Cigarette smoking and the risk of endometrial cancer

Independent of Primary Sclerosing Cholangitis and Cirrhosis, Early Adulthood Obesity Is Associated with Cholangiocarcinoma

BACKGROUND

It is estimated that 6% to 20% of all cholangiocarcinoma (CCA) diagnoses are explained by primary sclerosing cholangitis (PSC), but the underlying risk factors in the absence of PSC are unclear. We examined associations of different risk factors with intrahepatic cholangiocarcinoma (ICC) and extrahepatic cholangiocarcinoma (ECC) in the United States.

METHODS

We conducted a case-control study of 121 patients with ECC and 308 patients with ICC treated at MD Anderson Cancer Center between May 2014 and March 2020, compared with 1,061 healthy controls. Multivariable logistic regression analysis was applied to estimate the adjusted OR (AOR) and 95% confidence interval (CI) for each risk factor.

RESULTS

Being Asian, diabetes mellitus, family history of cancer, and gallbladder stones were associated with higher odds of developing ICC and ECC. Each 1-unit increase in body mass index in early adulthood (ages 20-40 years) was associated with a decrease in age at diagnosis of CCA (6.7 months, P < 0.001; 6.1 months for ICC, P = 0.001; 8.2 months for ECC, P = 0.007). A family history of cancer was significantly associated with the risk of ICC and ECC development; the AORs (95% CI) were 1.11 (1.06-1.48) and 1.32 (1.01-2.00) for ICC and ECC, respectively.

CONCLUSIONS

In this study, early adulthood onset of obesity was significantly associated with CCA and may predict early diagnosis at younger age than normal weight individuals.

IMPACT

The study highlights the association between obesity and CCA, independent of PSC. There is a need to consider the mechanistic pathways of obesity in the absence of fatty liver and cirrhosis.

Comparison of Mirena and Liletta levonorgestrel intrauterine devices for the treatment of endometrial intraepithelial neoplasia and grade 1 endometrioid endometrial cancer

Objective

Current standard nonsurgical management of endometrial intraepithelial neoplasia (EIN) and grade 1 endometrioid endometrial cancer (g1EEC) is the Mirena levonorgestrel intrauterine device (M-IUD). This retrospective study was designed primarily to determine noninferiority of the Liletta IUD (L-IUD) for pathologic regression of EIN and g1EEC compared to the M-IUD at 6 months of continuous use. Secondary objectives include to determine noninferiority as above at 3, 9, and 12 months of continuous use and to identify factors including DNA mismatch repair (MMR) status associated with pathologic regression after LNG-IUD use.

Methods

A retrospective observational study was performed with patients treated for EIN or g1EEC and managed continuously with M- or L-IUD. Patients with recent (within 6 months) or concurrent progesterone use were excluded. For the EIN group, the noninferiority margin of odds ratio was predetermined to be 0.58, and for the g1EEC group it was 0.64.

Results

62 patients from an academic center and a safety-net hospital were identified with continuous M-IUD (n = 44) or L-IUD (n = 18) use for EIN or g1EEC. 85% of patients treated with L-IUD were from a safety-net hospital, which had 63% with public insurance. At 3/6/9 months, 54/71/73% of patients with M-IUD and 80/83/100% with L-IUD had pathologic regression of EIN (95% confidence interval of estimated odds ratio 1.00-2.07/0.84-2.03/0.69-2.10). Lifetime smoking status, not MMR status, was significantly associated with pathologic regression.

Conclusions

L-IUD is an effective fertility-sparing treatment for EIN. L-IUD is noninferior to M-IUD for pathologic regression of EIN after 3,6, and 9 months. Further larger studies are warranted to validate findings in EIN and g1EEC.

Identifying women 45 years and younger at elevated risk for endometrial hyperplasia or cancer

OBJECTIVE

To estimate the prevalence of, and identify risk factors associated with, endometrial hyperplasia and/or cancer (EH/EC) in patients ≤45 years old undergoing endometrial sampling for abnormal uterine bleeding (AUB).

METHODS

We performed a retrospective cohort study of patients 18-45 years old with AUB who underwent endometrial sampling between 2016 and 2019 within a US-based multi-hospital system using billing code queries. We used multivariable Poisson regression to identify factors associated with EH/EC and calculated prevalence stratified by these factors. We estimated predicted probabilities within combinations of characteristics in order to examine the range of risk in this population.

RESULTS

Among 3175 patients, median age was 39 years (interquartile range [IQR]:35-43) and BMI was 29.7 kg/m² (IQR: 24.2-36.9). Thirty-nine percent were non-Hispanic White, 41% non-Hispanic Black, 9% Hispanic, and 11% Asian/Other/Unknown. BMI and polycystic ovarian syndrome (PCOS) were associated with higher EH/EC risk; non-Hispanic Black race was associated with lower risk. EH/EC prevalence ranged from 2% in BMI <25 to 16% in BMI ≥50 kg/m² (p-trend <0.001). These prevalence estimates differed by race/ethnicity with the lowest estimates in non-Hispanic Black patients (0.5% BMI <25 vs. 9% BMI ≥50) and highest in Hispanic patients (1.5% BMI <25 vs. 33% BMI ≥50). Accounting for combinations of risk factors, predicted probabilities were highest - 34-36% - among patients with PCOS, diabetes, BMI ≥50, and Hispanic or Asian/Other/Unknown race/ethnicity.

CONCLUSIONS

When accounting for combinations of key risk factors, risk of EH/EC in patients ≤45 years old with AUB ranges widely; the more nuanced estimates of risk presented here could help inform clinical decision-making about endometrial sampling in this population.

Nicotine Use Disorder in Older Adults

Nicotine is one of the most abused substances worldwide. Just as in adolescence and adulthood, tobacco use is also problematic in the elderly. Older people are more vulnerable to smoking consequences because of the additive effects of smoke. Cardiovascular diseases are the most common health problems associated with smoking; however, other systems are also affected, including the respiratory, nervous, integumentary, and many other systems. Smoking cessation is a difficult task especially in the elderly; therefore, physicians should encourage older patients to quit with every patient-physician encounter by offering counseling and replacement therapy.

Associations of perinatal characteristics with endometriosis: a nationwide birth cohort study

BACKGROUND

Perinatal characteristics are associated with subsequent risk of several chronic diseases. Previous studies regarding endometriosis were based on small samples and retrospective data and were limited by unmeasured confounding bias, leading to conflicting and inconclusive findings. We investigated the associations of maternal and birth characteristics with risk of endometriosis among Swedish women of reproductive age.

METHODS

This total-population register-based cohort study consisted of 628 312 singleton women born in Sweden between 1973 and 1987, who were followed for diagnosed endometriosis from age 15 years until the end of 2012. Multivariable Cox regression was applied to examine associations with perinatal characteristics. Residual unmeasured confounding was assessed through within-family and E-value analyses.

RESULTS

During follow-up, 8262 women received an endometriosis diagnosis. There were clear dose-response/linear associations of endometriosis with lower maternal education, endometriosis in the mother [adjusted hazard ratio (aHR): 2.24, 95% confidence interval (CI): 2.04-2.46], maternal smoking during pregnancy (aHR: 1.18, 95% CI: 1.04-1.33 for moderate smoker and aHR: 1.36, 95% CI: 1.18-1.57 for heavy smoker vs non-smoker), lower birthweight, and lower birthweight-for-gestational age (aHR: 0.93 per standard deviation increase, 95% CI: 0.91-0.95). Within-family and E-value analyses suggested that these perinatal characteristics are robust predictors of the incidence of endometriosis. We also found that an estimated 26% of the association between maternal smoking and early-onset endometriosis could be explained by birthweight-for-gestational age.

CONCLUSION

This study finds support for fetal origins of endometriosis, in that exposure to adverse environment or restricted development during the perinatal period may increase the risk. Further research is needed to provide an understanding of the underlying mechanisms.

Nut and peanut butter intake are not directly associated with the risk of endometrial or ovarian cancer: Results from a Dutch prospective cohort study

BACKGROUND & AIMS

Nut intake has been associated with reduced cancer-related mortality and cancer risk. However, very few studies investigated the association between nut consumption and the risk of endometrial and ovarian cancer, with inconclusive results. We prospectively examined the relation between total nut, tree nut, peanut, and peanut butter intake and the risk of endometrial and ovarian cancer in the prospective Netherlands Cohort Study (NLCS).

METHODS

In 1986, 62,573 women aged 55-69 years were included in the NLCS. At baseline, all participants filled in a questionnaire and a subcohort of 2589 women was randomly selected. After 20.3 years of follow-up, 389 endometrial and 347 ovarian cancer cases with complete data were included in the analysis. Hazard ratios (HRs) were calculated in multivariable-adjusted Cox regression analyses, using a case-cohort approach.

RESULTS

Compared to nonconsumers, the HRs (95% confidence intervals) for women consuming 10 + g total nuts/day were 1.23 (0.82-1.87) for endometrial cancer and 0.84 (0.57-1.24) for ovarian cancer. For tree nut, peanut, and peanut butter intake, also no significant relations with endometrial or ovarian cancer were observed. In the endometrial cancer analyses, significant interactions of total nut intake with body mass index and cigarette smoking status were found.

CONCLUSIONS

The results of this study suggest that intake of total nuts, tree nuts, peanuts, and peanut butter is not related to the risk of endometrial or ovarian cancer. The observed interactions in the endometrial cancer analyses, in particular with cigarette smoking status, require confirmation in other studies.

Analysis of differential genetic expression in endometrial polyps of postmenopausal women

OBJECTIVES

To evaluate the expression of four genetic markers (PTEN, BCL2, MLH1, and CTNNB1), linked to endometrial carcinogenesis, in endometrial polyps of patients with and without postmenopausal bleeding in order to determine whether symptomatic endometrial polyps have a genetic phenotype similar to that of endometrial cancer.

METHODS

Samples were obtained hysteroscopically from endometrial polyps of postmenopausal patients, and the expression of genetic markers involved in the pathogenesis of endometrial cancer (PTEN, BCL2, MLH1, and CTNNB1) was analyzed. The expression of these markers was then compared between patients with and without symptoms, which was characterized as postmenopausal bleeding. Other clinical characteristics of the patients, such as duration of menopause, polyp size, presence of systemic hypertension, diabetes mellitus, and smoking habits were also analyzed.

RESULTS

Samples from a total of 60 patients were obtained, as calculated for a test power of 0.80. No statistical differences (p > 0.05) were observed between the two groups concerning the expression of the studied endometrial cancer risk factor genes, or with regard to the clinical aspects evaluated.

CONCLUSION

The study found no evidence that symptomatic endometrial polyps have a similar phenotype to type 1 endometrial cancer; further studies are needed in order to establish whether endometrial polyps are in fact true cancer precursors, or simply raise cancer incidence due to a detection bias.

Dietary exposure to polychlorinated biphenyls and risk of breast, endometrial and ovarian cancer in a prospective cohort

BACKGROUND

Observational studies on polychlorinated biphenyl (PCB) exposure and hormone-related cancer risk are either inconsistent or lacking. We aimed to assess associations of dietary PCB exposure with breast, endometrial and ovarian cancer risk in middle-aged and elderly women.

METHODS

We included 36 777 cancer-free women at baseline in 1997 from the prospective population-based Swedish Mammography Cohort. Validated estimates of dietary PCB exposure were obtained via a food frequency questionnaire. Incident cancer cases were ascertained through register linkage.

RESULTS

During 14 years of follow-up, we ascertained 1593, 437 and 195 incident cases of breast, endometrial and ovarian cancer. We found no overall association between dietary PCB exposure and any of these cancer forms. The multivariable-adjusted relative risks comparing women in the highest and lowest tertile of PCB exposure were 0.96 (95% confidence interval (CI): 0.75, 1.24), 1.21 (95% CI: 0.73, 2.01) and 0.90 (95% CI: 0.45, 1.79) for breast, endometrial and ovarian cancer. In analyses stratified by factors influencing oestrogen exposure, possibly masking associations with PCBs, indications of higher risks were observed for endometrial cancer.

CONCLUSIONS

This study suggests that dietary exposure to PCBs play no critical role in the development of breast, endometrial or ovarian cancer during middle-age and old ages.

Molecular cues on obesity signals, tumor markers and endometrial cancer

Tumor markers are important tools for early diagnosis, prognosis, therapy response and endometrial cancer monitoring. A large number of molecular and pathologic markers have been described in types I and II endometrial cancers, which has served to define the main oncogenic, epidemiological, genetic, clinical and histopathological features. Ongoing attempts to stratify biological markers of endometrial cancer are presented. However, data on changes in tumor marker profiles in obesity-related endometrial cancer are scarce. Obesity is a pandemic in Western countries that has an important impact on endometrial cancers, albeit through not very well-defined mechanisms. Although endometrial cancer is more common in Caucasian women, higher mortality is found in African Americans who also show higher incidence of obesity. Here, we describe how obesity signals (estrogen, leptin, leptin induced-molecules, Notch; cytokines and growth factors) could affect endometrial cancer. Leptin signaling and its crosstalk may be associated to the more aggressive and poor prognosis type II endometrial cancer, which affects more postmenopausal and African-American women. In this regard, studies on expression of novel molecular markers (Notch, interleukin-1 and leptin crosstalk outcome) may provide essential clues for detection, prevention, treatment and prognosis.

Foreign- vs US-born Asians and the association of type I uterine cancer

OBJECTIVE

The purpose of this study was to determine the association of type I endometrioid uterine cancer in US-born vs immigrant Asian women.

STUDY DESIGN

Data were obtained from the Surveillance, Epidemiology, and End Results Program from 2001-2009. Chi-squared, Kaplan-Meier, and binomial logistic regression analyses were used for statistics.

RESULTS

Of 4834 Asian women with uterine cancer, 62% were US-born and 38% were immigrants. Of these women, 2972 (61%) had type I (grade 1 or 2, endometrioid histologic type) uterine cancer. Compared with patients with type II disease (grade 3, clear cell and serous histologic type), patients with type I disease were younger (age 55 vs 59 years; P < .01) and had lower stage disease (90% vs 71%; P < .01). US-born Asian women had a significantly higher proportion of type I uterine cancers in contrast to their immigrant counterparts (65% vs 56%; P < .01). Of all immigrants, the proportion of type I cancers was lowest in Japanese women followed by Chinese and Filipino women, respectively (48% vs 52% vs 58%; P < .01). The 5-year disease-specific survivals of US-born vs immigrant Asian women with type I cancer was 92% for both groups. Over 3 time periods (2001-2003, 2004-2006, and 2007-2009), there was an increase in type I cancers among US-born Asian women (61% to 65% to 68%; P < .01).

CONCLUSION

US-born Asian women are more likely to be diagnosed with type I uterine cancer compared with immigrants. Over the study period, there was a trend towards an increase in type I cancers among US-born Asian women.

Medical history, lifestyle, and occupational risk factors for hairy cell leukemia: the InterLymph Non-Hodgkin Lymphoma Subtypes Project

BACKGROUND

Little is known about the etiology of hairy cell leukemia (HCL), a rare B-cell lymphoproliferative disorder with marked male predominance. Our aim was to identify key risk factors for HCL.

METHODS

A pooled analysis of individual-level data for 154 histologically confirmed HCL cases and 8834 controls from five case-control studies, conducted in Europe and Australia, was undertaken. Age-, race and/or ethnicity-, sex-, and study-adjusted odds ratios (OR) and 95% confidence intervals (CI) were estimated using unconditional logistic regression.

RESULTS

The usual patterns for age and sex in HCL were observed, with a median age of 55 years and sex ratio of 3.7 males to females. Cigarette smoking was inversely associated with HCL (OR = 0.51, 95% CI = 0.37 to 0.71) with dose-response relationships observed for duration, frequency, and lifetime cigarette smoking (P(trend) < .001). In contrast, occupation as a farmer was positively associated with HCL (OR = 2.34, 95% CI = 1.36 to 4.01), with a dose-response relationship observed for duration (OR = 1.82, 95% CI = 0.85 to 3.88 for ≤ 10 years vs never; and OR = 2.98, 95% CI = 1.50 to 5.93 for >10 years vs never; P(trend) = .025). Adult height was also positively associated with HCL (OR = 2.69, 95% CI = 1.39 to 5.29 for upper vs lower quartile of height). The observed associations remained consistent in multivariate analysis.

CONCLUSIONS

Our observations of an increased risk of HCL from farming exposures and decreased risk from smoking exposures, independent of one another, support a multifactorial origin and an etiological specificity of HCL compared with other non-Hodgkin lymphoma subtypes. The positive association with height is a novel finding that needs replication.

Cigarette smoking, physical activity, and alcohol consumption as predictors of cancer incidence among women at high risk of breast cancer in the NSABP P-1 trial

BACKGROUND

NSABP P-1 provides an opportunity to examine the association of behavioral factors with prospectively monitored cancer incidence and interactions with tamoxifen.

METHODS

From 1992 to 1997, 13,388 women with estimated 5-year breast cancer risk greater than 1.66% or a history of lobular carcinoma in situ (87% younger than age 65; 67% postmenopausal) were randomly assigned to tamoxifen versus placebo. Invasive breast cancer, lung cancer, colon cancer, and endometrial cancer were analyzed with Cox regression. Predictors were baseline cigarette smoking, leisure-time physical activity, alcohol consumption, and established risk factors.

RESULTS

At median 7 years follow-up, we observed 395, 66, 35, and 74 breast cancer, lung cancer, colon cancer, and endometrial cancer, respectively. Women who had smoked were at increased risk of breast cancer (P = 0.007; HR = 1.3 for 15-35 years smoking, HR = 1.6 for ≥ 35 years), lung cancer (P < 0.001; HR = 3.9 for 15-35 years, HR = 18.4 for ≥ 35 years), and colon cancer (P < 0.001; HR = 5.1 for ≥ 35 years) versus never-smokers. Low activity predicted increased breast cancer risk only among women assigned to placebo (P = 0.021 activity main effect, P = 0.013 activity-treatment interaction; HR = 1.4 for the placebo group) and endometrial cancer among all women (P = 0.026, HR = 1.7). Moderate alcohol (>0-1 drink/day) was associated with decreased risk of colon cancer (P = 0.019; HR = 0.35) versus no alcohol. There were no other significant associations between these behaviors and cancer risk.

CONCLUSION

Among women with elevated risk of breast cancer, smoking has an even greater impact on breast cancer risk than observed in past studies in the general population.

IMPACT

Women who smoke or are inactive should be informed of the increased risk of multiple types of cancer.

Risk of colorectal cancer among long-term cervical cancer survivors

Because advances in therapy have increased long-term survival for women with cervical cancer, it is important to study the risk of secondary primary malignancies in high-dose organ areas. From the 1973-2009 National Cancer Institute Surveillance, Epidemiology, and End Results (SEER) program, we studied the risk of developing cancer of the colon and rectum in 64,507 cervical cancer patients over 35 years after initial radiation treatment. We also assessed change in risk over time. Kaplan-Meier estimator for survival curve and Cox proportional hazards models was used. More than half (52.6%) of the cervical cancer patients received radiation treatment. In the analyses adjusted for race/ethnicity, age, marital status, surgery status, stage and grade, the risk of colon cancer between those both with and without XRT diverged beginning at approximately 8 years. After 8 years, the hazard ratio for developing colon cancer was 2.00 (95% CI 1.43-2.80) for women with radiation versus those without radiation treatment. The risk of rectal cancer diverged after 15 years of follow-up (HR 4.04, 95% CI 2.08-7.86). After 35 years of follow-up, the absolute risk of developing colon cancer was 6.5% for those who received radiation versus 2.5% for those without, and 3.7 versus 0.8% for rectum. The risk of colon and rectum cancer over 20 years of follow-up after radiation remained the same across three eras (1973-1980, 1981-1990, and 1991-2000). Radiation-induced second cancers of the colon and rectum may occur 8 years after radiation treatment for cervical cancer.

Cigarette smoking and endometrial carcinoma risk: the role of effect modification and tumor heterogeneity

PURPOSE

The inverse relationship between cigarette smoking and endometrial carcinoma risk is well established. We examined effect modification of this relationship and associations with tumor characteristics in the National Institutes of Health-AARP Diet and Health Study.

METHODS

We examined the association between cigarette smoking and endometrial carcinoma risk among 110,304 women. During 1,029,041 person years of follow-up, we identified 1,476 incident endometrial carcinoma cases. Multivariable Cox proportional hazards regression models were used to estimate relative risks (RRs) and 95 % confidence intervals (CIs) for the association between smoking status, years since smoking cessation, and endometrial carcinoma risk overall and within strata of endometrial carcinoma risk factors. Effect modification was assessed using likelihood ratio test statistics. Smoking associations by histologic subtype/grade and stage at diagnosis were also evaluated.

RESULTS

Reduced endometrial carcinoma risk was evident among former (RR 0.89, 95 % CI 0.80, 1.00) and current (RR 0.65, 95 % CI 0.55, 0.78) smokers compared with never smokers. Smoking cessation 1-4 years prior to baseline was significantly associated with endometrial carcinoma risk (RR 0.65, 95 % CI 0.48, 0.89), while cessation ≥ 10 years before baseline was not. The association between smoking and endometrial carcinoma risk was not significantly modified by any endometrial carcinoma risk factor, nor did we observe major differences in risk associations by tumor characteristics.

CONCLUSION

The cigarette smoking-endometrial carcinoma risk relationship was consistent within strata of important endometrial carcinoma risk factors and by clinically relevant tumor characteristics.

Contemporary clinical management of endometrial cancer

Although the contemporary management of endometrial cancer is straightforward in many ways, novel data has emerged over the past decade that has altered the clinical standards of care while generating new controversies that will require further investigation. Fortunately most cases are diagnosed at early stages, but high-risk histologies and poorly differentiated tumors have high metastatic potential with a significantly worse prognosis. Initial management typically requires surgery, but the role and extent of lymphadenectomy are debated especially with well-differentiated tumors. With the changes in surgical staging, prognosis correlates more closely with stage, and the importance of cytology has been questioned and is under evaluation. The roles of radiation in intermediate-risk patients and chemotherapy in high-risk patients are emerging. The therapeutic index of brachytherapy needs to be considered, and the best sequencing of combined modalities needs to balance efficacy and toxicities. Additionally novel targeted therapies show promise, and further studies are needed to determine the appropriate use of these new agents. Management of endometrial cancer will continue to evolve as clinical trials continue to answer unsolved clinical questions.

Cigarette smoking and endometrial cancer risk: the modifying effect of obesity

The objective of this study was to evaluate the association between cigarette smoking and endometrial cancer risk by investigating potential modifying effects of menopausal status, obesity, and exogenous hormones. We pooled data from three case-control studies with the same study design conducted in Italy and Switzerland between 1982 and 2006. Overall, 1446 incident endometrial cancers and 4076 hospital controls were enrolled. Odds ratios (OR) and 95% confidence intervals (CI) were estimated using logistic regression models, conditioned on study and centre, and adjusted for age, period of interview, age at menarche, parity, and body mass index. In comparison with never smokers, current smokers showed reduced endometrial cancer risk (OR: 0.80; 95% CI: 0.66-0.96), with a 28% decrease in risk for smoking ≥ 20 cigarettes/day. The association did not vary according to menopausal status, oral contraceptive use, or hormone replacement therapy. However, heterogeneity emerged according to body mass index among postmenopausal women, with obese women showing the greatest risk reduction for current smoking (OR: 0.47; 95% CI: 0.27-0.81). In postmenopausal women, obesity turned out to be an important modifier of the association between cigarette smoking and the risk of endometrial cancer. This finding calls for caution in interpreting the favorable effects of cigarette smoking, considering the toxic and carcinogenic effects of tobacco.

Cigarette smoking and risk of meningioma: the effect of gender

BACKGROUND

A number of studies have reported on the association between smoking and meningioma risk, with inconsistent findings. We examined the effect of gender on the association between cigarette smoking and risk of intracranial meningioma in a large population-based, case-control study.

METHODS

The data include 1,433 intracranial meningioma cases aged 29 to 79 years diagnosed among residents of the states of Connecticut, Massachusetts, North Carolina, the San Francisco Bay Area and eight Texas counties between May 1, 2006 and April 28, 2011 as well as 1,349 controls that were frequency matched on age, sex, and geography. The data are analyzed separately and in a meta-analysis with six previously reported studies.

RESULTS

Female cases who reported having ever smoked were at significantly decreased risk of intracranial meningioma (OR, 0.8; 95% CI, 0.7-0.9) in contrast to male cases who were at increased risk (OR, 1.3; 95% CI, 1.0-1.7). Similar findings were noted for current and past smokers. Smoking-induced risk for females did not vary by menopausal status. For males, increased duration of use (P = 0.04) as well as increasing number of pack-years (P = 0.02) was associated with elevated risk. A meta-analysis including 2,614 cases and 1,179,686 controls resulted in an OR for ever smoking of 0.82 (95% CI, 0.68-0.98) for women and 1.39 (95% CI, 1.08-1.79) for men.

CONCLUSION

The association of cigarette smoking and meningioma case status varies significantly by gender with women at reduced risk and men at greater risk.

IMPACT

Whether the observed differences are associated with a hormonal etiology will require additional investigation.

The epidemiology of endometrial and ovarian cancer

This review highlights similarities in the epidemiology of endometrial and ovarian cancer, including highly correlated incidence rates and similar risk factor profiles. Factors that decrease risk for both cancers include a late menarche, early age at first birth, giving birth and breastfeeding, and use of oral contraceptives. Short or irregular cycles and late menopause are associated with increased risk for both. Other risk factors that appear to operate in a similar direction include decreased risk associated with IUD use or a tubal ligation, and increased risk associated with obesity, lack of exercise, and use of talc powders in genital hygiene. Estrogen excess is proposed as the underlying mechanism for most endometrial cancers, whereas incessant ovulation has been suggested as the explanation for ovarian cancer. However, an increased number of estimated ovulatory cycles correlates directly with risk for both endometrial and ovarian cancer, suggesting that reproductive tissue turnover with an accumulation of PTEN or p53 mutations represents a possible common mechanism. An immune-based explanation involving mucin proteins represents another common mechanism that could explain additional risk factors. Maintenance of ideal weight, breastfeeding children, use of oral contraceptives, and avoidance of talc powders in genital hygiene are measures that could lower the risk for both types of cancer. Careful selection of patients for prophylactic oophorectomy for those women who are coming to hysterectomy for benign disease is an additional measure to consider for ovarian cancer.

Possible interaction between ionizing radiation, smoking, and gender in the causation of meningioma

Data on the association between smoking and meningioma are inconsistent. The aim of this study was to assess the role of smoking in radiation- and non-radiation-related meningiomas. The study was designed as a 4-group case-control study, balanced for irradiation, including 160 irradiated meningioma case patients, 145 irradiated control subjects, 82 nonirradiated case patients, and 135 nonirradiated control subjects. The sources of these groups included a cohort of individuals who underwent radiotherapy (mean dose, 1.5 Gy to the brain) during childhood for treatment of tinea capitis, claims filed for radiation damage in the framework of a compensation law, and the Israel Cancer Registry. All tests of statistical significance were 2-sided. A statistically significantly elevated risk of meningioma was found among men who had ever smoked, compared with those who were never smokers (odds ratio [OR], 2.13; 95% confidence interval [CI], 1.09-4.15), increasing with smoking pack-years from 1.67 to 2.69 for <10 to >20 pack-years, respectively. Among women, an interaction between radiation and smoking was observed, expressed by a significant protective effect for meningioma (OR, 0.32; 95% CI, 0.14-0.77), with a strong dose-response association (P < .01) in non-irradiated women and a nonsignificant increased risk of meningioma among those who were irradiated (OR, 1.23; 95% CI, 0.68-2.23). Variation in the association between smoking and meningioma may be explained by effects of distinct host factors, such as past exposure to ionizing radiation and/or hormonal factors.

GSTM1 and GSTT1 copy number variation in population-based studies of endometrial cancer risk

BACKGROUND

Glutathione S-transferases (GST) detoxify a broad range of carcinogenic metabolites and lack of GSTM1 and GSTT1 activity due to gene deletions are prevalent. The associations of GSTM1 and GSTT1 polymorphisms with endometrial cancer risk have been inconsistent.

METHODS

We investigated gene dosage effects of GSTM1 and GSTT1 copy number in 441 endometrial cancer cases and 1,237 matched controls selected from the Nurses' Health Study and Women's Health Study, as well as gene-environment interactions.

RESULTS

Carriers of at least 2 GSTT1 genes had an increased risk of endometrial cancer (OR = 1.51, 95% CI = 1.04-2.19; P(trend) = 0.04) compared with women who were GSTT1 null. GSTM1 was not associated with endometrial cancer risk (OR(2/3 vs. 0 copies) = 0.82, 95% CI = 0.52-1.27; P(trend) = 0.41). We did not observe effect modification of either the GSTM1 or GSTT1 association with cancer risk by smoking status, postmenopausal hormone use, or body mass index.

CONCLUSIONS

Our results suggested GSTM1 copy number does not influence endometrial cancer risk, whereas higher GSTT1 copy number may be associated with increased risk. Our findings supported that GSTT1 differs in its substrate specificity from GSTM1 and may generate intermediates more genotoxic to endometrial cells than the parent chemical. Future studies are needed to clarify this relationship.

IMPACT

We hypothesized risk associated with GST enzymes may differ depending on environmental and/or occupational exposures. Our assessment of gene-environment interactions suggested GSTM1 and GSTT1 are not involved in the in vivo human metabolism of estrogen and its metabolites.

Biomonitoring of urinary cotinine concentrations associated with plasma levels of nicotine metabolites after daily cigarette smoking in a male Japanese population

Human biomonitoring of plasma and urinary levels of nicotine, cotinine, and 3′-hydroxycotinine was conducted after daily cigarette smoking in a population of 92 male Japanese smokers with a mean age of 37 years who had smoked an average of 23 cigarettes per day for 16 years. Members of the population were genotyped for the nicotine-metabolizing enzyme cytochrome P450 2A6 (CYP2A6). The mean levels of nicotine, the levels of its metabolites cotinine and 3′-hydroxycotinine, and the sum of these three levels in subjects one hour after smoking the first cigarette on the sampling day were 20.1, 158, 27.7, and 198 ng/mL in plasma and 846, 1,020, 1,010, and 2,870 ng/mL in urine under daily smoking conditions. Plasma levels of 3′-hydroxycotinine and urinary levels of nicotine and 3′-hydroxycotinine were dependent on the CYP2A6 phenotype group, which was estimated from the CYP2A6 genotypes of the subjects, including those with whole gene deletion. Plasma cotinine levels were significantly correlated with the number of cigarettes smoked on the day before sampling (r = 0.71), the average number of cigarettes smoked daily (r = 0.58), and the Brinkman index (daily cigarettes × years, r = 0.48) under the present conditions. The sum of nicotine, cotinine, and 3′-hydroxycotinine concentrations in plasma showed a similar relationship to that of the plasma cotinine levels. Urinary concentrations of cotinine and the sum of nicotine metabolite concentrations also showed significant correlations with the plasma levels and the previous day’s and average cigarette consumption. The numbers of cigarettes smoked per day by two subjects with self-reported light smoking habits were predicted by measuring the urinary cotinine concentrations and using linear regression equations derived from above-mentioned data. These results indicate that biomonitoring of the urinary cotinine concentration is a good, easy-to-use marker for plasma levels of cotinine and the sum of nicotine metabolites in smokers independent of genetic polymorphism of CYP2A6.

Molecular pathogenesis of endometrial and ovarian cancer

Pregnancy, breastfeeding, and oral contraceptive pill use interrupt menstrual cycles and reduce endometrial and ovarian cancer risk. This suggests the importance of turnover within Mullerian tissues, where the accumulation of mutations in p53 and PTEN has been correlated with number of cycles. The most common type of endometrial cancer (Type I) is endometrioid and molecular abnormalities include mutations in PTEN, KRAS and β-catenin. The Type I precursor is Endometrial Intraepithelial Neoplasia which displays PTEN defects. Type II endometrial cancer (whose precursors are less clear) includes serous and clear cell tumors and the most common alteration is p53 mutation. For ovarian cancer, histopathologic types parallel endometrial cancer and include serous, mucinous, endometrioid, and clear cell; some molecular features are also shared. The most frequent type of ovarian cancer is high grade serous that often displays p53 mutation and its precursor lesions may originate from normal-appearing fallopian tube epithelium that contains a p53 "signature". Mutations in KRAS, BRAF and PTEN are described in mucinous, endometrioid and low grade serous cancers and these may originate from ovarian cortical inclusion cysts. A consideration of molecular and other pathogenetic features, like epidemiology and histopathology, may provide a better understanding of endometrial and ovarian cancer.

Active and passive cigarette smoking and the risk of endometrial cancer in Poland

BACKGROUND

Epidemiological studies have consistently reported that active cigarette smoking is inversely associated with endometrial cancer risk. However, dose-response relationships with quantitative measures of active smoking or passive smoking remain less clear.

METHODS

Data on lifetime active and passive smoking were collected for 551 endometrial cancer cases and 1925 controls in a population-based case-control study conducted during 2001-2003 in Poland (Warsaw and Łódz).

RESULTS

Compared with never active smokers, active current (Odds Ratio (OR)=0.51, 95% Confidence Interval (CI): 0.39, 0.68) and former smokers (OR=0.60, 95% CI: 0.45, 0.80) were at a statistically significantly decreased risk. We did not observe statistically significant inverse dose-response relationships with increasing exposure with duration and cumulative measures. However, there was some indication that the highest category of number of years (OR=0.35, 95% CI: 0.23-0.55), intensity (OR=0.41, 95% CI: 0.24-0.69), and dose (OR=0.38, 95% CI: 0.24-0.60) of smoking among current smokers had the greatest inverse association compared to never smokers. Our data did not support the presence of an inverse association with passive smoking among never active smokers (OR=0.92; 95% CI: 0.65, 1.29).

CONCLUSION

Our results support that long-term and heavy smoking among current smokers strongly influence endometrial cancer risk.

Exposure to cadmium and persistent organochlorine pollutants and its association with bone mineral density and markers of bone metabolism on postmenopausal women

Environmental contaminants such as cadmium and persistent organochlorine pollutants have been proposed as risk factors of osteoporosis, and women may be at an increased risk. To assess associations between exposure to cadmium and two different POPs (2,2',4,4',5,5'-hexachlorobiphenyl CB-153, 1,1-dichloro-2,2-bis(p-chlorophenyl)-ethylene p,p'-DDE), on one hand, and bone effects, on the other, in a population-based study among postmenopausal (60-70 years) Swedish women with biobanked blood samples. The study included 908 women and was designed to have a large contrast of bone mineral densities, measured with a single photon absorptiometry technique in the non-dominant forearm. Biochemical markers related to bone metabolism were analyzed in serum. Exposure assessment was based on cadmium concentrations in erythrocytes and serum concentrations of CB-153 and p,p'-DDE. Cadmium was negatively associated with bone mineral density and parathyroid hormone, positively with the marker of bone resorption. However, this association disappeared after adjustment for smoking. The major DDT metabolite (p,p'-DDE) was positively associated with bone mineral density, an association which remained after adjustment for confounders, but the effect was weak. There was no evidence that the estrogenic congener (CB-153) was associated with any of the bone markers. In conclusion, no convincing associations were observed between cadmium and POPs, on one hand, and bone metabolism markers and BMD, on the other.

The influence of smoking on uterine bleeding during sequential oral hormone therapy

OBJECTIVE

To study the influence of smoking on uterine bleeding patterns during sequentially administered oral hormone therapy (HT).

METHODS

Using a post-hoc strategy, we included four sequential oral HT groups from two studies. The therapies consisted of estradiol from days 1 to 28 (estradiol or estradiol valerate) and progestogen (levonorgestrel or gestodene) on days 17-28. A total of 111 healthy, early postmenopausal women (38 smokers and 73 non-smokers) followed for 2 years were included in the analyses. Uterine bleeding data were collected from bleeding calendars.

RESULTS

On the regimen containing levonorgestrel, smoking women had a cyclical bleeding significantly earlier than non-smoking women (about 2 days' difference). Moreover, smoking women had significantly longer bleeding than non-smoking women (about 1 day in difference). This was in contrast to the three regimens containing gestodene, where smoking seemed to have far less influence on uterine bleeding.

CONCLUSIONS

On a regimen containing levonorgestrel, smokers exhibit an earlier and longer uterine bleeding than do non-smokers. This is in contrast to regimens containing gestodene, where smoking women are less likely to differ from non-smoking women with regard to bleeding. This indicates that smoking influences progestogen metabolism, and that this influence may vary with different progestogens. Further studies are needed.

Long-term dietary cadmium intake and postmenopausal endometrial cancer incidence: a population-based prospective cohort study

Environmental pollutants mimicking the effects of estrogen are suggested to contribute to the high incidence of hormone-related cancers, but supporting data are sparse. A potent estrogen-like activity of the pollutant cadmium, mediated via the estrogen receptor-alpha, has been shown in vivo. We prospectively examined the association between cadmium exposure and incidence of postmenopausal endometrial cancer. The Swedish Mammography Cohort is a population-based prospective cohort of 30,210 postmenopausal women free of cancer diagnose at baseline (1987) and who completed a food frequency questionnaire at baseline and in 1997. We estimated the dietary cadmium intake based on the questionnaire data and the cadmium content in all foods. During 16.0 years (484,274 person-years) of follow-up between the baseline and mid-2006, we ascertained 378 incident cases of endometrioid adenocarcinoma. The average estimated dietary cadmium intake was 15 mug/day (80% from cereals and vegetables). Cadmium intake was statistically significantly associated with increased risk of endometrial cancer in all women; the multivariate relative risk (RR) was 1.39 [95% confidence interval (CI), 1.04-1.86; P(trend) = 0.019], comparing highest tertile versus lowest. Among never-smoking women with body mass index (BMI) of <27 kg/m(2), the RR was 1.86 (95% CI, 1.13-3.08; P(trend) = 0.009). We observed a 2.9-fold increased risk (95% CI, 1.05-7.79) associated with long-term cadmium intake consistently above the median at both baseline 1987 and in 1997 in never-smoking women with low bioavailable estrogen (BMI of <27 kg/m(2) and nonusers of postmenopausal hormones). Our results support the hypothesis that cadmium may exert estrogenic effects and thereby increase the risk of hormone-related cancers.

Risks of cancer among a cohort of 23,935 men and women with osteoporosis

Low hormone levels among persons with osteoporosis may decrease risk of some cancers. Other osteoporosis risk factors, such as smoking and alcohol consumption, however, may increase risk. As these deleterious factors are more often associated with osteoporosis diagnosed prior to age 70 years, cancer risk may be higher in these younger persons than in the general population. To examine this hypothesis, a cohort study of 23,935 persons with osteoporosis was conducted in Denmark. Patients hospitalized with osteoporosis between 1978 and 1993 were identified in the Danish Inpatient Register. Linkage to the Danish Cancer Registry identified all cancer outcomes through 2003. Standardized incidence ratios (SIR) and 95% confidence intervals (95%CI) were calculated to compare cancer incidence in the cohort with that in the general population. Persons diagnosed prior to age 70 years were at increased cancer risk (women: SIR = 1.11, 95%CI = 1.04-1.19; men: SIR = 1.31, 95%CI = 1.13-1.50) due, in part, to increased risks of cancers of the buccal cavity, esophagus, liver, pancreas and lung. Persons diagnosed at ages 70 and older were at decreased risk (women: SIR = 0.91, 95%CI = 0.87-0.96; men: SIR = 0.89, 0.77-1.01) due, in part, to decreased risks of breast, endometrial, colon, rectal and brain cancers in women and prostate cancer in men. These results suggest that risk factors associated with earlier onset osteoporosis may be associated with increased risk of cancer. Conversely, factors associated with later onset osteoporosis may be related to a decreased risk of cancer.

Cytochrome P450 1A1, cigarette smoking, and risk of endometrial cancer (United States)

Cytochrome P450 1A1 (CYP1A1) is involved in the metabolism of estradiol and the activation of polycyclic aromatic hydrocarbons found in tobacco products. Polymorphic variation in CYP1A1 activity may modify susceptibility to endometrial cancer through the oxidative metabolism of estradiol and the activation of tobacco-smoke constituents. We prospectively evaluated the associations between three common CYP1A1 polymorphisms and endometrial cancer risk, as well as the potential modification of these associations by cigarette smoking, in a case-control study nested within the Nurses' Health Study. We investigated the MspI restriction-site polymorphism, a C --> A transversion at nucleotide 4887 (Thr461Asn) and a A --> G transition at nucleotide 4889 (Ile462Val) among 456 women with endometrial cancer and 1,134 matched controls. We used conditional logistic regression to calculate the adjusted odds ratios (OR) and 95% confidence intervals (CI) to quantify the risk of endometrial cancer among subjects who had at least one variant allele compared with that of subjects homozygous for the wild-type allele. We did not observe any statistically significant associations between the MspI, Thr461Asn or Ile462Val polymorphisms and endometrial cancer risk or any significant effect modification by cigarette-smoking status. These data suggest that these three polymorphisms are not important in determining genetic susceptibility to endometrial cancer, although larger sample sizes are needed to confirm these findings.

Alcohol consumption, cigarette smoking, and endometrial cancer risk: results from the Netherlands Cohort Study

Objective

To examine the association between alcohol consumption, cigarette smoking, and endometrial cancer.

Methods

In 1986, the Netherlands Cohort Study was initiated. A self-administered questionnaire on dietary habits and other cancer risk factors was completed by 62,573 women. Follow-up for cancer was established by record linkage to the Netherlands Cancer Registry.

Results

After 11.3-years of follow-up, 280 incident endometrial cancer cases were available for analyses. In multivariate analysis, the rate ratio (RR) for alcohol users versus non-users was 1.06 (95% Confidence Interval (95% CI) = 0.78–1.43). There were neither dose-dependent trends nor associations with different types of beverages. The RR for former and current smokers versus never-smokers was 0.83 (95% CI = 0.58–1.20) and 0.59 (95% CI = 0.40–0.88), respectively. These estimates did not change significantly when body mass index (BMI) and age at menopause were added to the models.

Conclusions

There is no association between alcohol consumption and endometrial cancer. Current smoking is associated with a reduced risk of endometrial cancer. This association is neither mediated by BMI nor by age at menopause.

Medical history, cigarette smoking and risk of acoustic neuroma: an international case-control study

Acoustic neuroma (vestibular schwannoma) is a benign tumor of the vestibulocochlear nerve. Its recorded incidence is increasing but risk factors for this tumor have scarcely been investigated. We conducted a population-based case-control study of risk factors for acoustic neuroma in the UK and Nordic countries, including 563 cases and 2,703 controls. Tumor risk was analyzed in relation to medical history and cigarette smoking. Risk of acoustic neuroma was significantly raised in parous compared with nulliparous women (OR = 1.7, 95% CI: 1.1-2.6), but was not related to age at first birth or number of children. Risk was not associated with a history of allergic disease, past head injury, past diagnosis of a neoplasm or birth characteristics, but was significantly raised for past diagnosis of epilepsy (OR = 2.5, 95% CI: 1.3-4.9). Tumor risk was significantly reduced in subjects who had ever regularly smoked cigarettes (OR = 0.7, 95% CI: 0.6-0.9), but the reduction applied only to current smokers (OR = 0.5, 95% CI: 0.4-0.6), not ex-smokers (OR = 1.0, 95% CI: 0.8-1.3). The reduced risk of acoustic neuroma in smokers and raised risk in parous women might relate to sex hormone levels, or smoking might suppress tumor growth, but effects of parity and smoking on timing of diagnosis of the tumor are also a potential explanation. The raised risk in relation to past diagnosis of epilepsy might be a surveillance artefact or imply that epilepsy and/or antiepileptic medication use predispose to acoustic neuroma. These findings need replication by other studies and possible mechanisms need to be clarified.

Risk of endometrial cancer in relationship to cigarette smoking: Results from the EPIC study

Current epidemiologic evidence indicates that cigarette smoking reduces the risk of endometrial cancer. We examined data from the European Prospective Investigation into Cancer and Nutrition (EPIC) cohort to analyze further aspects of the smoking-endometrial cancer relationship, such as possible modifying effects of menopausal status, HRT use, BMI and parity. In a total of 249,986 women with smoking exposure and menopausal status information, 619 incident endometrial cancer cases were identified during 1.56 million person-years of follow-up. Among postmenopausal women, the hazard ratio (HR) for current smokers versus never smokers was 0.70 (95% CI = 0.53-0.93), while it was 1.75 (95% CI = 1.13-2.70) among premenopausal women at recruitment. After adjustment for risk factors, the HR for postmenopausal women was slightly attenuated to 0.78 (95% CI = 0.59-1.03). No heterogeneity of effect was observed with HRT use or BMI. Among premenopausal women, current smokers of more than 15 cigarettes per day or who smoked for 30 years or more at the time of recruitment had a more than 2-fold increased risk of endometrial cancer compared to never smokers (HR = 2.54; 95% CI = 1.47-4.38 and HR = 2.23; 95% CI = 1.04-4.77, respectively). Past smoking was not associated with endometrial cancer risk, either among pre- or postmenopausal women. In this prospective study, we observed an increased risk of endometrial cancer with cigarette smoking in premenopausal women. The reduction of endometrial cancer risk observed among postmenopausal women does not have direct public health relevance since cigarette smoking is the main known risk factor for cancer.

Hormonal and reproductive factors and the risk of bladder cancer in women

Gender and cigarette smoking are among the most consistent predictors of bladder cancer risk. After adjustment for known risk factors, an excess risk remains for males, suggesting that other factors may be responsible for the gender differences. Given limited data on hormonal or reproductive factors and bladder cancer risk, the authors examined these factors among women in the US Nurses' Health Study cohort. During 26 years of follow-up (1976-2002), 336 incident cases of bladder cancer were diagnosed. Cox proportional hazards models were used to estimate incidence rate ratios and 95% confidence intervals between hormonal and reproductive factors and bladder cancer risk. Postmenopausal women, compared with premenopausal women, were at increased risk (incidence rate ratio = 1.93, 95% confidence interval: 0.99, 3.78). For postmenopausal women, early age at menopause (</=45 years) compared with late age at menopause (>/=50 years) was associated with a statistically significant increased risk of bladder cancer (incidence rate ratio = 1.63, 95% confidence interval: 1.20, 2.23). The association between age at menopause and bladder cancer risk was modified by cigarette smoking status (p for interaction = 0.01). The authors observed no significant associations of age at menarche, parity, age at first birth, and exogenous hormone use with bladder cancer risk. Findings suggest that menopausal status and age at menopause may play a role in modifying bladder cancer risk among women.

Inflammation and Endometrial Cancer: A Hypothesis

Endometrial cancer is the most common gynecologic malignancy in the United States. Substantial epidemiologic data implicate an imbalance of estrogens and progestogens in the etiology of this disease. We propose that inflammation also plays a role in endometrial cancer development. Emerging laboratory data suggest that elevated levels of prostaglandin E(2) may underlie the transformation of normal endometrium to neoplastic tissue and that in vitro nonsteroidal anti-inflammatory drugs may inhibit endometrial cancer cell growth. In this review, we suggest that the risk factors for endometrial cancer--unopposed estrogens, anovulation, polycystic ovary syndrome, excessive menstruation, early menarche, and late menopause--may be viewed as factors increasing the exposure of the endometrium to inflammation, whereas pregnancy and smoking, two likely protective factors, have the opposite effect. Chronic inflammation can induce rapid cell division, increasing the possibility for replication error, ineffective DNA repair, and subsequent mutations. A proinflammatory milieu can also directly increase estrogen production. Hence, inflammation may work in conjunction with or in addition to estrogen exposure in the development of endometrial cancer.

Smoking and the risk of endometrial cancer: results from the Nurses' Health Study

An inverse association between smoking and endometrial cancer has generally been observed, primarily among current smokers. To assess this association, we analyzed data from the prospective Nurses' Health Study. From 1976 to 2000, 702 cases of invasive endometrial cancer were identified during 1.8 million person-years of follow-up. Smoking status was assessed in 1976 and updated every 2 years. Cox proportional hazards models were used to calculate multivariate relative risks (RRs), controlling for endometrial cancer risk factors. Compared to never smokers, the multivariate RR of endometrial cancer was significantly lower among both current smokers (RR = 0.63; 95% CI = 0.50-0.79) and past smokers (RR = 0.73; 95% CI = 0.62-0.87). When additionally adjusting for body mass index (BMI), the RR for current smokers was attenuated (RR = 0.72; 95% CI = 0.57-0.90), but the RR for past smokers did not change. Risk was lower among women who smoked 35 or more cigarettes a day (RR = 0.60; 95% CI = 0.39-0.91) and among those who smoked for 40 or more years (RR = 0.63; 95% CI = 0.45-0.87). Tests for trend, which excluded never smokers, were not statistically significant for any of the smoking variables analyzed. These data indicate that both current and past smoking are associated with a lower risk of endometrial cancer. The findings provide insight into disease etiology and suggest that the influence of smoking on endometrial cancer risk occurs even in early adulthood, is long-lasting, and may not be attributed solely to short-term hormonal modulation.

Endometrial Cancer Incidence Trends in Europe: Underlying Determinants and Prospects for Prevention

More than one in 20 female cancers in Europe are of the endometrium. Surveillance of incidence rates is imperative given the rapidly changing profile in the prevalence and distribution of the underlying determinants. This study presents an analysis of observed and age-period-cohort-modeled trends in 13 European countries. There were increasing trends among postmenopausal women in many Northern and Western countries. Denmark and possibly France and Switzerland were exceptions, with decreasing trends in postmenopausal women. In premenopausal and perimenopausal women, declines were observed in Northern and Western Europe, most evidently in Denmark, Sweden, and the United Kingdom, affecting consecutive generations born after 1925. These contrast with the increasing trends regardless of menopausal age in some Southern and Eastern European countries, particularly Slovakia and Slovenia. These observations provide evidence of changes in several established risk factors over time and have implications for possible primary prevention strategies. In postmenopausal women, changes in reproductive behavior and prevalence of overweight and obesity may partially account for the observed increases, as well as hormone replacement therapy use in certain countries. Combined oral contraceptive use may be responsible for the declines observed among women aged <55 years. Whereas there are some prospects for chemoprevention in premenopausal women as oral contraceptive use becomes more widespread in Europe, increases in obesity and decreases in fertility imply that endometrial cancer in postmenopausal women will become a more substantial public health problem in the future.

Geographic and temporal variations in cancer of the corpus uteri: Incidence and mortality in pre- and postmenopausal women in Europe

Corpus uteri cancer is the fourth most common neoplasm in women in Europe and the tenth most common cause of cancer death. We examined geographic and temporal variations in corpus uteri cancer incidence and mortality rates in the age groups 25-49 and 50-74 in 22 European countries. The disease is considerably less common in premenopausal women, with incidence and mortality rates decreasing throughout Europe and mortality declines more marked in western and southern European countries. Incidence rates among postmenopausal women are highest in the Czech Republic, Slovakia, Sweden and Slovenia and lowest in France and the United Kingdom. Increasing incidence trends in this age group are observed in the Nordic countries (except Denmark) and in the United Kingdom. Some increases are also seen in eastern (Slovakia) and southern Europe (Spain and Slovenia), while relatively stable or modestly decreasing trends are observed in Italy and most western European countries. Postmenopausal mortality rates are systematically higher in eastern Europe, with death rates in the Ukraine, Latvia, Czech Republic, Russia and Belarus 2-3 times those seen in western Europe. Declining mortality trends are seen in most populations, though in certain Eastern European countries, the declines began rather recently, during the 1980s. In Belarus and Russia, recent postmenopausal death rates are stable or increasing. The rates are adjusted for misclassification of uterine cancer deaths but remain unadjusted for hysterectomy, and where there is an apparent levelling off of incidence or mortality rates recently, rising prevalence of hysterectomy cannot be discounted as an explanation. However, the trends by age group can be viewed in light of several established risk factors for endometrial cancer that are highly prevalent and most likely changing with time. These are discussed, as are the prospects for preventing the disease.

Environmental tobacco smoke and breast cancer incidence

To evaluate whether environmental tobacco smoke (ETS) influences breast cancer incidence, data from a population-based case-control study were analyzed. Respondents with available ETS information assessed by in-person questionnaires included 1356 newly diagnosed cases and 1383 controls. Relative to nonsmokers who reported no residential ETS exposure throughout the life course, the odds ratios (OR) for breast cancer were not substantially elevated in relation to ETS exposure, active smoking, or a joint measure of active and passive smoking (OR, 1.15, 95% CI, 0.90, 1.48). An increased OR, however, was noted among nonsmokers who lived with a smoking spouse for over 27 years (2.10, 95% CI, 1.47, 3.02), although no dose-response was evident. Also, among women with hormone-receptor-positive tumors only, the OR for both active and passive smoking was increased (1.42 for ER+ PR+, 95% CI, 1.00, 2.00). Our data suggest that if there is an effect for ETS on breast cancer, that effect is restricted to selected subgroups of women, such as those with long-term exposure from a smoking spouse.

Cytochrome P450 1B1 Gene Polymorphisms and Postmenopausal Endometrial Cancer Risk

Estrogen unopposed by progestins is a key factor in endometrial cancer etiology. Cytochrome P450 1B1 (CYP1B1), responsible for the 4-hydroxylation of estrogen, may be important in endometrial carcinogenesis, either as a regulator of estrogen availability or as a producer of potentially genotoxic estrogen metabolites. We investigated the association of CYP1B1 genotype and endometrial cancer risk in a population-based case-control study of postmenopausal Swedish women. We used the Expectation-Maximization algorithm to estimate the haplotype frequencies in the population and calculated odds ratios and 95% confidence intervals from conditional logistic regression models. In stratified analysis, we investigated the possible effects of CYP1B1 genotype on endometrial cancer risk in subgroups defined primarily by menopausal hormone use and also by body mass index, smoking, use of combined oral contraceptives, and family history. We genotyped 689 cases and 1,549 controls for the CYP1B1 single nucleotide polymorphisms m2, m3, and m4 and estimated the haplotype frequencies among controls to 0.086, 0.291, 0.452, and 0.169 for the CYP1B1*1, CYP1B1*2, CYP1B1*3, and CYP1B1*4 alleles, respectively. We found no evidence for an overall association between CYP1B1 genotype and endometrial cancer risk, nor was there any clear indication of gene-environment interaction.