Endometrial cancer and menopausal hormone therapy in the National Institutes of Health-AARP Diet and Health Study cohort

Factors associated with use of hormone therapy after preventive oophorectomy in BRCA mutation carriers

OBJECTIVE

Bilateral salpingo-oophorectomy (oophorectomy) is recommended to women with a germline BRCA1 or BRCA2 mutation before natural menopause to prevent ovarian and fallopian tube cancer. The adverse effects of early surgical menopause are well established. Although many of the side effects can be ameliorated by the use of hormone therapy (HT); use of HT in this group of predominantly young patients remains suboptimal. The goal of this study was to identify the frequency of HT use, as well as predictors of HT uptake in BRCA mutation carriers who underwent preventive oophorectomy before natural menopause.

METHODS

Eligible participants were identified from a longitudinal study of BRCA mutation carriers. We included premenopausal women with no personal history of cancer who underwent oophorectomy before age 50 and who had a minimum of 2 years of follow-up. Detailed information on HT use and other important variables was collected by a research questionnaire every 2 years. Descriptive statistics were used to evaluate the use of HT in various subgroups.

RESULTS

A total of 793 women with a BRCA1 or BRCA2 mutation were included in this analysis. The mean age at oophorectomy was 42 years (range 28-49). Sixty-one percent of the women reported using HT after oophorectomy. Factors associated with HT use included young age at surgery, a high level of education and preventive mastectomy.

CONCLUSIONS

The uptake of HT after oophorectomy in women with a BRCA1 or BRCA2 mutation varies by age, education, and surgical history. Clinician and patient awareness may lead to better utilization of HT in women who undergo oophorectomy at an early age to help mitigate the adverse effects associated with surgical menopause.

Menopausal Hormone Therapy and Risk of Endometrial Cancer: A Systematic Review

Background: Menopausal hormone therapy (MHT) is an appropriate treatment for women with the climacteric syndrome. The estrogen component of MHT effectively alleviates climacteric symptoms but also stimulates the endometrium and thus may increase the risk of endometrial cancer (EC). Materials and Methods: We performed a systematic literature search of the databases PubMed and Cochrane Central Register of Controlled Trials to identify controlled and uncontrolled clinical trials reporting on the prevalence and/or incidence of EC among women using MHT. Results: 31 publications reporting on 21,306 women with EC diagnosed during or after MHT were identified. A significantly reduced risk of EC among continuous-combined (cc)MHT users with synthetic progestins (SPs) was demonstrated in 10/19 studies with odds ratios (ORs)/hazard ratios (HRs) between 0.24 and 0.71. Only one study documented an increased risk of EC among long-term users (≥10 years), not confirmed in three other sub-group analyses of women with ≥6, ≥5, and >10 years of ccMHT use. A significantly increased risk of EC among users of sequential-combined (sc)MHT with SPs was demonstrated in 6/12 studies with ORs/HRs between 1.38 and 4.35. Number of days of progestin per month was a significant modulator of EC risk. A decreased risk of EC was seen in obese women. Two studies documented an increased risk of EC among users of cc/scMHT with micronized progesterone. A significantly increased risk of EC among estrogen-only MHT users was demonstrated in 9/12 studies with ORs/HRs between 1.45 and 4.46. The adverse effect of estrogen-only MHT was greatest among obese women. Conclusion: ccMHT with SPs reduces the risk of EC, whereas estrogen-only MHT increases the risk. scMHT with SPs and cc/scMHT with micronized progesterone increase the risk of EC depending on type of progestin, progestin dosage, and duration of MHT use.

Risk factors for endometrial cancer: An umbrella review of the literature

Although many risk factors could have causal association with endometrial cancer, they are also prone to residual confounding or other biases which could lead to over- or underestimation. This umbrella review evaluates the strength and validity of evidence pertaining risk factors for endometrial cancer. Systematic reviews or meta-analyses of observational studies evaluating the association between non-genetic risk factors and risk of developing or dying from endometrial cancer were identified from inception to April 2018 using PubMed, the Cochrane database and manual reference screening. Evidence was graded strong, highly suggestive, suggestive or weak based on statistical significance of random-effects summary estimate, largest study included, number of cases, between-study heterogeneity, 95% prediction intervals, small study effects, excess significance bias and sensitivity analysis with credibility ceilings. We identified 171 meta-analyses investigating associations between 53 risk factors and endometrial cancer incidence and mortality. Risk factors were categorised: anthropometric indices, dietary intake, physical activity, medical conditions, hormonal therapy use, biochemical markers, gynaecological history and smoking. Of 127 meta-analyses including cohort studies, three associations were graded with strong evidence. Body mass index and waist-to-hip ratio were associated with increased cancer risk in premenopausal women (RR per 5 kg/m2 1.49; CI 1.39-1.61) and for total endometrial cancer (RR per 0.1unit 1.21; CI 1.13-1.29), respectively. Parity reduced risk of disease (RR 0.66, CI 0.60-0.74). Of many proposed risk factors, only three had strong association without hints of bias. Identification of genuine risk factors associated with endometrial cancer may assist in developing targeted prevention strategies for women at high risk.

The management of sexuality, intimacy, and menopause symptoms (SIMS) after prophylactic bilateral salpingo-oophorectomy: How to maintain sexual health in "previvors"

"Previvors", or "pre-survivors", are individuals who do not have cancer but have a genetic predisposition to cancer. One such example is women with BRCA mutations. As a result of their predisposition to cancer, many will undergo a bilateral salpingo-oophorectomy when they are premenopausal. For premenopausal women, the removal of ovaries results in the depletion of estrogen, immediate menopause, and, in many cases, resultant Sexuality, Intimacy, and Menopausal Symptoms (SIMS). Furthermore, they may undergo changes in body image. SIMS are underreported by patients and underdiagnosed by practitioners. At the time of diagnosis or at preoperative visits, women should be informed of the potential physiologic, hormonal, and psychosocial effects of their risk-reducing surgery. There are many modalities for management of these symptoms. Successful treatment requires the provider's awareness of the problem, ability to identify it, and willingness to treat it.

Epidemiology of Endometrial Carcinoma: Etiologic Importance of Hormonal and Metabolic Influences

Endometrial carcinoma is the most common gynecologic cancer in developed nations, and the annual incidence is projected to increase, secondary to the high prevalence of obesity, a strong endometrial carcinoma risk factor. Although endometrial carcinomas are etiologically, biologically, and clinically diverse, hormonal and metabolic mechanisms are particularly strongly implicated in the pathogenesis of endometrioid carcinoma, the numerically predominant subtype. The centrality of hormonal and metabolic disturbances in the pathogenesis of endometrial carcinoma, combined with its slow development from well-characterized precursors in most cases, offers a substantial opportunity to reduce endometrial carcinoma mortality through early detection, lifestyle modification, and chemoprevention. In this chapter, we review the epidemiology of endometrial carcinoma, emphasizing theories that link risk factors for these tumors to hormonal and metabolic mechanisms. Future translational research opportunities related to prevention are discussed.

Surveillance and Care of the Gynecologic Cancer Survivor

BACKGROUND

Care of the gynecologic cancer survivor extends beyond cancer treatment to encompass promotion of sexual, cardiovascular, bone, and brain health; management of fertility, contraception, and vasomotor symptoms; and genetic counseling.

METHODS

This is a narrative review of the data and guidelines regarding care and surveillance of the gynecologic cancer survivor. We searched databases including PubMed, Cochrane, and Scopus using the search terms gynecologic cancer, cancer surveillance, and cancer survivor and reached a consensus for articles chosen for inclusion in the review based on availability in the English language and publication since 2001, as well as key older articles, consensus statements, and practice guidelines from professional societies. However, we did not undertake an extensive systematic search of the literature to identify all potentially relevant studies, nor did we utilize statistical methods to summarize data. We offer clinical recommendations for the management of gynecologic cancer survivors based on review of evidence and our collective clinical experience.

RESULTS

Key messages include the limitations of laboratory studies, including CA-125, and imaging in the setting of gynecologic cancer surveillance, hormonal and non-hormonal management of treatment-related vasomotor symptoms and genitourinary syndrome of menopause, as well as recommendations for general health screening, fertility preservation, and contraception.

CONCLUSIONS

A holistic approach to care extending beyond cancer treatment alone benefits gynecologic cancer survivors. In addition to surveillance for cancer recurrence and late treatment side effects, survivors benefit from guidance on hormonal, contraceptive, and fertility management and promotion of cardiovascular, bone, brain, and sexual health.

Menopausal hormone therapy and mortality among women diagnosed with ovarian cancer in the NIH-AARP Diet and Health Study

BACKGROUND

Although menopausal hormone therapy (MHT) use has been linked with an increased risk of ovarian cancer, whether pre-diagnosis MHT use affects ovarian cancer-specific mortality is unknown.

METHODS

Our analysis included 395 incident epithelial ovarian cancer patients with data on pre-diagnosis MHT use from the National Institutes of Health-AARP (NIH-AARP) Diet and Health Study. We used Cox proportional hazards regression models to estimate hazard ratios (HRs) and 95% confidence intervals (CIs) for MHT type and ovarian cancer-specific mortality, adjusted for tumor characteristics, treatment, and other risk factors. Effect modification by histology (serous vs. non-serous) was examined using likelihood ratio tests comparing models with and without interaction terms between MHT type and histology.

RESULTS

Ovarian cancer-specific mortality was not associated with pre-diagnosis estrogen-only therapy (ET) (HR = 1.09, 95% CI = 0.70-1.68) or estrogen plus progestin-only therapy (EPT) (HR = 0.97, 95% CI = 0.68-1.38). Neither recency of use nor specific regimen of EPT-only (sequential vs. continuous) was related to mortality. In analyses stratified by histology, no significant association between MHT type and ovarian cancer-specific mortality was observed among serous or non-serous cases; however, a significant interaction between MHT type and histology was noted (p-heterogeneity = 0.01).

CONCLUSION

Our results suggest that pre-diagnosis MHT use is not related to risk of ovarian cancer-specific death.

Menopausal hormone therapy and risk of endometrial cancer

Endometrial cancer is clearly a hormonally responsive tumor, with a critical role played by estrogens unopposed by progestins. Numerous epidemiologic studies have shown substantial risk increases associated with use of unopposed estrogens, especially among thin women. This risk, however, can be reduced if progestins are added to the therapy. The manner in which progestins are prescribed is a critical determinant of risk. Most studies show that women who have ever used progestins continuously (>25 days/months) are at somewhat reduced risk relative to non-users (meta-analysis relative risk, RR, based on observational studies=0.78, 95 confidence intervals, CI, 0.72-0.86). The reduced risk in greatest among heavy women. In contrast, women who have ever used progestins sequentially for <10 days each month are at increased risk, with meta-analysis results showing on overall RR of 1.76 (1.51-2.05); in contrast, progestins given for 10-24 days/month appear unrelated to risk (RR=1.07, 0.92-1.24). These risks were based on varying patterns of usage, with little information available regarding how endometrial cancer risk is affected by duration of use, type and/or dose of estrogen or progestin, or mode of administration. Effects may also vary by clinical characteristics (e.g., differences for Type I vs. II tumors). Further resolution of many of these relationships may be dependent on pooling data from multiple studies to derive sufficient power for subgroups of users. With changing clinical practices, it will be important for future studies to monitor a wide range of exposures and to account for divergent effects of different usage patterns. This article is part of a Special Issue entitled 'Menopause'.

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.

An aggregated analysis of hormonal factors and endometrial cancer risk by parity

BACKGROUND

Nulliparity is associated with an increased risk of endometrial cancer. It is less clear whether nulliparity modifies the association between other established hormone-related risk factors. The proportion of nulliparous women has increased since the mid-1970s, but most individual studies to date have been too small to test the hypothesis that endometrial cancer risk factors may be associated more strongly with risk among nulliparous women compared with parous women.

METHODS

Data were aggregated on 26,936 postmenopausal, Caucasian, nulliparous women (360 endometrial cancers) and 146,583 postmenopausal, Caucasian, parous women (1378 endometrial cancers) from 4 US prospective studies (1979-2006). Hazard ratios (HRs) and 95% confidence intervals (CIs) were estimated in stratified analyses.

RESULTS

The risk of endometrial cancer was higher among nulliparous women than among parous women, as expected (nulliparous vs parous: HR, 1.42; 95% CI, 1.26-1.60). Stratified associations between endometrial cancer and hormone-related risk factors did not differ between nulliparous versus parous women: For both groups, oral contraceptives and earlier menopause were associated with reduced risk. The highest HRs were for obesity: A body mass index ≥30 kg/m(2) (vs <25 kg/m(2) ) increased the risk of endometrial cancer 3-fold among nulliparous women (HR, 3.04; 95% CI, 2.34-3.94) and parous women (HR, 2.88; 95% CI, 2.52-3.29).

CONCLUSIONS

The results from this large, pooled analysis of data from 4 large prospective studies suggested that nulliparity does not modify the risks of endometrial cancer associated with established hormone-related risk factors.

Is estrogen plus progestin menopausal hormone therapy safe with respect to endometrial cancer risk?

Given the strong link between use of unopposed estrogens and development of endometrial cancers, estrogens are usually prescribed with a progestin, particularly for women with intact uteri. Some studies suggest that sequential use of progestins may increase risk; however, the moderating effects of usage patterns or patient characteristics, including body mass index (BMI), are unknown. We evaluated menopausal hormone use and incident endometrial cancer (n = 885) in 68,419 postmenopausal women with intact uteri enrolled in the National Institutes of Health-American Association of Retired Persons Diet and Health study. Participants completed a risk factor questionnaire in 1996-1997 and were followed up through 2006. Hazard rate ratios (RRs) and 95% confidence intervals (CIs) were estimated using Cox regression. Among 19,131 women reporting exclusive estrogen plus progestin use, 176 developed endometrial cancer (RR = 0.88; 95% CI = 0.74-1.06). Long-duration (≥ 10 years) sequential (<15 days progestin per month) estrogen plus progestin use was positively associated with risk (RR = 1.88; 95% CI = 1.36-2.60], whereas continuous (>25 days progestin per month) estrogen plus progestin use was associated with a decreased risk (RR = 0.64; 95% CI = 0.49-0.83). Increased risk for sequential estrogen plus progestin was seen only among thin-to-normal weight women (BMI < 25 kg/m(2); RR = 2.53). Our findings support that specific categories of estrogen plus progestin use increases endometrial cancer risk, specifically long durations of sequential progestins, whereas decreased endometrial cancer risk was observed for users of short-duration continuous progestins. Risks were highest among thin-to-normal weight women, presumably reflecting their lower endogenous estrogen levels, suggesting that menopausal hormones and obesity increase endometrial cancer through common etiologic pathways.

Primary fallopian tube carcinoma risk in users of postmenopausal hormone therapy in Finland

OBJECTIVE

Primary fallopian tube carcinoma (PFTC) is a rare malignancy and only sparse data exist on its possible association with postmenopausal hormone therapy (HT). We therefore studied this association in a nationwide cohort of Finnish HT users.

METHODS

All women> 50 years using systemic estradiol-only therapy (ET) (n=117,820 hysterectomized women) or estradiol-progestin therapy (EPT) (n=247,781 nonhysterectomized women) for ≥ 6 months during 1994-2008 were identified from the national medical reimbursement register. The incidence of PFTC in HT users was compared to that in the comparable background population (standardized incidence ratio, SIR, with 95% confidence interval, CI).

RESULTS

A total of 160 cases of PFTC were encountered in users of ET (n=34) or EPT (n=126). The use of EPT ≥ 5 years was accompanied by an increased risk for PFTC (SIR 2.15; 95% CI 1.66-2.72). The SIR increased further to 3.36 (95% CI 2.02-5.24) when EPT use lasted ≥ 10 years. The EPT-related risk for PFTC was restricted to the sequential EPT and it was not seen for continuous EPT. Two leading progestins in EPT, norethisterone acetate and medroxyprogesterone acetate, associated with comparable risk elevations. ET use was not associated with the risk for PFTC.

CONCLUSIONS

The long-term, sequential use of EPT associates with an increased risk for PFTC. In absolute terms, 4 additional cases of PFTC would be detected in 10-year follow-up of 10,000 women who have used EPT for at least 5 years.

Postmenopausal vaginal bleeding in women using hormone replacement therapy

Objective

To estimate the risk of endometrial cancer in postmenopausal women presenting with vaginal bleeding using estrogen–progestogen hormone replacement therapy (HRT) regimens and to assess if the duration of HRT use has an effect on the risk of diagnosing endometrial cancer.

Study design

Cross-sectional study of consecutive women presenting with postmenopausal vaginal bleeding at a gynaecological oncology centre in the UK.

Main outcome measures

Endometrial cancer diagnosis.

Results

Over a 62-month period, 4847 women were investigated for postmenopausal vaginal bleeding. The majority of women (4097, 84.5%) did not use any HRT preparation at the time of initial referral and 750 (15.5%) women were using combined HRT preparations. A total of 298 (6.1%) women were diagnosed with endometrial carcinoma. Women using HRT preparations were significantly less likely to be diagnosed with endometrial cancer compared with women not using HRT (adjusted odds ratio = 0.229, 95% CI 0.116–0.452; P < 0.0001). The longer duration of HRT use did increase the risk of diagnosing endometrial cancer in women presenting with postmenopausal vaginal bleeding, but this was not statistically significant.

Conclusions

Postmenopausal women presenting with vaginal bleeding and using combined HRT preparations have significantly lower risk of being diagnosed with endometrial cancer when compared with women not using HRT.

Long-term use of continuous-combined estrogen-progestin hormone therapy and risk of endometrial cancer

The daily administered dose of progestin in continuous-combined estrogen-progestin therapy is provided to counteract the proliferative effect of estrogen on the postmenopausal endometrium. However, there remains some uncertainty as to whether use of such a combined regimen, over the long term, is associated with an altered risk of endometrial cancer. We pooled data from four population-based case-control studies of endometrial cancer in western Washington State. Cases, ages 45-74, were diagnosed between 1985 and 2005. Using logistic regression with the adjustment for confounding factors, women who had exclusively used continuous-combined estrogen-progestin therapy (90 endometrial cancer cases, 227 controls) were compared with women who had never used any type of hormone therapy (774 cases, 1,116 controls). Associations with duration and recency of use were evaluated overall and within strata defined by body mass index. Long-term use of continuous-combined estrogen-progestin therapy (≥10 years) was associated with a reduced risk of endometrial cancer (OR = 0.37, 95% CI: 0.21-0.66). This association was most pronounced in women with a body mass index ≥30 kg/m(2) (OR = 0.19, 95% CI: 0.05-0.68). Associations did not differ according to recency of use. These results suggest that long duration of use of continuous-combined estrogen-progestin therapy is associated with a reduced risk of endometrial cancer.

Menopausal hormone therapy and risk of endometrial carcinoma among postmenopausal women in the European Prospective Investigation Into Cancer and Nutrition

Estrogen-only menopausal hormone therapy (HT) increases the risk of endometrial cancer, but less is known about the association with other types of HT. Using Cox proportional hazards regression, the authors examined the association of various types of HT with the risk of endometrial cancer among 115,474 postmenopausal women recruited into the European Prospective Investigation into Cancer and Nutrition between 1992 and 2000. After a mean follow-up period of 9 years, 601 incident cases of endometrial cancer were identified. In comparison with never users of HT, risk of endometrial cancer was increased among current users of estrogen-only HT (hazard ratio (HR) = 2.52, 95% confidence interval (CI): 1.77, 3.57), tibolone (HR = 2.96, 95% CI: 1.67, 5.26), and, to a lesser extent, estrogen-plus-progestin HT (HR = 1.41, 95% CI: 1.08, 1.83), although risks differed according to regimen and type of progestin constituent. The association of HT use with risk was stronger among women who were older, leaner, or had ever smoked cigarettes. The finding of a strong increased risk of endometrial cancer with estrogen-only HT and a weaker association with combined HT supports the hypothesis that progestins have an attenuating effect on endometrial cancer risk. The increased risk associated with tibolone use requires further investigation.

Alcohol and endometrial cancer risk in the NIH-AARP diet and health study

Previous investigations have provided conflicting results regarding whether alcohol consumption affects endometrial cancer risk, although in many of these studies the highest category of alcohol intake examined was limited. Further, most were unable to resolve how alcohol associations are affected by beverage type, the presence of other endometrial cancer risk factors, or tumor characteristics. To address these issues, we prospectively evaluated the association between alcohol intake and incident endometrial cancer (n = 1,491) in a cohort of 114,414 US women enrolled in the NIH-AARP Diet and Health Study. We calculated relative risks (RR) and 95% confidence intervals (CI) using Cox proportional hazards regression. After adjustment for age, body mass index (BMI), smoking and other potential confounders, the multivariable RRs (and 95% CIs) compared with nondrinkers were 0.97 (0.87-1.09) for >0-<12 g of alcohol/day, 1.06 (0.87-1.31) for 12-<24 g/day and 0.93 (0.71-1.20) for ≥ 24 g/day (p trend = 0.90). There was, however, some suggestion of higher risks associated with alcohol consumption among lean women (BMI, <25) and users of menopausal hormone therapy, with significant interactions with both parameters (respective interaction p-values of 0.002 and 0.005). The relationship was also enhanced, albeit nonsignificantly so, for low grade cancers. Our results do not support that alcohol is a strong contributor to endometrial cancer risk, but slight risk increases may prevail among some users or for selected tumor characteristics.

Intake of fruits and vegetables, and risk of endometrial cancer in the NIH-AARP Diet and Health Study

BACKGROUND

Fruits and vegetables contain a wide variety of phytochemicals which may have anti-carcinogenic effects. Although the results of case-control studies have suggested a possible protective effect of fruit and vegetable intake on the risk of endometrial carcinoma, few cohort studies have examined this association.

MATERIALS AND METHODS

We used data from the NIH-AARP Diet and Health Study to assess the association of fruit and vegetable consumption, as well as intake of specific botanical groupings of fruits and vegetables, with endometrial cancer risk among 112,088 women who completed a food-frequency questionnaire at baseline, in 1995-1996. During 8 years of follow-up 1142 incident cases of endometrial cancer were ascertained. Cox proportional hazards models were used to estimate hazard ratios (HR) and 95% confidence intervals (95% CI).

RESULTS

After adjustment for covariates, HRs for the highest compared to the lowest quintile of total fruit and total vegetable intake were 1.30 (95% CI 1.04-1.61, P for trend 0.05) and 1.09 (95% CI 0.90-1.33, P for trend 0.55), respectively. No inverse associations were observed for intake of any of 13 botanical groupings of fruits and vegetables.

CONCLUSIONS

Results from this large prospective study do not support a protective role of a high intake of fruits or vegetables on the risk of endometrial cancer in older women.

Circulating 25-hydroxyvitamin D and risk of endometrial cancer: Cohort Consortium Vitamin D Pooling Project of Rarer Cancers

A nested case-control study, including 830 cases and 992 controls from 7 cohorts, was conducted to evaluate the association of circulating 25-hydroxyvitamin D (25(OH)D), the best indicator of vitamin D status, with risk of endometrial cancer. Matching factors included age at blood donation, date of blood donation, and race. Conditional logistic regression was used in the main analysis. The median concentration of 25(OH)D was slightly lower in cases (49.4 nmol/L) than in controls (50.8 nmol/L) (P = 0.08). However, there was no association between 25(OH)D concentration and disease risk, after adjustment for body mass index. Compared with the 50-<75 nmol/L 25(OH)D category, the body mass index-adjusted odds ratios and 95% confidence intervals were 1.08 (95% confidence interval: 0.73, 1.57) for the <25 nmol/L category and 0.90 (95% confidence interval: 0.51, 1.58) for the > or =100 nmol/L category (P(trend) = 0.99). Similarly null results were observed after further adjustment for other known risk factors and in stratified analyses. Although an effect of circulating 25(OH)D at high concentrations cannot be ruled out (the highest category of 25(OH)D was > or =100 nmol/L, and for stratified analyses, > or =75 nmol/L), these results do not support a protective role of vitamin D against endometrial cancer.

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

BACKGROUND

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

Endometrial cancer in postmenopausal women using estradiol-progestin therapy

OBJECTIVE

To estimate the risk of endometrial cancer in all Finnish postmenopausal women using various forms of estradiol-progestin therapy.

METHODS

All Finnish women (aged more than 50 years) who had used estradiol-progestin therapy in 1994-2006 for at least 6 months (n=224,015) were identified from the national medical Reimbursement Registry and linked to the Finnish Cancer Registry. A total of 1,364 type I and 38 type II endometrial cancers were recorded by the end of 2006. The incidence of endometrial cancer in estradiol-progestin therapy users was compared with that in the general population in this cohort study.

RESULTS

The use of a continuous estradiol-progestin therapy regimen for 3 years or more was associated with a 76% reduction of the risk for type 1 cancer (95% confidence interval [CI] 6-60%). In contrast, the use of a sequential estradiol-progestin therapy regimen for at least 5 years was accompanied with a 69% elevation (95% CI 43-96%) if the progestin was added monthly, and with a significantly higher, 276% risk elevation (95% CI 190-379%) if progestin was added at 3-month intervals. Sequential regimens containing norethisterone acetate, medroxyprogesterone acetate or dydrogesterone administered orally showed no significant differences in the endometrial safety. Oral and transdermal norethisterone acetate were associated with similar risk elevations. Women using a monthly sequential estradiol-progestin regimen tended to be diagnosed with endometrial cancer in an earlier stage than the background population.

CONCLUSION

Use of a continuous rather than a sequential estradiol-progestin regimen decreases the risk of endometrial cancer, whereas the route of administration or type of progestin does not differ in terms of endometrial cancer risk.

LEVEL OF EVIDENCE

II.

Reproductive factors and postmenopausal hormone use in relation to endometrial cancer risk in the Nurses' Health Study cohort 1976-2004

Endometrial cancer is a disease primarily driven by cumulative exposure to estrogen unopposed by progesterone. Reproductive factors associated with changes in endogenous hormone levels and use of exogenous hormones such as postmenopausal hormones influence the risk of disease. The authors used the Nurses' Health Study, comprised of 121,700 nurses, to assess the above associations. Over 28 years of follow-up, 778 adenocarcinoma cases were diagnosed and 1,850,078 person-years were accumulated. Cox proportional hazards models were used to estimate relative risks (RR) and 95% confidence intervals (CI). A late age at menarche decreased the risk independent of body mass index (BMI) (P-trend = 0.02). A late age at menopause increased cancer risk (P-trend = 0.0003). An advanced age at last birth reduced the risk (P-trend < 0.0001), however, an inverse association with age at first birth and parity diminished after adjustment for age at last birth. Compared with never users, an increased risk was observed among long-term (> or =5 years) users of both estrogen (E) (RR = 7.67, 95% CI: 5.57, 10.57) and combined estrogen plus progesterone (E+P) (RR = 1.52, 95% CI: 1.03, 2.23). Normal-weight (BMI < 25) women had the highest risk following E or E+P use (P-interaction-E = 0.0008, P-interaction-E+P = 0.02). The findings from this study underscore the importance of hormonal mechanisms in endometrial carcinogenesis.

The influence of menopausal hormone therapy on tumour characteristics and survival in endometrial cancer patients

INTRODUCTION

Menopausal hormone therapy (MHT) is a well-established factor in endometrial carcinogenesis, and therefore, could have prognostic implications. We investigated the effects of ever use of MHT on tumour grade and depth of myometrial invasion and 5-year relative survival in postmenopausal endometrial cancer patients.

MATERIALS AND METHODS

We used a nationwide, population-based case-case design, of 683 Swedish women aged 50-74 years diagnosed with endometrial cancer during 1994 to 1995, followed up to 5 years after diagnosis. We applied polytomous multiple logistic regression to investigate the associations between the use of MHT and tumour grade, and myometrial invasion and Poisson regression for modelling 5-year excess mortality.

RESULTS

Compared to never use, ever use of any MHT entailed lower risks of having moderately and poorly differentiated tumours. The lowest odds ratios for poorly differentiated tumours were seen for ever users of cyclically combined oestrogen-progestin [OR=0.23 (95% CI=0.07-0.73)]. Ever users of any form of MHT; particularly, medium potency MHT users, had significantly lower risks for tumours with deep myometrial invasion. Adjusted estimated relative excess hazard ratios revealed significantly improved survival for ever users of any form of MHT [RER=0.40 (95% CI=0.16-0.97)]; in particular ever users of any form of oestrogens [RER=0.38 (95% CI=0.15-0.99)].

CONCLUSION

Endometrial cancer patients who were ever users of MHT had more favourable tumour characteristics and better survival compared to never users of MHT. These findings support the notion that MHT induces endometrial cancer with less aggressive characteristics.

Physical activity, sedentary behavior, and endometrial cancer risk in the NIH-AARP Diet and Health Study

Consistent with a strong hormonal etiology, endometrial cancer is thought to be influenced by both obesity and physical activity. Although obesity has been consistently related to risk, associations with physical activity have been inconclusive. We examined relationships of activity patterns with endometrial cancer incidence in the NIH-AARP Diet and Health Study cohort, which included 109,621 women, ages 50-71, without cancer history, who in 1995-1996 completed a mailed baseline questionnaire capturing daily routine and vigorous (defined as any period of >or=20 min of activity at work or home causing increases in breathing, heart rate, or sweating) physical activity. A second questionnaire, completed by 70,351 women, in 1996-1997 collected additional physical activity information. State cancer registry linkage identified 1,052 primary incident endometrial cancers from baseline through December 31, 2003. In multivariate proportional hazards models, vigorous activity was inversely associated with endometrial cancer in a dose-response manner (p for trend = 0.02) (relative risk (RR) for >or=5 times/week vs. never/rarely = 0.77, 95% confidence interval (CI): 0.63-0.95); this association was more pronounced among overweight and obese women (body mass index >or=25; RR = 0.61, 95% CI: 0.47-0.79) than among lean women (body mass index <25; RR = 0.76, 95% CI: 0.52-1.10; p for interaction = 0.12). Although we observed no associations with light/moderate, daily routine or occupational physical activities, risk did increase with number of hours of daily sitting (p for trend = 0.02). Associations with vigorous activities, which may interact with body mass index, suggest directions for future research to clarify underlying biologic mechanisms, including those relating to hormonal alterations.

Cigarette smoking and the risk of endometrial cancer: a meta-analysis

OBJECTIVE

Epidemiologic findings are inconsistent concerning the association of endometrial cancer risk with cigarette smoking. We conducted a meta-analysis of epidemiologic studies to examine this relation.

METHODS

A systematic literature search up to June of 2007 was performed in MEDLINE and EMBASE. Study-specific risk estimates were pooled using a random-effects model.

RESULTS

Ten prospective and 24 case-control studies were included in the analysis of the effect of ever smoking. Ever smoking was statistically significantly associated with a reduced risk of endometrial cancer among prospective studies (relative risk 0.81; 95% confidence interval [CI], 0.74-0.88) and case-control studies (odds ratio 0.72; 95% CI, 0.66-0.79). The inverse association was significant among current and former smokers. Six prospective and 6 case-control studies were included in the quantitative analysis. We noted that an increase in smoking of 20 cigarettes per day was statistically significantly associated with 16% and 27% reduced risks of endometrial cancer in prospective and case-control studies, respectively. We also found that cigarette smoking was significantly associated with a decreased risk of endometrial cancer among postmenopausal women (relative risk 0.71; 95% CI, 0.65-0.78) but not among premenopausal women. In addition, the risk reduction seemed to be stronger among hormone replacement therapy users than nonusers.

CONCLUSION

Cigarette smoking was found to be significantly associated with a reduced risk of endometrial cancer, especially among postmenopausal women.

Variants in hormone biosynthesis genes and risk of endometrial cancer

We investigated the risk associated with variants in three genes involved in estrogen biosynthesis, CYP11A1, CYP17A1, and CYP19A1, in the population-based case-control study of Estrogen, Diet, Genetics, and Endometrial Cancer. This study was conducted in New Jersey in 2001-2006 with 417 cases and 402 controls. For CYP11A1, there was no association between the number of [TTTTA]( n ) repeats (D15S520) and risk. For CYP17A1, risk was somewhat lower among women with the C/C genotype at T-34C (rs743572) (adjusted OR = 0.65, 95% CI 0.41-1.02). For CYP19A1, risk was lower among women homozygous for the 3-bp deletion (rs11575899) in exon 4 (adjusted OR = 0.44, 95% CI 0.26-0.76), while the number of [TTTA]( n ) repeats was not significantly related to risk: the adjusted OR for n = 7/7 repeats versus n > 7/>7 repeats was 0.81 (95% CI 0.54-1.23). In stratified analyses, results for CYP19A1 were stronger among women with higher (> or =27.4) body mass index: for the homozygous deletion, OR = 0.30 (95% CI 0.15-0.62); for the n = 7/7 genotype, OR = 0.49 (95% CI 0.26-0.93). The interaction between the n = 7/7 genotype and BMI was statistically significant (p = 0.01). The insertion/deletion variant in CYP19A1 appears to be related to risk of endometrial cancer; risk associated with variants in this gene may vary according to BMI.