Effect of hysterectomy on incidence trends of endometrial and cervical cancer in Finland 1953-2010

Social factors and age play a significant role in cervical cancer and advanced-stage disease among Danish women

BACKGROUND

For cervical cancer (CC), the implementation of preventive strategies has the potential to make cervical cancer occurrence and death largely avoidable. To better understand the factors possibly responsible for cervical cancer, we aimed to examine possible differences in age and social parameters as well as screening status between women with low- or high-stage cervical cancer and matched controls.

METHODS

Through the Danish Cancer Registry (DCR), women diagnosed with cervical cancer in Denmark between 1987 and 2016 were included. These were age- and residence-matched in a 1:5 ratio with controls from the general female population. The study population was sub grouped into a low-stage subpopulation with women with early-stage cervical cancer and matched controls and a high-stage subpopulation with women with late-stage cervical cancer and matched controls. Age and social parameters were compared within the subpopulations as well as between low- and high-stage cases. For part of the study population, screening attendance was examined to compare differences in adherence.

RESULTS

Overall, we found that the risk of cervical cancer is significantly increased in socially disadvantaged women and not least non-attenders in screening. Interestingly, the high-stage subpopulation was significantly older than the low-stage subpopulation (p < 0.001), and when examining the impact of age further, we found that for cervical cancer cases, the risk of having low-stage disease decreases significantly with increasing age, whereas the risk of having high-stage disease increases significantly with increasing age. In the screening cohort, significantly less cases than controls were attenders in screening with the most pronounced differences seen in the old subpopulation (women aged 50-64 years) and in the high-stage subpopulation (p-values all < 0.001). Interestingly, when examining the risk of CC for attenders and non-attenders, we demonstrated that many social parameters continue to influence the risk of cervical cancer, even in women attending screening.

CONCLUSIONS

Older women, socially disadvantaged women, and non-attenders in screening are particularly vulnerable in terms of developing cervical cancer, especially high-stage disease. Therefore, improvements in the participating rate in screening as well as a revision of the current screening guidelines are needed.

Factors associated with advanced-stage diagnosis of cervical cancer in Estonia: a population-based study

OBJECTIVES

Cervical cancer (CC) remains a crucial public health issue in Estonia, with high incidence and late diagnosis. The aim of this study was to examine time trends of stage-specific CC incidence in Estonia and factors associated with advanced-stage diagnosis of CC.

STUDY DESIGN

This was a nationwide population-based retrospective study.

METHODS

Data on CC cases diagnosed in Estonia in 2007-2018 were obtained from the Estonian Cancer Registry, including tumour, nodes, metastases stage at diagnosis. Sociodemographic data were obtained from the Population Registry. To estimate the risk of advanced-stage diagnosis (stages II-IV vs stage I) associated with sociodemographic factors, Poisson regression with robust variance was used to calculate univariate and multivariate prevalence ratios (PR) with 95% confidence intervals (CIs). Time trends of stage-specific CC incidence for 2005-2019 were examined with joinpoint analysis.

RESULTS

Incidence of stage I CC showed a significant decline of 4.9% per year since 2007, whereas no change was seen for other stages. Of the 2046 women diagnosed in 2007-2018, 1137 (55.6%) were diagnosed at an advanced stage; this proportion increased from 51% in 2007-2009 to 58% in 2015-2018 (P = 0.004). Multivariate regression analysis showed that advanced-stage diagnosis was associated with age (PR 2.16, 95% CI 1.87-2.49 for women aged ≥75 years compared with those aged 30-44 years), educational level (PR 1.32, 95% CI 1.15-1.51 for women with basic/primary education compared to university education) and marital status (PR 1.14, 95% CI 1.01-1.29 for single women compared to married/cohabiting women). No associations were observed by region of residence or nationality.

CONCLUSIONS

To reduce CC mortality, it is crucial to improve prevention and early diagnosis of CC in Estonia through human papillomavirus vaccination and effective and quality-assured screening particularly targeting high-risk groups as well as encouraging symptom awareness and regular check-ups among older women.

Effectiveness of Cervical Testing in and outside a Screening Program-A Case-Control Study

In many countries with organized cervical cancer screening, opportunistic Pap and human papillomavirus (HPV) tests are common. However, little is known about their effectiveness. We examined the effect of testing in and outside the Finnish screening program on the risk of cervical cancer. We conducted a case-control study that involved 1677 cases with invasive cervical cancer that were diagnosed between 2010 and 2019. Five- and three-year test intervals were analyzed across all ages, by age group and by cancer morphology subtype. Conditional logistic regression was used, adjusting for socioeconomic variables. Women undergoing any kind of cervical test had a significantly lowered risk of cervical cancer (adjusted OR = 0.43, 95% CI = 0.38-0.48, tests in five-year intervals). The results were similar, regardless of whether the test had been taken in the screening program or outside of it, or whether the interval was five years or three years. Testing of women at ages 35-64 showed the strongest effects, but moderate preventive effects were seen until age 79. No significant effect was seen below age 30. Tests in and outside the program were effective at the screening target age. However, participation in the program should be encouraged for optimal cost-effectiveness. Preventive effects were also seen above the program target ages.

Incidence and Trend of Type I and II Endometrial Cancer in Women from Two Population-Based European Cancer Registries (1998-2012)

Endometrial cancer (EC) is the most frequent female genital tract cancer in Europe. This cohort study aimed to determine age-standardised incidence rates and long-term trends of type I and II endometrial cancer in women from population-based cancer registries in the Region of Murcia (Spain) and the Bas-Rhin area (France). Data of new cases of endometrial cancer between 1998 and 2012 were obtained from the Murcia and Bas-Rhin cancer registries. In that period, 3756 cases of endometrial cancer were recorded, with 3270 corresponding to type I EC and 486 corresponding to type II EC. The Bas-Rhin area presented higher age-adjusted incidence rates than those in the Region of Murcia for both type I EC (24.2 and 19.3 cases/100,000 person-years (py), respectively) and type II EC (4.4 and 2.3 cases/100,000 py, respectively). Joinpoint regression showed no changes in trends. In both populations, there was an increasing trend for both EC types, but the trend was steeper in the Region of Murcia and larger overall for type II EC. Finally, a significant increase was observed in the annual trend of type II EC. Further studies are warranted to determine the potential risk factors, and continued efforts are needed to improve the recording and monitoring of EC types.

Setting the record straight-Correcting uterine cancer incidence and mortality in the Nordic countries by reallocation of unspecified cases

INTRODUCTION

The incidence of and mortality from cancers of the cervix uteri and corpus uteri are underestimated if the presence of uterine cancers, where the exact topography (site of origin) is not specified, is omitted. In this paper we present the corrected figures on mortality from and incidence of cervix and corpus uteri cancers in the Nordic countries by reallocating unspecified uterine cancer deaths and cases to originate either from the corpus uteri or cervix uteri. To further validate the accuracy of reallocation, we also analyzed how well the reallocation captures the changes occurring as the result of a transition in cause of death coding in Norway that took place in 2005.

MATERIAL AND METHODS

This study uses data available in the NORDCAN database, which contains aggregated cancer data from all the Nordic countries for the years 1960-2016. The unspecified uterine cancer cases and deaths were reallocated to either cervix uteri or corpus uteri based on the estimated probability that follows the distribution of cases and deaths with verified topography. The estimated proportions of cases and deaths for both cancers were calculated for each combination of age group, year, and country as a proportion of cases (and deaths, respectively) with known topography. Annual age-standardized rates were calculated by direct age-adjustment.

RESULTS

The proportions of unspecified uterine cancers were higher in the mortality data than in incidence data, with mean values for 1960-2016 ranging between 5.1% and 26.6% and between 0.2% and 6.8% by country, respectively. In the Nordic countries combined, the reallocation increased the number of cases by 4% and deaths by approximately 20% for both cancers. Finland was the only Nordic country where the mortality rate did not increase substantially after reallocation.

CONCLUSIONS

The reallocation procedure had a significant impact on mortality from cancers of the cervix and corpus uteri for countries where the proportion of cancer deaths coded as uterus, not otherwise specified, is substantial. More effort to validate cause of death data with incidence data from cancer registries is warranted to avoid erroneous conclusions of temporal trends based on uncorrected cancer burden.

Effects of m6A RNA methylation regulators on endometrial cancer

Background

The modification 6‐methyladenine (m⁶A) is the most common type in RNA methylation. Our study aims to explore the bioinformatic analysis of m⁶A in endometrial cancer.

Methods

The expression of 23 m⁶A RNA methylation regulators was compared through The Cancer Genome Atlas (TCGA) database among 406 endometrial tissue and 19 normal tissue samples. The Wilcoxon test was applied to compare the relationship between the clinicopathological characteristics and expression. Cox regressions were performed to identify the prognostic factors associated with overall survival. Gene ontology (GO) and Gene Set Enrichment Analysis (GSEA) were performed to evaluate the potential pathways.

Results

YTHDF2, HNRNPA2B1, HDRNPA2B1, YTHDF1, FMR1, IGF2BP3, METTL13, RBM15B, IGF2BP1, YTHDF3, YTHDC1, ZC3H13 IGF2BP2, KIAA1429, METTL14, RBMX, FTO, ALKBH5, and METTL16 were significantly abnormally expressed in endometrial cancer tissue samples. Both univariate and multivariate Cox regression analyses indicated that age, grade, and risk score were independent risk factors. High expression of FTO was associated with worse overall survival.

Conclusion

M⁶A RNA methylation regulators play vital role in endometrial cancer.

Decreasing trend and changing indications of hysterectomy in Finland

INTRODUCTION

Hysterectomy has been one of the most common surgical procedures in women in Finland. We studied the population-based trends of hysterectomy and its indications from 1986 to 2017.

MATERIAL AND METHODS

A retrospective population-based cohort was created from the Care Register for Health Care by identifying women who had a hysterectomy from 1986 to 2017 and calculating the number of women from the Digital and Population Data Services Agency. We estimated the number and incidence of hysterectomy by period and age as well as by indication. We considered the primary diagnosis at the time of surgery as the indication of hysterectomy.

RESULTS

The number of hysterectomies increased from 7492 procedures in 1986 to 12 404 procedures in 1998, and reduced substantially after that to 5971 procedures in 2017, the turning point being in 1999. The incidence rate of hysterectomy has decreased on average by 2.5% annually from 432.6 per 100 000 women in 1998-2001 to 224.5 per 100 000 women in 2014-2017. The median age at the time of hysterectomy has increased from 51 years in 1998-2001 to 55 years in 2014-2017. The cumulative burden of hysterectomy by age of 60 years has nearly halved from the first 4-year period (23%) to the last (12%). After 2010, the most common indication has been genital prolapse and incontinence, whereas earlier it was uterine fibroids.

CONCLUSIONS

The number and incidence of hysterectomies have fluctuated during the observation period 1986-2017 and decreased considerably during the past 17 years in Finland. This is probably a result of the availability of hormonal and other conservative treatment options for bleeding disorders and uterine fibroids. As hysterectomy practically removes the risk for endometrial cancer, the change in hysterectomy incidence over time emphasizes the importance of correcting endometrial cancer incidence according to hysterectomy incidence.

Circular RNAs: A Promising Biomarker for Endometrial Cancer

Endometrial cancer (EC) is one of the most common malignant tumors of the female reproductive tract. EC patients have high morbidity and mortality rates and remain an important cause of cancer-related morbidity and mortality worldwide. More and more studies have shown that a large number of non-coding RNAs (such as microRNAs and long non-coding RNAs) are associated with the occurrence of diseases. Circular RNAs (circRNAs) is an endogenous non-coding RNA. It has a unique covalent structure. Many studies in recent years have found circRNAs differential expression in a variety of tumor tissues compared to matched normal tissues. In endometrial carcinoma, there also are multiple circRNAs differentially expressed and therefore circRNAs perhaps can be used as a diagnostic and prognosis biomarkers of EC. In this review, we described the biogenesis, function and characteristics of circRNAs, and the circRNAs with potential influence and clinical significance on the development of EC were summarized. Adenocarcinoma is the most common form of EC, so this review focuses on endometrioid adenocarcinoma.

Trends in hysterectomy-corrected uterine cancer mortality rates during 2002 to 2015: mortality of nonendometrioid cancer on the rise?

Corpus uteri cancer is the most common gynecological malignancy in most developed countries. The disease is typically diagnosed at an early stage, is of endometrioid histologic subtype, and has a fairly good prognosis. Here, we describe hysterectomy-corrected mortality rates of corpus uteri cancer, overall and stratified by age, stage and histologic subtype. Using data from nationwide Danish registries, we calculated uncorrected and hysterectomy-corrected age-standardized mortality rates of corpus uteri cancer among women ≥35 years during 2002 to 2015. Individual-level hysterectomy status was obtained from national registries; hysterectomy-corrected mortality rates were calculated by subtracting posthysterectomy person-years from the denominator, unless hysterectomy was performed due to corpus uteri cancer. Correction for hysterectomy resulted in a 25.5% higher mortality rate (12.3/100000 person-years vs 9.8/100000 person-years). Mortality rates were highest in women aged 70+, irrespective of year of death, histologic subtype and stage. A significant decline was observed in overall hysterectomy-corrected mortality rates from 2002 to 2015, particularly among women aged 70+. Mortality rates of endometrioid cancer declined significantly over time (annual percent change [APC]: -2.32, 95% CI -3.9, -0.7, P = .01), whereas rates of nonendometrioid cancer increased (APC: 5.90, 95% CI: 3.0, 8.9, P < .001). With respect to stage, mortality rates increased significantly over time for FIGOI-IIa (APC: 6.18 [95% CI: 1.9, 10.7] P = .01) but remained unchanged for FIGO IIb-IV. In conclusion, increasing mortality rates of nonendometrioid cancer paralleled the previously observed rise in incidence rates of this histologic subtype. Given the poor prognosis of nonendometrioid cancer, more studies are needed to clarify the underlying reason for these findings.

Risk of Gynecologic Cancer According to the Type of Endometriosis

OBJECTIVE

To assess the risks of gynecologic cancer according to the type of endometriosis in women with surgically verified endometriosis.

METHODS

This is a population-based study of women with surgically verified endometriosis retrieved from the Finnish Hospital Discharge Register 1987-2012 (N=49,933); the subtypes of ovarian (n=23,210), peritoneal (n=20,187), and deep infiltrating (n=2,372) endometriosis were analyzed separately. Gynecologic cancers were obtained from the Finnish Cancer Registry. The outcome measure was the standardized incidence ratio (95% CI) calculated as the ratio between the observed to the expected number of cancers and defined for each gynecologic cancer and further stratified according to the histology, follow-up time since surgery, and age at follow-up. The follow-up was 838,685 person-years, and the Finnish female population served as the reference.

RESULTS

Endometriosis was associated with increased risk of ovarian cancer (standardized incidence ratio 1.76 [95% CI 1.47-2.08]), especially with endometrioid (3.12 [2.15-4.38]) and clear cell (5.17 [3.20-7.89]) histologic type and to a lesser extent with serous type (1.37 [1.02-1.80]). The risk of ovarian cancer was highest among women with ovarian endometriosis and especially for endometrioid (4.72 [2.75-7.56]) and clear cell (10.1 [5.50-16.9]) ovarian cancer, occurring 5-10 years after the index surgery. The overall risk of ovarian cancer was not increased among women with peritoneal and deep infiltrating endometriosis. However, peritoneal endometriosis was associated with a twofold increase in risk of endometrioid histology. The risk of endometrial cancer was not altered in the entire cohort. The standardized incidence ratio for precancerous cervical lesions was 0.81 (0.71-0.92) and for invasive squamous cell carcinoma of the cervical cancer 0.46 (0.20-0.91).

CONCLUSION

The excess risk of ovarian cancer among women with ovarian endometriosis translates into two excess cases per 1,000 patients followed for 10 years. Acknowledging these risks is important when planning long-term management of women with endometriosis.

Effectiveness of cervical cancer screening at age 65 - A register-based cohort study

Most cervical cancer deaths in Finland occur after the termination of the national screening program, targeted at women aged 30 to 64 years. The purpose of this study was to examine the effectiveness of screening at age 65 in reducing cervical cancer mortality. A register-based cohort study was performed with a follow-up period between 1991 and 2014. Mortality risk ratios for incident cervical cancer cases diagnosed at age 65 or older were compared between women invited and not invited for screening. The background risk difference between the studied areas was accounted for by using a reference cohort. The relative risk of death for women invited for cervical cancer screening at the age of 65 was 0.52 (95% CI: 0.29-0.94). The relative risks for women not attending and attending to screening with respect to the uninvited were 1.28 (CI: 0.65-2.50) and 0.28 (CI: 0.13-0.59), respectively. Inviting 65-year-old women for screening has been effective in reducing cervical cancer mortality.

Declining hysterectomy prevalence and the estimated impact on uterine cancer incidence in Scotland

AIM

The prevalence of hysterectomy is decreasing worldwide. It is not clear whether changes in the population at risk (women with intact uteruses) have contributed to an increased uterine cancer incidence. This study aims to assess the effect of changing trends in hysterectomy prevalence on uterine cancer incidence in Scotland.

METHODS

The population of women aged ≥25 years with intact uteri was estimated using the estimated hysterectomy prevalence in 1995 and the number of procedures performed in Scotland (1996-2015). Age-standardized uterine cancer incidence was estimated using uncorrected (total) or corrected (adjusted for hysterectomy prevalence) populations as denominators and the number of incident cancers as numerators. Annual percentage change in uterine cancer was estimated.

RESULTS

Hysterectomy prevalence fell from 13% to 10% between 1996-2000 and 2011-2015, with the most marked decline (from 20% to 6%) in the 50-54-year age group. After correction for hysterectomy prevalence, age-standardized incidence of uterine cancer increased by 20-22%. Annual percentage change in incidence of uterine cancer remained stable through the study period and was 2.2% (95%CI 1.8-2.7) and 2.1% (95%CI 1.7-2.6) for uncorrected and corrected estimates, respectively.

CONCLUSION

Uterine cancer incidence in Scotland corrected for hysterectomy prevalence is higher than estimates using a total female population as denominator. The annual percentage increase in uterine cancer incidence was stable in both uncorrected and corrected populations despite a declining hysterectomy prevalence. The rise in uterine cancer incidence may thus be driven by other factors, including an ageing population, changing reproductive choices, and obesity.

International Patterns and Trends in Endometrial Cancer Incidence, 1978-2013

Background

Cancers of the corpus uteri-primarily of the endometrium-rank as the sixth most common neoplasm in women worldwide. Analyses of the global patterns and trends of uterine cancer rates are needed in view of the ongoing obesity epidemic, a major risk factor for the disease.

Methods

Data on endometrial cancer (ICD-10 C54) incidence from population-based cancer registries in 43 populations, published in CI5plus or by registries, were extracted for 1978 to 2013. Age-standardized incidence rates were computed for all ages and for pre- (25-49 years) and postmenopausal ages (50 years and older). Temporal trends were assessed with Joinpoint analysis, and the effects of birth cohort and year of diagnosis on the overall trends were examined using age-period-cohort modeling.

Results

In 2006 to 2007, rates varied 10-fold across countries. The highest rates were in North America, Eastern and Northern Europe (19 cases per 100 000 among whites in the United States, 95% confidence interval [CI] = 18 to 20, and in Slovakia, 95% CI = 18 to 21), and the lowest rates were in middle-income countries (South Africa 1, 95% CI = 0 to 3, and India 3, 95% CI = 3 to 4). Rates during the most recent 10 data years increased in 26 of the 43 populations considered in this study, with South Africa and several countries in Asia showing the largest increase. The risk of endometrial cancer increased both in consecutive generations and over time in 11 of 23 populations, with the increases more pronounced in Japan, the Philippines, Belarus, Singapore, Costa Rica, and New Zealand.

Conclusions

Endometrial cancer incidence rates increased over time and in successive generations in several countries, especially in those countries with rapid socioeconomic transitions.

An overview of cervical cancer epidemiology and prevention in Scandinavia

New technologies such as human papillomavirus (HPV) testing and vaccination necessitate comprehensive policy analyses to optimize cervical cancer prevention. To inform future Scandinavian-specific policy analyses, we aimed to provide an overview of cervical cancer epidemiology and existing prevention efforts in Denmark, Norway and Sweden. We compiled and summarized data on current prevention strategies, population demography and epidemiology (for example, age-specific HPV prevalence and cervical cancer incidence over time) for each Scandinavian country by reviewing published literature and official guidelines, performing registry-based analyses using primary data and having discussions with experts in each country. In Scandinavia, opportunistic screening occurred as early as the 1950s and by 1996, all countries had implemented nationwide organized cytology-based screening. Prior to implementation of widespread screening and during 1960-66, cervical cancer incidence was considerably higher in Denmark than in Norway and Sweden. Decades of cytology-based screening later (i.e. 2010-2014), cervical cancer incidence has been considerably reduced and has converged across the countries since the 1960s, although it still remains lowest in Sweden. Generally, Scandinavian countries face similar cervical cancer burdens and utilize similar prevention approaches; however, important differences remain. Future policy analyses will need to evaluate whether these differences warrant differential prevention policies or whether efforts can be streamlined across Scandinavia.

Time trends in the incidence of hysterectomy-corrected overall, type 1 and type 2 endometrial cancer in Denmark 1978-2014

OBJECTIVE

To investigate time trends in the incidence of overall, type 1 and type 2 endometrial cancer in Denmark 1978-2014, correcting for hysterectomy.

METHODS

Based on the Danish Cancer Registry and the Danish National Patient Registry we calculated hysterectomy-corrected incidence rates of overall, type 1 and type 2 endometrial cancer. Separate analyses for women <55years (defined as pre- and perimenopausal age) and women aged ≥55years (defined as postmenopausal age) and analyses allowing for different time trends before and after the study period midyear 1996 were performed. Log-linear Poisson models were used to estimate annual percentage change (APC) in incidence with 95% confidence intervals (CI).

RESULTS

The overall incidence of endometrial cancer decreased slightly from 1978 to 1995, but in the last two decades of the study period the incidence has been stable (APC=0.16; 95% CI: -0.19; 0.50). In the study period (1978-2014) type 1 endometrial cancer incidence decreased slightly (APC=-0.67; 95% CI:-0.83; -0.52), whereas the incidence of type 2 endometrial cancer increased substantially (APC=4.85; 95% CI: 4.47; 5.23). The decrease in type 1 endometrial cancer was most pronounced before 1996 in women younger than 55 years (APC=-2.79; 95% CI: -3.65; -1.91), while the largest increase in type 2 endometrial cancer was observed after 1996 (APC=6.42; 95% CI: 5.72; 7.12).

CONCLUSIONS

Over a period of more than 35 years, the incidence of type 1 endometrial cancer decreased, mainly in pre- and perimenopausal women, while type 2 endometrial cancer incidence increased.

Cervical cancer incidence in elderly women-biology or screening history?

AIM

In many countries, the age-specific pattern of cervical cancer incidence is currently bipolar with peaks at for instance 45 and 65 years of age. Consequently, a large proportion of cervical cancer cases are presently diagnosed in women above the screening age. The purpose of the study was to determine whether this bipolar pattern in age-specific incidence of cervical cancer reflects underlying biology or can be explained by the fact that the data come from birth cohorts with different screening histories.

METHODS

Combination of historical data on cervical screening and population-based cancer incidence data from Denmark 1943-2013, Finland and Norway 1953-2013, and Sweden 1958-2013.

RESULTS

Since the implementation of screening, the incidence of cervical cancer has decreased for each successive birth cohort. All birth cohorts showed a unipolar age-specific pattern. In unscreened women in Denmark and Sweden, the incidence peaked around the age of 50; the peak was less marked in Finland; while peak age for unscreened women could not be determined for Norway due to widespread opportunistic screening. The current old-age peak in the incidence of cervical cancer represents residuals from unscreened or underscreened birth cohorts.

CONCLUSION

The current bipolar pattern in age-specific incidence of cervical cancer can largely be explained by the different screening histories of successive birth cohorts. While it is reasonable to offer screening to elderly women today, birth cohort trends in disease burden should be carefully monitored to justify permanent changes in upper screening age.

The End of the Hysterectomy Epidemic and Endometrial Cancer Incidence: What Are the Unintended Consequences of Declining Hysterectomy Rates?

Population-level cancer incidence rates are one measure to estimate the cancer burden. The goal is to provide information on trends to measure progress against cancer at the population level and identify emerging patterns signifying increased risk for additional research and intervention. Endometrial cancer is the most common of the gynecologic malignancies but capturing the incidence of disease among women at risk (i.e., women with a uterus) is challenging and not routinely published. Decreasing rates of hysterectomy increase the number of women at risk for disease, which should be reflected in the denominator of the incidence rate calculation. Furthermore, hysterectomy rates vary within the United States by multiple factors including geographic location, race, and ethnicity. Changing rates of hysterectomy are important to consider when looking at endometrial cancer trends. By correcting for hysterectomy when calculating incidence rates of cancers of the uterine corpus, many of the disparities that have been assumed for this disease are diminished.

Global epidemiology of hysterectomy: possible impact on gynecological cancer rates

Despite the fact that hysterectomy is the most common surgical procedure worldwide in gynecology, national reporting of the incidence rate of gynecological cancers rarely removes the proportion no longer at risk of the disease from the population-at-risk-denominator (ie, women who have had a hysterectomy). The incidence rate of gynecological cancers is thus likely underestimated. Because hysterectomy, as well as oophorectomy, incidence varies across countries, age, and over time, meaningful comparison of gynecological cancer incidence rates may be compromised. Without accurate estimates of gynecological cancer incidence rates, performed via removing the proportion of hysterectomized or oophorectomized women from the population-at-risk-denominator, the impact of prevention strategies may be masked or misinterpreted. Furthermore, because national cervical cancer screening guidelines are at least in part based on the national reporting of cervical cancer incidence, it is important that the incidence rate reflects the true population at risk.

Hysterectomy and its impact on the calculated incidence of cervical cancer and screening coverage in Denmark

BACKGROUND

The incidence rates of cervical cancer and the coverage in cervical cancer screening are usually reported by including in the denominator all women from the general population. However, after hysterectomy women are not at risk anymore of developing cervical cancer. Therefore, it makes sense to determine the indicators also for the true at-risk populations. We described the frequency of total hysterectomy in Denmark and its impact on the calculated incidence of cervical cancer and the screening coverage.

MATERIAL AND METHODS

With data from five Danish population-based registries, the incidence rate of cervical cancer and the screening coverage for women aged 23-64 years on 31 December 2010 were calculated with and without adjustments for hysterectomies undertaken for reasons other than cervical cancer. They were calculated as the number of cases divided by 1) the total number of woman-years from the general population; and 2) the at-risk population after exclusion of post-hysterectomy woman-years. Cases were defined as women with cervical cancer (incidence), or as women screened in the recommended interval, with or without adjustment for hysterectomies (coverage).

RESULTS AND CONCLUSIONS

In 2010, the all-age prevalence of hysterectomy was estimated at 6%, and ≥ 16% at age ≥ 65. This translated into an overall 6% increase in the incidence rate of cervical cancer, from 12.8 (unadjusted) to 13.5 (adjusted) per 100,000 woman-years. The screening coverage increased from 76% (unadjusted) to 79% (adjusted). In Denmark, hysterectomies do not have a large overall impact on the calculated cancer incidence and screening coverage. Nevertheless, at ≥ 65 years adjusted rates would increase by almost 20% compared to unadjusted rates. This suggests that calculating disease risks per organ-years may have a role in understanding the true burden of the disease in a population at risk of developing that disease.

Recent trends in incidence of five common cancers in 26 European countries since 1988: Analysis of the European Cancer Observatory

BACKGROUND

Individual country- and cancer site-specific studies suggest that the age-adjusted incidence of many common cancers has increased in European populations over the past two decades. To quantify the extent of these trends and the recent burden of cancer, here we present a comprehensive overview of trends in population-based incidence of the five common cancers across Europe derived from a new web-based portal of the European cancer registries.

METHODS

Data on incidence for cancers of the colon and rectum, prostate, breast, corpus uteri and stomach diagnosed from 1988 to 2008 were obtained from the European Cancer Observatory for cancer registries from 26 countries. Annual age-standardised incidence rates and average annual percentage changes were calculated.

RESULTS

Incidence of four common cancers in eastern and central European countries (prostate, postmenopausal breast, corpus uteri and colorectum) started to approach levels in northern and western Europe, where rates were already high in the past but levelled off in some countries in recent years. Decreases in stomach cancer incidence were seen in all countries.

DISCUSSION

Increasing trends in incidence of the most common cancers, except stomach cancer, are bad news to public health but can largely be explained by well-known changes in society in the past decades. Thus, current and future efforts in primary cancer prevention should not only remain focussed on the further reduction of smoking but engage in the long-term efforts to retain healthy lifestyles, especially avoiding excess weight through balanced diets and regular physical exercise.

State-level uterine corpus cancer incidence rates corrected for hysterectomy prevalence, 2004 to 2008

BACKGROUND

The interpretation of uterine cancer rates is hindered by the inclusion of women whose uterus has been surgically removed in the population at risk. Hysterectomy prevalence varies widely by state and race/ethnicity, exacerbating this issue.

METHODS

We estimated hysterectomy-corrected, age-adjusted uterine corpus cancer incidence rates by race/ethnicity for 49 states and the District of Columbia during 2004 to 2008 using case counts obtained from population-based cancer registries; population data from the U.S. Census Bureau; and hysterectomy prevalence data from the Behavioral Risk Factor Surveillance System. Corrected and uncorrected incidence rates were compared with regard to geographic and racial/ethnic disparity patterns and the association with obesity.

RESULTS

Among non-Hispanic Whites, uterine cancer incidence rates (per 100,000 woman-years) uncorrected for hysterectomy prevalence ranged from 17.1 in Louisiana to 32.1 in New Jersey, mirrored regional hysterectomy patterns, and were not correlated with obesity prevalence (Pearson correlation coefficient, r = 0.06, two-sided P = 0.68). In comparison, hysterectomy-corrected rates were higher by a minimum of 30% (District of Columbia) to more than 100% (Mississippi, Louisiana, Alabama, and Oklahoma), displayed no discernible geographic pattern, and were moderately associated with obesity (r = 0.37, two-sided P = 0.009). For most states, hysterectomy correction diminished or reversed the Black/White deficit and accentuated the Hispanic/White deficit.

CONCLUSION

Failure to adjust uterine cancer incidence rates for hysterectomy prevalence distorts true geographic and racial patterns and substantially underestimates the disease burden, particularly for Southern states.

IMPACT

Correction for hysterectomy is necessary for the accurate evaluation of uterine cancer rates.

Cost-effectiveness analysis for Pap smear screening and human papillomavirus DNA testing and vaccination

INTRODUCTION

As the effectiveness of cytology-based screening programme for cervical cancer in mortality reduction has reached a plateau, various preventive strategies have been considered, including intensive Pap smear screening and the supplemental use of human papillomavirus (HPV) DNA test or HPV vaccination. Cost and effectiveness of these various preventive strategies are therefore of great concern for health policy makers.

OBJECTIVE

We intended to assess whether the combination of HPV DNA testing or HPV vaccination with Pap smear screening programme or the sole annual Pap smear screening is more effective and cost-effective in prevention of cervical cancer than the existing triennial Pap smear screening programme.

METHODS

A Markov decision model was constructed to compare total costs and effectiveness between different preventive strategies (including annual Pap smear, HPV DNA testing or HPV vaccination together with Pap smear screening programme) as opposed to the triennial Pap smear screening alone (the comparator). Probabilistic cost-effectiveness (C-E) analysis was adopted to plot a series of simulated incremental C-E ratios scattered over C-E plane and also to yield the acceptability curve for different comparisons of strategies. The threshold of vaccine cost and the influence of attendance rate were also investigated.

RESULTS

Compared with triennial Pap smear screening programme, most of preventive strategies cost more but gain additional life years (quadrant I of C-E plane) except HPV DNA testing with Pap smear every 5 years dominated by triennial Pap smear screening programme. The most cost-effective strategy was annual Pap smear (incremental C-E ratio = $31 698), followed by HPV DNA testing with Pap smear every 3 years ($36 627), and vaccination programme with triennial Pap smear screening ($44 688) with the corresponding cost-effective probabilities by the acceptability curve being 65.52%, 52.08% and 35.84% given the threshold of $40 000 of willingness to pay. Vaccination combined with triennial Pap smear would be as cost-effective as annual Pap smear provided the cost of vaccination was lowered to $250 per full course of injection.

CONCLUSIONS

Among various preventive strategies annual Pap smear screening programme is still the most cost-effective and additional HPV DNA testing is a cost-effective choice under a reasonable threshold of willingness to pay. Vaccination programme in combination with triennial screening would be cost-effective if vaccine cost can be greatly reduced in a large economic scale.

Leiomyoma-related hospitalization and surgery: prevalence and predicted growth based on population trends

OBJECTIVE

To estimate leiomyoma-related inpatient care in the United States for 2007 with predictions for the ensuing 40 years.

STUDY DESIGN

We used the 2007 Nationwide Inpatient Sample to estimate hospitalizations and inpatient surgeries for uterine leiomyoma in US women 15 to 54 years. We used the US Census Bureau population projections to predict leiomyoma-related inpatient care through 2050.

RESULTS

In 2007, 355,135 women were hospitalized for leiomyoma (rate = 42 per 10,000 women-years). Black women had increased rates of hospitalization, hysterectomy, and myomectomy (relative risk, 3.5, 2.4, 6.8, respectively) compared with white women. Leiomyoma-related hospitalizations are predicted to increase 23% (to 437,874) between 2007 and 2050, with 20% and 31% increases in leiomyoma-related hysterectomies and myomectomies.

CONCLUSION

Leiomyoma-related inpatient care and major surgery remains substantial despite advances in less invasive treatment options. Given population growth, the projected burden of leiomyoma-related inpatient care will increase significantly by 2050, differentially impacting black vs white women.

Representations of hysterectomy as a transition process in Finnish women's and health magazines

Representations of hysterectomy as a transition process in Finnish women's and health magazines The purpose of this article was to describe representations of hysterectomy in Finnish women's and health magazines. The data used in the study were obtained from six Finnish women's and health magazines. Using content analysis, 42 articles were analysed. We identified two main categories, information about care and treatment and women's experiences. In the first category, there emerged six subcategories: role of uterus, indications for hysterectomy, operative techniques of hysterectomy, alternative methods of treatment, pros and cons of hysterectomy and patient guidance. The second category consisted of women's experiences of hysterectomy as a period of transition. The components of the transition theory were confirmed by the women's stories. We also wanted to highlight the fact that the result shows that nurses were missing from the media coverage regarding hysterectomy.

Biobanks and registers in epidemiologic research on cancer

The Nordic countries have a long tradition of register-based epidemiologic studies. Numerous population-based specialized registers offer high-quality data from individuals, and the extensive use of register data further improves the quality of the registers. Unique personal identity codes given to every resident and used in all registers guarantee easy and accurate record linkage. A legislation that makes the use of the existing data possible for purposes that benefit both registered individuals and the society - instead of forcing researchers to use their energy in repeated questionnaire studies, disturbing individuals' privacy and leading to response and recall biases - is a prerequisite for effective epidemiologic research. Biobanks can be considered an additional type of registers. They may offer data from individuals that cannot be reliably collected via questionnaire surveys. In turn, other types of registers are crucial in biobank-based studies (1) in defining for how long the persons in biobank cohorts are at risk of getting the diseases, (2) to get information on cofactors that may modify the relative risk measured by the biomarkers, and (3) to get information on the long-term outcome events. This chapter describes the possibilities of register use mainly in Finland - a typical representative of the Nordic "paradise of register-based epidemiological research" - in research of cancer etiology. The ongoing Nordic research project Changing work life and cancer risk in the Nordic countries (NOCCA) will be described as an example of a massive register use, including both direct linkages on an individual level and indirect group level linkages.

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.

Hormone therapy and ovarian cancer: incidence and survival

OBJECTIVE

We conducted a population-based case-control study to investigate the association between hormone therapy (HT) and ovarian cancer incidence, and followed all these cancer cases to determine the association of HT use with ovarian cancer mortality.

METHODS

Seven hundred fifty-one incident cases of invasive epithelial ovarian cancer aged 40-79 years were diagnosed in Massachusetts and Wisconsin between 1993-1995 and 1998-2001 and matched to similarly aged controls (n = 5,808). Study subjects were interviewed by telephone, which ascertained information on HT use and specific preparation, estrogen alone (E-alone) or estrogen plus progestin (EP). Ovarian cancer cases were followed-up for mortality through December 2005. Multivariate logistic regression was used to estimate odds ratios and 95% confidence intervals (CI) for ovarian cancer incidence, and Cox proportional hazards modeling was used to estimate hazard ratios and corresponding confidence intervals for ovarian cancer mortality.

RESULTS

Ever use of HT was significantly associated with an increased risk of ovarian cancer (odds ratio 1.57, 95% CI 1.31-1.87). The excess risk was confined to women who used E-alone preparations (OR 2.33, 95% CI 1.85-2.95). No significant associations were detected between pre-diagnosis HT use and ovarian cancer survival.

CONCLUSIONS

Hormone therapy increases risk of ovarian cancer among E-alone users, but there is no substantial impact on survival after diagnosis.

Breast Cancer Risk in Postmenopausal Women Using Estrogen-Only Therapy

OBJECTIVE

To evaluate whether the risk of estrogen-only therapy on breast cancer varies by dose, constituent, and route of administration.

METHODS

All Finnish women older than age 50 years using oral or transdermal estradiol (n=84,729), oral estriol (n=7,941), or vaginal estrogens (n=18,314) for at least 6 months during 1994-2001 were identified from the national medical reimbursement register. They were followed for breast cancer with the aid of the Finnish Cancer Registry to the end of 2002.

RESULTS

Altogether, 2,171 women with breast cancer were identified. The standardized incidence ratio of breast cancer with systemic estradiol for less than 5 years was 0.93 (95% confidence interval 0.80-1.04), and for estradiol use for 5 years or more, 1.44 (1.29-1.59). Oral and transdermal estradiol was accompanied by a similar risk of breast cancer. The risk was most prominent with the dose greater than 1.9 mg/d orally; whereas the risk associated with transdermal route was not dose-dependent. The standardized incidence ratio for the lobular type of breast cancer (1.58) was slightly higher than that for the ductal type (1.36). The use of estradiol was associated with both localized breast cancer (1.45; 1.26-1.66) and cancer spread to regional nodes (1.35; 1.09-1.65). The incidence of carcinoma in situ (n=32) was increased (2.43; 1.66-3.42) among estradiol users.

CONCLUSION

Estradiol for 5 years or more, either orally or transdermally, means 2-3 extra cases of breast cancer per 1,000 women who are followed for 10 years. Oral estradiol use for less than 5 years, oral estriol, or vaginal estrogens were not associated with a risk of breast cancer.

LEVEL OF EVIDENCE

II-2.

Impact of Hysterectomy on Endometrial Carcinoma Rates in the United States

In the United States, endometrial carcinoma incidence rates, uncorrected for hysterectomy prevalence, are higher among white women than black women. We estimated corrected endometrial carcinoma rates by racial/ethnic groups and age (30-74 years) for 1992-2000 using data from the Surveillance, Epidemiology, and End Results program and the Behavioral Risk Factor Surveillance Survey. Hysterectomy prevalence was higher among black women than among Hispanic and white non-Hispanic women. Correcting for hysterectomy prevalence increased age-adjusted endometrial carcinoma rates per 10(5) woman-years from 29.2 to 48.7 (66.8% increase) overall, from 14.6 to 28.5 (95.3% increase) in blacks, from 18.8 to 29.6 (57.6% increase) in Hispanics, and from 33.2 to 54.9 (65.1%) in white non-Hispanics. This correction reduced the rate ratio for white non-Hispanics compared with blacks from 2.27 to 1.93. Among blacks but not Hispanics or white non-Hispanics, the endometrial carcinoma risk factors of obesity and diabetes were more prevalent among hysterectomized than nonhysterectomized women. Failure to correct for hysterectomy prevalence may lead to underestimates of endometrial carcinoma risk, especially among blacks. The high prevalence of hysterectomy among blacks with strong endometrial cancer risk factors may partly account for lower cancer rates in this group.

Endometrial cancer

Each year, endometrial cancer develops in about 142,000 women worldwide, and an estimated 42,000 women die from this cancer. The typical age-incidence curve for endometrial cancer shows that most cases are diagnosed after the menopause, with the highest incidence around the seventh decade of life. The appearance of symptoms early in the course explains why most women with endometrial cancer have early-stage disease at presentation. For all stages taken together, the overall 5-year survival is around 80%. There is a substantial prognostic difference between the histological types of endometrial cancers. The most common lesions (type 1) are typically hormone sensitive and low stage and have an excellent prognosis, whereas tumours of type 2 are high grade with a tendency to recur, even in early stage. The cornerstone of treatment for endometrial cancer is surgery, which not only is important for staging purposes but also enables appropriate tailoring of adjuvant treatment modalities that benefit high-risk patients only. We review current concepts about epidemiology, pathology, pathogenesis, risk factors and prevention, diagnosis, staging, prognostic factors, treatment, and follow-up of endometrial cancer.

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.

Hysterectomy with or without unilateral oophorectomy and risk of ovarian cancer

OBJECTIVE

To analyze the role of hysterectomy, performed on benign indications, on the risk of developing ovarian cancer.

METHODS

Multicenter case-control study conducted in four Italian areas. Cases were 1031 women with epithelial ovarian cancer. Controls were 2411 women admitted to the same network of hospitals for a wide spectrum of acute non-neoplastic conditions, unrelated to known risk factors for ovarian cancer.

RESULTS

Compared to women with intact uterus and ovaries, the multivariate odds ratios (OR) was 0.6 (95% confidence interval 0.4-0.9) for women who reported hysterectomy. The OR was 0.5 > or =15 years after surgery. The OR was similar for women who had had pelvic surgery before age 45 and for those who had surgery later. No appreciable heterogeneity emerged across strata of parity and family history of ovarian/breast cancer.

CONCLUSION

Women who had undergone hysterectomy had a long-term reduced risk of epithelial ovarian cancer.

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.