Nutritional factors and cancers of the breast, endometrium and ovary

Obesity in post menopausal women with a family history of breast cancer: prevalence and risk awareness

BACKGROUND

Obesity and physical activity are modifiable risk factors in the development of post-menopausal breast cancer. The aim of this study was to assess the level of awareness and prevalence of these factors in women attending family history clinics.

METHODS

Women attending the breast cancer family history clinic from 2004 to 2006 completed a questionnaire (SP15 format) about their knowledge of and exposure to various diet and lifestyle factors. All women had been counselled by a Consultant Cancer Geneticist and were given verbal and written information on the effect of life style on breast cancer risk. Responses were analysed using SPSStrade mark software.

RESULTS

The response rate was 70% and two thirds of women were post-menopausal. The prevalence of obesity in post-menopausal women was 37% with 40% being overweight. The majority of women consumed a healthy balanced diet. Only 15% of post-menopausal women exercised for more than 4 hours per week. Two-thirds of women correctly stated that obesity increases their breast cancer risk and 73% of these were overweight or obese. Over 87% were correctly aware of the role of family history, 68% of a high fat diet, and 57% of hormone replacement therapy in the development of breast cancer.

CONCLUSION

Women attending family history clinics lead a high risk lifestyle for the development of breast cancer with high prevalence of obesity and low levels of physical activity. A campaign of patient education is needed to promote healthy lifestyle choices, especially physical activity, in these high-risk women.

Wine and other alcohol consumption and risk of ovarian cancer in the California Teachers Study cohort

Objective

Whether alcohol consumption influences ovarian cancer risk is unclear. Therefore, we investigated the association between alcohol intake at various ages and risk of ovarian cancer.

Methods

Among 90,371 eligible members of the California Teachers Study cohort who completed a baseline alcohol assessment in 1995–1996, 253 women were diagnosed with epithelial ovarian cancer by the end of 2003. Multivariate Cox proportional hazards regression analysis was performed to estimate relative risks (RRs) and 95% confidence intervals (CIs).

Results

Consumption of total alcohol, beer, or liquor in the year prior to baseline, at ages 30–35 years, or at ages 18–22 years was not associated with risk of ovarian cancer. Consumption of at least one glass per day of wine, compared to no wine, in the year before baseline was associated with increased risk of developing ovarian cancer: RR = 1.57 (95% CI 1.11–2.22), P_trend = 0.01. The association with wine intake at baseline was particularly strong among peri-/post-menopausal women who used estrogen-only hormone therapy and women of high socioeconomic status.

Conclusions

Alcohol intake does not appear to affect ovarian cancer risk. Constituents of wine other than alcohol or, more likely, unmeasured determinants of wine drinking were associated with increased risk of ovarian cancer.

Obesity and prognosis of breast cancer

Obesity has a complicated relationship to both breast cancer risk and the clinical behaviour of the established disease. It is suggested that obesity is associated with both an increased risk of developing breast cancer risk and worse prognosis after disease onset. In post-menopausal women, various measures of obesity such as body mass index, weight, weight gain and waist : hip ratio have all been positively associated with risk of developing breast cancer. In most but not all case-control and prospective cohort studies, an inverse relationship has been found between weight and breast cancer among pre-menopausal women. Some data suggest that adult weight gain and central obesity increase the risk of pre-menopausal breast cancer. Obesity at the time of diagnosis is thought to be significant as a poor prognostic factor. Obesity is associated with adverse outcomes in both pre- and post-menopausal women with breast cancer. Many cancer survivors seek ways to minimize the risk of recurrence and death because of breast cancer. Despite complex and at times controversial data, enough evidence is available at present to suggest that weight management should be a part of the strategy to prevent the occurrence, recurrence and death because of breast cancer. In this review the effect of obesity on the prognosis of breast cancer is examined in detail.

Local biosynthesis and metabolism of oestrogens in the human breast

The origin of oestrogens at the level of the breast itself is discussed. In particular in postmenopausal women an accumulation of oestradiol at the site of breast tumours has been documented by a number of independent studies. The mechanism behind the high local oestrogens concentrations is thought to be the in situ production of these steroids by local processes with androstenedione as the main precursor. The presence of all enzymes required for this production has been demonstrated in a large proportion of breast tumours, with probably aromatase, hydroxysteroid dehydrogenase type 1 and sulfatase as the most important enzymes leading to the biologically highly active oestradiol. The individual enzymes that are relevant for the biosynthesis and the metabolism of oestrogens are discussed. The conclusion is reached that a number of these local processes may be involved in the promotion of premalignant lesions and in stimulation of growth of malignant tumours in the human breast.

Obesity and breast cancer: a review of the literature

A woman's build, the risk of breast cancer and its subsequent prognosis seem to be related. In most but not all case-control and prospective cohort studies, an inverse relationship has been found between weight and breast cancer among premenopausal women. However, most large epidemiological studies have found that overweight or obese women are at increased risk of developing postmenopausal breast cancer. It is suggested that higher body mass index is associated with a more advanced stage of breast cancer at diagnosis in terms of tumour size but data on lymph node status is not so consistent. All treatment modalities for breast cancer such as surgery, radiotherapy, chemotherapy and hormonal treatment may be adversely affected by the presence of obesity. The overall and disease-free survival is worse in most but not all studies of prognosis of obese pre- and postmenopausal women with breast cancer.

Glycemic index and glycemic load in endometrial cancer

Glycemic index (GI) and glycemic load (GL) are measures of the metabolic effects of dietary carbohydrates. The higher their value, the greater the glucose and insulin responses. Raised insulin levels are associated with endometrial cancer and with its risk factors including obesity, diabetes and hypertension. To study the role of the GI and GL we analyzed the data of two hospital-based case-control studies on endometrial cancer conducted between 1988-98 in Italy and Switzerland, including a total of 410 women with incident, histologically confirmed endometrial cancer and 753 controls admitted for acute, non-neoplastic diseases. A food frequency questionnaire was used to assess the subjects usual diet and to derive estimates of dietary GI and GL. The odds ratios (OR) of endometrial cancer, after adjustment for major risk factors, for the highest versus the lowest quintile of dietary GI and GL were 2.1 (95% confidence interval [CI] = 1.4-3.2) and 2.7 (95% CI = 1.8-4.2), respectively. The associations were stronger in older women, in those with higher body mass index and in hormone replacement therapy users. Our study supports the hypothesis of a direct association between GI and endometrial cancer risk.

Use of alternative therapies in menopause

Hormone replacement therapy has traditionally been used to treat the accompanying symptoms of oestrogen deficiency in menopause. However, not all women can, or prefer to, receive this treatment and alternatives should be considered to reduce the increased risk of osteoporosis and heart disease in menopausal women. This chapter reviews the current literature on the efficacy of phyto-oestrogens in preventing cardiovascular disease, various cancers and osteoporosis, as well as treating the vasomotor and other menopause-related symptoms. Select herbal therapies, as well as selective oestrogen receptor modulators, are also considered.

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 incidence and mortality in the European Union: cancer registry data and estimates of national incidence for 1990

Members of the European Network of Cancer Registries (ENCR) provide population-based data on cancer incidence for some countries and regions of Europe. These were supplemented by estimates in order to provide comparable information on cancer incidence and mortality in the 15 member states of the European Union (EU). The estimated numbers of new cases of cancer (excluding nonmelanoma skin cancer) in 1990 were approximately 706,900 in men and 644,200 in women. Approximately 497,500 men and 398,200 women died of cancer in the same year. The main sites of incident cases in men were lung (21%), large bowel (13%), prostate (12%), bladder (7%) and stomach (7%). For women, the predominant sites were breast (28%), large bowel (15%), lung (6%), uterine corpus (5%) and stomach (5%). The overall incidence rates for males were highest in continental Western Europe (France, The Netherlands, Austria, Luxembourg, Belgium, Germany and Italy) while the rates of Greece, Portugal, Sweden, Ireland, Spain, Finland, the U.K. and Denmark were below the average value for the EC. Rates for females were highest in Northern and Western Europe, with the exception of France, which had a relatively low rate for females, in common with Greece, Spain and Portugal. The geographical variations in incidence of the major cancers are discussed in relation to risk factors. The estimates show the substantial burden of cancer in European Union populations, but there are also indications of effects of past preventive measures and there is scope for further intervention. Cancer registries are an important source of information for cancer control since they provide population-based incidence and survival statistics. These, along with mortality data, are required to obtain a full picture of the frequency of cancer and its effects at the population level. Some 44% of the EU population is covered by registries. The European Network of Cancer Registries aims to standardise the information provided by existing registries and to provide practical assistance to those in development.

Dietary factors and cancers of breast, endometrium, and ovary: strategies for modifying fat intake in African American women

Modification of dietary fat and fiber could help prevent cancers of the breast, endometrium, and ovary that are prevalent in African-American women. Dietary intervention programs aimed at reducing fat intake have had mixed results in this population. The transtheoretic model is proposed for achieving dietary change. Strategies for changing health behaviors in African-American women include heightening sensitivity to cultural values among health educators and the use of multiple strategies to reinforce messages. To stimulate healthier eating, it is important to incorporate the distinct habitual eating patterns into innovative intervention methods, using effective behavioral change methods.

Phytoestrogens--a short review

The wide distribution of plant estrogens or 'phytoestrogens' in cereals, vegetables and medicinal plants raises questions concerning the possible health risks and benefits associated with their consumption. In this article, we provide a synopsis of the literature relating principally to the clinical effects of phytoestrogens on the diseases associated with ageing. The sources, metabolism and properties of the different phytoestrogens are also discussed. The studies included were primarily restricted to those with data pertinent to clinical practice. Our contention is that phytoestrogens are at least part of the reason why vegetarians and Asian populations have a low rate of cancer and heart disease.

Incidence trends for cancers of the breast, ovary, and corpus uteri in urban Shanghai, 1972-89

Incidence data from the Shanghai (People's Republic of China) Cancer Registry were used to assess the temporal trends of three major female cancers during 1972-89. Rates for cancers of the breast, corpus uteri and, to a lesser extent, ovary rose over the study period. The increases in breast and ovarian cancer were most pronounced among women under age 50, whereas those for corpus uteri cancer were restricted generally to those aged 55 to 69 years. When considered by cohort year of birth, risk of breast and ovarian cancers rose among women born since 1925 and 1935, respectively, but little evidence of cohort effect was apparent for corpus uteri cancer. Potential explanations for these patterns are explored.

Dietary factors and the risk of endometrial cancer

BACKGROUND

Endometrial cancer is associated with overweight, but little is known on its possible relationship with specific aspects of diet.

METHODS

The relationship between dietary factors and the risk of endometrial cancer was investigated in a case-control study conducted in Switzerland and Northern Italy on 274 patients with histologically confirmed endometrial cancers and 572 control subjects admitted to the hospital for acute nongynecologic disorders that were not hormone related, metabolic, or neoplastic.

RESULTS

Significant direct associations were observed with (1) the total energy intake (odds ratio [OR] for the highest versus the lowest consumption tertile = 2.7) and, after allowance for energy intake, (2) the frequency of consumption of most types of meats, eggs, beans or peas, added fats (OR for total added fat = 2.5), and sugar (OR = 2.5). Significant protection, of the order of 40-60% reduction in the highest versus the lowest consumption tertile, was conferred by elevated intake of most vegetables and fresh fruit and whole grain bread and pasta. This was reflected in the low OR for the highest tertiles of intake of beta-carotene and ascorbic acid (OR for the highest versus the lowest consumption tertile after allowance for energy intake = 0.5).

CONCLUSIONS

The current study suggests that, aside from the predictable adverse effects of overeating and consequent overweight, some qualitative aspects of the habitual diet may also be associated with the risk of endometrial cancer, chiefly, the intake of animal proteins and fat (directly) and of fresh fruit, vegetables, and fibers (inversely).

Selected physical activities and the risk of endometrial cancer

The relationship between various indicators of physical activity and endometrial cancer risk was analysed using data of a case-control study conducted in 1988-1991 in Switzerland and Italy on 274 histologically confirmed cases and 572 controls admitted to hospital for acute, non neoplastic, non hormone-related diseases. Using a self-rated assessment of total physical activity, there was a systematic tendency for the cases to report more frequently 'low' or 'very low' physical activity. The relative risks were similar for 'very high' or 'moderately high' physical activity, but increased in the two lowest levels, with point estimates, in various decades of age, between 1.3 and 2.3 for 'moderately low' and over 2.5 for 'very low' physical activity. Although the association was apparently stronger at older ages, all the trends in risk were significant. Allowance for major identified potential distorting factors, including body mass index and a measure of total energy intake, could explain only in part the association, and the inverse trends in risk remained statistically significant. When selected types of physical activity were analysed, no association was observed with climbing stairs or walking, but the risk estimates for the lowest level of activity was over 4 for housework, and between 1.5 and 1.9 for sport and leisure and occupational activity. Thus, the present findings suggest that a moderate or high physical activity is an indicator of reduced endometrial cancer risk, although this observation still requires epidemiologic confirmation and clearer definition from a pathogenic point of view.

Serum beta-lipoprotein, serum cholesterol and Quetelet's index as predictors for survival of breast cancer patients

We studied the survival of breast cancer patients in relation to serum cholesterol level, serum beta-lipoprotein level (BLP) and being overweight among women having breast cancer diagnosed during a follow-up period of 20 years. A cohort of 46,570 women attended a general health screening including examination of serum lipid levels, height and weight during 1963-1965. Of these, 1170 women developing breast cancer; 196 were below the age of 50 and 974 were above 50 years of age. 66 of the younger women, and 341 of the older women were reported to have died of breast cancer. A correlation was found between high serum BLP and decreased survival of breast cancer patients < 50 years of age. For women > or = 60 years of age, BLP was positively correlated to breast cancer survival. No correlation was found between serum cholesterol level and breast cancer survival in any age group. Increasing obesity was statistically significantly correlated to decreased survival with breast cancer. The latter findings were in accordance with other studies which have shown being overweight as a risk factor for breast cancer. As for the relationships between ischaemic heart disease and serum lipid levels, in studies of cancer risks in relation to serum cholesterol level, the different fractions of cholesterol seem to be of importance.

Dietary factors and breast cancer risk in Vaud, Switzerland

The relationship between dietary factors and the risk of breast cancer was investigated in a case-control study conducted in the Canton of Vaud, Switzerland as a pilot phase for a larger cooperative study within the SEARCH Programme of the International Agency for Research on Cancer (Lyon, France). A total of 107 incident, histologically confirmed cases of breast cancer and 318 controls admitted to hospital for acute, nonhormone-related, gynecological, metabolic, or neoplastic disorders were interviewed. Significant direct trends in risk were observed with total energy intake [relative risk (RR) for highest vs. lowest intake tertile = 1.9] and, after allowance for energy intake, with frequency of consumption of various types of meat (RR = 2.1 for the highest tertile), cheese (RR = 2.7), and alcohol (RR = 2.1). Significant protections, on the order of 40-60% reductions for the highest vs. lowest consumption tertile, were conferred by total green vegetable consumption, selected types of vegetables and fruits (cucumbers, onions, pears), and a summary index of beta-carotene intake (RR = 0.4 for highest consumption tertile). Thus the present study confirmed the existence of an unfavorable dietary pattern for breast cancer risk (characterized by high-calorie, selected sources of animal fat and alcohol intake). Moreover, a significant protection could be gained by consuming a diet rich in vegetables and perhaps fruits.

Alcohol and epithelial ovarian cancer

The relationship between alcohol consumption and the risk of epithelial ovarian cancer was analysed using data from a case-control study of 801 histologically confirmed epithelial ovarian cancers and 2114 controls in hospital for acute, non-neoplastic, gynecological, or hormone-related conditions, admitted to a network of teaching and general hospitals in the greater Milan area, northern Italy, i.e. a region with comparatively frequent alcohol consumption by women. Compared to alcohol abstainers, the multivariate relative risks (RRs) were 1.0 [95% confidence interval (CI), 0.7 to 1.4] for less than one, 1.1. (95% CI 0.9 to 1.6) for one to two, 1.2 (95% CI 1.0 to 1.5) for two to three and 1.3 (95% CI 0.9 to 1.8) for three or more drinks per day. A significant direct trend in risk with dose emerged. This finding chiefly derived from an association between ovarian cancer risk and consumption of wine (which accounts for over 90% of alcohol intake in this female population). Although no significant interaction between the effect of alcohol consumption and various women's characteristics emerged, there was a hint that the adverse influence of alcohol consumption is more marked in middle-age and less educated women. Thus, the results of this study suggest that relatively elevated alcohol intake (of the order of 40 g per day or more) may cause a modest increase of epithelial ovarian cancer risk.

Body mass at different ages and subsequent endometrial cancer risk

The relationship between body mass index (BMI) at different ages and subsequent endometrial-cancer risk was investigated in a multicentre case-control study conducted between 1988 and 1991 in Vaud, Switzerland, and Northern Italy on 272 histologically confirmed incident cases of endometrial cancer and 571 controls admitted to hospital for acute, non-neoplastic conditions, unrelated to known or potential risk factors for endometrial cancer. The risk of endometrial cancer increased with increasing BMI in the 3rd decade of age (20 to 29 years), in the 5th decade (40 to 49 years) and in the 7th decade (60 to 69 years), although the risk estimates tended to be substantially higher at older ages: compared with women whose BMI (kg m-2) was less than 20, the relative risks (RR) were 1.8 for BMI greater than or equal to 25 at age 20 to 29, 2.7 for BMI greater than or equal to 30 at age 40 to 49 and 3.8 at age 60 to 69. All the trends in risk were significant, except that for BMI at age 25 after allowance for current BMI. When data were examined in separate strata of current BMI, among women of normal body mass at diagnosis no significant effect of past overweight was observed. In contrast, among subjects over-weight at diagnosis, there were significant direct relationships with BMI at ages 20 to 29 and 40 to 49. To reduce endometrial cancer risk, it is therefore important to avoid obesity in later middle and older age, and the benefit can be even greater for women who were overweight at younger age.

Endogenous steroid hormones and local aromatase activity in the breast

To test the hypothesis of an increased activity of the enzyme aromatase in adipose tissue from affected when compared with non-affected quadrants of patients with breast cancer, the aromatase activity has been measured in tumour and fatty tissues dissected at specific sites from the breasts of 16 patients. Activity was measured after extensive purification of the product formed. Results, expressed in fmol/g of tissue, did not show a higher activity in the affected vs the non-affected quadrants. In the tumours, higher activities were found when expressed per g of tissue. Per mg of DNA, an indicator of the number of cells, tumour enzymatic activity was lower than in fatty tissues. The relations between the products of aromatase, oestrone and oestradiol in the various tissues point to the importance of additional enzymatic processes, especially of the reductive 17 beta-oestradiol dehydrogenase, in the accumulation of high quantities of oestradiol in the malignant tissue.

The epidemiology of ovarian cancer

The descriptive and analytical epidemiology of ovarian cancer is reviewed, starting from the substantial geographical differences, with high rates in North America and Europe and low rates in developing countries and Japan, although, on a worldwide scale, almost 50% of 140,000 total cases occur in developing countries. Over the past decades, incidence and mortality rates have remained approximately stable in high-risk areas, but have generally tended to rise in low-risk areas. In the past, ovarian cancer was more common in higher social classes, but sociocultural differences seem to have flattened off over recent decades. In etiological terms, the protection afforded by multiparity and oral contraceptive (OC) use is well established, with relative risks (RRs) of the order of 0.5 for multiparae and OC users. There is also consistent evidence that risk increases with late age at menopause. Less consistent and weak, if any, are the effects of age at menarche and first birth, although there is hint that a first birth over age 35 is not protective. It is conceivable that diet can play an important role in ovarian carcinogenesis, but only scattered data are available to suggest that high fat consumption may represent an indicator of risk. Available knowledge on ovarian cancer epidemiology is also discussed in relation to models of carcinogenesis and implications for prevention and public health.