Oesophageal cancer in women: tobacco, alcohol, nutritional and hormonal factors

The association of serum choline concentrations with the risk of cancers: a community-based nested case-control study

Few studies have been designed to investigate the effect of serum choline on the risk of incident cancer. This study aims to explore the association between serum choline and the risk of new-onset cancer. We conducted a case-control study, including 199 patients with incident cancer and 199 matched controls during a median of 3.9 years of follow-up, nested within the China Stroke Primary Prevention Trial. Cubic spline regression (RCS) and conditional logistic regression analysis was used to assess the association of serum choline and incident cancer risk. We observed a positive dose-response association between serum choline levels and the risk of overall (p for overall = 0.046) and digestive system cancer (p for overall = 0.039). Compared with patients with the lowest choline levels (Q1 group), patients in the highest levels of choline (Q4) had a 3.69-fold and 6.01-fold increased risk of overall (OR = 3.69, 95% CI 1.17-11.63) and digestive system cancer (OR = 6.01, 95% CI 1.14-31.67). Elevated choline levels (per SD, 11.49 μg/mL) were associated with a higher risk of overall cancer among participants who were older, male, and smokers in the subgroup analyses. We found a positive association between elevated levels of serum choline with increased risk of incident cancer. Our findings have critical clinical implications for cancer prevention and diagnosis.Trial registration CSPPT, NCT00794885. Registered: November 20, 2008. https://www.clinicaltrials.gov/ct2/show/study/NCT00794885 https://www.clinicaltrials.gov/ct2/show/study/NCT00794885.

Use of anti-androgenic 5α-reductase inhibitors and risk of oesophageal and gastric cancer by histological type and anatomical sub-site

Background

To investigate if anti-androgenic medications 5α-reductase inhibitors (5-ARIs) decrease the risk of developing oesophageal and gastric tumours, analysed by histological type and anatomical sub-site.

Methods

A Swedish population-based cohort study between 2005 and 2018 where men using 5-ARIs were considered exposed. For each exposed participant, ten male age-matched non-users of 5-ARIs (non-exposed) were included. Multivariable Cox regression provided hazard ratios (HR) with 95% confidence intervals (CI) adjusted for age, calendar year, smoking, non-steroidal anti-inflammatory drugs/aspirin use, and statins use. Further adjustments were made depending on the tumour analysed.

Results

The cohort included 191,156 users of 5-ARIs and 1,911,560 non-users. Overall, the use of 5-ARIs was not associated with any statistically significantly reduced risk of oesophageal or cardia adenocarcinoma (adjusted HR 0.92, 95% CI 0.82–1.02) or gastric non-cardia adenocarcinoma (adjusted HR 0.90, 95% CI 0.80–1.02). However, the use of 5-ARIs indicated a decreased risk of oesophageal or cardia adenocarcinoma among obese or diabetic participants (adjusted HR 0.55, 95% CI 0.39–0.80) and a reduced risk of oesophageal squamous cell carcinoma (adjusted HR 0.49, 95% CI 0.37–0.65).

Conclusion

Users of 5-ARIs may have a decreased risk of developing oesophageal or cardia adenocarcinoma among those obese or diabetic, and a decreased risk of oesophageal squamous cell carcinoma.

Obesity and incident gastrointestinal cancers: overall body size or central obesity measures, which factor matters?

BMI does not reflect the location or amount of body fat. We aimed to investigate the role of general and central obesity measures in the prediction of incident gastrointestinal cancers. In this analysis of the Golestan Cohort Study, we included 47 586 cancer-free individuals followed for 12.3 years (IQR: 10.5-13.2). We investigated the association of obesity measures including BMI, waist circumference and waist-to-hip ratio (WHR) at enrollment and the incidence of esophageal, gastric, colorectal and pancreatic cancers. Cox proportional hazard models were used to estimate the association between covariates and gastrointestinal cancer risk. We observed no significant associations between obesity measures and incidence of the above-mentioned gastrointestinal cancers in men. In women, BMI, waist circumference and WHR were associated with significant reductions in the risk of esophageal squamous cell carcinoma (ESCC): hazard ratio (HR): 0.67 [95% confidence interval (CI): 0.56-0.81], HR: 0.71 (95% CI: 0.60-0.84) and HR: 0.80 (95% CI: 0.68- 0.94), respectively. In addition, WHR was associated with significantly increased risks for colorectal cancer (HR: 1.39, 95% CI: 1.08-1.78) and gastric cancer (HR: 1.24, 95% CI: 1.01-1.51) in women. In this study, statistically significant associations between obesity measures and incident esophageal, gastric and colorectal cancers were seen in women.

[Benefit-risk balance of hormone replacement therapy: Cancers and mortality. Postmenopausal women management - CNGOF and GEMVi clinical practice guidelines]

The use of hormone replacement therapy (HRT) for menopausal women has been the subject of much controversy in recent years, particularly concerning the carcinologic risks. The purpose of this review is to evaluate the impact of the use of HRT on the risk of gynecological but also extra-gynecological cancers. The effect of the type and the duration of use of HRT in menopausal women will also be discussed. The beneficial impact of HRT on overall mortality is also an element that will be discussed and must be taken into account when evaluating the benefit-risk balance of HRT for menopausal women.

Gender Differences in Oesophageal Squamous Cell Carcinoma in a South African Tertiary Hospital

(1) Oesophageal squamous cell carcinoma is common in Africa and has a male preponderance. The gender-based differences in clinical presentation and risk factor exposure are poorly studied in the African context. Our aim was to compare males and females with this disease. We analyzed the differences in clinical features and risk factor exposure between males and females with oesophageal cancer. (2) Data from patients presenting to a tertiary hospital in South Africa with oesophageal squamous cell carcinoma were analyzed. Data collected included patient demographics, clinical presentation, pathology and risk factor exposure. (3) Three hundred and sixty three patients were included in the study. The male to female ratio was 1.4:1. The mean age was 66 years for females and 61 years for males (p < 0.0001). A significantly larger percentage of males were underweight compared to females (60% vs. 32%, p < 0.001). There were no differences between the genders with regards to performance status, dysphagia grade and duration and tumor length, location and degree of differentiation. There were significant differences between risk factor exposure between the two genders. Smoking and alcohol consumption was an association in more than 70% of males but in less than 10% of females There was no difference survival. (4) Female patients with oesophageal squamous cell carcinoma (OSCC) are older and have a higher body mass index (BMI) than their male counterparts. Traditionally purported risk factors of smoking and alcohol consumption are infrequent associations with OSCC in female patients and other environmental risk factors may be more relevant in this gender.

Alcohol, Alcoholic Beverages and Risk of Esophageal Cancer by Histological Type: A Dose–Response Meta-Analysis of Observational Studies

Aims

We conducted a dose–response meta-analysis to explore the association between alcohol and particular alcoholic beverages with risk of esophageal cancer (EC) by histological type [esophageal squamous cell carcinoma (ESCC) and esophageal adenocarcinoma (EAC)] and whether the association differs according to gender.

Methods

PubMed and Web of Science databases were searched for relevant articles published between January 1960 and December 2019. The pooled relative ratios (RRs) and 95% confidence interval (CI) were calculated with the fixed or random effect model. The dose–response relationship was assessed by restricted cubic spline.

Results

A total of 74 published articles involving 31,105 cases among 3,369,024 participants were included in this meta-analysis. The pooled RRs of the highest versus lowest alcohol intake were 3.67 (95% CI, 2.89,4.67) for EC, 5.11 (95% CI, 3.60,7.25) for ESCC and 0.96 (95% CI, 0.79,1.16) for EAC. The above-mentioned associations were observed in cohort design, for different alcoholic beverages (beer, wine and liquor/spirits) and gender. Evidence of a nonlinear dose–response relationship for EC risk with alcohol intake was found (Pnon-linearity &lt; 0.001), and a linear relationship (Pnon-linearity = 0.216) suggested that the risk of ESCC increased by 33% for every 12.5 g/day increment of alcohol intake.

Conclusions

This meta-analysis suggests that alcohol intake might significantly increase the incidence of EC, especially for ESCC.

Esophageal cancer genetics in South Africa

Esophageal cancer (EC) is an extremely aggressive cancer with one of the highest mortality rates. The cancer is generally only diagnosed at the later stages and has a poor 5-year survival rate due to the limited treatment options. China and South Africa are two countries with a very high prevalence rate of EC. EC rates in South Africa have been on the increase, and esophageal squamous cell carcinoma is the predominant subtype and a primary cause of cancer-related deaths in the black and male mixed ancestry populations in South Africa. The incidence of EC is highest in the Eastern Cape Province, especially in the rural areas such as the Transkei, where the consumption of foods contaminated with Fusarium verticillioides is thought to play a major contributing role to the incidence of EC. China is responsible for almost half of all new cases of EC globally. In China, the prevalence of EC varies greatly. However, the two main areas of high prevalence are the southern Taihang Mountain area (Linxian, Henan Province) and the north Jiangsu area. In both countries, environmental toxins play a major role in increasing the chance that an individual will develop EC. These associative factors include tobacco use, alcohol consumption, nutritional deficiencies and exposure to environmental toxins. However, genetic polymorphisms also play a role in predisposing individuals to EC. These include single-nucleotide polymorphisms that can be found in both protein-coding genes and in non-coding sequences such as miRNAs. The aim of this review is to summarize the contribution of genetic polymorphisms to EC in South Africa and to compare and contrast this to the genetic polymorphisms observed in EC in the most comprehensively studied population group, the Chinese.

The long-term spatial-temporal trends and burden of esophageal cancer in one high-risk area: A population-registered study in Feicheng, China

BACKGROUND

Feicheng County is a high-risk area for esophageal cancer in Shandong province, China. It is important to determine the long-term spatio-temporal trends in epidemiological characteristics and the burden of esophageal cancer, especially since the implementation of the national esophageal cancer screening program for early detection and treatment in 2005.

METHODS

The data collected in Feicheng County from 2001 to 2012 was extracted from the whole-population cancer registry system. The incidence, mortality, disability-adjusted life years (DALY) and changing trends in esophageal cancer according to age and sex were calculated and described.

RESULTS

The incidence rate of esophageal cancer in Feicheng was consistently high, and increased significantly for male, but not for female from 2001 to 2012, according to the joinpoint regression analysis. The highest and lowest yearly crude incidence rates were 160.78 and 95.97 per 100000 for males, and 81.36 and 52.17 per 100000 for females. The highest and lowest crude yearly mortality rates were 122.26 and 94.40 per 100000 for males, and 60.75 and 49.35 per 100000for females. Esophageal squamous cell carcinoma was the main pathology type and the tumor location changed significantly from 2001 to 2012. Overall, the DALY remained roughly stable and was estimated as 11.50 for males and 4.90 for females per 1000 people. The burden was mainly caused by premature death. There is an obvious spatial pattern in the distribution of incidence density and burden.

CONCLUSION

Esophageal cancer remains a public health issue in Feicheng County with a high incidence, mortality and disease burden. The incidence and burden have obvious spatial heterogeneity, and further studies should be conducted to identify geographical risk factors for precise local prevention and control measures.

Hormonal and reproductive factors and risk of esophageal cancer in women: a meta-analysis

Currently published studies on the relationship between hormonal and reproductive factors and esophageal cancer (EC) risk in women have yielded contradictory findings. For a better understanding of this relationship, we first performed this meta-analysis by pooling all available publications. Sixteen independent studies were retrieved after a comprehensive search in PubMed and Embase databases. The pooled relative risks (RRs) with 95% confidence intervals (95% CIs) were calculated. The pooled RRs implicated that hormone replacement therapy was negatively associated with the risk of EC (RR = 0.72, 95% CI 0.60-0.86, P < 0.001) and esophageal squamous cell carcinoma (RR = 0.68, 95% CI 0.48-0.97, P = 0.031). Menopausal women were at an increased risk of EC (RR = 1.47, 95% CI 1.07-2.03, P = 0.018), particularly esophageal squamous cell carcinoma (RR = 1.66, 95% CI 1.12-2.48, P = 0.012). Additionally, decreased risk of EC (RR = 0.79, 95% CI 0.68-0.92, P = 0.003) and esophageal adenocarcinoma (RR = 0.66, 95% CI 0.53-0.82, P < 0.001) was demonstrated among women with breast-feeding history. Moreover, such associations were more significant among Caucasians, but not Asians. Our study suggests that menopause is an independent risk factor for EC, while hormone replacement therapy and breast-feeding history play a protective role against EC, particularly among Caucasians. All results are consistent with the hypothesis that effects of estrogen may lower the risk of EC in women.

Younger women have a better prognosis among patients with esophageal squamous cell carcinoma after esophagectomy

BACKGROUND

Epidemiological studies have suggested a potential role for sex hormones in esophageal squamous cell carcinoma (ESCC) etiology. However, the significance of gender as an independent prognostic factor remains uncertain. Our retrospective study was designed to investigate the prognostic role of gender for survival after esophagectomy.

METHODS

Data from 674 patients with ESCC who underwent surgical resection were retrospectively analysed. Age 55 years was selected as a surrogate for menopause. Patients were assigned to age-gender groups: A (female younger than age 55 years), B (female age 55 years and older), C (male younger than age 55 years) and D (male age 55 years and older). Univariate and multivariate analyses were performed to identify prognostic factors for survival.

RESULTS

There were 520 males and 154 females with median age was 58 years. The 1-, 3-, 5-year survival rates of group A, B, C and D were 93.6%, 70.2%, 61.7% vs. 86.9%, 47.7%, 40.2% vs. 77.8%, 43.9%, 37.0% and 80.3%, 47.9%, 36.6%, respectively (P=0.003). Multivariate analysis suggested that age-gender groups and pTNM staging were independent prognostic factors.

CONCLUSIONS

Among patients with ESCC after esophagectomy, women younger than age 55 years attained a favorable prognosis.

The Male Predominance in Esophageal Adenocarcinoma

The incidence of esophageal adenocarcinoma (EAC) has increased rapidly during the past 4 decades in many Western populations, including North America and Europe. The established etiological factors for EAC include gastroesophageal reflux and obesity, Helicobacter pylori infection, tobacco smoking, and consumption of fruit and vegetables. There is a marked male predominance of EAC with a male-to-female ratio in incidence of up to 9:1. This review evaluates the available literature on the reasons for the male predominance, particularly an update on epidemiologic evidence from human studies during the past decade. The striking sex difference does not seem to be explained by established risk factors, given that the prevalence of the etiological factors and the strengths of associations between these factors and EAC risk are similar between the sexes. Sex hormonal factors may play a role in the development of EAC; estrogenic exposures may prevent such development, whereas androgens might increase the risk of EAC. However, continuing research efforts are still needed to fully understand the reasons for the male predominance of EAC.

Reproductive factors and risk of esophageal squamous cell carcinoma in northern Iran: a case-control study in a high-risk area and literature review

Several epidemiologic studies have suggested an inverse association between female reproductive factors and the risk of esophageal squamous cell carcinoma (ESCC), but the evidence is not conclusive. We examined the association of the number of pregnancies, live births, and miscarriages/stillbirths in women and the association of the number of children in both sexes with the risk of ESCC in Golestan Province, a high-risk area in Iran. Data from 297 histopathologically confirmed ESCC cases (149 women) and 568 controls (290 women) individually matched to cases for age, sex, and neighborhood of residence were included in this analysis. Conditional logistic regression was used to calculate odds ratios (ORs) and the corresponding 95% confidence intervals (CIs). The average numbers of live births and miscarriages/stillbirths among the controls were 8.2 and 0.8, respectively. Women with six or more live births were at ~1/3 the risk of ESCC as those with 0-3 live births; the OR (95% CI) for having 6-7 live births was 0.33 (0.12-0.92). In contrast, the number of miscarriages/stillbirths was associated with an increase in the risk of ESCC. The OR (95% CI) for at least three versus no miscarriages/stillbirths was 4.43 (2.11-9.33). The number of children in women was suggestive of an inverse association with ESCC, but this association was not statistically significant; in men, no association was observed. The findings of this study support a protective influence of female hormonal factors on the risk of ESCC. However, further epidemiological and mechanistic studies are required to prove a protective association.

Systematic review with meta-analysis: race-specific effects of alcohol and tobacco on the risk of oesophageal squamous cell carcinoma

BACKGROUND

Oesophageal squamous cell carcinoma (OSCC) is associated with alcohol use, tobacco use and African or Asian descent. However, little is known about how racial background modifies the effects of alcohol or tobacco.

AIM

To investigate how racial and geographical background modifies the effect of alcohol and tobacco on OSCC via a systematic review and meta-analysis of published literature.

METHODS

We performed a literature search in multiple online databases regardless of language. Eligible studies were population-based assessments of the effect of tobacco and/or alcohol on the risk of OSCC allowing stratification by race. The quality of studies was assessed by the Newcastle-Ottawa Scale. Meta-analyses were performed to estimate summary effects using random effect models.

RESULTS

Systematic review identified 9668 unique citations of which 34 were eligible. The majority were of high quality. The effect of current smoking vs. never-smoking was weaker among Asians than among Europeans [European: odds ratio (OR) = 4.21, 95% confidence interval (CI) 3.13, 5.66; Asian: OR = 2.31, 95% CI 1.78, 2.99], with the 95% CIs not crossing, indicating statistical significance. Asians also trended towards weaker effects of long-duration cigarette use and of heavy daily cigarette use. There was no difference in the effect of alcohol on OSCC risk by race.

CONCLUSIONS

Contrary to our hypothesis, a weaker effect of tobacco for OSCC was observed among Asians than among Europeans. Differences in other factors must explain the higher incidence of OSCC among Asians. More studies are needed to understand the cause of the disparate incidence of OSCC between races.

Sex differences in the proportion of esophageal squamous cell carcinoma cases attributable to tobacco smoking and alcohol consumption

OBJECTIVE

Alcohol and tobacco are the two major established environmental factors associated with squamous cell carcinoma of the esophagus (ESCC). However, the prevalence of these exposures differs substantially between men and women. Moreover, the prevalence of smoking has declined in recent years, whereas per capita consumption of alcohol has remained steady in both sexes. Quantifying the burden of ESCC attributable to these causal factors is necessary to inform potential preventive strategies.

METHODS

We estimated the population attributable fraction (PAF) of ESCC due to smoking and alcohol, using data from an Australian population based case-control study (305 ESCC cases, 1554 controls).

RESULTS

Estimated PAF for ESCC were 49% (95% CI: 38-60) and 32% (95% CI: 25-40) due to smoking and heavy alcohol consumption respectively. More than 75% of the ESCC burden in men could be attributed to smokers with heavy alcohol consumption. The highest burden was among ≥30 pack years smokers who also consumed alcohol heavily (>17 drinks/week); this differed significantly between men (PAF 36%, 95% CI 29-44) and women (PAF 5%, 95% CI 2-10). Among women only, low intakes of fruit and vegetables accounted for about 9% of the ESCC burden.

CONCLUSION

The burden of ESCC attributable to smoking combined with heavy alcohol consumption is remarkably high in men. In women, the burden of ESCC due to these factors is lower, and poor nutrition may also play a role.

Genetic variants in sex hormone metabolic pathway genes and risk of esophageal squamous cell carcinoma

In China, esophageal cancer is the fourth leading cause of cancer death where essentially all cases are histologically esophageal squamous cell carcinoma (ESCC), in contrast to esophageal adenocarcinoma in the West. Globally, ESCC is 2.4 times more common among men than women and recently it has been suggested that sex hormones may be associated with the risk of ESCC. We examined the association between genetic variants in sex hormone metabolic genes and ESCC risk in a population from north central China with high-incidence rates. A total of 1026 ESCC cases and 1452 controls were genotyped for 797 unique tag single-nucleotide polymorphisms (SNPs) in 51 sex hormone metabolic genes. SNP-, gene- and pathway-based associations with ESCC risk were evaluated using unconditional logistic regression adjusted for age, sex and geographical location and the adaptive rank truncated product (ARTP) method. Statistical significance was determined through use of permutation for pathway- and gene-based associations. No associations were observed for the overall sex hormone metabolic pathway (P = 0.14) or subpathways (androgen synthesis: P = 0.30, estrogen synthesis: P = 0.15 and estrogen removal: P = 0.19) with risk of ESCC. However, six individual genes (including SULT2B1, CYP1B1, CYP3A7, CYP3A5, SHBG and CYP11A1) were significantly associated with ESCC risk (P < 0.05). Our examination of genetic variation in the sex hormone metabolic pathway is consistent with a potential association with risk of ESCC. These positive findings warrant further evaluation in relation to ESCC risk and replication in other populations.

Why is there a change in patterns of GE cancer?

Recent decades have seen a worrying trend in incidence rates of distal oesophageal and proximal gastric cancers. Fuelled by radical changes in lifestyle, diet, physical activity and environmental exposures, as well as an ageing population and host genetic predisposition, the incidence of oesophageal adenocarcinoma (OAC) is on the rise in Western populations. While overall incidence of gastric cancers is declining, the ageing of society means that an increase in absolute numbers is expected over coming years. Both cancers tend to present at an advanced stage, hence prognosis remains poor despite increasingly effective screening and treatment strategies. The development of gastric and oesophageal malignancies is influenced by myriad factors, not least geographical, racial and socioeconomic differences in addition to lifestyle choices. The multidimensional nature of these risk factors requires a holistic understanding of their net influence in the development of malignancy. This review explores the evidence base for established and putative risk factors in the development of gastric and oesophageal cancers. It is hoped that with a clear understanding of important risk factors, a multidisciplinary approach including effective primary prevention, regular screening of high-risk groups and continued research into the molecular biology of gastrointestinal carcinogenesis may facilitate a reduction in incidence rates, as well as early detection and optimal management of upper gastrointestinal malignancies.

Dietary intake of lignans and risk of adenocarcinoma of the esophagus and gastroesophageal junction

PURPOSE

The strong male predominance in esophageal and gastroesophageal junctional adenocarcinoma remains unexplained. Sex hormonal influence has been suggested, but not proven. A protective role of dietary phytoestrogen lignans was hypothesized.

METHODS

A Swedish nationwide population-based case-control study was conducted in 1995-1997, including 181 cases of esophageal adenocarcinoma, 255 cases of gastroesophageal junctional adenocarcinoma, 158 cases of esophageal squamous cell carcinoma, and 806 control subjects. Data on various exposures, including dietary data, were collected through personal interviews and questionnaires. Dietary intake of lignans was assessed using a food frequency questionnaire and categorized into quartiles based on the consumption among the control participants. Unconditional logistic regression was used to calculate odds ratios (ORs) with 95 % confidence intervals (CIs), including adjustment for all established risk factors.

RESULTS

Participants in the highest quartile of intake of lignans compared with the lowest quartile were at a decreased risk of esophageal adenocarcinoma (OR, 0.65; 95 % CI, 0.38-1.12; p for trend =0.03), gastroesophageal junctional adenocarcinoma (OR, 0.37; 95 % CI, 0.23-0.58; p for trend <0.0001), and these adenocarcinomas combined (OR, 0.45; 95 % CI, 0.31-0.67; p for trend <0.0001). No clear associations were found between lignan intake and risk of esophageal squamous cell carcinoma.

CONCLUSIONS

This population-based study indicates that a high dietary intake of lignans decreases the risk of adenocarcinoma of the esophagus and gastroesophageal junction.

[Interactions of insulin and estrogen in the regulation of cell proliferation and carcinogenesis]

Equilibrium of sexual steroids and metabolic processes has close correlations. Insulin is a potent regulator of human sexual steroid hormone production and modulates their signals at receptor level. Insulin resistance and excessive insulin production provoke hyperandrogenism and estrogen deficiency in women resulting not only in anovulatory dysfunction but also a high risk for cardiovascular diseases and cancer. Physiologic functions of all female organs have higher estrogen demand as compared with men. In healthy women estrogen predominance against androgens is a favor in their reproductive period, which means a strong defense against insulin resistance and its complications. However, in postmenopausal cases the increasing prevalence of insulin resistance and type-2 diabetes associated with estrogen deficiency and androgen excess, result in a gender specific higher risk for precancerous lesions and cancer as compared with men. Estrogen has beneficial effect on the energy metabolism, glucose homeostasis and on the lipid metabolism of liver and of peripheral tissues as well. A moderate or severe decrease in serum estrogen level enhances the prevalence of insulin resistant states. In premenopausal women long or irregular menstrual cycles are predictors for the risk of insulin resistance and type-2 diabetes. Moreover, in postmenopausal estrogen deficient cases elevated fasting glucose, increased body weight and abdominal fat deposition are often observed progressively with age in correlation with an impaired glucose tolerance. In the rare cases of estrogen deficient men severe type-2 diabetes seems to be a characteristic complication. Upon becoming familiar with the cancer risk of insulin resistance and estrogen deficiency, there would be plenty of possibilities for primary cancer prevention. In patients with cancer the treatment of hormonal and metabolic disturbances may become effective adjuvant therapy.

Reproductive factors and risk of oesophageal and gastric cancer in the Million Women Study cohort

Background:

Hormonal factors may influence risk for upper gastrointestinal cancers in women. We examined risk of oesophageal and gastric cancers in relation to reproductive factors in a large UK cohort, the Million Women Study.

Methods:

Among 1 319 409 women aged on average 56 years at recruitment, 1186 incident cancers of the oesophagus and 1194 of the stomach were registered during 11.9 million person-years’ observation. Adjusted relative risks (RRs) and 95% confidence intervals (CIs) were estimated using Cox proportional hazards models.

Results:

Risks of both oesophageal and gastric cancer were significantly higher in postmenopausal than in pre- or peri-menopausal women (RRs 1.46, 1.07–2.00 and 1.59, 1.15–2.20, respectively; P⩽0.01 for both); and, among postmenopausal women, risk was higher the younger women were at menopause (RR, 95% CI per 5 years younger at menopause 1.18, 1.05–1.34 for oesophageal cancer and 1.18, 1.04–1.34 for stomach cancer, P_trend=0.01 for both). For factors relating to childbearing, including women's age at first birth, their number of children, and breastfeeding history, the only significant association was a higher risk of oesophageal cancer in nulliparous, compared with parous, women (RR 1.31, 1.11–1.55; P=0.002). When risks for squamous cell and adenocarcinomas of the oesophagus were compared, most did not differ significantly, but statistical power was limited.

Conclusion:

Both oesophageal and gastric cancer risks appeared to be related to menopausal status and age at menopause, but there was little consistent evidence for associations with factors related to childbearing.

Interplay between insulin resistance and estrogen deficiency as co- activators in carcinogenesis

Both insulin resistance and estrogen deficiency result in complex metabolic disorder based mainly on defective cellular glucose uptake and on an atherogenic serum lipid profile. These alterations may be regarded as high risks for several life-threatening human diseases, such as type-2 diabetes, cardiovascular lesions and malignancies. Insulin resistance and estrogen deficiency are concomitant disorders with mutual interrelationship. Insulin resistance and the compensatory hyperinsulinemia provoke increased androgen synthesis at the expense of decreased estrogen production. Similarly, a moderate or severe decrease in serum estrogen levels enhances the prevalence of insulin resistant states both in men and women. Healthy premenopausal women enjoy the defensive effect of estrogens against metabolic and hormonal disorders. However, even a slight decrease in their circulatory estrogen levels associated with insulin resistance may increase the risk for cancers, particularly in the organs having high estrogen demand (breast, endometrium and ovary). On the other hand, postmenopausal state with profound estrogen deficiency confers high risk for cancers in different organs with either high or moderate estrogen demand. After menopause, hormone replacement therapy improves insulin sensitivity and decreases the enhanced inclination to malignancies in postmenopausal women. Recognition of the thorough interplay between insulin resistance and estrogen deficiency may illuminate many apparently controversial experimental and clinical findings concerning cancer development and therapeutic possibilities. Moreover, their interactions in the initiation and progression of human malignancies may supply new strategies in primary cancer prevention and cancer cure.

Menopausal hormone therapy and risk of gastrointestinal cancer: nested case-control study within a prospective cohort, and meta-analysis

Use of menopausal hormone therapy (HT) has been associated with reduced risk of colorectal cancer; evidence for its effect on other gastrointestinal cancers is limited. We conducted a nested case-control study within a UK cohort, and meta-analyses combining our results with those from published studies. Our study included women aged 50+ in the UK General Practice Research Database (GPRD): 1,054 with oesophageal, 750 with gastric and 4,708 with colorectal cancer, and 5 age- and practice-matched controls per case. Relative risks (RRs) and 95% confidence intervals (CIs) for cancer in relation to prospectively-recorded HT prescriptions were estimated by conditional logistic regression. Women prescribed HT had a reduced risk of oesophageal cancer (adjusted RR for 1+ vs. no HT prescriptions, 0.68, 95% CI 0.53-0.88; p = 0.004), gastric cancer (0.75, 0.54-1.05; p = 0.1) and colorectal cancer (0.81, 0.73-0.90; p < 0.001). There were no significant differences in cancer risk by HT type, estimated duration of HT use or between past and current users. In meta-analyses, risks for ever vs. never use of HT were significantly reduced for all three cancers (summary RR for oesophageal cancer, 0.68, 0.55-0.84, p < 0.001; for gastric cancer, 0.78, 0.65-0.94, p = 0.008; for colorectal cancer, 0.84, 0.81-0.88, p < 0.001). In high-income countries, estimated incidence over 5 years of these three cancers combined in women aged 50-64 was 2.9/1,000 in HT users and 3.6/1,000 in never users. The absolute reduction in risk of these cancers in HT users is small compared to the HT-associated increased risk of breast cancer.

Hormonal factors and risks of esophageal squamous cell carcinoma and adenocarcinoma in postmenopausal women

The incidences of esophageal adenocarcinoma and squamous cell carcinoma (SCC) are higher in males than in females. We investigated whether female-related hormonal factors are associated with risks of these two types of esophageal cancer. We examined the association between use of hormone therapy (HT) and the risks of esophageal adenocarcinoma and SCC in postmenopausal women enrolled in the Women's Health Initiative (WHI) clinical trials and observational studies. Twenty-three esophageal adenocarcinoma and 34 esophageal SCC cases were confirmed among the 161,080 participants, after a median of 11.82 years of follow-up. Risk of esophageal SCC was lower among HT users (past users: HR = 0.25, 95% CI: 0.06-1.10 in 2 cases; current users: HR = 0.41, 95% CI: 0.18-0.94 in 9 cases). A decreased esophageal SCC risk was observed for current users of estrogen plus progestin (E+P) therapy (HR = 0.25, 95% CI: 0.07-0.86 in 3 cases) but not for current users of estrogen-only therapy (HR = 0.96, 95% CI: 0.28-3.29 in 6 cases). No association was observed between the use of HT and the risk of esophageal adenocarcinoma. No other reproductive or hormonal factors were significantly associated with the risk of either SCC or adenocarcinoma. Current use of E+P therapy was found to be associated with a decreased risk of esophageal SCC, but no association was observed with esophageal adenocarcinoma. To provide more definitive evidence, a pooled analysis of all available studies or a much larger study would be needed.

Hormonal factors and risks of esophageal squamous cell carcinoma and adenocarcinoma in postmenopausal women

The incidences of esophageal adenocarcinoma and squamous cell carcinoma (SCC) are higher in males than in females. We investigated whether female-related hormonal factors are associated with risks of these two types of esophageal cancer. We examined the association between use of hormone therapy (HT) and the risks of esophageal adenocarcinoma and SCC in postmenopausal women enrolled in the Women's Health Initiative (WHI) clinical trials and observational studies. Twenty-three esophageal adenocarcinoma and 34 esophageal SCC cases were confirmed among the 161,080 participants, after a median of 11.82 years of follow-up. Risk of esophageal SCC was lower among HT users (past users: HR = 0.25, 95% CI: 0.06-1.10 in 2 cases; current users: HR = 0.41, 95% CI: 0.18-0.94 in 9 cases). A decreased esophageal SCC risk was observed for current users of estrogen plus progestin (E+P) therapy (HR = 0.25, 95% CI: 0.07-0.86 in 3 cases) but not for current users of estrogen-only therapy (HR = 0.96, 95% CI: 0.28-3.29 in 6 cases). No association was observed between the use of HT and the risk of esophageal adenocarcinoma. No other reproductive or hormonal factors were significantly associated with the risk of either SCC or adenocarcinoma. Current use of E+P therapy was found to be associated with a decreased risk of esophageal SCC, but no association was observed with esophageal adenocarcinoma. To provide more definitive evidence, a pooled analysis of all available studies or a much larger study would be needed.

Smoking and alcohol drinking increased the risk of esophageal cancer among Chinese men but not women in a high-risk population

Although the association for esophageal cancer with tobacco smoking and alcohol drinking has been well established, the risk appears to be less strong in China. To provide more evidence on the effect of smoking and alcohol consumption with esophageal cancer in China, particularly among Chinese women, a population-based case–control study has been conducted in Jiangsu, China, from 2003 to 2007. A total of 1,520 cases and 3,879 controls were recruited. Unconditional multivariate logistic regression analysis was applied. Results showed that the odds ratio (OR) and confidence interval (CI) for ever smoking and alcohol drinking were 1.57 (95% CI: 1.34–1.83) and 1.50 (95% CI: 1.29–1.74). Dose–response relationships were observed with increased intensity and longer duration of smoking/drinking. Risk of smoking and alcohol drinking at the highest joint level was 7.32 (95% CI: 4.58–11.7), when compared to those never smoked and never drank alcohol. Stratifying by genders, smoking and alcohol drinking increased the risk among men with an OR of 1.74 (95% CI: 1.44–2.09) and 1.76 (95% CI: 1.48–2.09); however, neither smoking nor alcohol consumption showed a significant association among women. In conclusion, smoking and alcohol drinking were associated with esophageal cancer risk among Chinese men, but not among Chinese women.

The risk of oesophageal cancer is not affected by a diagnosis of breast cancer

Oesophageal adenocarcinoma (OAC) is less common and develops at a later age in women compared with men. Endogenous oestrogen may therefore protect against OAC development. A cohort of women with breast cancer, a tumour commonly treated with oestrogen antagonists, was examined to identify the subsequent risk of developing OAC. Earlier studies have implicated radiotherapy in increasing oesophageal cancer (OC) risk among women with breast cancer. West Midlands Cancer Intelligence Unit data recording cancer diagnosis and treatment information was examined to identify patients with a first malignant primary breast cancer during 1977-2004. Patients were followed until diagnosis of a second primary cancer, death or end of the time period examined. Age-adjusted and period-adjusted standardized incidence ratios (SIR) were calculated as an estimate of relative risk for a second primary OC. Seventy-three thousand six hundred and thirteen women were eligible for the study, providing 486 679 person years at risk for analysis. One hundred and thirty-two second primary OCs were observed, compared with 121 expected (SIR 1.09; 95% confidence interval: 0.91-1.29). Radiotherapy treatment in 37 888 women did not affect the risk of a second primary OC (SIR 1.07; 95% confidence interval: 0.79-1.41). No difference was identified when examined by OC morphology.There was no association between breast cancer and a second primary OC. Radiotherapy that avoids deep irradiation in the treatment of breast cancer, local nodes or recurrence was not associated with an increased risk of developing a second primary OC.

The association of menstrual and reproductive factors with upper gastrointestinal tract cancers in the NIH-AARP cohort

BACKGROUND

In most populations, incidence rates of upper gastrointestinal (UGI) tract cancers (head and neck, esophagus, and stomach) are higher among men than among women. Established risk factors do not appear to explain these differences, suggesting a possible role for sex hormones.

METHODS

201,506 women of the NIH-AARP Diet and Health cohort completed a questionnaire in 1995-1996. Hazard ratios and 95% confidence intervals were estimated from Cox proportional hazards models.

RESULTS

During follow-up through 2003, 162 incident adenocarcinomas (ACs; esophagus, N = 25, and stomach, N = 137) and 353 incident squamous cell carcinomas (SCCs; head and neck, n = 297, and esophagus, N = 56) occurred. Among examined exposures, older age at menopause was associated inversely with SCC (P(trend) across categories = .013) but not AC (P(trend) = .501). Use of menopausal hormone therapy (MHT) was significantly associated with lower risk of SCC (hazard ratio [HR] = 0.77, 0.62-0.96) and nonsignificantly associated with lower risk of AC (HR = 0.81, 0.59-1.12). A subset (N = 127,386) of the cohort completed a more detailed MHT questionnaire a year after baseline. In 74,372 women with intact uteri, ever use of estrogen-progestin MHT conferred 0.47 (0.30-0.75) times the risk for SCC and 0.52 (0.26-1.07) times the risk for ACC. In 51,515 women with a hysterectomy before baseline, we found no associations between use of estrogen MHT and AC or SCC.

CONCLUSIONS

Higher estrogen and progesterone levels may be related inversely to UGI cancers and in this way help explain lower incidence rates in women compared with men.

Alcohol drinking, cigarette smoking, and the development of squamous cell carcinoma of the esophagus: epidemiology, clinical findings, and prevention

Both cigarette smoking and alcohol drinking are well-established risk factors for esophageal squamous cell carcinoma (ESCC), and the relationship of dose to cancer risk has already been described. Furthermore, the synergistic effect of these two factors has been reported. Our case-control study revealed the odds ratio of ESCC to be 50.1 for those who were both heavy smokers and heavy drinkers in comparison to people who neither drank nor smoked. In patients with ESCC, head and neck cancers as well as dysplastic lesions are frequently observed. Heavy smoking and heavy drinking are closely related to such multicentric carcinogenesis events in the upper aerodigestive tract (UADT), including the esophagus and head andneck region. Polymorphisms in acetaldehyde dehydrogenase 2 (ALDH2) are reported to be a key event in deciding individual susceptibility to UADT cancer. Patients with inactive ALDH2, in whom facial flushing is usually observed after the drinking of alcohol, are at high risk for ESCC as well as multiple UADT cancers. For the early detection of the disease, effective follow up using endoscopy with Lugol staining or narrow band imaging endoscopy is strongly recommended for high-risk populations, such as smokers, heavy drinkers, people with experience of flushing after the drinking of alcohol, and patients with UADT cancer.

The mystery of male dominance in oesophageal cancer and the potential protective role of oestrogen

Oesophageal cancer is the sixth most common form of cancer death globally with almost 400,000 deaths annually. More than 90% of all cases are either adenocarcinomas (OAC) or squamous-cell carcinomas (OSCC). There is a strong male predominance with up to 8 and 3 men for every woman affected with OAC and OSCC, respectively. It has been hypothesised that sex hormonal factors may play a role in the development of oesophageal cancer or more specifically that oestrogen prevents such development. This article reviews the available literature on this topic. Basic science studies suggest an inhibitory effect of oestrogen in the growth of oesophageal cancer cells, and a possible mechanism of any oestrogen protection might be mediated through oestrogen receptors. But from the few epidemiological studies in which the hypothesis of oestrogen protection has been tested, no firm conclusions can yet be drawn of the role of oestrogen in human oesophageal cancer aetiology. More evidence from valid and large human studies is needed before any conclusions can be drawn.

[Role of hormonal risk factors in oral cancer development]

Male: female ratio of oral cancer cases (OC) is fairly high. Lower rate of female cases as compared with males suggests that some endocrine factors may play role in the development of tumors. The aim of the present study was to clarify the differences of risk factors for OC among male and female cases. In the Oral and Maxillofacial Department of Semmelweis University 2660 OC (2130 males and 530 females) patients were included into the study. Ratio of smoking, alcohol consumption, elevated serum glucose level and menopausal data of the female patients were registered. Concordant to the literary data, smoking and excessive alcohol consumption proved to be an important risk factor for OC both among male and female patients. However, moderate alcohol consumption was a weak risk factor among male and no risk factor among female cases. Elevated serum glucose level was not significant OC risk among male cases, but was a high risk factor among female patients, especially in gingival cancer cases. The female OC cases were near exclusively postmenopausal, and the term between the time of menopause and clinical OC diagnosis was fairly long (average: 17 year). These results suggest that estrogen-deficiency may play an important role in the initiation of OC. In the female OC cases menopause appeared in significantly younger age, and the rate of hysterectomy was also significantly higher as compared with the tumor-free control cases. These data also support the estrogen-deficiency theory of cancer initiation. In postmenopausal female patients both estrogen-deficiency and elevated fasting glucose proved to be risk factors for OC. These results reveal new aspects concerning the etiology of OC and give a possible explanation how smoking-associated tumors may develop even without smoking.

[Carcinogenesis theory based on estrogen deficiency]

Earlier, estrogens were considered simply the most important hormones involved in female physiology and reproduction. Nowadays it has become familiar that they have pivotal roles in gene regulation of cell differentiation and proliferation. There are many contradictions concerning the associations of female sexual steroids and cancer. Cancers of the highly estrogen dependent organs are in the forefront of tumors as they are regarded as hormone associated ones. However, re-evaluation of earlier results supporting the carcinogenic capacity of estrogen exhibited many shortcomings and controversies. Recently, the clinical studies on hormone replacement therapy in postmenopausal women justified beneficial anticancer effects in several organs even in the female breast. The newly revealed association between estrogen deficiency and oral cancer risk also means a contradiction of the traditional concept of estrogen-induced cancer. Distinction between cancers of moderately and highly estrogen dependent tumors can be based on their different epidemiological features. The vast majority of the so-called smoking associated malignancies of the moderately estrogen dependent organs occur typically in the late postmenopausal life of women when the ovarian estrogen production is fairly decreased. However cancers of the highly estrogen dependent organs such as breast, endometrium and ovary exhibit both premenopausal and postmenopausal occurrence. In spite of the different epidemiological data of these two groups of cancers the mechanism of gene regulation disorder in the background of tumor initiation cannot act through quite opposite pathways. This suggests that in moderately estrogen sensitive organs a serious, in the highly estrogen dependent sites even a mild estrogen deficiency is enough to provoke gene regulation disorders. The new findings both on smoking associated and hormone related cancers might lead to the same conversion; not estrogen but rather its deficiency may provoke cancer initiation.

Estrogen and its receptors in cancer

The involvement of estrogen and its receptors in the development of cancer has been known for years. However, the exact mechanism responsible is far from clear. The estrogen-mediated carcinogenic process is complicated by recent findings, which reveal that estrogens have multiple functions in cells, which can be either adverse or beneficial, and that the effects of estrogen may be cell-type or organ dependent. The estrogenic effect may be also greatly influenced by the state of two estrogen receptors, ERalpha and ERbeta. This review will discuss the role and function of estrogens and its receptors in cancers of three categories: (1) Breast cancer and gynecologic cancers, (2) Cancers of endocrine organs, (3) Lung cancer and cancers of digestive system. We will also review some novel treatments aiming to interfere with relevant pathways mediated by estrogens and its receptors.

Gender-related hormonal risk factors for oral cancer

Oral cancer (OC) is a neoplasm with fairly high male to female ratio in most populations. The conspicuously lower incidence of this tumor among women than man is suggestive of certain endocrine involvement in its development. The aim of the present case-control study was to clarify the origin of this gender-specific risk of OC incidence. 2660 inpatients (530 females and 2130 males) with squamous cell OC at the Department of Oral and Maxillofacial Surgery were included in a case-control study. Smoking, alcohol consumption, elevated fasting serum glucose level and menopausal histories of female cases were registered. Smoking and excessive alcohol intake proved to be strong risk factors for OC both in the male and female group. However, moderate alcohol consumption was a weaker risk factor for male patients, and it presented no risk for female cases. Elevated fasting glucose level was not a demonstrable OC risk factor among males, however, it proved to be strong risk factor for OC among female patients, especially in gingival cancer cases. The almost exclusively postmenopausal state of female OC patients and the long mean interval (17 years) between their menopause and OC diagnosis suggested an important role of estrogen deficiency in OC epidemiology. The significantly younger mean age at menopause and the significantly higher rate of hysterectomy among female OC cases in comparison with their controls also support the estrogen deficiency hypothesis. This novel hypothesis of estrogen deficiency and elevated fasting glucose as risk factors for OC in postmenopausal women may provide new insights into the etiology of oral malignancies.

Esophageal Squamous Cell Carcinoma and Aldehyde Dehydrogenase-2 Genotypes in Japanese Females

BACKGROUND

Aldehyde dehydrogenase-2 (ALDH2) is the key enzyme for elimination of acetaldehyde, an established animal carcinogen produced after drinking. In persons with inactive ALDH2, the body fails to metabolize acetaldehyde rapidly, leading to excessive accumulation of acetaldehyde. Inactive heterozygous ALDH2 enhances the risk of esophageal squamous cell carcinoma (SCC) in Japanese male drinkers.

METHODS

We studied whether this is the case for women. The risk factors of esophageal SCC were examined in 52 Japanese women with esophageal SCC and 412 cancer-free Japanese women.

RESULTS

The increasing trend in cancer risk according to the quantity of alcohol consumption was significantly steeper in women with inactive heterozygous ALDH2 than in those with active ALDH2 [adjusted odds ratios (ORs) (95% confidence intervals (CIs)) per +7 U/wk increment of alcohol drinking were 3.91 (2.09-7.31) and 1.39 (0.92-2.09), respectively; p = 0.006 for difference in OR; 1 Ut = 22 g of ethanol]. The results obtained using an alcohol-flushing questionnaire were essentially comparable with those obtained by ALDH2 genotyping [adjusted ORs (95% CIs) per +7 U/wk increment of alcohol drinking were 3.94 (1.87-8.31) and 1.46 (0.96-2.23) in those with and without flushing, respectively; p = 0.021 for difference in OR]. The risk of esophageal cancer was markedly higher in heavy drinkers with ALDH2*1/*2 than in never/rare drinkers with ALDH2*1/*1 [adjusted OR (95% CI) = 59.1 (4.65-750)]. Other independent significant risk factors of esophageal SCC were smoking, a preference for hot food or drinks, and lower intake of green and yellow vegetables.

CONCLUSIONS

Japanese men and women shared several common risk factors of esophageal SCC, including drinking with inactive heterozygous ALDH2.

Hormone replacement therapy and risks of oesophageal and gastric adenocarcinomas

Oesophageal and gastric adenocarcinoma share an unexplained male predominance, which would be explained by the hypothesis that oestrogens are protective in this respect. We carried out a nested case–control study of hormone replacement therapy (HRT) among 299 women with oesophageal cancer, 313 with gastric cancer, and 3191 randomly selected control women, frequency matched by age and calendar year in the General Practitioners Research Database in the United Kingdom. Data were adjusted for age, calendar year, tobacco smoking, alcohol consumption, body mass index, hysterectomy, and upper gastrointestinal disorders. Among 1 619 563 person-years of follow-up, more than 50% reduced risk of gastric adenocarcinoma was found among users of HRT compared to nonusers (odds ratio (OR), 0.48, 95% confidence interval (CI) 0.29–0.79). This inverse association appeared to be stronger for gastric noncardia (OR 0.34, 95% CI 0.14–0.78) and weaker for gastric cardia tumours (OR 0.68, 95% CI 0.23–2.01). There was no association between HRT and oesophageal adenocarcinoma (OR 1.17, 95% CI 0.41–3.32).

Dieta e câncer: um enfoque epidemiológico

Epidemiologistas que estudam câncer têm observado que a sua prevalência no mundo tem aumentado de maneira significativa no último século. Acredita-se que este resultado está relacionado, entre outros aspectos, com a industrialização e a urbanização ocorridas neste período. De fato, a morbi-mortalidade associada ao câncer observada em países desenvolvidos é maior do que em países em desenvolvimento. Além disso, algumas formas específicas de câncer, como o de cólon e reto, próstata e mama feminina, são mais freqüentes em países desenvolvidos, enquanto outras, como de estômago, esôfago e colo de útero têm maior incidência nos países em desenvolvimento. Padrões distintos de câncer também são observados entre indivíduos que emigram para um novo país ou região. Com base em estudos epidemiológicos, analisou-se a relação entre câncer e nutrição, e algumas modificações na alimentação que podem prevenir alguns tipos de cânceres.

Genetic susceptibility and environmental factors of esophageal cancer in Xi’an

AIM: To analyse the role of genetic susceptibility and environmental factors in the process of esophageal cancer (EC) formation in Xi’an, China.

METHODS: A hospital based case-control study, combined with molecular epidemiological method, was carried out. A total of 127 EC cases and 101 controls were interviewed with questionnaires containing demographic items, habit of tobacco smoking, alcohol drinking, and family history of EC. Polymorphism of CYP1A1 and GSTM1 of 127 EC cases and 101 controls were detected by PCR method. The interactions between genetic susceptibility and environmental factors were also discussed.

RESULTS: Tobacco smoking, alcohol drinking and a family history of EC were risk factors for EC with an OR of 2.04 (95%CI 1.15-3.60), 3.45(95%CI 1.74-6.91), 3.14 (95%CI 1.28-7.94), respectively. Individuals carrying CYP1A1 Val/Val genotype compared to those with CYP1A1 Ile/Ile genotype had an increased risk for EC (OR 3.35, 95%CI 1.49-7.61). GSTM1 deletion genotype was a risk factor for EC (OR1.81, 95%CI 1.03-3.18). Gene-environment interaction analysis showed that CYP1A1 Val/Val genotype, GSTM1 deletion genotype had synergetic interactions with tobacco smoking, alcohol drinking and family history of EC.

CONCLUSION: Tobacco smoking, alcohol drinking and a family history of EC are risk factors for EC. CYP1A1 Val/Val and GSTM1 deletion genotypes are genetic susceptibility biomarkers for EC. There are synergic interactions between genetic susceptibility and environmental factors.

Cigarette smoke exposure increases ulcerative colitis-associated colonic adenoma formation in mice

Both chronic ulcerative colitis and smoking are associated with colorectal cancer in humans. In the present study, we investigated the effects of cigarette smoke (CS) exposure on inflammation-associated tumorigenesis in the mouse colon. Male balb/c mice were allocated into six groups: control, CS (2%), CS (4%), colitis, colitis + CS (2%) and colitis + CS (4%). They were given water or 3% dextran sulfate sodium (DSS) in drinking water for 7 days to induce colitis, with or without 1 h daily exposure to 2 or 4% CS. They were then allowed to drink water for 14 days. The cycle of 7 day DSS +/- CS/14 day H2O treatments were repeated twice. Mice were killed immediately or 1 month after the three cycles of treatments. Results indicated colonic adenoma was only found in the colitis group (one out of 11), Colitis + CS (2%) group (seven out of 12) and colitis + CS (4%) group (four out of five) 1 month after three cycles of DSS and/or CS treatment. CS exposure dose-dependently increased adenoma formation in mice with inflamed mucosa. CS exposure plus colitis was strongly associated with a high incidence of dysplasia (P < 0.01) and adenocarcinoma formation (P < 0.01) compared with induction of colitis alone. Colitis induced cell proliferation and apoptosis in colonic tissues. Cigarette smoking significantly attenuated the apoptotic effect by DSS probably via the induction of anti-apoptotic protein bcl-2. The ratio of apoptosis over proliferation was also significantly lower in the colitis + CS groups. Vascular endothelial growth factor and angiogenesis in the colon were also increased by cigarette smoking in animals with colitis. In conclusion, CS promotes inflammation-associated adenoma/adenocarcinoma formation in the mouse colon in a dose-dependent manner. This tumor development is associated with the inhibition of cellular apoptosis and supported by increased angiogenesis.

Nutrition and diet in the development of gastrointestinal cancer

Diet plays a role in the prevention and development of gastrointestinal cancers. The majority of available research consists of case-control studies, but the number of clinical trials is growing. The dietary recommendations to reduce gastrointestinal cancer risk include lowering total energy, fat, and saturated fat intake; avoidance of grilled and smoked foods; avoidance of alcohol; and increasing intake of fruits, vegetables, and fiber. Studies of esophageal cancer support these dietary approaches, with the exception of dietary fat reduction and increased green tea intake. For gastric cancer, consuming additional fruits and vegetables, including those high in ascorbic acid, may reduce risk, and the capacity for diet to alter Helicobacter pylori infection should be explored. Recent interventional trials do not support a role for high-fiber or low-fat diets in reducing development of colon adenomas, although the evidence does not rule out efficacy at earlier stages of disease. Finally, the evidence for a relationship between pancreatic cancer and diet remains sparse and warrants additional investigation.

Session: whole cereal grains, fibre and human cancer wholegrain cereals and cancer in Italy

The relationship between frequency of consumption of whole-grain foods and cancer risk has been analysed using data from an updated series of case-control studies conducted in Northern Italy between 1983 and 1997. The overall dataset included the following incident histologically-confirmed neoplasms: oral cavity and pharynx 524, oesophagus 410, stomach 745, colon 955, rectum 625, liver 435, gallbladder 65, pancreas 402, larynx 388, soft tissue sarcomas 217, breast 3412, endometrium 750, ovary 971, prostate 127, bladder 431, kidney 190, thyroid 428, Hodgkin's disease 201, non-Hodgkin's lymphomas 529, multiple myelomas 185. Controls were 10 058 patients admitted to hospital for acute non-neoplastic conditions unrelated to long-term modifications in diet, tobacco or alcohol use. The multivariate odds ratios for the highest category of wholegrain cereal consumption were 0.3-0.5 for upper digestive tract and respiratory neoplasms and colon, 0.6 for rectum and liver, 0.4 for gallbladder, 0.8 for pancreas, 0.2 for soft tissue sarcomas, 0.9 for breast and endometrium, 0.7 for ovary, 0.7 for prostate, 0.4 for bladder and kidney, 1.1 for thyroid and about 0.5 for lymphomas and 0.6 for myelomas. In this population whole-grain food consumption is an indicator of reduced risk of several neoplasms.

Cancer of the oesophagus in Africans in sub-Saharan Africa: any hopes for its control?

Oesophageal cancer, a highly lethal tumour, occurs to a variable extent in Africans in sub-Saharan African countries. In many, its incidence remains low, as in the Ivory Coast, Mali and the Gambia. However, in other African countries, the incidence rate has risen considerably, especially in city populations, as in Durban, South Africa, in Kyadondo, Uganda, and in Harare, Zimbabwe, rising to levels far higher than those reported in white populations. As to risk factors, in some African settings, smoking is a factor, and in others, alcohol consumption. Nutritionally, one enquiry, made in Durban, indicated the use of less-refined cereal products, with higher consumptions of vegetables and fruit, to be protective. In developed populations, protective factors are considered to be those characteristic of a "prudent" lifestyle. However, known risk factors largely fail to explain the high variability in the disease's occurrence. In seeking to combat the disease, it is thought unlikely that most Africans, especially urban dwellers, are willing to alter their lifestyle appropriately, even with the understanding that the changes would confer other protective benefits. This suggests that further rises, especially in the contexts of high incidence rates, are inevitable.

Tobacco use and cancer causation: association by tumour type

In the second part of our review we describe the association between tobacco use and risk of specific cancer types. There is evidence for an established association of tobacco use with cancer of the lung and larynx, head and neck, bladder, oesophagus, pancreas, stomach and kidney. In contrast, endometrial cancer is less common in women who smoke cigarettes. There are some data suggesting that tobacco use increases the risk for myeloid leukaemia, squamous cell sinonasal cancer, liver cancer, cervical cancer, colorectal cancer after an extended latency, childhood cancers and cancer of the gall bladder, adrenal gland and small intestine. Other forms of cancer, including breast, ovarian and prostate cancer, are unlikely to be linked to tobacco use.