Breast cancer in Denmark. Incidence, risk factors, and characteristics of survival

Postdiagnosis dietary factors, supplement use and breast cancer prognosis: Global Cancer Update Programme (CUP Global) systematic literature review and meta-analysis

Little is known about how diet might influence breast cancer prognosis. The current systematic reviews and meta-analyses summarise the evidence on postdiagnosis dietary factors and breast cancer outcomes from randomised controlled trials and longitudinal observational studies. PubMed and Embase were searched through 31st October 2021. Random-effects linear dose-response meta-analysis was conducted when at least three studies with sufficient information were available. The quality of the evidence was evaluated by an independent Expert Panel. We identified 108 publications. No meta-analysis was conducted for dietary patterns, vegetables, wholegrains, fish, meat, and supplements due to few studies, often with insufficient data. Meta-analysis was only possible for all-cause mortality with dairy, isoflavone, carbohydrate, dietary fibre, alcohol intake and serum 25-hydroxyvitamin D (25(OH)D), and for breast cancer-specific mortality with fruit, dairy, carbohydrate, protein, dietary fat, fibre, alcohol intake and serum 25(OH)D. The results, with few exceptions, were generally null. There was limited-suggestive evidence that predefined dietary patterns may reduce the risk of all-cause and other causes of death; that isoflavone intake reduces the risk of all-cause mortality (relative risk (RR) per 2 mg/day: 0.96, 95% confidence interval (CI): 0.92-1.02), breast cancer-specific mortality (RR for high vs low: 0.83, 95% CI: 0.64-1.07), and recurrence (RR for high vs low: 0.75, 95% CI: 0.61-0.92); that dietary fibre intake decreases all-cause mortality (RR per 10 g/day: 0.87, 95% CI: 0.80-0.94); and that serum 25(OH)D is inversely associated with all-cause and breast cancer-specific mortality (RR per 10 nmol/L: 0.93, 95% CI: 0.89-0.97 and 0.94, 95% CI: 0.90-0.99, respectively). The remaining associations were graded as limited-no conclusion.

Postdiagnosis body fatness, weight change and breast cancer prognosis: Global Cancer Update Program (CUP global) systematic literature review and meta-analysis

Previous evidence on postdiagnosis body fatness and mortality after breast cancer was graded as limited-suggestive. To evaluate the evidence on body mass index (BMI), waist circumference, waist-hip-ratio and weight change in relation to breast cancer prognosis, an updated systematic review was conducted. PubMed and Embase were searched for relevant studies published up to 31 October, 2021. Random-effects meta-analyses were conducted to estimate summary relative risks (RRs). The evidence was judged by an independent Expert Panel using pre-defined grading criteria. One randomized controlled trial and 225 observational studies were reviewed (220 publications). There was strong evidence (likelihood of causality: probable) that higher postdiagnosis BMI was associated with increased all-cause mortality (64 studies, 32 507 deaths), breast cancer-specific mortality (39 studies, 14 106 deaths) and second primary breast cancer (11 studies, 5248 events). The respective summary RRs and 95% confidence intervals per 5 kg/m2 BMI were 1.07 (1.05-1.10), 1.10 (1.06-1.14) and 1.14 (1.04-1.26), with high between-study heterogeneity (I2  = 56%, 60%, 66%), but generally consistent positive associations. Positive associations were also observed for waist circumference, waist-hip-ratio and all-cause and breast cancer-specific mortality. There was limited-suggestive evidence that postdiagnosis BMI was associated with higher risk of recurrence, nonbreast cancer deaths and cardiovascular deaths. The evidence for postdiagnosis (unexplained) weight or BMI change and all outcomes was graded as limited-no conclusion. The RCT showed potential beneficial effect of intentional weight loss on disease-free-survival, but more intervention trials and well-designed observational studies in diverse populations are needed to elucidate the impact of body composition and their changes on breast cancer outcomes.

The evolving epidemic of breast cancer in sub-Saharan Africa: Results from the African Cancer Registry Network

Breast cancer (BC) is the leading cause of cancer in sub-Saharan Africa (SSA) with rapidly increasing incidence rates reported in Uganda and Zimbabwe. However, the magnitude of these rising trends in premenopausal and postmenopausal women is unknown in most African countries. We used data from the African Cancer Registry Network on incident breast cancers in women from 11 population-based cancer registries in 10 countries representing each of the four SSA regions. We explored incidence changes among women before and after age 50 by calendar period and, where possible, generational effects in this unique sub-Saharan African cohort. Temporal trends revealed increasing incidence rates in all registries during the study period, except in Nairobi where rates stabilised during 2010 to 2014 after rapidly increasing from 2003 to 2010 (APC = 8.5 95%, CI: 3.0-14.2). The cumulative risk varied between and within regions, with the highest risks observed in Nairobi-Kenya, Mauritius and the Seychelles. There were similar or more rapidly increasing incidence rates in women aged 50+ compared to women <50 years in all registries except The Gambia. Birth cohort analyses revealed increases in the incidence rates in successive generations of women aged 45 and over in Harare-Zimbabwe and Kampala-Uganda. In conclusion, the incidence of BC is increasing rapidly in many parts of Africa; however, the magnitude of these changes differs. These results highlight the need for urgent actions across the cancer continuum from in-depth risk factor studies to provision of adequate therapy as well as the necessity of supporting the maintenance of good quality population-based cancer registration in Africa.

The Global and Regional Survival Rate of Women With Breast Cancer: A Systematic Review and Meta-analysis

Breast cancer is the most common cancer among women in the world. The aim of this study was to measure the global and regional survival rates of women with breast cancer. We searched Medline/PubMed, Web of Science, Scopus, and Google Scholar to identify cohort studies on the survival rate of women with primary invasive breast cancer until the end of June 2017. We used random effect models to estimate the pooled 1-, 3-, 5-, and 10-year survival rates. Subgroup analysis and meta-regression models were used to investigate the potential sources of heterogeneity. One hundred twenty-six studies were included in the meta-analysis. Between-study heterogeneities in the 1-, 3-, 5-, and 10-year survival rates were significantly high (all I²s > 50%; P = .001). The global 1-, 3-, 5-, and 10-year pooled survival rates in women with breast cancer were 0.92 (95% confidence interval [CI], 0.90-0.94), 0.75 (95% CI, 0.71-0.79), 0.73 (95% CI, 0.71-0.75), and 0.61% (95% CI, 0.54-0.67), respectively. Subgroup analysis revealed that survival rates varied in different World Health Organization regions, age and stage at diagnosis, year of the studies, and degree of development of countries. Meta-regression indicated that year of the study (β = 0.07; P = .002) and development of country (β = -0.1; P = .0001) were potential sources of heterogeneity. The survival rate was improved in recent decades; however, it is lower in developing regions than developed ones.

Do Pre-Diagnostic Drinking Habits Influence Breast Cancer Survival?

Aims and background

Alcohol consumption increases the risk of developing breast cancer and may also be associated with late diagnosis, recurrence, distant metastases and death. Many studies have examined the role of alcohol as a risk factor for the development of breast cancer, but very few studies have addressed the role of alcohol as a prognostic factor for survival among women diagnosed with breast cancer. The aim of this study was to investigate the survival of women with breast cancer in relation to pre-diagnostic alcohol intake and other factors known to influence prognosis.

Methods

We analyzed data for 264 women in the EUROCARE and ORDET studies who were diagnosed with breast cancer from 1987 up to 31 December 2001 and for whom information was available on follow-up, stage at diagnosis, HER-2 and hormone receptor status, and pre-diagnostic dietary alcohol intake, categorized as zero (0 g/day, non-drinkers), moderate (up to 13 g/day, about 1 serving) and high (>13 g/day). Ten-year relative survival was estimated using the maximum-likelihood approach. The excess risk of death within 10 years of diagnosis was modeled by level of alcohol intake, adjusting separately for age, stage, body mass index and tumor subtype.

Results

Ten-year relative survival was lowerin women who drank more than 13g/day (65%; 95% CI, 47–78) than in non-drinkers (88%; 95% CI, 75–95). The excess risk of death within 10 years was significantly higher in women who drank more than 13 g/day than non-drinkers (relative excess risk, 4.13; 95% CI, 1.69–10.10) and was not altered by adjustment for other prognostic factors. The excess risk within 10 years was higher for women with a body mass index of 25 kg/m2 or higher (relative excess risk, 2.20; 95% CI, 1.01–4.70) and higher for those with more advanced disease.

Conclusions

Women who drank more than 13 g alcohol per day had lower survival than non-drinkers. The excess risk of death within 10 years of diagnosis was unaffected by other known risk factors. High alcohol consumption may be an adverse prognostic factor for breast cancer.

Impact of very low physical activity, BMI, and comorbidities on mortality among breast cancer survivors

The purpose of this study was to examine post-diagnosis BMI, very low physical activity, and comorbidities, as predictors of breast cancer-specific and all-cause mortality. Data from three female US breast cancer survivor cohorts were harmonized in the After Breast Cancer Pooling Project (n = 9513). Delayed entry Cox proportional hazards models were used to examine the impact of three post-diagnosis lifestyle factors: body mass index (BMI), select comorbidities (diabetes only, hypertension only, or both), and very low physical activity (defined as physical activity <1.5 MET h/week) in individual models and together in multivariate models for breast cancer and all-cause mortality. For breast cancer mortality, the individual lifestyle models demonstrated a significant association with very low physical activity but not with the selected comorbidities or BMI. In the model that included all three lifestyle variables, very low physical activity was associated with a 22 % increased risk of breast cancer mortality (HR 1.22, 95 % CI 1.05, 1.42). For all-cause mortality, the three individual models demonstrated significant associations for all three lifestyle predictors. In the combined model, the strength and significance of the association of comorbidities (both hypertension and diabetes versus neither: HR 2.16, 95 % CI 1.79, 2.60) and very low physical activity (HR 1.35, 95 % CI 1.22, 1.51) remained unchanged, but the association with obesity was completely attenuated. These data indicate that after active treatment, very low physical activity, consistent with a sedentary lifestyle (and comorbidities for all-cause mortality), may account for the increased risk of mortality, with higher BMI, that is seen in other studies.

Body mass index and survival in women with breast cancer-systematic literature review and meta-analysis of 82 follow-up studies

BACKGROUND

Positive association between obesity and survival after breast cancer was demonstrated in previous meta-analyses of published data, but only the results for the comparison of obese versus non-obese was summarised.

METHODS

We systematically searched in MEDLINE and EMBASE for follow-up studies of breast cancer survivors with body mass index (BMI) before and after diagnosis, and total and cause-specific mortality until June 2013, as part of the World Cancer Research Fund Continuous Update Project. Random-effects meta-analyses were conducted to explore the magnitude and the shape of the associations.

RESULTS

Eighty-two studies, including 213 075 breast cancer survivors with 41 477 deaths (23 182 from breast cancer) were identified. For BMI before diagnosis, compared with normal weight women, the summary relative risks (RRs) of total mortality were 1.41 [95% confidence interval (CI) 1.29-1.53] for obese (BMI >30.0), 1.07 (95 CI 1.02-1.12) for overweight (BMI 25.0-<30.0) and 1.10 (95% CI 0.92-1.31) for underweight (BMI <18.5) women. For obese women, the summary RRs were 1.75 (95% CI 1.26-2.41) for pre-menopausal and 1.34 (95% CI 1.18-1.53) for post-menopausal breast cancer. For each 5 kg/m(2) increment of BMI before, <12 months after, and ≥12 months after diagnosis, increased risks of 17%, 11%, and 8% for total mortality, and 18%, 14%, and 29% for breast cancer mortality were observed, respectively.

CONCLUSIONS

Obesity is associated with poorer overall and breast cancer survival in pre- and post-menopausal breast cancer, regardless of when BMI is ascertained. Being overweight is also related to a higher risk of mortality. Randomised clinical trials are needed to test interventions for weight loss and maintenance on survival in women with breast cancer.

Coffee, tea, caffeine and risk of breast cancer: a 22-year follow-up

The relation between consumption of coffee, tea and caffeine and risk of breast cancer remains unsettled. We examined data from a large, long-term cohort study to evaluate whether high intake of coffee and caffeine is associated with increased risk of breast cancer. This was a prospective cohort study with 85,987 female participants in the Nurses' Health Study. Consumption of coffee, tea and caffeine consumption was assessed in 1980, 1984, 1986, 1990, 1994, 1998 and the follow-up continued through 2002. We documented 5,272 cases of invasive breast cancer during 1,715,230 person-years. The multivariate relative risks (RRs) of breast cancer across categories of caffeinated coffee consumption were: 1.0 for <1 cup/month (reference category), 1.01 (95% confidence interval: 0.92-1.12) for 1 month to 4.9 week, 0.92 (0.84-1.01) for 5 week to 1.9 days, 0.93 (0.85-1.02) for 2-3.9 days, 0.92 (0.82-1.03) for >or=4 cups per day (p for trend = 0.14). Intakes of tea and decaffeinated coffee were also not significantly associated with risk of breast cancer. RRs (95% CI) for increasing quintiles of caffeine intake were 1.00, 0.98 (0.90-1.07), 0.92 (0.84-1.00), 0.94 (0.87-1.03) and 0.93 (0.85-1.01) (p for trend = 0.06). A significant inverse association of caffeine intake with breast cancers was observed among postmenopausal women; for the highest quintile of intake compared to the lowest RR 0.88 (95% CI = 0.79-0.97, p for trend = 0.03). We observed no substantial association between caffeinated and decaffeinated coffee and tea consumption and risk of breast cancer in the overall cohort. However, our results suggested a weak inverse association between caffeine-containing beverages and risk of postmenopausal breast cancer.

Comorbidity and survival of Danish breast cancer patients from 1995 to 2005

Comorbid diseases can affect breast cancer prognosis. We conducted a population-based study of Danish women diagnosed with a first primary breast cancer from 1995 to 2005 (n=9300), using hospital discharge registry data to quantify comorbidities by Charlson score. We examined the influence of comorbidities on survival, and quantified their impact on relative mortality rates. The prevalence of patients with a Charlson score='0' fell from 86 to 81%, with an increase in those with Charlson score='1-2' from 13 to 16%, and score='3+' from 1 to 2%. One- and five-year survival for patients with Charlson score='0' and '1-2' was better for those diagnosed in 1998-2000 than in 1995-1997. Overall, patients diagnosed in 2001-2004 (mortality ratio (MR)=0.80, 95% CI=0.68-0.95) and 1998-2000 (MR=0.92, 95% CI=0.78-1.09) had lower 1-year age-adjusted mortality compared to those diagnosed in 1995-1997 (reference period). Patients with Charlson scores '1-2' and '3+' had higher age-adjusted 1-year mortality than those with a Charlson score='0' in each time period (2001-2004: MR('1-2')=1.76, 95% CI=1.35-2.30, and MR('3+')=3.78, 95% CI=2.51-5.68; and 1998-2000: MR('1-2')=1.60, 95% CI=1.36-1.88 and MR('3+')=2.34, 95% CI=1.65-3.33). Similar findings were observed for 5-year age-adjusted mortality. Additional analyses, adjusted for stage, indicated that confounding by stage could not explain these findings. Despite continued improvements in breast cancer survival, we found a trend of poorer survival among breast cancer patients with severe comorbidities even after adjusting for age and stage. Such poorer survival is an important public health concern and can be expected to worsen as the population ages.

Continuing evidence for poorer treatment outcomes for single male patients: Retreatment data from RTOG 97-14

PURPOSE

The specific aim of this study was to evaluate outcome differences by gender and partner status for patients treated on Radiation Therapy Oncology Group (RTOG) protocol 97-14.

METHODS AND MATERIALS

RTOG 97-14 randomized patients with metastatic breast or prostate cancer to bone to receive 8 Gy in 1 fraction or 30 Gy in 10 fractions. Retreatment rates and overall survival were made based upon gender, marital status, and Karnofsky Performance Status (KPS). The cumulative incidence method was used to estimate retreatment time at 36 months from enrollment, and Gray's test was used to test for treatment differences within the same groupings. Marital status, gender, KPS, and treatment were variables tested in a univariate Cox model evaluating the time to retreatment.

RESULTS

Married men and women and single women receiving 30 Gy had significantly longer time to retreatment, p = 0.0067, p = 0.0052, and p = 0.0009 respectively. We failed to show a difference in retreatment rates over time in single men receiving either 30 Gy or 8 Gy. Univariate analysis of the entire group determined patients receiving 30 Gy in 10 fractions significantly less likely to receive retreatment, p < 0.0001, with a trend toward single patients less likely to be re-treated, p = 0.07.

CONCLUSION

Non-disease-related variables, such as social support, might influence the results of clinical trials with subjective endpoints such as retreatment rates. The statistically nonsignificant difference in the 36-month retreatment rates observed in single male patients receiving 8 Gy may be a result of inadequate social support systems in place to facilitate additional care. Patients receiving 8 Gy in a single fraction had significantly higher retreatment rates compared with patients receiving 30 Gy in 10 fractions.

The relation between socioeconomic and demographic factors and tumour stage in women diagnosed with breast cancer in Denmark, 1983-1999

The authors investigated the association between socioeconomic position and stage of breast cancer at the time of diagnosis in a nationwide Danish study. All 28 765 women with a primary invasive breast cancer diagnosed between 1983 and 1999 were identified in a nationwide clinical database and information on socioeconomic variables was obtained from Statistics Denmark. The risk of being diagnosed with a high-risk breast cancer, that is size >20 mm, lymph-node positive, ductal histology/high histologic grade and hormone receptor negative, was analysed by multivariate logistic regression. The adjusted odds ratio (OR) for high-risk breast cancer was reduced with longer education with a 12% reduced risk (95% confidence interval (CI), 0.80,0.96) in women with higher education and increased with reduced disposable income (low income group: OR, 1.22; 95% CI, 1.10,1.34). There was an urban–rural gradient, with higher risk among rural women (OR 1.10; 95 % CI, 1.02, 1.18) and lower risk among women in the capital suburbs (OR, 0.85; 95% CI, 0.78, 0.93) and capital area (OR, 0.93; 95% CI, 0.84–1.02). These factors were significant only for postmenopausal women, although similar patterns were observed among the premenopausal women, suggesting a subgroup of aggressive premenopausal breast cancers less influenced by socioeconomic factors.

Tea, hormone-related cancers and endogenous hormone levels

Tea is one of the most popular beverages consumed around the world, second only to water. There has been substantial interest in the potential role of tea in cancer prevention, particularly in respiratory and gastrointestinal tract cancers. Recent epidemiological data have linked tea intake to reduced risk of hormone-related cancers, including breast, ovarian and prostate cancers. Based on sparse data, there is suggestion that tea intake may influence circulating hormone levels, providing a plausible mechanism whereby tea intake may influence risk of hormone-related cancers. The major objectives of this paper are to review the epidemiological evidence on tea and risk of breast, ovarian, and prostate cancers as well as the human and non-human studies on tea and circulating hormone levels. We pay special attention to some of the limitations of the human studies and discuss future research needs.

Green tea, black tea and breast cancer risk: a meta-analysis of epidemiological studies

Experimental studies have shown that tea and tea polyphenols have anti-carcinogenic properties against breast cancer. A number of epidemiologic studies, both case-control and cohort in design, have examined the possible association between tea intake and breast cancer development in humans. This meta-analysis included 13 papers which examined populations in eight countries and provided data on consumption of either green tea or black tea, or both in relation to breast cancer risk. Summary odds ratios (ORs) for highest versus non/lowest tea consumption level were calculated based on fixed and random effects models. Heterogeneity between studies was examined via the Q statistics. For green tea, the combined results from the four studies indicated a reduced risk of breast cancer for highest versus non/lowest intake (OR = 0.78, 95% CI = 0.61-0.98). For black tea, conflicting results were observed in case-control versus cohort studies. The combined results from the eight case-control studies showed a minor inverse association between black tea consumption and risk of breast cancer (OR = 0.91, 95% CI = 0.84-0.98). This inverse association was stronger in hospital-based (OR = 0.77, 95% CI = 0.50-1.19) than population-based case-control studies (OR = 0.94, 95% CI = 0.81-1.09). Five cohort studies demonstrated a modest increase in risk associated with black tea intake (OR = 1.15, 95% CI = 1.02-1.31). The results of this meta-analysis indicate a lower risk for breast cancer with green tea consumption. Available data suggest a possible late-stage, promotional effect of black tea on breast carcinogenesis.

Association Between Body Mass Index and Risk of Formation of Breast Cancer in Chinese Women

OBJECTIVE

To analyse the association between body mass index (BMI) and breast cancer risk among Chinese women in Hong Kong.

METHODS

We conducted a population-based case control study of breast cancer in June 2002. Standardized questionnaires concerning BMI and other anthropometric data were completed by patients at the Queen Mary Hospital (QMH). The cases were 198 women aged 24-85 years who had documented breast cancer in 1995-2000 by triple assessment criteria, and the controls were 353 women who were followed up at QMH for benign breast disease after breast cancer had been excluded by triple assessment. The controls were frequency-matched to the cases by age.

RESULTS

BMI at diagnosis was positively correlated with the risk of breast cancer among postmenopausal women (p < 0.001 for trend). Also, when compared with women with a low BMI (< 19), women with a BMI of 23-27 and 27-31 had a 1.73-fold (95% confidence interval, CI, 1.04-2.86) and 2.06-fold (95% CI, 1.08-3.93) increased risk of breast cancer, respectively, after adjustment for non-anthropometric risk factors. BMI at diagnosis, however, was not related to the risk of breast cancer among premenopausal women. The odds ratios for premenopausal women with a BMI of 23-27 and 27-31 were 1.5 (95% CI, 0.82-2.71) and 1.32 (95% CI, 0.39-4.43), respectively. Furthermore, present BMI and BMI 5 years before diagnosis were poorly associated with breast cancer risk among both pre- and postmenopausal women.

CONCLUSION

Weight control in obese women may be an effective measure for breast cancer prevention in postmenopausal women.

Coffee consumption and breast cancer risk amongBRCA1 andBRCA2 mutation carriers

Although there are several plausible biologic mechanisms whereby coffee consumption might influence the risk of breast cancer, epidemiologic evidence is limited. We assessed the association between coffee consumption and breast cancer risk among high-risk women who carry BRCA mutations. We performed a matched case-control analysis on 1,690 women with a BRCA1 or BRCA2 mutation from 40 centers in 4 countries. Average lifetime coffee consumption was estimated via a self-administered questionnaire. Odds ratios (ORs) and 95% confidence intervals (CIs) were estimated using conditional logistic regression. After adjustment for potential confounders, the ORs for breast cancer in BRCA carriers who habitually drank 0, 1-3, 4-5 and 6 or more cups of coffee were 1.00, 0.90 (95% CI 0.72-1.12), 0.75 (95% CI 0.47-1.19) and 0.31 (95% CI 0.13-0.71; p-trend = 0.02). The effect was limited to the consumption of caffeinated coffee. These results suggest that among women with BRCA gene mutation, coffee consumption is unlikely to be harmful and that high levels of consumption may in fact be related to reduced breast cancer risk.

Smoking before the birth of a first child is not associated with increased risk of breast cancer: findings from the British Women's Heart and Health Cohort Study and a meta-analysis

It has been suggested that the period between puberty and first birth is a time when the breast is particularly susceptible to carcinogenic effects. In a cohort of 3047 women aged 60–79 years (N=139 breast cancer cases), we found no association between smoking before the birth of a first child and breast cancer risk: fully adjusted (for age, number of children, age at birth of first child, age at menarche, age at menopausal, hysterectomy and/or oophorectomy, ever use of oral contraception, use of hormone replacement therapy, alcohol consumption, body mass index, childhood and adulthood social class) odds ratio 1.06 (95% confidence interval: 0.72, 1.56). The pooled estimate from a meta-analysis of our study and 11 previously published studies (N=6528 cases) was 1.07 (0.94, 1.22). We conclude that smoking prior to the birth of a first child is not associated with increased risk of breast cancer.

Fertility pattern does not explain social gradient in breast cancer in denmark

The present study was undertaken to assess the impact of reproductive behavior on the social class gradient in breast cancer occurrence in Denmark. Objectives were to study whether the gradient across socioeconomic groups could be explained by fertility differences, whether the gradient across educational groups could be explained by fertility differences and whether the effect of socioeconomic group on breast cancer incidence and mortality could be explained by education and vice versa. We studied 674,084 women aged 20-39 at the census on 9 November 1970 for whom we had complete data on fertility history. The cohort was followed up for breast cancer incidence and mortality until 8 November 1998. Fertility history varied considerably across socioeconomic group, where 38% of the academics were childless at the age of 30, in contrast to only 8% of women in agriculture. The academics had the highest risk of breast cancer and women in agriculture had the lowest risk. For incidence, the gradient in the relative risks was 1.74, which changed to 1.49 when fertility history was incorporated and to 1.29 when school education was also taken into account. For school education, women with > or = 12 years of schooling had the highest risk and women with < or = 7 years of schooling had the lowest risk. For incidence, the gradient in the relative risk was 1.38, which changed to 1.26 when fertility history was incorporated and to 1.22 when socioeconomic group was also taken into account.

Genotoxicity of Aspartame

In the present study, the genotoxic effects of the low-calorie sweetener aspartame (ASP), which is a dipeptide derivative, was investigated using chromosome aberration (CA) test, sister chromatid exchange (SCE) test, micronucleus test in human lymphocytes and also Ames/Salmonella/ microsome test. ASP induced CAs at all concentrations (500, 1000 and 2000 microg/ml) and treatment periods (24 and 48 h) dose-dependently, while it did not induce SCEs. On the other hand, ASP decreased the replication index (RI) only at the highest concentration for 48 h treatment period. However, ASP decreased the mitotic index (MI) at all concentrations and treatment periods dose-dependently. In addition, ASP induced micronuclei at the highest concentrations only. This induction was also dose-dependent for 48 hours treatment period. ASP was not mutagenic for Salmonella typhimurium TA98 and TA100 strains in the absence and presence of S9 mix.

Green tea and risk of breast cancer in Asian Americans

There is substantial in vitro and in vivo evidence implicating tea polyphenols as chemopreventive agents against various cancers. However, epidemiologic data obtained from mainly Western populations are not supportive of a protective role of tea, mainly black tea, in the etiology of breast cancer. Much less is known about the relationship between green tea and breast cancer risk. During 1995-1998, we conducted a population-based, case-control study of breast cancer among Chinese, Japanese and Filipino women in Los Angeles County and successfully interviewed 501 breast cancer patients and 594 control subjects. Detailed information on menstrual and reproductive factors; dietary habits, including intake of black and green tea; and other lifestyle factors was collected. Risk of breast cancer was not related to black tea consumption. In contrast, green tea drinkers showed a significantly reduced risk of breast cancer, and this was maintained after adjusting for age, specific Asian ethnicity, birthplace, age at menarche, parity, menopausal status, use of menopausal hormones, body size and intake of total calories and black tea. Compared to women who did not drink green tea regularly (i.e., less than once a month), there was a significant trend of decreasing risk with increasing amount of green tea intake, adjusted odds ratios being 1.00, 0.71 (95% confidence interval [CI] 0.51-0.99) and 0.53 (95% CI 0.35-0.78), respectively, in association with no, 0-85.7 and >85.7 ml of green tea per day. The significant inverse association between risk of breast cancer and green tea intake remained after further adjustment for other potential confounders, including smoking; alcohol, coffee and black tea intake; family history of breast cancer; physical activity; and intake of soy and dark green vegetables. While both green tea and soy intake had significant, independent protective effects on breast cancer risk, the benefit of green tea was primarily observed among subjects who were low soy consumers. Similarly, the protective effect of soy was primarily observed among subjects who were nondrinkers of green tea. In summary, our results point to an important role of both green tea and soy intake in relation to breast cancer risk in Asian-American women.

Cigarette smoking and breast cancer risk: a long latency period?

The association between cigarette smoking and breast cancer risk remains unclear. Few studies have examined cigarette smoking of very long duration as there may not have been a sufficient number of long-term smokers in studies conducted before the 1980s. Therefore, we examined the association between smoking and breast cancer risk using data from participants in a randomized controlled trial of screening for breast cancer involving 89,835 women aged 40-59 years at recruitment and with up to 40 years of smoking duration at that time. Women with breast cancer diagnosed through 31 December 1993 were identified by linkage to the Canadian Cancer Database. Cox proportional hazards models were used to estimate rate ratios (RRs) and 95% confidence intervals (CIs). During an average of 10.6 years of follow-up, we observed 2,552 incident cases of breast cancer. We found a positive association between cigarette smoking and breast cancer risk, driven mainly by women who had smoked for several decades and who, therefore, had commenced smoking many years earlier. Relative to never-smokers, women who had smoked 40 years or more and 20 cigarettes/day or more were at the highest risk (RR = 1.83, 95% CI 1.29-2.61); for women who had commenced smoking 40 years or more before assessment (a measure of smoking latency rather than duration and intensity), the RR was 1.22 (95% CI 0.99-1.59). Our findings suggest that smoking of very long duration and high intensity may be associated with increased risk of breast cancer.

The impact of marital status on cancer survival

Marital differentials in survival from 12 common types of cancer are assessed by estimating a mixed additive multiplicative hazard regression model on the basis of individual register and census data for the whole Norwegian population. These data cover the period 1960-91 and include more than 100,000 cancer deaths. The data and method make it possible to take into account the marital mortality differentialsin the absence of cancer. The excess all-cause mortality among cancer patients compared with similar persons without a cancer diagnosis is, on the whole, more than 15% higher for never-married men, never-married women and divorced men, than for the married of the same sex. Other previously married have an excess mortality elevated by about 7%. This protective effect of marriage is not due to stage, which is controlled for. The possible importance of treatment and host factors is discussed.

Dietary and familial determinants of 10-year survival among patients with gastric carcinoma

BACKGROUND

Although the role of diet in gastric carcinoma (GC) causation has been investigated extensively, its association with long term survival has never been explored in detail.

METHODS

The authors assessed the vital status on December 31, 1997 of a series of 382 patients with GC who were interviewed in 1985-1987 in the framework of a population-based case-control study in a high risk area for GC in Italy. Follow-up information at 10 years was available for all but three patients. The risk of dying was evaluated by Cox proportional hazard models, including patient age, gender, social status, disease stage at diagnosis, and lymph node involvement as confounding variables.

RESULTS

The overall survival probability was 0.26 at 5 years and 0.18 at 10 years after interview. The most important predictors were disease stage, lymph node involvement, and histopathologic grading (TNM classification). Overall, a high intake of alcohol was associated with an increased risk of dying (P = 0.02). In contrast, survival was increased in patients with a high intake of alpha-tocopherol (P = 0.04). A positive first-degree family history of GC was reported by 84 patients and tended to be associated with a reduced risk of death. A significant protective trend was found with increasing intake of vegetable fat and starch among these familial cases, with a 50% risk reduction. In contrast, this subgroup showed a two-fold increased risk of dying with a high intake of animal protein, animal fat, and preformed N-nitrosodimethylamine.

CONCLUSIONS

The current results provide evidence that premorbid diet may influence the prognosis of patients with GC, and they suggest that specific pathways for disease progression may exist among familial cases.

Relationship between the risk of breast cancer and physical activity. An epidemiological perspective

The possible protective effect of physical exercise on the risk of breast cancer has gained attention during the last few years. According to the current concepts of biological mechanisms underlying the possible protection, physical activity may alter menstrual function by reducing the number of ovulatory menstrual cycles via a hormone-related pathway and, thus, reducing the cumulative exposure to progesterone and estrogen. Experimental studies on the effects of exercise suggest changes in menstrual characteristics and in ovarian hormone serum levels. The majority of epidemiological studies, in spite of limitations in estimating physical activity and partly incomplete control of confounding factors, suggest a protective effect of physical activity. Whether physical activity offers a means of primary prevention of breast cancer is still an open issue.

Breast cancer: aetiological factors and associations (a possible protective role of phytoestrogens)

BACKGROUND

In spite of many known and suspected factors associated with the risk of breast cancer there has until recently been no explanation for its continuing increase in women of Western societies over recent decades or why there has not been an equivalent increase in women of most Asian and other less Westernized societies. It has long been suspected that a significant factor has been an increasing change of diet in Western societies from one predominantly vegetarian to one with a high content of meat and dairy products as well as 'refined' foods. Although diet has long been suspected there has otherwise been no real explanation as to the mechanism of the change in incidence of breast cancer.

METHODS

A comprehensive literature review has been made of aetiological factors and associations concerning breast cancer to determine whether any consistent trend can explain the rising incidence in Western societies.

RESULTS

There are a number of likely contributory factors but there is now accumulating evidence that the single most important difference is that people having a vegetarian diet have a high intake of legumes and other plant foods containing a variety of lignans and isoflavonoids. These appear to have an important role as nature's sex hormone modulators. These agents appear to be biologically active in a number of ways not yet completely understood but they do have both a weak oestrogenic effect and an anti-oestrogenic competitive effect, thus reducing the potential carcinogenic action of prolonged oestrogen activity. A probable additional benefit of such diets could be the role of dietary fibre.

CONCLUSIONS

A major problem of Western diets may not be the presence of meat or dairy products in the diet but the absence of desirable ingredients of vegetarian diets, namely dietary fibre and certain plant lignans and isoflavonoids. A modification of diet to include a greater proportion of fibre and soy or other leguminous plant food should be studied. Alternatively addition of more fibre and lignans and especially isoflavonoids to traditional Western diets would seem worthy of serious investigation. Such influences appear to have their greatest impact early in life and therefore could be especially important for girls and young women in Western societies.

Cancer risk and prognosis in Norway: comparing women in their first marriage with women who have never married

STUDY OBJECTIVE

The difference in risk of cancer between never married women and married women in their first marriage and whether survival from cancer was any different between the two groups were studied.

DESIGN

This was a population based, nested case-control study of cancer in Norwegian women diagnosed between 1966 and 1990, and followed up with regard to overall survival until the end of 1991.

SETTING

Norway.

PARTICIPANTS

These were Norwegian women born between 1935 and 1954. The case-control study included 12,237 married and 1466 unmarried cases, and 26,075 married and 2768 unmarried controls. In the survival analysis, 11,943 married and 1473 unmarried cases were included.

MAIN RESULTS

Unmarried women had an overall increased cancer risk (OR = 1.13, 95% CI 1.05, 1.21), which could be attributed to cancer of the ovaries, uterus, brain and haematological malignancies. For cervical and thyroid cancer, the risk was lower than for married women. In the survival analysis, unmarried cases had an overall 26% increased risk of dying (HR = 1.26, 95% CI 1.15, 1.39), after adjustment for age and stage at diagnosis. The increased death rate was seen for cancer of the cervix, lung, and thyroid.

CONCLUSIONS

Since most unmarried women were nulliparous, this might explain their increased risk of ovarian and uterine cancer. The increased risk of brain tumours and haematological malignancies may result from selection bias, since disease among unmarried women may cause a large proportion to remain unmarried. The lower survival in unmarried cases may support the hypothesis that psychosocial factors play a role in the prognosis of cancer patients.

Tobacco and diet as determinants of survival in male laryngeal cancer patients

In a series of 213 incident cases of laryngeal cancer, interviewed 10 years ago in the framework of a population-based case-control study, survival has been evaluated in relation to tobacco, alcohol consumption and dietary habits. The occurrence of other primaries and stage at diagnosis were taken into account as possible confounding factors. Heavy tobacco smoking appeared to worsen the prognosis in a dose-dependent manner. No effect was apparent for alcohol. The consumption of vegetables, citrus fruit, olive oil and orange juice was associated with a better prognosis; an opposite association was found for butter and milk. A tentative differentiation between dietary patterns showed a 36% advantage in survival for those whose dietary habits corresponded to the "Mediterranean diet". Our results support the hypothesis that diet may interfere with the mechanisms of cancer progression, and suggest that dietary intervention could be a means of improving survival in laryngeal cancer patients.

Sociodemographic factors associated with the diagnostic staging of breast cancer in southern Italy

BACKGROUND

There are marked regional differences in breast cancer mortality rates in Italy, probably linked to factors such as diagnostic delay, therapeutic strategies, and biologic and sociodemographic differences. To investigate a possible link between sociodemographic factors (e.g. age, education, and residence) and delay in the diagnosis of breast cancer, data were evaluated from all such patients from our Institute living in the Campania Region of Southern Italy for 1991-1993.

METHODS

Patients were grouped into Tis-T1/N0-N+ versus T2-4/N0-N+ and the variables examined were age (< 40, 41-50, 51-60, > 60 years), education (< or = 5 vs. > 5 school years) and residence (urban vs. rural). An analysis was made using the Pearson's Chi-square test and the multiple logistic regression.

RESULTS

Statistically significant differences were found for both residence (P = 0.04) and education level (P = 0.03) in the older than 60 years age group, but only for residence (P = 0.03) in the 51-60 years age group. The risks according to Mantel-Haenszel were 1.28 for education (P = 0.08) and 1.32 for residence in rural municipalities (P = 0.05). The odds ratio for residence in rural municipalities, adjusted by education and by the education-residence interaction, was 2.26 (95% confidence interval [CI], 1.12-4.54) in the 51-60 years age group and 1.74 (95% CI, 1.01-3.00) in the older than 60 years age group.

CONCLUSIONS

These data clearly indicate that residents of rural municipalities, as well as poorly educated subjects, are more likely than their respective counter-parts to have a delayed diagnosis of breast cancer.

Better breast cancer survival for postmenopausal women who are less overweight and eat less fat. The Iowa Women's Health Study

BACKGROUND

The authors sought to determine whether prediagnosis obesity, body-fat distribution, and dietary intake of fats, antioxidants, and fiber may be related to survival after the diagnosis of breast cancer.

METHODS

The mortality rates of 698 postmenopausal patients with unilateral breast cancer in a large cohort study were analyzed. Body-mass index, waist-to-hip ratio, and food-frequency data were collected by questionnaire within 6 years before breast cancer was diagnosed.

RESULTS

Adjusted for age, women in the highest tertile of body mass index had a 1.9-fold higher risk (95% confidence interval = 1.0-3.7) of dying after breast cancer than those in the lowest tertile; adjusted for other prognostic variables (age, smoking, education level, extent of breast cancer, and tumor size), this relative risk was 1.5 (95% CI = 0.7 to 2.9). Waist-to-hip ratio was not related to risk of dying nor was intake of fiber or several dietary antioxidants. Independent of other prognostic variables, risk of death after breast cancer was statistically significantly elevated, with a relative risk greater than 2.0 for the highest tertiles of total fat, saturated fat, and monounsaturated fat intake, expressed as grams per day. An adjustment for energy intake, which also was associated positively with fatality, weakened these associations somewhat.

CONCLUSIONS

Although clinical trials are required, these findings support the hypothesis that a high fat intake is associated with reduced survival of postmenopausal women with breast cancer and suggest that women with breast cancer should consider limiting their intake of fat.

Widowhood and divorce in relation to overall survival among middle-aged Norwegian women with cancer

The aim of the study was to examine the relations between widowhood and divorce and overall survival among women with cancer. All Norwegian women born between 1935 and 1954, and diagnosed with cancer between 1966 and 1990, were followed up until 1991. In all, 14,231 cases were followed up for a median length of approximately 4.5 years (mean = 6 years), and 4311 women died during follow-up. In addition to overall cancer, separate analyses have been made for cancer at specific sites. Widows had a risk of dying which was nearly identical to that of married women for all sites except colorectal cancer, for which widows had a 2-fold increased death rate compared with married women. Divorced women had an overall increased hazard ratio of 1.17 (95% CI 1.07-1.27), which was confined to cancer of the breast, lung and cervix. With few clear exceptions women with children had a better survival than nulliparous women (overall hazard ratio = 0.80, 95% CI 0.74-0.87).

Lifetime alcohol consumption and risk of breast cancer

The relation of lifetime alcohol intake to risk of breast cancer in pre- and postmenopausal women was examined in a case-control study in western New York. Cases with incident primary histologically confirmed breast cancer diagnosed during the period 1986-1991 (n = 740) and controls, frequency age-matched women drawn from New York state driver's license records (age < 65 yrs) and from records of the Health Care Finance Administration (age > or = 65 yrs, n = 810), were interviewed regarding intake of wine, beer, and hard liquor 2, 10, and 20 years ago and at 16 years of age. Although women in this study had generally low intakes of alcohol, there was little evidence of increased risk of breast cancer with intake of alcohol at any of the time periods or with an index of total lifetime intake. There was a weak indication of an increase in risk with beer for intakes of at least one drink per day. This risk was evident for 2, 10, and 20 years ago but not at 16 years of age. In this group with relatively low intakes of alcohol, evidence was weak for an association of increased risk of breast cancer with intake of alcohol, with the possible exception of a weak association with beer intake.