Nutrition and endometrial cancer

Role of Vitamin C in Selected Malignant Neoplasms in Women

Since the first reports describing the anti-cancer properties of vitamin C published several decades ago, its actual effectiveness in fighting cancer has been under investigation and widely discussed. Some scientific reports indicate that vitamin C in high concentrations can contribute to effective and selective destruction of cancer cells. Furthermore, preclinical and clinical studies have shown that relatively high doses of vitamin C administered intravenously in ‘pharmacological concentrations’ may not only be well-tolerated, but significantly improve patients’ quality of life. This seems to be particularly important, especially for terminal cancer patients. However, the relatively high frequency of vitamin C use by cancer patients means that the potential clinical benefits may not be obvious. For this reason, in this review article, we focus on the articles published mainly in the last two decades, describing possible beneficial effects of vitamin C in preventing and treating selected malignant neoplasms in women, including breast, cervical, endometrial, and ovarian cancer. According to the reviewed studies, vitamin C use may contribute to an improvement of the overall quality of life of patients, among others, by reducing chemotherapy-related side effects. Nevertheless, new clinical trials are needed to collect stronger evidence of the role of this nutrient in supportive cancer treatment.

Overweight, obesity and the risk of gallbladder and extrahepatic bile duct cancers: A meta-analysis of observational studies

OBJECTIVE

Epidemiological studies have repeatedly investigated the association between excess body weight and the risk of biliary tract cancer with inconsistent results. The objective of this study was to quantitatively assess the associations between overweight and obesity and the risk of biliary tract cancer.

METHODS

A comprehensive search of PubMed, Embase, Web of Science, and China National Knowledge Infrastructure databases up to August 2015 was conducted, and the reference lists of retrieved articles for additional relevant studies were manually searched.

RESULTS

Fourteen prospective cohort studies and 15 case-control studies were included in this meta-analysis. These studies included 11,448,397 participants (6,733 patients with gallbladder cancer [GBC] and 5,798 patients with extrahepatic bile duct cancer [EBDC]) with follow-up durations ranging from 5 to 23 years. Among overweight adults, the pooled RR was 1.17 (95% CI, 1.07-1.28) for GBC and 1.26 (95% CI, 1.14-1.39) for EBDC, and among people with obesity, the pooled RR was 1.62 (95% CI, 1.49-1.75) for GBC and 1.48 (95% CI, 1.21-1.81) for EBDC. Visual inspection of the funnel plots and the Begg's and the Egger's tests did not show enough evidence of publication bias.

CONCLUSIONS

Integrated evidence from this meta-analysis suggests that excess body weight is associated with a significantly increased risk of GBC and EBDC.

Parity and endometrial cancer risk: a meta-analysis of epidemiological studies

The association between parity and endometrial cancer risk is inconsistent from observational studies. We aimed to quantitatively assess the relationship by summarizing all relevant epidemiological studies. PubMed (MEDLINE), Embase and Scopus were searched up to February 2015 for eligible case–control studies and prospective studies. Random-effects model was used to pool risk estimations. Ten prospective studies, 35 case-control studies and 1 pooled analysis of 10 cohort and 14 case-control studies including 69681 patients were identified. Pooled analysis revealed that there was a significant inverse association between parity and risk of endometrial cancer (relative risk (RR) for parous versus nulliparous: 0.69, 95% confidence interval (CI) 0.65–0.74; I² = 76.9%). By evaluating the number of parity, we identified that parity number of 1, 2 or 3 versus nulliparous demonstrated significant negative association (RR = 0.73, 95% CI 0.64–0.84, I² = 88.3%; RR = 0.62, 95% CI 0.53–0.74, I² = 92.1%; and RR = 0.68, 95% CI 0.65–0.70, I² = 20.0% respectively). The dose-response analysis suggested a nonlinear relationship between the number of parity and endometrial cancer risk. The RR decreased when the number of parity increased. This meta-analysis suggests that parity may be associated with a decreased risk of endometrial cancer. Further studies are warranted to replicate our findings.

At the crossroad between obesity and gastric cancer

Obesity has reached epidemic proportions worldwide with disproportionate prevalence in different communities and ethnic groups. Recently, the American Medical Association recognized obesity as a disease, which is a significant milestone that opens the possibilities of treating obesity under standardized health plans. Obesity is an inflammatory disease characterized by elevated levels of biomarkers associated with abnormal lipid profiles, glucose levels, and blood pressure that lead to the onset of metabolic syndrome. Interestingly, inflammatory biomarkers, in particular, have been implicated in the risk of developing several types of cancer. Likewise, obesity has been linked to esophageal, breast, gallbladder, kidney, pancreatic, and colorectal cancers. Thus, there exists a link between obesity status and tumor appearance, which may be associated to the differential levels and the circulating profiles of several inflammatory molecules. For example, mediators of the inflammatory responses in both obesity and gastric cancer risk are the same: pro-inflammatory molecules produced by the activated cells infiltrating the inflamed tissues. These molecules trigger pathways of activation shared by obesity and cancer. Therefore, understanding how these different pathways are modulated would help reduce the impact that both diseases, and their concomitant existence, have on society.

Hormonal therapy in advanced or recurrent endometrial cancer

BACKGROUND

Endometrial cancer is a cancer of the lining of the womb and worldwide is the seventh most common cancer in women. Treatment with hormones is thought to be beneficial in patients with endometrial cancer.

OBJECTIVES

To assess the indications, effectiveness and safety of hormone therapy for advanced or recurrent epithelial endometrial cancer.

SEARCH STRATEGY

We searched the Cochrane Gynaecological Cancer Group Trials Register, MEDLINE, EMBASE up to May 2009 and and CENTRAL (Issue 2, 2009). We also searched registers of clinical trials, abstracts of scientific meetings, reference lists of included studies, and contacted experts in the field.

SELECTION CRITERIA

Randomised controlled trials (RCTs) that studied hormonal therapy in adult women diagnosed with advanced or recurrent endometrial cancer.

DATA COLLECTION AND ANALYSIS

Two review authors independently abstracted data and assessed risk of bias. Comparisons were restricted to single-trial analyses so we did not synthesise data in meta-analyses.

MAIN RESULTS

We found six trials (542 participants) that met our inclusion criteria. These trials assessed the effectiveness of hormonal therapy in women with advanced or recurrent endometrial cancer as a single agent, as part of combination therapy and as low versus high dose. All comparisons were restricted to single-trial analyses, where we found no evidence that hormonal therapy as a single agent or as a combination treatment prolonged overall or five-year disease-free survival of women with advanced or recurrent endometrial cancer. However, low-dose hormonal therapy may have had a benefit in terms of overall and progression-free survival (PFS) compared to high-dose hormonal therapy (HR 1.31, 95% CI 1.04 to 1.66 and HR 1.35, 95% CI 1.07 to 1.71 for overall and PFS, respectively).

AUTHORS' CONCLUSIONS

We found insufficient evidence that hormonal treatment in any form, dose or as part of combination therapy improves the survival of patients with advanced or recurrent endometrial cancer. However, a large number of patients would be needed to demonstrate an effect on survival and none of the included RCTs had a sufficient number of patients to demonstrate a significant difference. In the absence of a proven survival advantage and the heterogeneity of patient populations, the decision to use any type of hormonal therapy should be individualised and with the intent to palliate the disease. It is debatable whether outcomes such as quality of life, treatment response or palliative measures such as relieving symptoms should take preference over overall and PFS as the major objectives of future trials.

Substance use and women's health

Scientific findings show that substance abuse in women yields a higher risk of a variety of health problems than substance abuse in men. Research suggests that women experience addiction telescoping when they abuse alcohol, tobacco, specific stimulants, and possibly opioids. Medical side effects also develop more rapidly in women than men when they abuse many substances. Cancer and cardiac complications, specifically, pose a significant threat for women who abuse almost all types of substances. However, the physical consequences are not the only ones women suffer when they engage in substance abuse. Research on substance abuse in women ties opioids to mood and anxiety disorders, heroin to neurological deficiencies, cocaine to immune system suppression, and alcohol to intimate partner abuse. Additionally, female substance abusers, on average, have a lower level of education and lower rates of employment. In light of these gender-specific concerns, physicians should give particular consideration to detecting substance abuse in women.

Early gastric cancer shows different associations with adipose tissue volume depending on histological type

BACKGROUND

Visceral obesity is known to be a risk factor for diabetes and cardiovascular disease. Cancer of the gastric cardia has been shown to have a close association with obesity in Western countries. In order to examine the possible relationship between fat volume and the development of gastric cancer (GC), we quantified visceral and subcutaneous fat areas of computed tomography (CT) images of patients with early GC.

METHODS

A total of 210 patients who underwent endoscopic resection or surgical gastrectomy and whose disease was pathologically diagnosed as early GC were investigated for total fat area (TFA), visceral fat area (VFA), and subcutaneous fat area (SFA) with Fat Scan software, using a CT slice at the umbilical level, and the relationships of these findings with clinical and pathological data were analyzed. The same analysis was performed in 147 patients with early colorectal cancer (CRC).

RESULTS

TFA, VFA, and SFA values in GC patients were not significantly different from the values in CRC patients. These values did not differ with the location of the GC. However, patients with undifferentiated-type GC had significantly smaller VFAs and SFAs than those with differentiated-type GC. Among the patients with undifferentiated GC, TFA and SFA values in the patients with submucosal cancer were significantly smaller than those in the patients with mucosal cancer.

CONCLUSION

GC has different associations with adipose tissue volume according to its histological type. As compared with differentiated GC, lower adipose tissue volume may be a preferential environment for the development and progression of undifferentiated GC.

Reduced risk of endometrial cancer from alcohol drinking in Japanese

The role of alcohol consumption in the etiology of endometrial cancer has not been clarified. To examine the association between alcohol consumption and endometrial cancer risk, we conducted a case-control study with 148 histologically diagnosed incident endometrial cancer cases and 1468 matched non-cancer controls. Median consumption of alcohol was only 19.3 g/week among cases who drank and 28.2 g/week among controls who drank. These values are lower than in Western countries. Relative risk was analyzed in subjects classified into four groups according to weekly alcohol consumption (non-drinkers, 1-24 g/week, 25-175 g/week, and >175 g/week). Confounder-adjusted odds ratios for those consuming alcohol at <25 g/week, 25-175 g/week, and >175 g/week compared to non-drinkers were 0.79 (95% confidence interval (CI), 0.49-1.28), 0.42 (95% CI, 0.23-0.79), and 0.47 (95% CI, 0.14-1.58), respectively. Further analysis was conducted concerning self-reported physical reaction to alcohol. Among women without flushing after drinking, a significant inverse association between risk and alcohol intake was seen (trend P = 0.001). In contrast, no protective effect of alcohol was seen among women who experience flushing after drinking. These results suggest the presence of an inverse association between alcohol drinking and endometrial cancer risk among Japanese women, and that this association is evident among those without flushing. Further investigation of these findings is warranted.

Nutritional factors in relation to endometrial cancer: a report from a population-based case-control study in Shanghai, China

We evaluated the role of dietary nutrients in the etiology of endometrial cancer in a population-based case-control study of 1,204 newly diagnosed endometrial cancer cases and 1,212 age frequency-matched controls. Information on usual dietary habits was collected during an in-person interview using a validated, quantitative food frequency questionnaire. Logistic regression analysis was conducted to evaluate the association of nutrients with endometrial cancer risk using an energy density method (e.g., nutrient intake/1,000 kilocalories of intake). Higher energy intake was associated with increased risk, which was attributable to animal source energy and a high proportion of energy from protein and fat. Odds ratios comparing highest versus lowest quintiles of intake were elevated for intake of animal protein (Odds ratio (OR) = 2.0, 95% confidential interval: 1.5-2.7) and fat (OR = 1.5, 1.2-2.0), but reduced for plant sources of these nutrients (OR = 0.7, 0.5-0.9 for protein and OR = 0.6, 0.5-0.8 for fat). Further analysis showed that saturated and monounsaturated fat intake was associated with elevated risk, while polyunsaturated fat intake was unrelated to risk. Dietary retinol, beta-carotene, vitamin C, vitamin E, fiber, and vitamin supplements were inversely associated with risk. No significant association was observed for dietary vitamin B1 or vitamin B2. Our findings suggest that associations of dietary macronutrients with endometrial cancer risk may depend on their sources, with intake of animal origin nutrients being related to higher risk and intake of plant origin nutrients related to lower risk. Dietary fiber, retinol, beta-carotene, vitamin C, vitamin E, and vitamin supplementation may decrease the risk of endometrial cancer.

Weight change and risk of endometrial cancer

BACKGROUND

Obesity is an established risk factor for endometrial cancer. Less well understood is the role of weight gain and weight change in determining risk.

METHODS

We analysed data from a population-based case-control study to evaluate the associations of body mass index (BMI), weight gain, and weight cycling with risk of endometrial cancer. Cases (n=740) under age 80 with a new diagnosis of endometrial cancer were identified from Wisconsin's cancer registry. Controls (n=2342) were randomly selected from driver's license lists and Medicare beneficiary files. Body size at three time points and other risk factor information were ascertained by interview in 1992-95.

RESULTS

Endometrial cases were more likely than controls to be nulliparous, have early ages at menarche and late ages at menopause, be diabetic, smoke cigarettes, and use post-menopausal hormones. After adjustment for these factors, increasing BMI was associated with increased risk (P-trend<0.001); women in the top quartile of BMI (>29 kg/m2) had a 3-fold greater risk of endometrial cancer [95% confidence interval (95% CI) 2.4-4.2] compared with women in the lowest quartile (<23 kg/-m2). For each 5 kg weight gain, the odds ratio (OR) for endometrial cancer risk equalled 1.2 (95% CI 1.2-1.3). History of weight cycling modestly increased risk after adjustment for BMI and other factors (OR=1.3; 95% CI 1.0-1.6). In addition, women who reported sustained weight loss had a reduced risk of endometrial cancer (OR=0.7; 95% CI 0.6-0.9).

CONCLUSIONS

These results suggest that weight gain and lack of weight stability are associated with risk of endometrial cancer.

Cancer risk-reduction behaviors of breast cancer survivors

Using secondary data analysis, the aim was to determine if postmenopausal women, who have survived breast cancer, have adopted healthy nutritional and physical activity behaviors recommended in the American Cancer Society guidelines as cancer risk-reduction strategies, and in guidelines for prevention of other chronic diseases or for improving general health. From their personal health history, women who have survived breast cancer would be likely candidates to adopt healthy behaviors recommended as cancer risk-reduction strategies or for prevention of other chronic diseases. A secondary aim was to determine the perceived general health and affective state of these women. These breast cancer survivors had a high perception of their general health, a positive affective state, and have adopted some healthy lifestyle behaviors, but they are not fully adhering to the ACS nutrition and physical activity guidelines or other health related guidelines for cancer risk reduction or prevention of other chronic diseases.

Obesity and cancer

Large prospective studies show a significant association with obesity for several cancers, and the International Agency for Research on Cancer has classified the evidence of a causal link as 'sufficient' for cancers of the colon, female breast (postmenopausal), endometrium, kidney (renal cell), and esophagus (adenocarcinoma). These data, and the rising worldwide trend in obesity, suggest that overeating may be the largest avoidable cause of cancer in nonsmokers. Few obese people are successful in long-term weight reduction, and thus there is little direct evidence regarding the impact of weight reduction on cancer risk. If the correlation between obesity and cancer mortality is entirely causal, we estimate that overweight and obesity now account for one in seven of cancer deaths in men and one in five in women in the US.

Primary clinical analysis of medical disorders in Chinese women with endometrial carcinoma

The objectives of this study were to survey the prevalence of medical disorders in Chinese women with endometrial carcinoma and evaluate their potential impact on the clinical treatment and prognosis. Three hundred and seven women with endometrial carcinoma, from July 1, 1971 to October 31, 2001, were analyzed retrospectively. One hundred and forty-six of them (47.6%) were found to have associated medical disorders. The most common medical disorders were hypertension (33.9%), diabetes mellitus (9.8%), and coronary heart disease (9.4%). As many as 38.4% of the women had two or more medical disorders. The patients with medical disorders were on average elder than those without any medical disorders (P < 0.01). Radiotherapy and chemotherapy were administered more commonly in the group with medical disorders than in the one without (P < 0.01). The rate of surgical procedures was significantly lower in the group with medical disorders than in the group without (P < 0.01). However, the extent of surgical interventions was similar in both groups (P > 0.05). The occurrence of medical disorders was independent of the tumor stage, grade, and histological types (P > 0.05). In addition, follow-up data showed that the 3-year and 5-year survivals were not influenced by the medical disorders (P > 0.05). The results thus suggest that Chinese women with endometrial carcinoma have frequently concurrent medical disorders. Selection of treatment strategies can be influenced by these associated medical disorders, but the overall survival is little changed.

Phytoestrogen intake and endometrial cancer risk

BACKGROUND

The development of endometrial cancer is largely related to prolonged exposure to unopposed estrogens. Phytoestrogens (i.e., weak estrogens found in plant foods) may have antiestrogenic effects. We evaluated the associations between dietary intake of seven specific compounds representing three classes of phytoestrogens (isoflavones, coumestans, and lignans) and the risk of endometrial cancer.

METHODS

In a case-control study from the greater San Francisco Bay Area, we collected dietary information from 500 African American, Latina, and white women aged 35-79 years who were diagnosed with endometrial cancer between 1996 and 1999 and from 470 age- and ethnicity-matched control women identified through random-digit dialing. Unconditional logistic regression analyses were used to estimate odds ratios (ORs) and 95% confidence intervals (CIs).

RESULTS

Isoflavone (OR = 0.59, 95% CI = 0.37 to 0.93 for the highest versus lowest quartile of exposure) and lignan (OR = 0.68, 95% CI = 0.44 to 1.1) consumptions were inversely related to the risk of endometrial cancer. These associations were slightly stronger in postmenopausal women (OR = 0.44, 95% CI = 0.26 to 0.77 and OR = 0.57, 95% CI = 0.34 to 0.97 for isoflavones and lignans, respectively). Obese postmenopausal women consuming relatively low amounts of phytoestrogens had the highest risk of endometrial cancer (OR = 6.9, 95% CI = 3.3 to 14.5 compared with non-obese postmenopausal women consuming relatively high amounts of isoflavones); however, the interaction between obesity and phytoestrogen intake was not statistically significant.

CONCLUSION

Some phytoestrogenic compounds, at the levels consumed in the typical American-style diet, are associated with reduced risk of endometrial cancer.

Diet in relation to endometrial cancer risk: a case-control study in Greece

The risk of endometrial cancer is positively associated with obesity, but the role of specific nutrients remains unclear. Given the distinct characteristics of the Greek diet and the low incidence of this form of cancer among Greek women, we undertook a case-control study to investigate the association of endometrial cancer with food groups and micronutrients. Cases were 84 women with histologically confirmed endometrial cancer and controls were 84 women with intact uterus admitted to the same teaching hospital in Athens, Greece. Consumption of pulses, nuts, and seeds was significantly inversely related to the risk for endometrial cancer. No other significant association with food groups was detected, although a protective effect of added lipids, which in the Greek diet are primarily represented by olive oil, was highly suggestive. Retinol, nicotinic acid, vitamin B- 6, and riboflavin were inversely associated with the disease. These findings need to be replicated, because this was a relatively small study with the statistical power to detect only strong associations between cases and controls; they appear, however, to support a role of diet in the etiology of endometrial cancer.

Overweight, obesity, and mortality from cancer in a prospectively studied cohort of U.S. adults

BACKGROUND

The influence of excess body weight on the risk of death from cancer has not been fully characterized.

METHODS

In a prospectively studied population of more than 900,000 U.S. adults (404,576 men and 495,477 women) who were free of cancer at enrollment in 1982, there were 57,145 deaths from cancer during 16 years of follow-up. We examined the relation in men and women between the body-mass index in 1982 and the risk of death from all cancers and from cancers at individual sites, while controlling for other risk factors in multivariate proportional-hazards models. We calculated the proportion of all deaths from cancer that was attributable to overweight and obesity in the U.S. population on the basis of risk estimates from the current study and national estimates of the prevalence of overweight and obesity in the U.S. adult population.

RESULTS

The heaviest members of this cohort (those with a body-mass index [the weight in kilograms divided by the square of the height in meters] of at least 40) had death rates from all cancers combined that were 52 percent higher (for men) and 62 percent higher (for women) than the rates in men and women of normal weight. For men, the relative risk of death was 1.52 (95 percent confidence interval, 1.13 to 2.05); for women, the relative risk was 1.62 (95 percent confidence interval, 1.40 to 1.87). In both men and women, body-mass index was also significantly associated with higher rates of death due to cancer of the esophagus, colon and rectum, liver, gallbladder, pancreas, and kidney; the same was true for death due to non-Hodgkin's lymphoma and multiple myeloma. Significant trends of increasing risk with higher body-mass-index values were observed for death from cancers of the stomach and prostate in men and for death from cancers of the breast, uterus, cervix, and ovary in women. On the basis of associations observed in this study, we estimate that current patterns of overweight and obesity in the United States could account for 14 percent of all deaths from cancer in men and 20 percent of those in women.

CONCLUSIONS

Increased body weight was associated with increased death rates for all cancers combined and for cancers at multiple specific sites.

Dietary factors in relation to endometrial cancer: a nationwide case-control study in Sweden

The incidence of endometrial cancer varies up to 10-fold between high- and low-incidence regions, suggesting the importance of environmental factors, including diet, in the etiology of this disease. However, few studies have examined the role of diet in the etiology of endometrial cancer. Using unconditional logistic regression to estimate odds ratios (OR) and 95% confidence intervals (CI), we analyzed data from a large, case-control study of Swedish-born postmenopausal women aged 50-74 yr (709 cases and 2,887 controls) residing in Sweden between 1994 and 1995. We found no clear association between foods or food groups and endometrial cancer risk, although high consumption of certain foods, such as Brassica vegetables, coffee, and legumes, might be associated with small-to-moderate reduced risks of endometrial cancer, while red meat consumption might be associated with a small-to-moderate increased risk. Daily use of calcium supplements appeared to lower endometrial cancer risk (OR = 0.5, 95% CI = 0.3-0.9, P for trend = 0.04), especially among women with low calcium intake from dairy products. On the other hand, the use of iron supplements appeared to increase the risk (OR = 1.7, 95% CI = 0.9-3.3, P for trend = 0.03). The findings are discussed with respect to previous studies and the possible underlying mechanisms.

A cohort study of nutritional factors and endometrial cancer

To evaluate the role of nutritional factors in the etiology of endometrial cancer, we performed a case-cohort analysis using data from women enrolled in the National Breast Screening Study in Canada from 1980 to 1985. For this analysis, a subcohort was constructed by selecting a 10% random sample from the 56,837 women in the dietary cohort. Cases were the 221 women diagnosed with incident adenocarcinoma of the endometrium during follow-up to December 31, 1993 and ascertained by record linkage to the Canadian Cancer Database. Information on usual diet at enrollment and other epidemiological variables was collected by means of self-administered questionnaires. Hazard ratios were obtained from proportional hazards regression models, with estimation of robust standard errors. We found a strong association of endometrial cancer with body mass index > 25 kg/m2 (hazard ratio 2.72, 95% CI: 2.06-3.50). Endometrial cancer risk was not associated significantly with intakes of total energy, carbohydrates, proteins, total fat and major fatty acids, total dietary fiber and various types of fibers, vitamin C, E and A, folic acid, beta-carotene, lutein, or cryptoxanthin. Some decrease in risk was noted with relatively high intakes of saturated fat, animal fat or lycopene. The associations observed in the study were independent of total energy intake and most non-dietary risk factors. The study suggests that dietary intakes of energy and most major nutrients are not related to the risk of endometrial cancer among Canadian women.

Fruit and vegetable consumption in the prevention of cancer: an update

Fruit and vegetables are considered to be important means of preventing cancer through diet. However, several recent large prospective cohort studies and clinical trials have found no associations regarding several major cancers, including cancers of the colon, breast and stomach. Although these results are disconcerting, especially for health-conscious individuals, there is also mounting evidence that people who avoid fruit and vegetables completely, or consume very little, are indeed at increased risk of these cancers. These individuals in particular should be identified, with the goal of helping them find ways to include more fruit and vegetables in their diets.

A double-blind randomized study on the effects of red clover isoflavones on the endometrium

OBJECTIVE

To assess the effects of a red clover-derived isoflavone extract on the Ki-67 proliferative marker of endometrial biopsies in 45-to 50-year-old perimenopausal women. We hypothesized that we would be able to detect a decrease in the Ki-67 proliferative index during the late follicular phase after a 3-month course of approximately 50 mg red clover isoflavones. Isoflavones have been found to have some antiestrogenic effects, and an antiproliferative effect during the perimenopausal period may be especially useful owing to the excessive endometrial proliferation often characteristic of this period.

DESIGN

In a double-blind, randomized, controlled study, 30 women between the ages of 45 and 50 years consented to an endometrial biopsy before and after a 3-month course of either placebo or active isoflavone extract. The biopsies were timed as close as possible to days 7-11 of the menstrual cycle, and simultaneous measurements of transvaginal endometrial thickness, uterine artery Doppler, hormone profiles, lipids, and bone markers were performed.

RESULTS

Of 30 women, 2 did not return for a second biopsy, and a third had an unsuccessful second biopsy. Four subjects were excluded from the Intention to Treat analysis because they did not have a menstrual bleed within the time frame of the study (3 subjects) or were tested on day 13 instead of between days 7 and 11 of the cycle (1 subject). There was no change in the Ki-67 proliferation index after treatment in either group. Eight subjects in the placebo group and eight in the P-07 group had proliferative endometrial biopsies that were synchronized with estradiol levels at baseline and post-treatment, and analysis of these subjects revealed no detectable change in the relationship between estradiol levels and Ki-67 with treatment in either group. There was no change in fasting lipids, bone markers, uterine Doppler resistance, or pulsatility index.

CONCLUSION

In this small pilot study, we did not find, using immunohistochemical quantification of the Ki-67 antigen, that red clover isoflavones had an antiproliferative effect in the endometrium. Small sample size, examination of a relatively short interval in the menstrual cycle, and isoflavone formulation may have contributed to our lack of findings; however, we believe that the issue of isoflavones and their possible antiproliferative effect is deserving of further study. A simpler physiological model with less hormonal variability, such as healthy, recently menopausal women on predetermined doses of estrogen, may prove to be more informative.

Alcoholism and risk for endometrial cancer

Endogenous estrogens increase the risk of endometrial cancer and are also elevated among women with high alcoholic intake. It is incompletely known, however, whether alcohol intake in general and alcohol abuse in particular increases risk for endometrial cancer. We thus analyzed prospectively the risk for endometrial cancer among 36,856 women hospitalized with alcoholism between 1965 and 1994 through linkages between several national Swedish registers. Compared with the general population, women who were alcoholics had an overall 24% lower risk of developing endometrial cancer, a finding challenging our a priori hypothesis. However, among women below the age of 50 years at follow-up, the mean age of menopause among Swedish women, the risk was 70% higher, whereas the risk among women aged 50 years or more at follow-up was 40% lower compared with the general population. Hence, the effect of alcoholism on endometrial cancer appears to be age dependent.

Cancer-related risk indicators and preventive screening behaviors among lesbians and bisexual women

OBJECTIVES

This study examined whether lesbians are at increased risk for certain cancers as a result of an accumulation of behavioral risk factors and difficulties in accessing health care.

METHODS

Prevalence estimates of behavioral risk factors (nulliparity, obesity, smoking, and alcohol use), cancer screening behaviors, and self-reported breast cancer histories derived from 7 independently conducted surveys of lesbians/bisexual women (n = 11,876) were compared with national estimates for women.

RESULTS

In comparison with adjusted estimates for the US female population, lesbians/bisexual women exhibited greater prevalence rates of obesity, alcohol use, and tobacco use and lower rates of parity and birth control pill use. These women were also less likely to have health insurance coverage or to have had a recent pelvic examination or mammogram. Self-reported histories of breast cancer, however, did not differ from adjusted US female population estimates.

CONCLUSIONS

Lesbians and bisexual women differ from heterosexual women in patterns of health risk. These women would be expected to be at especially greater risk for chronic diseases linked to smoking and obesity.

Energy balance and cancer: the role of insulin and insulin-like growth factor-I

Recent theories propose that a Western lifestyle may increase cancer risk through alterations in the metabolism of insulin and insulin-like growth factors (IGF: McKeown-Eyssen, 1994; Giovannucci, 1995; Kaaks, 19%; Werner & LeRoith, 1996). Insulin regulates energy metabolism, and increases the bioactivity of IGF-I, by enhancing its synthesis. and by decreasing several of its binding proteins (IGFBP; IGFBP-1 and -2). Insulin and IGF-I both stimulate anabolic processes as a function of available energy and elementary substrates (e.g. amino acids). The anabolic signals by insulin or IGF-I can promote tumour development by inhibiting apoptosis, and by stimulating cell proliferation. Furthermore, both insulin and IGF-I stimulate the synthesis of sex steroids, and inhibit the synthesis of sex hormone-binding globulin (SFIBG), a binding protein that regulates the bioavailability of circulating sex steroids to tissues. The present paper reviews epidemiological findings relating the risk of cancers of the colo-rectum, pancreas, breast, endometrium and prostate to body size (obesity, height) and physical activity, and discusses the relationships between obesity and physical activity and plasma levels of insulin, IGF-I and IGFBP. Subsequent sections review epidemiological findings relating cancer risk to indices of chronic hyperinsulinaemia, and to plasma levels of IGF-I and IGFBP. Conclusions are that chronic hyperinsulinaemia may be a cause of cancers of the colon, pancreas and endometrium, and also possibly of the breast. On the other hand, elevated plasma IGF-I, as total concentrations or relative to levels of IGFBP-3, appears to be related to an increased risk of prostate cancer, breast cancer in young women, and possibly cob-rectal cancer. For cancers of the endometrium, breast and prostate, these findings are discussed in the context of relationships between insulin and IGF-I and levels of bioavailable sex steroids.

Dietary factors and cancer risk

OBJECTIVES

To discuss the relationship between dietary factors and cancer risk reduction, the status of prevention trials in progress, and current dietary recommendations.

DATA SOURCES

Published research and review articles, medical books, and web sites.

CONCLUSIONS

Evidence indicates that dietary factors can reduce the risk of developing cancer. The dietary recommendations for cancer risk reduction are consistent with those for prevention of other chronic diseases and are thus useful for the majority of the population.

IMPLICATIONS FOR NURSING PRACTICE

In their role as educators, it is essential for nurses to provide accurate and timely information on diet and cancer risk reduction to their patients and the public and to encourage compliance with dietary recommendations.

Cereals, legumes, and chronic disease risk reduction: evidence from epidemiologic studies

There is growing evidence that cereals and legumes play important roles in the prevention of chronic diseases. Early epidemiologic studies of these associations focused on intake of dietary fiber rather than intake of grains or legumes. Generally, these studies indicated an inverse association between dietary fiber intake and risk of coronary artery disease; this observation has been replicated in recent cohort studies. Studies that focused on grain or cereal intake are fewer in number; these tend to support an inverse association between intake of whole grains and coronary artery disease. Studies on the association of dietary fiber with colon and other cancers have generally shown inverse relations, but whether these relations are attributable to cereals, other fiber sources, or other factors is less clear. Although legumes have been shown to lower blood cholesterol concentrations, epidemiologic studies are few and inconclusive regarding the association of legumes with risk of coronary artery disease. It has been hypothesized that legumes, in particular soybeans, reduce the risk of some cancers, but epidemiologic studies are equivocal in this regard. Overall, there is substantial epidemiologic evidence that dietary fiber and whole grains are associated with decreased risk of coronary artery disease and some cancers, whereas the role of legumes in these diseases appears promising but as yet inconclusive.

Lifestyle and endometrial cancer risk: a cohort study from the Swedish Twin Registry

Case-control studies of lifestyle factors have been inconclusive in the study of endometrial cancer, and prospective data are scarce. Our aim was to examine the associations of physical activity, weight and weight change, fruit, vegetable, and alcohol consumption, socio-economic status, parity and presence of diabetes mellitus with the risk of endometrial cancer in a cohort study. In 1967, 11,659 women in the Swedish Twin Registry, born 1886-1925, answered a 107-item questionnaire, including questions about diet, physical activity and other lifestyle factors. Complete follow-up through 1992 was attained through record linkage to the Swedish Cancer and Death Registers. The relative risks for endometrial cancer were estimated in proportional hazards models that adjusted confidence limits for correlated outcomes. We observed 133 incident cases of endometrial cancer in the cohort. There was no clear pattern of risk over strata of alcohol or fruit and vegetable intake, although the data suggest an increased risk with very low fruit and vegetable intake. Increasing physical activity markedly decreased the risk of endometrial cancer (p for trend < 0.01), independently of weight and parity; the risk in the highest quartile, relative to the sedentary category, was 0.2 (95% CI 0.3-0.8). As expected, higher weight in middle age increased the risk (p for trend < 0.01), as did higher weight in early adulthood. Contrary to previous findings, weight gain did not have an effect independent of weight at enrollment. We did not find a genetic component to endometrial cancer. Our results confirm that environmental factors are the most important, especially physical activity, parity, and weight in young and middle age.

Specific versus non-specific effects of dietary fat on carcinogenesis

It will be apparent from this review that dietary fat can exert both specific and non-specific effects on carcinogenesis, at least in experimental animals. The non-specific effects appear to be related primarily to effects of dietary fat on energy balance. Although a positive energy balance can be achieved on a high-carbohydrate low-fat diet, it is much more likely to occur on a high-fat diet because of the high energy density of fat [101] and the fact that dietary fat is less capable of imparting a sense of satiety [102]. A continuing state of positive energy balance leads to obesity which has been associated with increased risk of cancer at a number of sites, including endometrium [103-106], postmenopausal breast cancer [107-113], renal cancer [114,115] and possibly cancers of the colorectum [116-122], pancreas [103,123] and prostate [124]. Whereas the non-specific effects of dietary fat appear to be deleterious for cancer, the specific effects in some cases can be beneficial. Examples are long-chain n-3 polyunsaturated fatty acids. CLA and tocotrienols. It is still too early to predict whether these may be of value in the prevention and/or treatment of human cancer but they seem worthy of further investigation. Knowledge of their mechanism of action may suggest novel approaches to the cancer problem and, as in the case of vitamins A and D, it may be possible to find analogues with more potent anti-cancer activity.

Obesity as a risk factor for certain types of cancer

In conclusion, obesity has been associated with increased risk for a number of different types of cancer. The evidence has been most consistent for endometrial cancer, breast cancer in postmenopausal women, and renal cell cancer. More variable results have been reported for colorectal, prostate and pancreatic cancer. Possible mechanisms by which obesity may influence cancer risk include alteration in hormonal patterns, including sex hormones and insulin, and factors such as the distribution of body fat and changes in adiposity at different ages. The increasing prevalence of obesity in many parts of the world emphasizes the importance of learning more about the relationship between obesity and cancer and the mechanisms involved in their interaction.

Cancer screening of older women : a primary care issue

PURPOSE

The purpose of this retrospective chart review was to examine whether family practice physicians and residents were screening older women for breast, gynecologic, and colorectal cancers as recommended by the American Cancer Society, the Guide to Clinical Preventive Services, and Healthy People 2000.

METHODS

A retrospective chart review of women 60 years and older who were seen at least twice between July 1, 1992, and June 30, 1993, in a midwestern family practice residency program was completed. From the original sample of 660 potential subjects, a systematic random selection of every third chart was identified for review, resulting in a sample of 201. Analysis of the data was performed by descriptive statistics and chi-square tests. A series of multiple regression models using age, number of visits, type and gender of provider, and personal or family history of cancer as predictor variables was performed.

RESULTS

Breast cancer screening was offered to approximately 70% of the sample, with only about one third of the older women receiving mammography or clinical breast examination. Recommendations for gynecologic cancer screening were given to 63% of the sample, with less than one third receiving Papanicolaou smears. Recommendations for digital rectal examination, fecal occult blood test, and flexible sigmoidoscopy were 58%, 59%, and 30%, respectively. The percentages of patients who actually received these tests were considerably lower.

CLINICAL IMPLICATIONS

Barriers for appropriate cancer screening for older women exist for both the provider and the patient; however, many of these obstacles can be overcome. Improving the resident's exposure to the current recommendations, increasing geriatric content in the training program, and initiating a reminder system may reduce some of the provider barriers. The use of midlevel providers may increase the preventive services offered to older women as well as educate and empower these women to become responsible for their own healthcare. Together, physicians and midlevel providers can become patient advocates through political activism, encouraging legislation that guarantees payment for cancer screening tests. Finally, primary care providers can become actively engaged in research that explores the healthcare concerns of older women.