Risk factors of female cancers in Ragusa population (Sicily)--1. Endometrium and cervix uteri cancers

Lifetime number of years of menstruation as a risk index for postmenopausal endometrial cancer in the Norwegian Women and Cancer Study

INTRODUCTION

Lifetime number of years of menstruation (LNYM) reflects a woman's cumulative exposure to endogenous estrogen and can be used as a measure of the combined effect of reproductive factors related to endometrial cancer (EC) risk.

MATERIAL AND METHODS

We aimed to study the association between LNYM and EC risk among postmenopausal women and calculate the population attributable fraction of EC for different LNYM categories. Our study sample consisted of 117 589 women from the Norwegian Women and Cancer (NOWAC) Study. All women were aged 30-70 years at enrollment and completed a baseline questionnaire between 1991 and 2006. Women were followed up for EC to December 2014 through linkages to national registries. We used Cox proportional hazards models to estimate hazard ratios with 95% confidence intervals (95% CIs), adjusted for potential confounders.

RESULTS

In all, 720 women developed EC. We found a statistically significant, positive dose-response relationship between LNYM and EC, with a 9.1% higher risk for each additional year of LNYM (P for trend < .001). Using the LNYM category ≥40 as a reference, the hazard ratios for LNYM <25, 25-29, 30-34, 35-39 were 0.17 (95% CI 0.22-0.27), 0.25 (95% CI 0.17-0.36), 0.43 (95% CI 0.32-0.58), and 0.68 (95% CI 0.51-0.92), respectively. The association between LNYM and EC was independent of incomplete pregnancies, menopausal hormone therapy, diabetes, and body mass index. When considering the population attributable fraction, 67% of EC was estimated to be attributable to LNYM ≥25 years.

CONCLUSIONS

Our study supports that increasing LNYM is an important and independent predictor of EC risk.

Survival of Patients with Cancer of the Stomach, Colon and Rectum, Lung and Breast in Ragusa, Sicily

Survival of 1747 patients with cancer of the stomach, colon/rectum, lung and female breast was investigated on incident cases registered by the Ragusa Cancer Registry, covering the Province of Ragusa (275,000 inhabitants) between 1981 and 1986. Cases known from the death certificate only were excluded. Date of death was obtained by a linkage with death certificates issued for Ragusa residents. Living status was assessed directly at the Registrar's Office. Analysis was performed also by sex, age group and presence of histologic verification. Relative survival at 5 years of Ragusa cancer cases was of the same order of magnitude as that observed in the U.S.A. (1980) and in Switzerland (1970-1980). However, the slight differences observed were mostly in favor of the Swiss and American patients. Sex did not significantly influence survival, but younger patients survived longer than older ones. Lack of histologic verification was associated with poor survival.

Breastfeeding and the incidence of endometrial cancer: A meta-analysis

Several epidemiological studies have investigated the association between breastfeeding and endometrial cancer (EC). However, the results of the studies are controversial. Thus, we conduct this meta-analysis to explore the association between breastfeeding and EC and to evaluate the possible does-response relationship between duration of breastfeeding and EC. PubMed, Web of Science, Chinese National Knowledge Infrastructure, China biology medical literature database, Wan fang databases and Database of Chinese Scientific and Technical Periodicals were searched for eligible observational studies up to 11 July 2015. Random effects model was used to calculate the pooled relative risks (RRs) and restricted cubic spline model was adopted for the does-response analysis.

Fifteen articles with 623570 participants were identified. The RRs of these studies suggested that breastfeeding was associated with the reduced risk of EC (high versus low/no: RR = 0.74; 95% confidence interval (CI), 0.58–0.95). In subgroup analyses, a significant association of breastfeeding with EC risk was found in Asia (RR = 0.57, 95% CI 0.37–0.87), and an inverse association of breastfeeding with EC risk was found in cohort studies (RR = 0.62, 95% CI 0.41–0.94). The results were also significant after adjusted for hormone use (RR = 0.63, 95% CI 0.41–0.97) and body mass index (RR=0.65, 95% CI 0.44–0.96). A linear relationship was found of breastfeeding with EC (p for nonlinearity = 0.93), and it indicated that EC risk decreased by 1.2% for one month increment of breastfeeding. This meta-analysis indicates that long term breastfeeding might be associated with decreased risk of EC.

Alcohol intake and endometrial cancer risk: a meta-analysis of prospective studies

Background:

Studies on alcohol intake in relation to endometrial cancer risk have produced inconsistent results.

Methods:

For a meta-analysis, we identified cohort studies of alcohol and endometrial cancer by a literature search of Pub-Med and Embase up to 1 March 2010 and by searching the reference lists of relevant articles.

Results:

Seven cohort studies, including 1 511 661 participants and 6086 endometrial cancer cases, were included in the dose–response random-effect meta-regression model. Compared with non-drinkers, women drinking less than 1 drink of alcohol (13 g of ethanol) per day had a lower risk for endometrial cancer; this risk was lower by 4% (95% confidence interval (95% CI): 0.93–1.00) for consumption up to 0.5 drink per day and by 7% (95% CI: 0.85–1.02) for consumption up to 1 drink. However, we found evidence of an increased risk for endometrial cancer for intakes higher than two alcoholic drinks per day: compared with non-drinkers, the risk was higher by 14% (95% CI: 0.95–1.36) for 2–2.5 drinks per day and by 25% (95% CI: 0.98–1.58) for >2.5 drinks per day.

Conclusion:

Our meta-analysis indicates a possible J-shaped relationship between alcohol intake and endometrial cancer risk.

Alcohol and endometrial cancer risk: a case-control study and a meta-analysis

To evaluate the association between alcohol consumption and endometrial cancer risk, we analyzed data from a hospital-based case-control study, conducted in Italy between 1992 and 2006, on 454 endometrial cancer cases and 908 controls, and performed a meta-analysis updated to October 2009. Compared to never alcohol drinkers, the odds ratio was 1.03 (95% confidence interval, CI, 0.76-1.41) for < or = 7, 1.27 (95% CI 0.86-1.87) for 8-14, and 1.19 (95% CI 0.80-1.77) for > or = 15 drinks/week, with no trend in risk. No association emerged for wine, beer, and spirit consumption analyzed separately. The meta-analysis included 20 case-control and seven cohort studies, for a total of 13,120 cases. Compared to non/low drinkers, the pooled relative risks for drinkers were 0.90 (95% CI 0.80-1.01) for case-control studies, 1.01 (95% CI 0.90-1.14) for cohort studies, and 0.95 (95% CI 0.88-1.03) overall, with no heterogeneity between study design (p = 0.156). The overall estimate for heavy versus non/low drinkers was 1.12 (95% CI 0.87-1.45). The results were consistent according to selected study characteristics, including geographic area, definition of alcohol drinkers, and type of controls in case-control studies. Our findings provide evidence that alcohol drinking is not associated with endometrial cancer risk, although a weak positive association for very high drinkers cannot be excluded.

Meta-analysis of social inequality and the risk of cervical cancer

Previous studies of the relationship between socio-economic status and cervical cancer have been mainly based on record linkage of routine data, such as cancer registry incidence rates and regional measures of social class based on census data. These routine data are liable to substantial misclassification with respect to socio-economic status. Previous reports are also primarily from developed countries, whereas the major burden of cervical cancer is in developing countries. We have therefore pooled the data from previously reported case-control studies of cervical cancer or dysplasia, which contain individual-level information on socio-economic characteristics to investigate the relationship between cervical cancer, social class, stage of disease, geographical region, age and histological type. Based on 57 studies, we found an increased risk of approximately 100% between high and low social class categories for the development of invasive cervical cancer, and an increased risk of approximately 60% for dysplasia, including carcinoma in situ. Although the difference was observed in all countries, it was stronger in low/middle income countries and in North America than in Europe. No clear differences were observed between squamous cell carcinoma and adenocarcinoma, or between younger and older women. These results indicate that both cervical infection with human papillomavirus, which is linked to both female and male sexual behaviour, and access to adequate cervical cancer screening programmes are likely to be important in explaining the large cervical cancer incidence rates observed in different socio-economic groups, and that the importance of these factors may vary between different geographical regions.

Cancers of the female genital tract in Ragusa, Sicily

A descriptive study of cancers of the female genital tract (cervix, endometrium, ovary, labia, vulva and vagina) in the province of Ragusa (Sicily) was carried out using incidence and mortality data of the Ragusa Cancer Registry, covering the years 1981-1987. Corpus uteri was the most frequent site of cancer, followed by cervix utery and ovary; the highest mortality rates were exhibited by ovary cancer, whose survival at five years was 18.1 percent. A comparison of incidence and mortality rates with those observed by Italian and European registries shows that while in Ragusa rates for cancers of all sites were lower, female genital tract cancers, particularly of the uterus, were more frequent in Ragusa than in other Italian and European areas. In contrast with what has been reported by cancer registries of most developed countries, incidence of cervix cancer in Ragusa has apparently not decreased between 1981 and 1987, while mortality has increased.

Risk factors of female cancers in Ragusa population (Sicily). 2. Breast cancer

A case-control study on breast, cervix and corpus uteri cancer cases registered in Ragusa between January 1, 1983 and June 30, 1985 has been conducted. Information on risk factors has been obtained by means of a structured questionnaire. Risk factors for breast cancer were: few pregnancies (1-2 vs greater than 4 OR 2.14, 95% CL 1.13-4.04), few children (for postmenopausal only, chi trend 4.84), previous breast disease (OR 1.97, 95% CL 1.20-3.23), family history (OR 3.57, 95% CL 1.92-6.63), alcohol (OR 1.68, 95% CL 1.12-2.53), high socioeconomical status (1 vs 4 OR 2.93, 95% CL 1.22-70.03). A protective role was evident for: early age at first birth (for premenopausal only, less than 20 vs greater than 20 OR 0.11, 95% CL 0.01-0.90), previous ovary disease (OR 0.26, 95% CL 0.08-0.88). Age at menarche, age at menopause, years of fertile life and breast feeding were not found to be related to breast cancer. A different distribution of risk factors among cases with and without family history has been suggested. A synoptic table shows the distribution of the most important risk factors of the three investigated female cancers in the Ragusa population, reported in the present and in an accompanying paper.