) and male scalp-neck tumors (1.65), with the upper extremity used as reference (RH = 1.00). Except for lesions of the trunk, no significant differences in RH were found between the various sites after 4 years of observation.

Adult↗
PubMed1987

Long-term survival in malignant melanoma with special reference to age and sex as prognostic factors.

A total of 12,353 (97.5%) of all patients with a first malignant melanoma newly diagnosed in Sweden during the period 1960-82 were subjected to a complete computerized follow-up with respect to survival through December 31, 1982. Calculation of relative survival rates (RSs) revealed a consistently more favorable course in women than in men, the 5-year RSs being 80.8 and 68.0% and the 10-year RSs being 75.0 and 61.8%, respectively. Prolonged follow-up and analyses of annual excess mortality showed, in addition, that men surviving about 10 years constituted an apparently cured fraction, whereas among women there was an excess mortality throughout the observation period. The prognosis was increasingly more favorable at younger ages in males, whereas no regular age trend emerged in the female group of patients. A multivariate analysis indicated that the findings were not confounded by temporal trends in RSs or by differences in tumor location between the groups compared and also that the relative hazard was significantly higher for men than for women only during the first 8 years after diagnosis.

Adult↗