Estrogen metabolism and risk of breast cancer: a prospective study of the 2:16alpha-hydroxyestrone ratio in premenopausal and postmenopausal women

Experimental and clinical evidence suggests that 16alpha-hydroxylated estrogen metabolites, biologically strong estrogens, are associated with breast cancer risk, while 2-hydroxylated metabolites, with lower estrogenic activity, are weakly related to this disease. This study analyzes the association of breast cancer risk with estrogen metabolism, expressed as the ratio of 2-hydroxyestrone to 16alpha-hydroxyestrone, in a prospective nested case-control study. Between 1987 and 1992, 10,786 women (ages 35-69 years) were recruited to a prospective study on breast cancer in Italy, the "Hormones and Diet in the Etiology of Breast Cancer" (ORDET) study. Women with a history of cancer and women on hormone therapy were excluded at baseline. At recruitment, overnight urine was collected from all participants and stored at -80 degrees C. After an average of 5.5 years of follow-up, 144 breast cancer cases and four matched controls for each case were identified among the participants of the cohort. Among premenopausal women, a higher ratio of 2-hydroxyestrone to 16alpha-hydroxyestrone at baseline was associated with a reduced risk of breast cancer: women in the highest quintile of the ratio had an adjusted odds ratio (OR) for breast cancer of 0.58 [95% confidence interval (CI) = 0.25-1.34]. The corresponding adjusted OR in postmenopausal women was 1.29 (95% CI = 0.53-3.10). Results of this prospective study support the hypothesis that the estrogen metabolism pathway favoring 2-hydroxylation over 16alpha-hydroxylation is associated with a reduced risk of invasive breast cancer risk in premenopausal women.

Understanding variations in survival for colorectal cancer in Europe: a EUROCARE high resolution study

BACKGROUND

Marked differences in population based survival across Europe were found for colorectal cancers diagnosed in 1985-1989.

AIMS

To understand the reasons for these differences in survival in a new analysis of colorectal cancers diagnosed between 1988 and 1991.

SUBJECTS

A total of 2720 patients with adenocarcinoma of the large bowel from 11 European cancer registries (CRs).

METHODS

We obtained information on stage at diagnosis, diagnostic determinants, and surgical treatment (not routinely collected by CRs) and analysed the data in relation to three year observed survival, calculating relative risks (RRs) of death and adjusting for age, sex, site, stage, and determinants of stage.

RESULTS

Three year observed survival rates ranged from 25% (Cracow) to 59% (Modena), and were low in the Thames area (UK) (38%). Survival rates between registries for "resected" patients varied less than those for all patients. When age, sex, and site were considered, RRs ranged from 0.7 (95% confidence intervals (CI) 0.6-0.9) (Modena) to 2.3 (95% CI 1.9-2.9) (Cracow). After further adjustment by stage, between registry RR variation was between 0.8 (95% CI 0.6-0.9) and 1.8 (95% CI 1.5-2.2). Inter-registry RR differences were slightly reduced when the determinants of stage (number of nodes examined and liver imaging) were included in the model. The reduction was marked for the UK registries.

CONCLUSIONS

The wide differences across Europe in colorectal cancer survival depend to a large extent on differences in stage at diagnosis. There are wide variations in diagnostic and surgical practices. There was a twofold range in the risk of death from colorectal cancer even after adjustment for surgery and disease stage.

High endogenous estradiol is associated with increased venous distensibility and clinical evidence of varicose veins in menopausal women

OBJECTIVE

The purpose of this study was to determine if there is an association between elevated sex hormones (ie, serum estradiol, sex hormone binding globulin [SHBG], testosterone) and increased venous distension and clinical evidence of varicose veins in menopausal women.

METHODS

Participants were 104 healthy volunteer menopausal women, aged 48 to 65 years, who were not undergoing hormonal treatment. Of these 104, 14 were excluded from analyses because their estradiol levels were compatible with a premenopausal condition (4), because they had missing values for insulin concentration (5), and because they did not show up at venous vessel examination (5). Patients underwent a physical examination to determine the presence of varicose veins; a venous strain-gauge plethysmographic examination to compute instrumental measures of venous distensibility; and laboratory analyses of blood so serum testosterone, estradiol, SHBG, glucose, and insulin could be measured. There were also prevalence ratios and odds ratios used to test the presence of an association between biochemical and instrumental variables.

RESULTS

Serum levels of estradiol in the upper tertile of the frequency distribution were significantly associated with clinical evidence of varicose veins (prevalence odds ratios 3.6; 95% CI 1.1-11.6) and with increased lower limb venous distensibility (prevalence odds ratios 4.4; 95% CI 1.2-15.5). No association was found for SHBG and testosterone.

CONCLUSIONS

Our finding that high serum levels of estradiol are associated with clinical evidence of varicose veins and instrumental measurements indicating increased venous distensibility in menopausal women suggests that endogenous estrogens may play a role in the development of this very common venous vessel abnormalities.

Large-scale hormone replacement therapy and life expectancy: results from an international comparison among European and North American populations

OBJECTIVES

An analysis was performed to determine the risks and benefits of a 10-year hormone replacement therapy regimen that had been applied to all women at 50 years of age in 8 countries.

METHODS

Cumulative mortality with and without hormone replacement therapy over 20 years was estimated, with both current and predicted total and disease-specific secular mortality trends and the influence of a generational cohort effect taken into account.

RESULTS

In countries with high ischemic heart disease frequency and predictable relative predominance of ischemic heart disease rates over breast cancer rates for the next 20 years, hormone replacement therapy could result in benefits with regard to overall mortality; this advantage decreases in younger-generation cohorts. In countries in which breast cancer mortality predominates over ischemic heart disease in early postmenopause and in which the predictable trends for both diseases reinforce this condition, a negative effect on overall mortality would be observed. In the United States, the effect of large-scale hormone replacement therapy would change over time.

CONCLUSIONS

The long-term effect of hormone replacement therapy on life expectancy of postmenopausal women may vary among countries.

Markers of insulin resistance and sex steroid hormone activity in relation to breast cancer risk: a prospective analysis of abdominal adiposity, sebum production, and hirsutism (Italy)

OBJECTIVE

Insulin resistance and increased levels of serum steroids have been hypothesized to be relevant etiological factors for breast cancer. Measurements of markers of insulin resistance and elevated serum steroids may identify women at high risk for breast cancer. The present study analyzed the association of breast cancer with markers of insulin resistance and elevated serum sex steroids, abdominal adiposity, increase in sebum production and hirsutism in a case-control study nested in a prospective cohort study.

METHODS

Between 1987 and 1992, 10,786 women (aged 35-69) were recruited in a prospective study on breast cancer in Italy, the ORDET study. Women with a history of cancer and on hormone therapy were excluded at baseline. At recruitment, abdominal adiposity was calculated from the ratio of waist-to-hip circumferences. Sebum production was measured on the forehead under standardized conditions using a sebumeter. Nine androgen-sensitive body areas were evaluated for hirsutism and a total hirsutism score was computed. After an average of 5.5 years of follow-up, 144 breast cancer cases were identified among the participants of the cohort. For each breast cancer case, four matched controls were randomly chosen from members of the cohort who did not develop breast cancer during the follow-up period.

RESULTS

Waist-to-hip ratio was associated with breast cancer in premenopausal women: age and body mass index (BMI) adjusted relative risk (RR) for the highest tertile of waist-to-hip ratio was 2.2 [95% confidence interval (CI) 1.04-4.75], p for trend 0.03. In the analysis conducted within strata of BMI, the effect of waist-to-hip ratio was confined to the group of thinner women: RR for the highest tertile of waist-to-hip ratio was 3.4 (95% CI 1.2-9.5). Sebum production and hirsutism were associated with breast cancer among postmenopausal women. Age and BMI adjusted RRs for the upper tertiles were 2.2 (95% CI 1.1-4.6), p for trend 0.01, and 2.3 (95% CI 1.1-4.9), p for trend 0.03, for sebum and hirsutism, respectively.

CONCLUSION

These results add evidence for a role of hormones and metabolic alterations in breast cancer etiology and for different relations of these risk factors with breast cancer in premenopausal and postmenopausal women.

Toward a comparison of survival in American and European cancer patients

BACKGROUND

Only recently have extensive population-based cancer survival data become available in Europe, providing an opportunity to compare survival in Europe and the United States.

METHODS

The authors considered 12 cancers: lung, breast, stomach, colon, rectum, melanoma, cervix uteri, corpus uteri, ovary, prostate, Hodgkin disease, and non-Hodgkin lymphoma. The authors analyzed 738,076 European and 282,398 U.S. patients, whose disease was diagnosed in 1985-1989, obtained from 41 EUROCARE cancer registries in 17 countries and 9 U.S. SEER registries. Relative survival was estimated to correct for competing causes of mortality.

RESULTS

Europeans had significantly lower survival rates than U.S. patients for most cancers. Differences in 5-year relative survival rates were higher for prostate (56% vs. 81%), skin melanoma (76% vs. 86%), colon (47% vs. 60%), rectum (43% vs. 57%), breast (73% vs. 82%), and corpus uteri (73% vs. 83%). Survival declined with increasing age at diagnosis for most cancers in both the U.S. and Europe but was more marked in Europe.

CONCLUSIONS

Survival for most major cancers was worse in Europe than the U.S. especially for older patients. Differences in data collection, analysis, and quality apparently had only marginal influences on survival rate differences. Further research is required to clarify the reasons for the survival rate differences.

Diet, metabolic polymorphisms and dna adducts: the EPIC-Italy cross-sectional study

DNA adducts in peripheral leukocytes are considered a reliable indicator of internal dose exposure to genotoxic agents and, possibly, of cancer risk. We investigated their association with diet and other individual characteristics in healthy adults. The prospective study EPIC-Italy, a section of a larger European project, enrolled 47,749 men and women, aged 35-64 years, in 5 centres: all provided individual information about dietary and life-style habits and a blood sample. In a cross-sectional study, approximately 100 volunteers were randomly selected from each of the three main geographical study areas (Northern, Central and Southern Italy). DNA adducts and four polymorphic metabolic genotypes were determined in peripheral leukocytes by using (32)P-postlabelling technique and PCR methods. Among 309 subjects (153 men), 72.8% had detectable levels of DNA adducts (mean: 8.1 +/- 0.6 per 10(9) nucleotides). Strong negative associations emerged with the reported frequency of consumption of fresh fruit and vegetables, olive oil, and the intake of antioxidants. DNA adducts were higher in subjects with GSTT1 null genotype (p = 0.05). Significant differences between study centres emerged in multivariate analyses (mean levels: 11.0, 10.0, 7.2, 6.5 and 5.2 for Florence, Naples, Turin, Varese and Ragusa, respectively). A possible opposite seasonal variation was found according to latitude: adduct levels tended to be lower in winter in Florence and the southern centres, and during summer in the two northern centres. Frequent consumption of fresh fruit and vegetables is associated with reduced levels of DNA adducts, possibly contributing to the role of diet in modulating cancer risk.

Variations in survival for invasive cervical cancer among European women, 1978-89. EUROCARE Working Group

OBJECTIVES

To analyze cervical cancer survival trends in 10 European countries using models that estimate the proportion of cured patients (having the same life expectancy as the general population) and the survival of fatal cases (who die from cervical cancer).

METHODS

We considered 40,906 cases diagnosed over 12 years (1978-89) collected from cancer registries participating in EUROCARE.

RESULTS

From 1978 to 1989, 5-year relative survival in Europe improved (60%-->63%). The proportion of cured patients increased slightly but significantly (53%-->55%, p = 0.05). For countries with poorer survival at the end of the 1970s the proportion of cured patients increased faster than average, particularly evident in England (49%-->56%) and Scotland (44%-->53%). By contrast, in Finland, Sweden and Germany with organized screening, 5-year survival and cure rate did not improve, but incidence declined to very low levels.

CONCLUSIONS

Cervical screening can explain the trends in cervical cancer survival: this identifies premalignant lesions, reduces incidence and selectively prevents less aggressive cancers. The decreased proportion of the latter means that survival does not improve in countries with low incidence of cervical cancer. The increased proportion of cured patients with time shows that survival improvement was not due simply to earlier diagnosis with no patient advantage.

[Diet, hormones, genes, and breast cancer]

The review describes on-going studies at the Unit of cancer epidemiology of the National Cancer Institute in Milan-Breast carcinogenesis is reviewed addressing: 1) Hormones and breast cancer 2) Diet and breast cancer 3) Diet and hormones 4) Potentiality of dietary prevention in women at high genetic risk.

Reducing colorectal cancer mortality by repeated faecal occult blood test: a nested case-control study

Randomised trials have shown the efficacy of faecal occult blood testing (FOBT) in reducing colorectal cancer mortality, but observational studies are needed to monitor such efficacy in population programmes. We conducted a nested case-control study on a cohort of 21,879 subjects who participated in a colorectal screening programme from 1978 to 1995, undergoing at least one FOBT test. 95 fatal cases of colorectal cancer were eligible for the study. For each fatal case, 5 non-fatal matched controls were randomly selected from the cohort. FOBT screening history was less common among cases than controls. The odds ratio of colorectal cancer mortality among 'attenders' (defined as those who underwent a second FOBT within 2 years of study entry) with respect to 'non-attenders' was 0.64 (95% confidence interval 0.36-1.15). We also computed odds ratios defining exposure as one or more tests in the detectable preclinical period, hypothesising various lengths for the latter, which, however, yielded an efficacy estimate biased towards the null. A strong inverse relationship was observed between mortality and the number of tests, but this phenomenon is interpretable as 'healthy screenee bias'. The results suggest that the potential efficacy in preventing colorectal cancer mortality through annual FOBT screening may be of the order of one third.

Variation in survival for adults with nasopharyngeal cancer in Europe, 1978-1989. EUROCARE Working Group

During the period 1978-1989, 2,054 new patients with nasopharyngeal carcinoma (NPC) were registered in the EUROCARE study, which, during 1985-1989 involved 45 population-based cancer registries in 17 countries. The follow-up time was at least 5 years. 48% of all cases were squamous cell carcinomas and 39% undifferentiated carcinomas, which were more frequent in males. The overall relative 1- and 5-year survival rates (data included from 8 countries with complete data) were 75 and 34%, respectively, for males, and 72 and 32%, respectively, for females, but in a multivariate analysis, there was no significant difference in risk between males and females (0.93 (0.84-1.01), hazard ratio (HR) with 95% confidence interval (95% CI) for females). The overall relative 5-year survival (data included from nine countries with complete data) declined with age, from 53% for patients aged 15-44 years to 31% for patients aged 65-74 years. For patients with undifferentiated tumours, higher survival rates were observed in Scandinavia, Slovakia and Mediterranean countries, with lower rates for patients from the U.K. and Estonia. Survival for patients with squamous cell carcinoma was lowest in Scotland, England and Estonia. In a multivariate analysis, there was a significant difference in risk of death between those with squamous cell carcinomas and those with undifferentiated (HR 0.82, 95% CI 0.74-0.90). Between 1978 and 1989, the prognosis did not change.

Variation in survival of patients with head and neck cancer in Europe by the site of origin of the tumours. EUROCARE Working Group

The study describes the prognosis of head and neck cancer in Europe on the basis of information available to population-based cancer registries collaborating in the EUROCARE II project. Variation in survival in relation to country and the anatomical site/sub-site of origin of the tumours was examined. Survival analysis was carried out on 35,004 head and neck cancer cases (ICD 141, 143-148 and 161) diagnosed between 1985 and 1989 in 17 European countries. Prognosis varied considerably according to anatomical site: the best 5-year survival rates were seen for cancer of the larynx (63% in men) and the worst for cancer of the hypopharynx (22% in men). Five-year relative survival of male patients with cancer of the tongue, mouth and pharynx (ICD 141, 143-148) was 34% and ranged from over 45% in Iceland, Sweden, The Netherlands and Austria to less than 25% in Eastern European countries. Survival for larynx cancer ranged from over 70% in Iceland, Sweden, The Netherlands and Germany to less than 50% in Slovakia, Poland and Estonia. Apparently, France had the lowest survival (relative risk (RR) of dying versus Finland = 1.29) in Western Europe; after adjustment for ICD 3-digit anatomical sites the difference disappeared (RR = 1.04). Eastern European countries remained at the bottom of the survival range (RR > 1.4). The analyses adjusting by sub-site (ICD fourth digit) were confined to registries for which the proportion of unspecified sub-sites was less than 20%. Geographical differences in survival between Western European countries were largely due to a difference in case mix of anatomical sub-sites. However, after correcting for different sub-site distribution, differences persisted between Eastern and Western European countries. This is likely to be due to late diagnosis and to late referral or poor access of patients to adequately equipped treatment centres.

Introduction: the EUROCARE II Study

This introduction provides a general overview of the aims, methods and procedures used in the EUROCARE II study and the types of analyses presented in each article of this Special Issue of the European Journal of Cancer. The main aims of the EUROCARE II project are the updating of the survival database of the European Cancer Registries, the study of recent trends in relative survival rates and the interpretation of the survival differences observed both in time and across populations. Once having completed the preliminary stage of data checking, a total of 3,473,659 individual records from patients of all cancer sites, diagnosed between 1978 and 1989 and provided by 45 cancer registries in 17 European countries were accepted to build up the EUROCARE database. The quality of these data, in terms of the accuracy of the diagnosis and the validity of vital status assessment, was checked by indirect indicators, based on cross-validation analysis of consistency of the relevant variables. Statistical analysis was based on age-specific relative survival rates, computed for each cancer sites as the ratio of observed survival to the expected survival of the general population of the same area, gender and age, according to the Hakulinen method. An estimate of the European survival was computed as a weighted mean of the corresponding survival of the different countries, using as weights the expected yearly number of incident cases in each country. For comparison purposes, age-standardised survival was also calculated for Europe and for each country involved in the study.