Association of benign gynaecological diseases and risk of endometrial and ovarian cancers

The association between endometriosis and risk of endometrial cancer and breast cancer: a meta-analysis

Purpose

Endometriosis (EMS) is confirmed pathophysiologically to be an estrogen-dependent disease, similar to endometrial hyperplasia/cancer and breast cancer. Epidemiological and biological data on endometriosis might explain links between endometriosis and these cancers. We sought to identify the differences in the risk of endometrial cancer and breast cancer between women with and women without endometriosis.

Methods

We searched PubMed, EMBASE, the Cochrane Library, and four Chinese databases (CNKI, VIP, WanFang, CBM) to identify relevant studies published online between January 2011 and March 2021. In our meta-analysis, we used the Newcastle–Ottawa Scale (NOS) to evaluate the design and quality of all studies, and we calculated the pooled risk ratio (RR) using the random model. The Q test and I2 were used to evaluate the degree of heterogeneity of eligible studies. We used funnel plots and Begg’s and Egger’s tests to assess publication bias.

Results

Of the 1369 articles, we finally included 14 cohort studies and seven case–control studies. Data from large cohort and case–control studies indicate that women with endometriosis had an increased risk of both endometrial cancer [RR, 1.662; 95% CI, (1.148–2.407)] and breast cancer [RR, 1.082; 95% CI, (1.001–1.169)].

Conclusion

Endometriosis can increase the risk of endometrial cancer and breast cancer, and women with endometriosis are recommended to receive routine screening in long-term management.

History of Endometriosis Is Independently Associated with an Increased Risk of Ovarian Cancer

Background: Endometriosis is a complex gynecologic disorder that has been associated with a higher risk of ovarian cancer. The purpose of this work is to determine to what extent a history of endometriosis is a risk factor for ovarian cancer in a Spanish population. Methods: A retrospective case–control study was conducted using de-identified data from the Spanish National Health System’s “Primary Care Clinical Database” and “Hospital Minimum Basic Data Set” for the period 2013–2017. Multiple logistics regression analysis was conducted to determine associations between ovarian cancer and endometriosis controlled by sociodemographic characteristics and comorbidities. Results: Data from 608,980 women were analyzed, with 4505 presenting ovarian cancer. Endometriosis patients were shown to have a 2.66-fold increased risk of ovarian cancer when compared to those who did not have endometriosis by controlling age and other relevant comorbidities. Conclusions: This case–control study based on clinical administrative data has found that a history of endometriosis is independently associated with an increased risk of ovarian cancer. More research is needed to determine if a history of endometriosis affects survival results in ovarian cancer patients.

Endometrial Cancer Incidence in Endometriosis and Adenomyosis

Women with histologically proven endometriosis/adenomyosis have an increased risk of ovarian cancer. Small studies show conflicting results on the endometrial cancer risk in women with endometriosis/adenomyosis. Therefore, we assessed the incidence of endometrial cancer in women with histologically proven endometriosis or adenomyosis. We performed a population-based retrospective cohort study of 129,862 women with histologically proven endometriosis/adenomyosis, matched with 132,700 women with a nevus selected from the Dutch pathology registry between 1990 and 2015. Histology results for endometrial cancer were retrieved. Crude and age-adjusted odds ratios for endometrial cancer were estimated. In the endometriosis/adenomyosis group, 1827 (1.4%) women had a histological report on endometrial cancer, and in the nevus group, 771 (0.6%) women. The age-adjusted OR for endometrial cancer was 2.58 (95%CI 2.37-2.81). After excluding the first year of follow-up, the age-adjusted OR was 0.76 (95%CI 0.63-0.92), indicating that endometrial cancer is most often found at time of histological diagnosis of endometriosis/adenomyosis. In around 20% of the endometrial cancer cases, the endometrial cancer was not recognized until after hysterectomy. Of these women, 35% had no prior (micro)curettage or biopsy. This study shows an increased incidence of endometrial cancer in women with histologically proven endometriosis and adenomyosis.

Increased incidence of ovarian cancer in both endometriosis and adenomyosis

OBJECTIVE

Assessing the association between endometriosis and/or adenomyosis and ovarian cancer.

METHODS

We identified all women with histological proven endometriosis (51,544 women) and/or adenomyosis (85,015 women) from the Dutch pathology database (1990-2015) and matched with women with a benign dermal nevus (132,654 women). Histology results for ovarian cancer were retrieved. We estimated crude and age-adjusted incidence rate ratios (IRR) for ovarian cancer.

RESULTS

We found 1017 (2.0%), 1284 (1.5%) and 471 (0.4%) ovarian cancer cases in the endometriosis, adenomyosis and nevus cohort, respectively. The age-adjusted IRRs were 19.75 (95% CI 16.70-23.35) in the endometriosis cohort and 5.93 (95% CI 4.91-7.16) in the adenomyosis cohort. The highest IRRs were found for endometrioid and clear cell ovarian cancer subtypes. Excluding the first year of follow-up did not result in a significant IRR for ovarian cancer overall but resulted in a statistically significant age-adjusted IRR of 3.92 (95% CI 2.19-7.01) for clear cell ovarian cancer and 2.39 (95% CI 1.28-4.45) for endometrioid ovarian cancer in the endometriosis cohort. Additionally, we found a statistically significant age-adjusted IRR of 2.51 (95% CI 1.29-4.90) for endometrioid ovarian cancer in the adenomyosis cohort.

CONCLUSION

We found an increased ovarian cancer incidence in both histological proven endometriosis and adenomyosis. This increased incidence was largest for endometriosis. Excluding the first year of follow-up resulted in an increased incidence for endometrioid ovarian cancer in both cohorts and clear cell ovarian cancer in the endometriosis cohort. This study shows that gynecologist should also be aware of an increased ovarian cancer incidence in women with adenomyosis.

Origin and Pathogenic Mechanisms of Uterine Adenomyosis: What Is Known So Far

Uterine adenomyosis is a benign disease, commonly encountered in reproductive-age women and responsible for chronic pelvic pain, abnormal uterine bleeding, and infertility. Although the exact origin and pathogenic mechanisms involved in adenomyosis still need to be elucidated, significant progress has been made over recent years. Ever since the theory of endometrium invaginating the myometrium via a traumatized interface was first proposed, numerous molecular mechanisms have been reported to participate in this process. At the same time, an alternative theory has suggested de novo development of adenomyotic lesions from metaplasia of Müllerian remnants or adult stem cells. Hence, our understanding of the pathogenesis of adenomyosis has been greatly enhanced and is anticipated to pave the way for development of an effective and safe treatment. The goal of this review is to analyze current knowledge on the origin and pathogenic mechanisms of adenomyosis, ranging from the most widely accepted theories to newly reported data.