Is diabetes mellitus a risk factor for ovarian cancer? A case-control study in Utah and Washington (United States)

Systematic analysis and prediction for disease burden of ovarian cancer attributable to hyperglycemia: a comparative study between China and the world from 1990 to 2019

Background

Ovarian cancer is one of the most common female malignancies worldwide, and metabolic factors, such as hyperglycemia, are becoming potential risk factors. This study aimed to analyze the disease burden and its changing trend of ovarian cancer attributable to hyperglycemia in the Chinese population from 1990 to 2019.

Methods

Using the data released by the Global Burden of Disease study 2019 (GBD 2019), we analyze the disease burden of ovarian cancer attributable to hyperglycemia in Chinese from 1990 to 2019 via morbidity, death, disability-adjusted life years (DALY); compare it with the global population; and predict the incidence and death trend in Chinese women for the next 10 years (2020-2029).

Results

The incidence, death cases, and DALY numbers of ovarian cancer attributable to hyperglycemia in Chinese in 2019 were 2,751, 1,758, and 44,615 person-years, respectively, with an increase of 352.5%, 356.6%, and 329.0% compared with 1990, and the growth rate was higher than the global level. The age-standardized incidence rate (ASIR), age-standardized mortality rate (ASMR), and age-standardized DALY rate (ASDR) in 2019 were 0.270/100,000, 0.164/100,000, and 4.103/100,000, respectively. Moreover, the average annual percent changes (AAPCs) were 2.3%, 2.0%, and 2.0%, respectively, all higher than the global average. The disease burden of ovarian cancer attributable to hyperglycemia increased with age, reaching a peak in the 45-75 age group. The prediction of the neural network model showed that the incidence and death of the disease would remain high and rise in the next 10 years.

Conclusion

The disease burden caused by ovarian cancer attributable to hyperglycemia in Chinese accounts for a large proportion globally, and the ASIR, ASMR, and ASDR are increasing year by year. We should continue to pay attention to the role of metabolic factors, such as hyperglycemia, in the occurrence and development of ovarian cancer, perform a good job in tertiary prevention, and strive to reduce health losses.

Disease Burden and Attributable Risk Factors of Ovarian Cancer From 1990 to 2017: Findings From the Global Burden of Disease Study 2017

Aim: We aimed to estimate the disease burden and risk factors attributable to ovarian cancer, and epidemiological trends at global, regional, and national levels.

Methods: We described ovarian cancer data on incidence, mortality, and disability-adjusted life-years as well as age-standardized rates from 1990 to 2017 from the Global Health Data Exchange database. We also estimated the risk factors attributable to ovarian cancer deaths and disability-adjusted life-years. Measures were stratified by region, country, age, and socio-demographic index. The estimated annual percentage changes and age-standardized rates were calculated to evaluate temporal trends.

Results: Globally, ovarian cancer incident, death cases, and disability-adjusted life-years increased by 88.01, 84.20, and 78.00%, respectively. However, all the corresponding age-standardized rates showed downward trends with an estimated annual percentage change of −0.10 (−0.03 to 0.16), −0.33 (−0.38 to −0.27), and −0.38 (−0.32 to 0.25), respectively. South and East Asia and Western Europe carried the heaviest disease burden. The highest incidence, deaths, and disability-adjusted life-years were mainly in people aged 50–69 years from 1990 to 2017. High fasting plasma glucose level was the greatest contributor in age-standardized disability-adjusted life-years rate globally as well as in all socio-demographic index quintiles and most Global Disease Burden regions. Other important factors were high body mass index and occupational exposure to asbestos.

Conclusion: Our study provides valuable information on patterns and trends of disease burden and risk factors attributable to ovarian cancer across age, socio-demographic index, region, and country, which may help improve the rational allocation of health resources as well as inform health policies.

Clinical Implication of Metformin in Relation to Diabetes Mellitus and Ovarian Cancer

Since multiple reports established an association between diabetes mellitus and various cancers, emerging studies have surfaced to understand the effects of metformin as an anti-cancer agent. Although there was previous, but conflicting evidence, of a relationship between diabetes and ovarian cancer (OvCa), recent studies have supported this association. The mechanism of cancer development in patients with diabetes is likely to involve hyperglycemia, hyperinsulinemia, chronic inflammation, reactive oxygen species, regulation of cellular homeostasis, and activation of various pathways that lead to tumor cell proliferation. Preclinical evidence indicating that metformin, a medication commonly used to treat type 2 diabetes mellitus, may protect against OvCa. Metformin exerts anti-cancer properties by activating the MAPK pathway, inhibiting the PI3K/AKT/mTOR pathway, increasing tumor suppressor genes, inducing G2/M cycle arrest, and various other processes. Several studies have shown the efficacy of metformin as an adjunct with standard chemotherapeutic agents due to its synergistic effects on OvCa cells. This review highlights the epidemiologic evidence supporting a link between diabetes and OvCa, the fundamental molecular mechanism underlying carcinogenesis in patients with diabetes, the anti-cancer effects of metformin, and the need for further clinical investigations on combination therapies with metformin and standard chemotherapeutic agents for OvCa.

Complications of Pregnancy and the Risk of Developing Endometrial or Ovarian Cancer: A Case-Control Study

BACKGROUND

The association of complications of pregnancy and the risk of developing gynecological cancer is controversial with the limited study. In this study, we investigated the association of preeclampsia, or gestational diabetes mellitus (GDM), or large for gestational age (LGA), or intrauterine growth restriction (IUGR) and the risk of endometrial or ovarian cancer.

METHODS

In this case-control study, 189 women with endometrial cancer and 119 women with ovarian cancer were included. 342 women without gynecological cancers were randomly selected as a control group. Data on the history of pregnancy and age at diagnosis of gynecological cancer as well as the use of intrauterine devices (IUDs) were collected.

RESULTS

Women with a history of preeclampsia or IUGR did not have an increased risk of developing endometrial or ovarian cancer. While women with a history of GDM or with the delivery of LGA infant increased the risk of developing endometrial cancer but not ovarian cancer. The odds of women with a history of GDM or with the delivery of LGA infant developing endometrial cancer was 2.691 (95% CI: 1.548, 4.3635, p=0.0003), or 6.383 (95% CI: 2.812, 13.68, p<0.0001) respectively, compared to the controls. The odds ratio of women who did not use IUDs developing ovarian cancer was 1.606 (95% CI: 1.057, 2.434), compared to the controls. There was no association of age at first birth and developing endometrial or ovarian cancer.

CONCLUSION

Our observational data suggested that GDM and delivery of an LGA infant are associated with an increased risk of endometrial cancer.

Diabetes mellitus and the risk of ovarian cancer: a systematic review and meta-analysis of cohort and case-control studies

OBJECTIVE

Emerging evidence from observational studies (cohort and case-control studies) suggests that a history of diabetes mellitus (DM) has been linked to increased risk of ovarian cancer (OC), but the association between them remains inconclusive. The aim of this systematic review and meta-analysis of observational studies was to clarify this association.

DESIGN

Systematic review and meta-analysis.

METHODS

We searched PubMed, Embase and the Cochrane library databases published from the inception through 9 April 2020 without language restriction. Observational studies that evaluated the correlation between DM and the incidence of OC were included in our study. Relative risk (RR) with 95% CI was pooled by use of a random-effects model.

RESULTS

A total of 36 epidemiological articles, including 9 case-control and 27 cohort studies, were finally enrolled, consisting of 14 496 incident cases of OC. Synthesised RRs of developing OC by history of DM were 1.20 (95% CI=1.10 to 1.31) for all eligible studies, 1.08 (95% CI=0.77 to 1.53) for case-control studies and 1.22 (95% CI=1.11 to 1.33) for cohort studies. The above-mentioned positive association persisted across most of subgroup analyses, whereas it was not significant among studies from North American and European countries, level of unadjusted, and patients with low-quality and gestational DM group. The cumulative meta-analysis and sensitivity analysis showed pooled effect was stable and reliable, and no apparent publication bias was identified in this study.

CONCLUSIONS

Our study found weaker but still association between DM and OC risk. However, further well-designed prospective studies that control for potential confounders are warranted.

Impact of diabetes mellitus on epithelial ovarian cancer survival

Background

Diabetes mellitus (DM) is associated with poorer outcomes in some cancers. Its effect on ovarian cancer is less clear. We consider the effect of DM on overall survival (OS) and progression free survival (PFS) in patients with epithelial ovarian cancer (EOC).

Methods

A retrospective cohort study of 215 patients with EOC diagnosed between 2009 and 2016 was performed. Records were reviewed for standard demographic, pathologic and DM diagnosis data. Cox regression was used to evaluate the relationship between disease status and survival after adjustment for age, body mass index (BMI), parity, stage, grade, histology, debulking status, hypertension (HTN), menopause status and neoadjuant chemotherapy.

Results

Patients with DM (27.97, 95%CI: 23.63 to 32.30) had a significantly shorter OS rates compared to patients without DM (41.01, 95%CI: 38.84 to 43.17). The unadjusted hazard ratio (HR) for the association between OS time and DM was 4.76 (95%CI: 2.99 to 7.59, P < 0.001). Following adjustment for demographic and pathologic variables, the HR was 3.93 (95% CI: 2.01 to 7.68; P < 0.001). The PFS in patients with DM (14.10, 95%CI: 11.76 to 16.44) was significantly shorter compared to patients without DM (28.83, 95%CI: 26.13 to 31.54). The unadjusted HR for PFS and DM was 5.69 (95% CI: 3.05 to 10.61; P < 0.001). After adjustment for demographic and pathologic variables, the HR was 2.73 (95% CI, 1.18 to 6.95; P < 0.001).

Conclusions

DM can negatively effect on PFS and OS in EOC patients independent of the effect of other variables.

Evaluation of the Association between Gestational Diabetes Mellitus at First Pregnancy and Cancer within 10 Years Postpartum Using National Health Insurance Data in South Korea

This study aims to evaluate the association between gestational diabetes mellitus (GDM) at first pregnancy and the incidence of cancer within 10 years postpartum. We used customized health information data from the National Health Insurance Corporation (NHIC). This retrospective cohort study included data from women who were not previously diagnosed with diabetes or any kind of malignancy in the National Health Screening Examination through the NHIC during 2002–2003, and only women who had their first delivery between 2004 and 2005 was included. Follow-up cancer diagnosis was carried out up until 2015. Among the 102,900 primiparous women, 4970 (4.83%) were diagnosed with GDM. During 10 year total follow-up period, 6569 (6.38%) cases of primary cancer were identified. The incidence of cancer was higher in women with GDM and the most common type of cancer was thyroid cancer, followed by breast cancer. On the basis of survival analysis, we adopted the Cox proportional hazards model and found that GDM was positively associated with cancer, particularly in thyroid cancer (HR: 1.27, 95% CI: 1.054–1.532, p = 0.012). However, the incidence of other malignancies (including ovarian and breast cancers) were not significantly associated with GDM, though they did show positive trends. Our findings suggest that GDM is associated with the incidence of cancer, particular thyroid cancer.

Obesity and Ovarian Cancer

Ovarian cancer is the most fatal gynecologic cancer and is an important source of cancer-related mortality, particularly in developed countries. Despite substantial research examining adiposity (primarily adult body mass index [BMI]), the overall evidence suggests only a weak positive association between adiposity and risk of ovarian cancer, with stronger associations observed for population-based case-control studies compared to prospective studies. Ovarian cancer is not one disease and emerging data suggest that higher BMI may only be associated with risk of certain histologic subtypes, including low-grade serous and invasive mucinous tumors. Interestingly, some larger studies and meta-analyses have reported a stronger relationship with premenopausal ovarian cancers, which are more likely to be of these subtypes. Relatively few studies have conducted detailed examinations of other adiposity-related factors such as measures of abdominal adiposity, early-life body size and weight change. While the underlying mechanisms that may relate adiposity to risk are unclear, increased inflammatory biomarkers have been associated with risk and hormonal factors, including androgen levels, may be important for the development of mucinous tumors. Future research should leverage the large sample sizes of consortia to evaluate associations by key tumor characteristics as well as consider patterns of weight change over the life course with both ovarian cancer risk and survival.

Prevalence of Cancers of Female Organs among Patients with Diabetes Type 2 in Kelantan, Malaysia: Observations over an 11 Year Period and Strategies to Reduce the Incidence

INTRODUCTION

Kelantan is one of the states in Malaysia which has a high prevalence of type 2 diabetes (DM2). Other than with endometrial carcinoma, the association of DM2 with particular female cancers is not known.

OBJECTIVE

To determine the proportion of breast, cervical, ovarian and endometrial cancers among females with DM2 diagnosed in Hospital Universiti Sains Malaysia (HUSM) over an 11 year period.

MATERIALS AND METHODS

All histologically confirmed cases of breast, endometrial, cervical and ovarian carcinomas admitted to the Hospital were included in the study. The patient diabetic status was traced from the hospital medical records.

RESULTS

There was a total of 860 cases of breast, cervical, ovarian and endometrial carcinomas over this period. Breast carcinoma was the commonest, accounting for 437/860 (50.8%) followed by cervix, 159/860 (18.5%), ovarian, 143/860 (16.6%) and endometrial carcinomas, 121/860 (14.1%). Out of these, 228/860 (26.5%) were confirmed diabetics. Endometrial carcinoma patients showed the highest proportion being diabetics, 42.1% (51/121), followed by ovarian cancer, 25.9% (37/143), breast carcinoma, 23.6% (103/437) and cervical cancer 23.3% (37/159).

CONCLUSIONS

There is a significant proportion of DM2 among women with these four cancers, endometrial carcinoma being the highest followed by ovarian, breast and cervical carcinoma. The rising trend of these four cancers is in tandem with an increasing trend of DM2 in the community. In populations where diabetes is prevalent, screening for epithelial cancers should be rigourous. Diabetic clinics should include screening for these cancers among their female patients and gynecology clinics should screen the women they treat for their diabetes status.

The association between type 2 diabetes mellitus and women cancer: the epidemiological evidences and putative mechanisms

Type 2 diabetes mellitus (T2DM), a chronic disease increasing rapidly worldwide, is well established as an important risk factor for various types of cancer. Although many factors impact the development of T2DM and cancer including sex, age, ethnicity, obesity, diet, physical activity levels, and environmental exposure, many epidemiological and experimental studies are gradually contributing to knowledge regarding the interrelationship between DM and cancer. The insulin resistance, hyperinsulinemia, and chronic inflammation associated with diabetes mellitus are all associated strongly with cancer. The changes in bioavailable ovarian steroid hormone that occur in diabetes mellitus (the increasing levels of estrogen and androgen and the decreasing level of progesterone) are also considered potentially carcinogenic conditions for the breast, endometrium, and ovaries in women. In addition, the interaction among insulin, insulin-like growth factors (IGFs), and ovarian steroid hormones, such as estrogen and progesterone, could act synergistically during cancer development. Here, we review the cancer-related mechanisms in T2DM, the epidemiological evidence linking T2DM and cancers in women, and the role of antidiabetic medication in these cancers.

Diabetes in women: a life-course approach

The increasing prevalence of diabetes in combination with an aging population and increasing female longevity means that it is important to understand the effects of diabetes on women's health. Both type 1 and type 2 diabetes influence health outcomes throughout the life-course. This review article provides a summary of sex differences in diabetes epidemiology and covers specific aspects of the life-course in women including: the menarche, pregnancy and the menopause. It also discusses the associations with other conditions: cardiovascular disease, osteoporosis and cancer.

Diabetes Mellitus and Ovarian Cancer Risk: A Systematic Review and Meta-Analysis of Observational Studies

Objective

The objective of this study was to evaluate the epidemiologic association between diabetes and risk of ovarian cancer.

Methods

We searched PubMed, EMBASE, and The Cochrane Library for observational studies on the association between diabetes and ovarian cancer. Cohort studies that reported relative risks (RRs) and case-control studies that showed odds ratios were included in the analysis. Summary RRs with 95% confidence intervals (CIs) were calculated with a random-effects model.

Results

A total of 19 studies from 18 articles (7 case-control studies and 11 cohort studies) met the inclusion criteria. Combining data from all studies, diabetes was associated with an increased risk of ovarian cancer, compared with no diabetes (summary RR of ovarian cancer incidence, 1.17; 95% CI, 1.02–1.33). In cohort and nested case-control studies, patients with diabetes had statistically significant increased risk of ovarian cancer (RR, 1.16; 95% CI, 1.01–1.33), without significant heterogeneity (I2 = 27; P = 0.172). Among studies that control for age, body mass index, smoking, and alcohol, a prominent association between diabetes and ovarian cancer was found (RR, 1.55; 95% CI, 1.11–2.19).

Conclusions

This study suggests that women with diabetes have a moderately increased risk of ovarian cancer.

Type II diabetes mellitus and the incidence of epithelial ovarian cancer in the cancer prevention study-II nutrition cohort

BACKGROUND

Despite consistent associations of type II diabetes mellitus with hormonally related cancers such as breast and endometrium, the relation between type II diabetes mellitus and ovarian cancer risk is unclear.

METHODS

Associations of type II diabetes mellitus status, duration, and insulin use with epithelial ovarian cancer overall, and with serous and nonserous histologic subtypes were examined in the Cancer Prevention Study-II Nutrition Cohort, a prospective study of U.S. men and women predominantly aged 50 years and older. Between 1992 and 2007, 524 incident epithelial ovarian cancer cases were identified among 63,440 postmenopausal women. Multivariable-adjusted relative risks (RR) and 95% confidence intervals (CI) were computed using extended Cox regression to update diabetes status and bilateral oophorectomy status during follow-up.

RESULTS

Type II diabetes mellitus status (RR = 1.05; 95% CI, 0.75-1.46) and duration were not associated with epithelial ovarian cancer risk. Although not statistically significantly different (P(difference) = 0.39), the RR was higher for type II diabetes mellitus with insulin use (RR = 1.28; 95% CI, 0.74-2.24) than for type II diabetes mellitus without insulin use (RR = 0.96; 95% CI, 0.64-1.43). Diabetes seemed to be more strongly associated with nonserous (RR = 1.41; 95% CI, 0.70-2.85) than serous (RR = 0.71; 95% CI, 0.41-1.23) histologic subtypes.

CONCLUSIONS

Type II diabetes mellitus was not associated with risk of epithelial ovarian cancer, although higher risks with nonserous subtypes and among insulin users cannot be ruled out.

IMPACT

Larger studies are needed to clarify associations of type II diabetes mellitus with or without insulin use with risk of ovarian cancer overall and by histologic subtypes.

Gestational diabetes and risk of incident primary cancer: a large historical cohort study in Israel

PURPOSE

Gestational diabetes mellitus (GDM), a state of glucose intolerance associated with pregnancy, is increasing in prevalence. Data regarding the cancer risk associated with GDM are sparse and limited to cancers of the breast and pancreas. This study was conducted to examine the risk of incident overall and site-specific malignancies associated with prior GDM in a historical cohort of women in a large health maintenance organization in Israel.

METHODS

All pregnant women aged 15-50 years who underwent 50-g glucose challenge tests between 13 March 1995 and 27 May 2009, without history of malignancy, diabetes, and infertility, were included. Clinical and demographic parameters at index date including age, socioeconomic level, BMI, and parity were collected. Diagnosis of gestational diabetes was based on the 100-g oral glucose tolerance test using Carpenter and Coustan criteria. Cancer diagnoses were obtained from the Israel Cancer Register through linkage data.

RESULTS

Among the 185,315 women who had undergone glucose challenge during the study period, 11,264 (6.1%) were diagnosed with GDM. During a total follow-up period of 1.05 million person-years (mean = 5.19 ± 3.9, median = 4.3), 2,034 incident cases of cancer were identified. GDM was associated with a hazard ratio (HR) of 7.06 (95% CI: 1.69-29.45) for pancreatic cancer (nine cases) and a HR of 1.70 (95% CI: 0.97-2.99) for hematological malignancies (177 cases). The association between GDM and hematological malignancies was limited to women with 5 or more years of follow-up (HR = 4.53; 95% CI: 1.81-11.31).

CONCLUSION

GDM is associated with an increased risk of pancreatic cancer and hematologic malignancies.

Impaired glucose metabolism and diabetes and the risk of breast, endometrial, and ovarian cancer

BACKGROUND

Epidemiological evidence indicates that individuals with type 2 diabetes are at an increased risk of cancer. Elevated glucose levels, below the diagnostic threshold for diabetes, have also been suggested to be associated with increased cancer risks.

METHODS

We investigated possible associations between glucose levels and the risk of breast, endometrial, and ovarian cancer in a cohort of more than 230,000 women, for which information on outcome and potential confounders was obtained by record linkage to population-based registers.

RESULTS

Diabetes was associated with an increased risk of postmenopausal breast cancer (HR = 1.22, 95% CI 1.04-1.43). An indication of a slightly elevated breast cancer risk was also found in postmenopausal women with impaired glucose metabolism (HR = 1.11, 95% CI 0.96-1.28). Diabetes (HR = 1.46, 95% CI 1.09-1.96) and impaired glucose metabolism (HR = 1.41, 95% CI 1.08-1.85) were associated with an increased risk of endometrial cancer. No associations were found between glucose levels and ovarian cancer risk. Following adjustment for BMI, estimates were attenuated for endometrial cancer, while point estimates for breast and ovarian cancer remained essentially unchanged.

CONCLUSIONS

Our results indicate that glucose levels below the diagnostic threshold for diabetes modify the risk not only of endometrial cancer but possibly also of postmenopausal breast cancer.

Cancer risk in type 2 diabetes mellitus: metabolic links and therapeutic considerations

Type 2 diabetes mellitus (DM2) is increasing in incidence, creating worldwide public health concerns and impacting morbidity and mortality rates. An increasing number of studies have demonstrated shared associations between DM2 and malignancy, including key clinical, biochemical, and metabolic commonalities. This paper will attempt to explore the relationship between the various types of cancer and diabetes, the common metabolic pathways underlying cancer development, and the potential impact of various antidiabetes therapies on cancer risk.

Diabetes and risk of incident cancer: a large population-based cohort study in Israel

Type 2 diabetes mellitus has been associated with an increased risk of a variety of cancers in observational studies, but few have reported the relationship between diabetes and cancer risk in men and women separately. The main goal of this retrospective cohort study was to evaluate the sex-specific risk of incident overall and site-specific cancer among people with DM compared with those without, who had no reported history of cancer at the start of the follow-up in January 2000. During an average of 8 years of follow-up (SD = 2.5), we documented 1,639 and 7,945 incident cases of cancer among 16,721 people with DM and 83,874 free of DM, respectively. In women, DM was associated with an adjusted hazard ratio of 1.96 (95% CI: 1.53-2.50) and 1.41 (95% CI: 1.20-1.66) for cancers of genital organs and digestive organs, respectively. A significantly reduced HR was observed for skin cancer (0.38; 95% CI: 0.22-0.66). In men with DM, there was no significant increase in overall risk of cancer. DM was related with a 47% reduction in the risk of prostate cancer. These findings suggest that the nature of the association between DM and cancer depends on sex and specific cancer site.

Cancer incidence and mortality in patients with insulin-treated diabetes: a UK cohort study

Raised risks of several cancers have been found in patients with type II diabetes, but there are few data on cancer risk in type I diabetes. We conducted a cohort study of 28 900 UK patients with insulin-treated diabetes followed for 520 517 person-years, and compared their cancer incidence and mortality with national expectations. To analyse by diabetes type, we examined risks separately in 23 834 patients diagnosed with diabetes under the age of 30 years, who will almost all have had type I diabetes, and 5066 patients diagnosed at ages 30–49 years, who probably mainly had type II. Relative risks of cancer overall were close to unity, but ovarian cancer risk was highly significantly raised in patients with diabetes diagnosed under age 30 years (standardised incidence ratio (SIR)=2.14; 95% confidence interval (CI) 1.22–3.48; standardised mortality ratio (SMR)=2.90; 95% CI 1.45–5.19), with greatest risks for those with diabetes diagnosed at ages 10–19 years. Risks of cancer at other major sites were not substantially raised for type I patients. The excesses of obesity- and alcohol-related cancers in type II diabetes may be due to confounding rather than diabetes per se.

Endogenous Hormones and Ovarian Cancer: Epidemiology and Current Hypotheses

The effect of major epidemiologic risk factors for ovarian cancer has been reviewed in the light of several hormonal hypotheses, including the gonadotropin, androgens, progesterone, estrogens, insulin-like growth factor-I, and insulin hypotheses. The role of inclusion cyst formation and Mullerian epithelium differentiation in the pathology of the disease are also briefly outlined. Although based on limited data, the observed tendency in current evidence suggests possible etiologic roles for elevated androgens and estrogens and decreased progesterone in the pathogenesis of ovarian cancer. A direct effect of gonadotropins cannot be entirely ruled out, but it is plausible that their effect on ovarian cancer risk is mediated by stimulation of ovarian steroidogenesis. Insulin-like growth factor-I also emerges as a hormone that may be directly involved in the pathogenesis of the disease, but thus far only one prospective study has examined this association. Hyperinsulinemia is an unlikely risk factor for ovarian cancer. The observed tendency for an increased risk with androgens from ovarian origin (in premenopausal women), the lack of association with adrenal androgens, and the relatively weak associations observed with obesity, hormonal replacement therapy use, and endogenous hormones after menopause suggest that ovarian synthesis of sex steroids rather than their circulating levels may be etiologically important. More data from prospective studies will be crucial to improve our understanding of the etiologic role of endogenous hormones in the pathogenesis of ovarian cancer. Such data will ultimately provide opportunities for research targeted; at early detection and preventive interventions.

Some life-style factors and the risk of invasive epithelial ovarian cancer in Swedish women

The objective of this nationwide case-control study was to examine body mass index (BMI), alcohol use, coffee consumption, cigarette smoking, and leisure-time physical activity in relation to epithelial ovarian cancer (EOC) risk. Subjects were 655 newly diagnosed EOC cases and 3899 population controls, all 50-74 years of age at recruitment between 1993 and 1995. Data were collected through mailed questionnaires. Odds ratios (ORs) and 95% confidence intervals (CIs) were estimated using unconditional logistic regression. Women with a BMI > or = 30 kg/m2 compared with those with a BMI < 22 kg/m2 appeared to have an elevated EOC risk (OR = 1.37, 95% CI: 1.01-1.85), particularly of mucinous (OR = 2.76, 95% CI: 1.15-6.61) and clear-cell histologies (OR = 2.68, 95% CI: 0.96-7.48). The OR for EOC among coffee users reporting > or = 6 daily cups compared with non-users was 0.68 (95% CI: 0.42-1.10). Alcohol consumption was unrelated to EOC risk. Compared to non-smokers the ORs of EOC among current smokers were 0.70 (95% CI: 0.52-0.94) for those who smoked 1-10 cigarettes/day and 0.74 (95% CI: 0.53-1.02) for heavier smokers, while former smokers were at an unaltered risk (OR = 0.83, 95% CI: 0.66-1.04). Reduced EOC risks were observed among women in the highest compared with the lowest physical activity levels both at age 18-30 years (OR = 0.67, 95% CI: 0.52-0.87) and during the last years preceding study enrollment (OR = 0.68, 95% CI: 0.53-0.87). We conclude that women may avoid an excess risk of EOC through maintaining a normal BMI and reduce their risk by participation in leisure-time physical activity. The use of coffee, alcohol, or cigarette smoking does not appear to increase the risk of EOC.

Diabetes mellitus as a predictor of cancer mortality in a large cohort of US adults

Several studies have suggested that diabetes mellitus may alter the risk of developing a variety of cancers, and the associations are biologically plausible. To learn more about the relation between diabetes and cancer mortality, the authors examined associations with selected cancers in a large, prospective US cohort of 467,922 men and 588,321 women who had no reported history of cancer at enrollment in 1982. After 16 years of mortality follow-up, diabetes was significantly associated with fatal colon cancer in men (multivariate relative risk (RR) = 1.20, 95% confidence interval (CI): 1.06, 1.37) and women (RR = 1.24, 95% CI: 1.07, 1.43) and with pancreatic cancer in men (RR = 1.48, 95% CI: 1.27, 1.73) and women (RR = 1.44, 95% CI: 1.21, 1.72). For men, diabetes was significantly associated with liver cancer (RR = 2.19, 95% CI: 1.76, 2.72) and bladder cancer (RR = 1.43, 95% CI: 1.14, 1.80). In addition, diabetes was significantly associated with breast cancer in women (RR = 1.27, 95% CI: 1.11, 1.45). These associations were not explained by high body mass. Our findings suggest that diabetes is an independent predictor of mortality from cancer of the colon, pancreas, female breast, and, in men, of the liver and bladder.

Mortality from site-specific malignancies in type 2 diabetic patients from Verona

OBJECTIVE

The aim of the present work was to compare mortality from site-specific malignancies in type 2 diabetic patients with those in the general population.

RESEARCH DESIGN AND METHODS

Mortality from site-specific cancers was assessed in a population-based cohort of 7,148 type 2 diabetic patients from Verona (Northern Italy) during a 10-year follow-up (1987-1996) by reviewing death certificates. Standardized mortality ratio (SMR) data were computed using as reference mortality rates in the general population of Verona.

RESULTS

During follow-up, 641 patients (378 men and 263 women) died of malignancies. The most common causes of death among site-specific malignancies were digestive tumors both in men (140 of 378, 37.0%) and women (105 of 263, 39.9%), respiratory tumors in men (103 of 378, 27.2%), and tumors of the reproductive system in women (79 of 263, 30.0%). A slight increase in the overall mortality from malignancies was observed in diabetic patients and achieved statistical significance in women (observed/expected = 1.16, 95% CI 1.02-1.30; P = 0.019) but not in men (observed/expected = 1.07, 0.97-1.19; P = 0.163). Excess mortality from hepatic cancer (SMR = 1.86, 1.44-2.38) was observed in both men and women. In addition, women with diabetes experienced a higher mortality from pancreatic tumors (observed/expected = 1.78, 1.13-2.67) and breast tumors (observed/expected = 1.40, 1.06-1.81). Excess mortality from breast cancer was confined to obese women with diabetes.

CONCLUSIONS

Mortality from site-specific malignancies is different in type 2 diabetic patients than in the general population. Better control of body weight seems necessary to prevent the excess mortality from breast cancer in women.

Dietary glycemic index, glycemic load and ovarian cancer risk: a case-control study in Italy

BACKGROUND

Dietary carbohydrates vary in their ability to raise blood glucose and insulin levels, which, in turn, influence levels of sex hormones and insulin-like growth factors. We analyzed the effect of type and amount of carbohydrates on ovarian cancer risk, using the glycemic index (GI) and the glycemic load (GL) measurement in a large case-control study conducted in Italy.

MATERIALS AND METHODS

Cases included 1031 women with incident, histologically confirmed epithelial ovarian cancer, from four Italian regions. Controls included 2411 women admitted to the same hospital networks for acute, non-neoplastic conditions. Average daily GI and GL were calculated from a validated food frequency questionnaire. Odds ratios (OR) and the corresponding 95% confidence intervals (CI) were computed using multiple logistic regression.

RESULTS

Ovarian cancer was directly associated with dietary GI (OR for highest versus lowest quartile = 1.7, 95% CI 1.3-2.1) and GL (OR = 1.7, 95% CI 1.3-2.1). The associations were observed in pre- and postmenopausal women, and they remained consistent across strata of major covariates identified.

CONCLUSIONS

This study supports the hypothesis of a direct association between GI and GL and ovarian cancer risk and, consequently, of a possible role of hyperinsulinemia/insulin resistance in ovarian cancer development.

[The ovary and insulin resistance]

Insulin resistance appears to be responsible of approximately half of the cases of polycystic ovaries, the other half being probably provoked by an anomaly of the stimulation of ovaries by an excess of LH. Nevertheless, it is likely that in most cases the two factors conjugate. The excess of androgen production by the ovarian stroma is one of the major symptoms of this disease. Today, however, the diagnosis is carried mainly with the assistance of ultra-sounds which, besides the increased ovarian volume, have permitted to discover an increased ovarian stromal vascularity. Two essential datas derive from the whole works: the increased frequency of ovarian hyperstimulation syndrome and the great number of metabolic complications which requires an endocrinological supervision. But the most recent works focus on the extension to all ages of this form of pathology: from the intra-uterine life to the post menopause; and on the hereditary character of this disease. The mystery remains concerning the mechanism of the favourable effect in clomifene resistant PCOS, of surgical and laparoscopic methods of ovulation induction to which it may be useful to resort after mature consideration. More recently the benefit at the administration of metformine has been confirmed by several works.

Interphase fluorescence in situ hybridization studies of ovarian adenocarcinomas using the midisatellite probe

The genes involved in ovarian carcinogenesis are largely unknown. Cytogenetic studies have shown a large number of chromosomal abnormalities in ovarian cancers. Molecular studies have additionally found abnormalities. Few in situ hybridization studies have been performed on ovarian cancer tissues. We chose to study the distal region of chromosome 1p with the midisatellite probe and interphase fluorescence in situ hybridization. A total of 35 patient samples, including various controls and cancers, was collected from our pathology archives. Our cancer cases included some patients with stage I disease, in whom tumors arose in endometriotic cysts. In these cases, both tumor tissue and areas in the cyst distant from the tumor mass were examined. Results showed clear cell carcinoma nuclei to have an increase in both number and size of probe signals, interpreted as representing amplification of the probed region of chromosome 1. Serous carcinomas showed an increase in the number of signals, up to four. We felt this could be a result of amplification, or, because these cells exhibited the highest mitotic counts, to DNA doubling in preparation for mitosis. Endometrioid carcinomas resembled controls in showing up to two small probe signals, but not more. We conclude that amplification in distal chromosome 1p occurs in ovarian clear cell, and possibly serous, carcinomas and may not be important in endometrioid carcinomas. Because alteration was not found in the various control epithelia, including nonmalignant-looking areas from cysts which also contained cancer, we believe that the change, when present, may not be an early step in carcinogenesis.

Hormonal etiology of epithelial ovarian cancer, with a hypothesis concerning the role of androgens and progesterone

In the United States, ovarian cancer is the fourth most frequent cause of cancer death among women, following lung, breast, and colorectal cancers. Each year, approximately 26,000 women are diagnosed with ovarian cancer and 14,000 die of it. Germline mutations in BRCA1, BRCA2, or other genes have been implicated in a small fraction of cases. However, it has been suggested that, for the great majority of patients, the risk of epithelial ovarian cancer could be related to "incessant ovulation" (i.e., to the chronically repeated formation of stromal epithelial clefts and inclusion cysts following ovulation) or to some type of hormonal stimulation of ovarian epithelial cells, either on the surface of the ovary or within ovarian inclusion cysts, possibly mediated through excessive gonadotropin secretion. From the evidence to date, the relative importance of these two hypotheses--incessant ovulation and gonadotropin stimulation--cannot be distinguished. While either or both may play a role in the development of ovarian cancer, it appears that an additional major factor must also be involved. The purpose of this review is to evaluate evidence for and against the incessant ovulation and gonadotropin hypotheses, as well as to consider the possibility that risk of ovarian cancer may be increased by factors associated with excess androgenic stimulation of ovarian epithelial cells and may be decreased by factors related to greater progesterone stimulation. Many features of the evidence bearing on the pathophysiology of ovarian cancer appear to support a connection with androgens and progesterone.