Uterine cancer risk in "endometriosis" and "adenomyosis"

Uterine cancer risk in

Endometrial cancer risk in women with endometriosis/adenomyosis needs to be clarified.

Key Points


  • This study shows an increased incidence of endometrial cancer in women with histologically proven endometriosis and adenomyosis, especially for extensive endometriosis/adenomyosis disease burden.


  • Endometrial cancer risk in women with endometriosis/adenomyosis needs to be clarified and risk stratification for cancer development should be developed.
  • Endometrial sampling before hysterectomy should be required step false for cases of endometriosis or adenomyosis, as endometrial cancer can be incidentally diagnosed.

What's done here:

  • A research team from the Netherlands aimed to assess the uterine cancer risk in women histopathologically diagnosed with "endometriosis" and "adenomyosis".
  • A retrospective cohort study comprising approximately 130.000 endometriosis/adenomyosis diagnosed women matched with a similar number of dermal nevus patients.
  • Histopathologically diagnosed endometrial cancer were retrieved from the registry and the probability for endometrial cancer was estimated.

Key Results:

  • Endometrial cancer detection was frequent at the time of histological diagnosis of endometriosis/adenomyosis.
  • In one-fifth of the endometrial cancer cases, endometrial cancer was not recognized until hysterectomy was performed.
  • Among the endometrial cancer patients, one-third did not have a prior endometrial biopsy. 
  • The highest risk is for endometrioid type endometrial cancer.

Strengths and Limitations:

The strength of this study is that it is a large nationwide study in which we only included women with histologically proven endometriosis or adenomyosis, which is still considered the gold standard for these diagnoses. However, using a histological database can also be considered a limitation, as no clinical data were available. As women with endometriosis/adenomyosis often have other known risk factors for cancer development, studies adjusting for these possible confounders are warranted. Due to the nature of our database, it was not possible to correctly differentiate endometriosis subtypes. Furthermore, women in the nevus cohort could have had a clinical diagnosis of endometriosis/adenomyosis without histological confirmation. Another limitation of our study is the high number of hysterectomies in the adenomyosis cohort, and consequently the low number of exposure years. We, therefore, performed logistic regression analysis to calculate odds ratios. Additionally, it is not known whether the women in the nevus cohort had had a hysterectomy before the start of the study, but since the median age at inclusion was 45 years, a high rate of hysterectomies before the start of the study seems unlikely. Previously, two studies showed a slightly increased incidence (2–3% increase) of benign dermal nevi in women with laparoscopically confirmed endometriosis [36,37]. To our knowledge, no association between ovarian cancer and nevi exists; we, therefore, believe the effect of this association on our results is limited. Moreover, this study is prone to detection bias, and therefore we performed a second analysis excluding the first year of follow-up. Lastly, PALGA uses identification codes based on the first eight letters of the family name and birth date, therefore results from different women may have been combined. We believe the effect of this is minimized by using a large control cohort with the same risk of merged cases.

Lay Summary

Adenomyosis and endometriosis share similar characteristics, and endometriosis is reported to have an increased risk of ovarian cancer. However, the risk of uterine cancer is not clear yet.

Hermens and colleagues from Catharina Hospital, from the Netherlands, designed a population-based retrospective cohort study from the Dutch pathology registry. The patients with the histological diagnosis of adenomyosis, endometriosis, and dermal nevus from this large patient pool between the years 1990-2015 were selected, and adenomyosis/endometriosis, solely endometriosis or adenomyosis; and dermal nevus they cohorts were compared.

When uterine cancer cases were evaluated, a synchronous histopathologic diagnosis of endometriosis/adenomyosis and endometrial cancer was surprising on the hysterectomy specimens. The cancer was not recognized until a hysterectomy was performed. One-third of endometrial cancer patients did not have a prior endometrial biopsy, and the highest risk was for endometrioid type endometrial cancer.

The endometrial cancer risk was low in patients who responded well to hormonal therapy with endometriosis/adenomyosis, after more than a year of follow-up. The authors thought that the reason could be "adequate exposure" to hormone therapy which may decrease the risk of endometrial cancer.

This paper was recently published in "Cancers (Basel)".

Research Source: https://pubmed.ncbi.nlm.nih.gov/34572823/

adenomyosis risk endometrial cancer ovarian cancer endometriosis.


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