Appendix 5: Endometrial cancer: eUpdate published online 8 June 2017 (www.esmo.org/Guidelines/Gynaecological-Cancers)

Expression of the Hippo Pathway Core Components in Endometrial Cancer and Its Association with Clinicopathologic Features

BACKGROUND

The Hippo signaling pathway has a key role in tumorigenesis. This study aimed to evaluate the relationship between the expression of core components of the Hippo signaling pathway and its association with clinicopathological features in endometrial cancer.

MATERIALS AND METHODS

We retrospectively collected endometrioid endometrial cancer specimens from 60 patients between January 2002 and December 2009 at Gyeongsang National University Hospital. Relevant clinicopathological data were obtained through electronic medical records of patients. The expression patterns of six core components (YAP, p-YAP, LATS1/2, MST1/2, KIBRA, and Merlin) were identified by immunohistochemistry on tissue microarray sections.

RESULTS

The positive expression ratio was 75.0% for YAP, 73.3% for p-YAP, 26.7% for MST1/2, 16.7% for KIBRA, 15.0% for Merlin, and 15.0% for LATS1/2. YAP expression was negatively correlated with MST 1/2 kinases (p = 0.045) and positively correlated with p-YAP (p = 0.012). Merlin, and MST 1/2 kinases (p = 0.043) showed a positive correlation. A subgroup of patients aged below 60 years (p = 0.004) and with myometrial invasion depth of less than 1/2 (p = 0.041) showed a positive association with YAP expression. p-YAP expression was negatively associated with a subset of patients with primary tumour size ≥4 cm (p = 0.03). Logistic regression analysis showed a significant association between age and YAP expression. The odds ratio of p-YAP expression was significantly lower in the group with tumour size ≥4 cm.

CONCLUSION

Two prognostic factors, age and tumour size, were significantly associated with the expression of YAP and p-YAP in endometrial cancer. Further research should focus on their expression as a marker for prediction of clinicopathological implications in endometrial cancer.

MRI in female pelvis: an ESUR/ESR survey

Objectives

While magnetic resonance imaging (MRI) is considered the gold standard for the imaging of female pelvis, there is an ongoing debate about the most appropriate indications and optimal imaging protocols. The European Society of Urogenital Radiology (ESUR) launched a survey to evaluate the current utilization of female pelvic MRI in clinical practice.

Methods

The ESUR female imaging subgroup developed an online survey that was then approved by the ESR board and circulated among the ESR members. The questions in the survey encompassed training and experience, indications for imaging and MR imaging protocols, reporting styles and preferences. The results of the survey were tabulated, and subgroups were compared using χ2 test.

Results

A total of 5900 ESR members with an interest in both MRI and female pelvic imaging were invited to participate; 840 (14.23%) members completed the survey. Approximately 50% of respondents were academic radiologists (50.6%) and nearly 60% women (59.69%). One third of the respondents were subspecialized in Gynecological imaging. Nearly half of the survey participants were aware of the presence of ESUR guidelines for imaging of the female pelvis (47.1%). The adoption of the ESUR recommendations was higher among subspecialized and/or academic and/or senior and/or European radiologists compared to all others. The current ESUR recommendations about female pelvic MRI protocols were generally followed. However wide variations in practice were identified with respect to the use of contrast media.

Conclusion

Female pelvic MRI protocol was generally following the ESUR recommendations, especially among subspecialized and academic radiologists. However, the fact that they are followed by only half of the participants highlights the need for wider awareness of these recommendations.

The Association between Lower Uterine Segment Involvement in Corpus Located Endometrioid Adenocarcinoma with the (International Federation of Gynecology and Obstetrics) Grade and Stage

BACKGROUND: Although lower uterine segment (LUS) is regarded as an anatomically defined part that possess some histological differences, it is involvement by carcinoma have not been included in the criteria for definition in the staging system for endometrial carcinoma and there are few conflicting data focused on the effect of LUS involvement as a prognostic factor in endometrial cancer. AIM: To find the association between LUS involvement in corpus located endometrioid carcinoma with the grading and staging system established by the international federation of gynecology and obstetrics (FIGO). METHODS: This was a retrospective study involving data collected from achieves of histopathology departments of teaching laboratories within successive 4 years period in Medical City complex at Bagdad. Pathological analysis of 70 hysterectomy specimens of corpus located endometriod adenocarcinoma was done, histological sections from each case of endometrioid adenocarcinoma carcinoma were microscopically reviewed for appropriate grading and staging, in addition, meticulous search was applied for histological finding consistent with LUS involvement. The statistical comparison between the results was done using either independent sample t-test (for continuous data; mean ± SD) or Chi-square test at a significant p < 0.05. RESULTS: The study enrolled 70 histological samples of endometrioid adenocarcinoma, the majority of the samples were of low grade and stage at presentation. Of total sample, 46 (65.71%) showed LUS involvement by tumor cells. There was a significant statistical relationship between LUS involvement and FIGO stage while a non-significant statistical association with FIGO grade was found. CONCLUSION: LUS involvement by corpus located endometrioid adenocarcinoma is associated with an advanced FIGO stage at presentation while non-significant relationship was found between patient age and tumor grade.

Fertility-Sparing Approaches in Atypical Endometrial Hyperplasia and Endometrial Cancer Patients: Current Evidence and Future Directions

Endometrial cancer (EC) is the fourth most common cancer in women in developed countries. Although it is usually diagnosed in postmenopausal women, its incidence has increased in young women, as well in recent decades, with an estimated rate of 4% in those under 40 years of age. Factors involved in this increase, particularly in resource-rich countries, include delayed childbearing and the rise in obesity. The new molecular classification of EC should help to personalize treatment, through appropriate candidate selection. With the currently available evidence, the use of oral progestin either alone or in combination with other drugs such as metformin, levonorgestrel-releasing intrauterine devices and hysteroscopic resection, seems to be feasible and safe in women with early-stage EC limited to the endometrium. However, there is a lack of high-quality evidence of the efficacy and safety of conservative management in EC. Randomized clinical trials in younger women and obese patients are currently underway.

Defining Substantial Lymphovascular Space Invasion in Endometrial Cancer

Lymphovascular space invasion (LVSI) occurs in a minority of endometrial cancer (EC) cases, and the extent of LVSI is an important risk factor for recurrence and/or metastases. Our aim was to improve the reproducibility of measuring clinically meaningful LVSI by performing a quantitative analysis of the correlation between LVSI and the risk of pelvic lymph node recurrence in EC. EC samples from PORTEC-1 and PORTEC-2 trials were retrieved and used to collect quantitative data, including the number of LVSI-positive vessels per H&E-stained slide. Using a predefined threshold for clinical relevance, the risk of pelvic lymph node recurrence risk was calculated (Kaplan-Meier method, with Cox regression) using a stepwise adjustment for the number of LVSI-positive vessels. This analysis was then repeated in the Danish Gynecological Cancer Database (DGCD) cohort. Among patients in PORTEC-1 and PORTEC-2 trials who did not receive external beam radiotherapy, the 5-yr pelvic lymph node recurrence risk was 3.3%, 6.7% (P=0.51), and 26.3% (P<0.001), respectively when 0, 1 to 3, or ≥4 vessels had LVSI involvement; similar results were obtained for the DGCD cohort. Furthermore, both the average number of tumor cells in the largest embolus and the number of LVSI-positive H&E slides differed significantly between focal LVSI and substantial LVSI. On the basis of these results, we propose a numeric threshold (≥4 LVSI-involved vessels in at least one H&E slide) for defining clinically relevant LVSI in EC, thereby adding supportive data to the semiquantitative approach. This will help guide gynecologic pathologists to differentiate between focal and substantial LVSI, especially in borderline cases.

HER2 Status in High-Risk Endometrial Cancers (PORTEC-3): Relationship with Histotype, Molecular Classification, and Clinical Outcomes

Simple Summary

HER2 testing in endometrial cancer (EC) has gained renewed interest as a therapeutic target. However, HER2 status has not been investigated in the context of the molecular EC classification. Here, we aimed to determine the clinicopathological features and prognostic significance of the HER2 status in the molecularly classified PORTEC-3 trial population of patients with high-risk EC. HER2 status of 407 high-risk EC was determined by HER2 immunohistochemistry and HER2 dual in situ hybridization. Twenty-four (5.9%) HER2-positive EC of various histological subtypes were identified, including serous (n = 9, 37.5%), endometrioid (n = 6, 25.0%), and clear cell (n = 5, 20.8%). HER2 positivity was highly associated with the p53-abnormal subgroup (p53abn, 23/24 cases; p < 0.0001). The correlation between p53abn and the HER2 status (ρ = 0.438; p < 0.0001) was significantly stronger (p < 0.0001) than between serous histology and the HER2 status (ρ = 0.154; p = 0.002). HER2 status did not have independent prognostic value for survival after correction for the molecular classification. Our study strongly suggests that molecular subclass-directed HER2 testing is superior to histotype-directed testing.

Abstract

HER2 status has not been investigated in the context of the molecular endometrial cancer (EC) classification. Here, we aimed to determine the clinicopathological features and prognostic significance of the HER2 status in the molecularly classified PORTEC-3 trial population of patients with high-risk EC (HREC). HER2 testing was performed on tumor tissues of 407 molecularly classified HREC. HER2 status was determined by HER2 immunohistochemistry (IHC; all cases) and subsequent HER2 dual in situ hybridization for cases with any (in) complete moderate to strong membranous HER2 IHC expression. The Χ² test and Spearman’s Rho correlation coefficient were used to compare clinicopathological and molecular features. The Kaplan–Meier method, log-rank test, and Cox proportional hazards models were used for survival analysis. We identified 24 (5.9%) HER2-positive EC of various histological subtypes including serous (n = 9, 37.5%), endometrioid (n = 6, 25.0%), and clear cell (n = 5, 20.8%). HER2 positivity was highly associated with the p53-abnormal subgroup (p53abn, 23/24 cases; p < 0.0001). The correlation between p53abn and the HER2 status (ρ = 0.438; p < 0.0001) was significantly stronger (p < 0.0001) than between serous histology and the HER2 status (ρ = 0.154; p = 0.002). HER2 status did not have independent prognostic value for survival after correction for the molecular classification. Our study strongly suggests that molecular subclass-directed HER2 testing is superior to histotype-directed testing. This insight will be relevant for future trials targeting HER2.

Effect of Radiotherapy in Addition to Surgery in Early Stage Endometrial Cancer: A Population-Based Study

BACKGROUND

The role of radiotherapy in the management of early (FIGO I) endometrial cancer is controversial with limited availability of prospective data from randomized trials.

METHODS

German Epidemiologic Cancer Registries provided by the Robert Koch Institute. We considered FIGO I cases with recorded operative treatment (n = 12,718, 2000-2017). We computed hazard ratios (HR) from relative survival models in relation to the mortality of the general population with 95% confidence intervals (CI). Multivariate models were adjusted for age, stage (IA vs. IB), grading, and chemotherapy. Radiotherapy included external radiotherapy and brachytherapy.

RESULTS

Cases with a favorable risk profile (FIGO IA, G1/G2) had a slightly lower survival rate, relative to the general population (FIGO IA: 0.9, G1: 0.91). The proportion of FIGO IA cases was lower in the radiotherapy group (52.6%) vs. cases without radiotherapy (78.6%). Additional treatment with radiotherapy was beneficial in FIGO IB (HR = 0.74) and all histopathological grades, but not FIGO IA cases (HR = 0.93) cases. Compared to IA tumors, IB cases had a HR of 1.51 (95% CI: 1.34-1.7).

CONCLUSIONS

Radiotherapy in addition to surgery is beneficial for patients in a FIGO IB stage. Further studies need to address the impact of new techniques and risk assessment.

Molecular Classification of the PORTEC-3 Trial for High-Risk Endometrial Cancer: Impact on Prognosis and Benefit From Adjuvant Therapy

PURPOSE

The randomized Adjuvant Chemoradiotherapy Versus Radiotherapy Alone in Women With High-Risk Endometrial Cancer (PORTEC-3) trial investigated the benefit of combined adjuvant chemotherapy and radiotherapy (CTRT) versus radiotherapy alone (RT) for women with high-risk endometrial cancer (EC). Because The Cancer Genome Atlas defined an EC molecular classification with strong prognostic value, we investigated prognosis and impact of chemotherapy for each molecular subgroup using tissue samples from PORTEC-3 trial participants.

METHODS

Paraffin-embedded tissues of 423 consenting patients were collected. Immunohistochemistry for p53 and mismatch repair (MMR) proteins, and DNA sequencing for POLE exonuclease domain were done to classify tumors as p53 abnormal (p53abn), POLE-ultramutated (POLEmut), MMR-deficient (MMRd), or no specific molecular profile (NSMP). The primary end point was recurrence-free survival (RFS). Kaplan-Meier method, log-rank test, and Cox model were used for analysis.

RESULTS

Molecular analysis was successful in 410 high-risk EC (97%), identifying the 4 subgroups: p53abn EC (n = 93; 23%), POLEmut (n = 51; 12%), MMRd (n = 137; 33%), and NSMP (n = 129; 32%). Five-year RFS was 48% for patients with p53abn EC, 98% for POLEmut EC, 72% for MMRd EC, and 74% for NSMP EC (P < .001). The 5-year RFS with CTRT versus RT for p53abn EC was 59% versus 36% (P = .019); 100% versus 97% for patients with POLEmut EC (P = .637); 68% versus 76% (P = .428) for MMRd EC; and 80% versus 68% (P = .243) for NSMP EC.

CONCLUSION

Molecular classification has strong prognostic value in high-risk EC, with significantly improved RFS with adjuvant CTRT for p53abn tumors, regardless of histologic type. Patients with POLEmut EC had an excellent RFS in both trial arms. EC molecular classification should be incorporated in the risk stratification of these patients as well as in future trials to target specific subgroups of patients.

Fertility-sparing treatment in early endometrial cancer: current state and future strategies

Endometrial cancer (EC) is the fifth most common cancer in women worldwide. Global estimates show rising incidence rates in both developed and developing countries. Most women are diagnosed postmenopausal, but 14–25% of patients are premenopausal and 5% are under 40 years of age. Established risk factors include age and hyperestrogenic status associated with nulliparity, obesity, and metabolic syndrome. Standard treatment for EC, which involves total hysterectomy and bilateral salpingo-oophorectomy, has excellent survival outcomes, particularly for low-grade endometrioid tumors. However, it leads to permanent loss of fertility among women who wish to preserve their reproductive potential. With current trends of reproductive-age women delaying childbearing, rising EC incidence rates, and a growing epidemic of obesity, particularly in developed countries, research on conservative non-surgical treatment approaches remains a top priority. Fertility-sparing treatment predominantly involves the use of oral progestins and levonorgestrel-releasing intrauterine devices, which have been shown to be feasible and safe in women with early stage EC and minimal or no myometrial invasion. However, data on the efficacy and safety of conservative management strategies are primarily based on retrospective studies. Randomized clinical trials in younger women and high-risk obese patients are currently underway. Here, we have presented a comprehensive review of the current literature on conservative, fertility-sparing approaches, defining the optimal candidates and evaluating tumor characteristics, reproductive and oncologic outcomes, and ongoing clinical trials. We have also summarized current guidelines and recommendations based on the published literature.

Clinicopathological and molecular characterisation of 'multiple-classifier' endometrial carcinomas

Endometrial carcinoma (EC) molecular classification based on four molecular subclasses identified in The Cancer Genome Atlas (TCGA) has gained relevance in recent years due to its prognostic utility and potential to predict benefit from adjuvant treatment. While most ECs can be classified based on a single classifier (POLE exonuclease domain mutations - POLEmut, MMR deficiency - MMRd, p53 abnormal - p53abn), a small but clinically relevant group of tumours harbour more than one molecular classifying feature and are referred to as 'multiple-classifier' ECs. We aimed to describe the clinicopathological and molecular features of multiple-classifier ECs with abnormal p53 (p53abn). Within a cohort of 3518 molecularly profiled ECs, 107 (3%) tumours displayed p53abn in addition to another classifier(s), including 64 with MMRd (MMRd-p53abn), 31 with POLEmut (POLEmut-p53abn), and 12 with all three aberrations (MMRd-POLEmut-p53abn). MMRd-p53abn ECs and POLEmut-p53abn ECs were mostly grade 3 endometrioid ECs, early stage, and frequently showed morphological features characteristic of MMRd or POLEmut ECs. 18/28 (60%) MMRd-p53abn ECs and 7/15 (46.7%) POLEmut-p53abn ECs showed subclonal p53 overexpression, suggesting that TP53 mutation was a secondary event acquired during tumour progression. Hierarchical clustering of TCGA ECs by single nucleotide variant (SNV) type and somatic copy number alterations (SCNAs) revealed that MMRd-p53abn tumours mostly clustered with single-classifier MMRd tumours (20/23) rather than single-classifier p53abn tumours (3/23), while POLEmut-p53abn tumours mostly clustered with single-classifier POLEmut tumours (12/13) and seldom with single-classifier p53abn tumours (1/13) (both p ≤ 0.001, chi-squared test). Finally, the clinical outcome of patients with MMRd-p53abn and POLEmut-p53abn ECs [stage I 5-year recurrence-free survival (RFS) of 92.2% and 94.1%, respectively] was significantly different from single-classifier p53abn EC (stage I RFS 70.8%, p = 0.024 and p = 0.050, respectively). Our results support the classification of MMRd-p53abn EC as MMRd and POLEmut-p53abn EC as POLEmut. © 2019 The Authors. The Journal of Pathology published by John Wiley & Sons Ltd on behalf of Pathological Society of Great Britain and Ireland.

Pregnancy and oncologic outcomes after fertility-sparing management for early stage endometrioid endometrial cancer

OBJECTIVE

Hormonal management is an alternative treatment for preserving fertility in patients with presumed early stage endometrioid endometrial cancer. This study aimed to define the pregnancy and oncologic outcomes and factors of successful conception after hormone therapy for endometrioid endometrial cancer.

METHODS

We retrospectively analyzed patients presumed to have stage IA, grade 1-2 endometrioid endometrial cancer who underwent fertility-sparing treatment. Concurrent medroxyprogesterone and levonorgestrel-release intra-uterine devices were used for treatment. The pregnancy outcomes and oncologic outcomes were compared between the pregnant and non-pregnant groups.

RESULTS

Seventy-one patients presumed to have stage IA, grade 1-2 endometrioid endometrial cancer had complete remission, and 49 of them tried to conceive. Twenty-two (44.9%) patients became pregnant; the total number of pregnancies was 30. These pregnancies resulted in seven abortions (23.3%), one pre-term birth (3.3%), and 20 full-term births (66.6%). The total live birth rate was 66.6 % (20/30). The median duration of hormonal treatment was 11.9 months (range 4-49) and 12.0 months (range 3-35) in the pregnant and non-pregnant groups, respectively. On multivariate analysis, age, body mass index, treatment duration, medroxyprogesterone dose, and number of dilatation and curettage biopsies were not significantly associated with pregnancy failure, but the association with grade (OR 6.2, 95% CI 1.0 to 38.9; P<0.05) was statistically significant. The median disease-free survival duration was 26 months (range 20-38) and 12 months (range 4-48) in the pregnant and non-pregnant groups, respectively (P<0.05, log-rank test).

CONCLUSIONS

A lower grade might be a positive factor for future pregnancy. Moreover, successful pregnancy might be a factor in preventing recurrence.

Early-stage endometrial cancer, CTNNB1 mutations, and the relation between lymphovascular space invasion and recurrence

INTRODUCTION

Women diagnosed with early-stage (FIGO 1) endometrial cancer, grade 1 and 2 can have a good prognosis. Most of these women can be treated successfully with a hysterectomy and bilateral salpingo-oophorectomy and without the additional adjuvant treatment that is accompanied by more risks for complications. However, when recurrence does occur, the consequences can be dire. Accurate decisions must therefore be made by surgeons to avoid either under- or over-treatment. Risk and patient stratification for tailoring treatment still need further improvement. Both histopathology and genetic variants could be integrated into the decision process if relevant factors were identified.

MATERIAL AND METHODS

Morphological features and the presence of selected genetic mutations in isolated malignant endometrial epithelial cells from these tumors were analyzed in a strictly defined cohort of FIGO 1, grade 1 and 2 low-risk endometrial cancer. Their presence in this cohort, their relation to recurrence, and the association between histopathological features and mutations were determined. This analysis was performed using archival formalin-fixed paraffin-embedded tissue, complete re-evaluation of histopathological features, laser capture microdissection of epithelial cells, and a polymerase chain reaction-based mutational screening assay.

RESULTS

Twenty-one women with recurrence, after initial identification as low-risk endometrial cancer, were compared with 20 matched control women. The histological marker of lymphovascular invasion was significantly associated with recurrence. There was also a very high prevalence of mutations in CTNNB1 gene, occurring in 50% of this cohort. PTEN mutations were also observed in 27.8% of cases and PIK3CA mutations in 22.2%; none of these mutations were significantly related to recurrence.

CONCLUSIONS

This study supports the importance of lymphovascular space invasion to identify women with significant risk for recurrence in initially low-risk, early-stage endometrial cancer. It also identifies CTNNB1 as a significant mutation in early-stage disease, and although it may not represent a marker for recurrence its high prevalence in early stage disease could have relevance for both pathogenesis and early treatment.

Pathologic Prognostic Factors in Endometrial Carcinoma (Other Than Tumor Type and Grade)

Although endometrial carcinoma (EC) is generally considered to have a good prognosis, over 20% of women with EC die of their disease, with a projected increase in both incidence and mortality over the next few decades. The aim of accurate prognostication is to ensure that patients receive optimal treatment and are neither overtreated nor undertreated, thereby improving patient outcomes overall. Patients with EC can be categorized into prognostic risk groups based on clinicopathologic findings. Other than tumor type and grade, groupings and recommended management algorithms may take into account age, body mass index, stage, and presence of lymphovascular space invasion. The molecular classification of EC that has emerged from the Cancer Genome Atlas (TCGA) study provides additional, potentially superior, prognostic information to traditional histologic typing and grading. This classifier does not, however, replace clinicopathologic risk assessment based on parameters other than histotype and grade. It is envisaged that molecular and clinicopathologic prognostic grouping systems will work better together than either alone. Thus, while tumor typing and grading may be superseded by a classification based on underlying genomic abnormalities, accurate assessment of other pathologic parameters will continue to be key to patient management. These include those factors related to staging, such as depth of myometrial invasion, cervical, vaginal, serosal surface, adnexal and parametrial invasion, and those independent of stage such as lymphovascular space invasion. Other prognostic parameters will also be discussed. These recommendations were developed from the International Society of Gynecological Pathologists Endometrial Carcinoma project.

Frequent Homologous Recombination Deficiency in High-grade Endometrial Carcinomas

PURPOSE

The elevated levels of somatic copy-number alterations (SCNAs) in a subset of high-risk endometrial cancers are suggestive of defects in pathways governing genome integrity. We sought to assess the prevalence of homologous recombination deficiency (HRD) in endometrial cancers and its association with histopathologic and molecular characteristics.

EXPERIMENTAL DESIGN

Fresh tumor tissue was prospectively collected from 36 endometrial cancers, and functional HRD was examined by the ability of replicating tumor cells to accumulate RAD51 protein at DNA double-strand breaks (RAD51 foci) induced by ionizing radiation. Genomic alterations were determined by next-generation sequencing and array comparative genomic hybridization/SNP array. The prevalence of BRCA-associated genomic scars, a surrogate marker for HRD, was determined in the The Cancer Genome Atlas (TCGA) endometrial cancer cohort.

RESULTS

Most endometrial cancers included in the final analysis (n = 25) were of non-endometrioid (52%), grade 3 (60%) histology, and FIGO stage I (72%). HRD was observed in 24% (n = 6) of cases and was restricted to non-endometrioid endometrial cancers (NEEC), with 46% of NEECs being HRD compared with none of the endometrioid endometrial cancers (EEC, P = 0.014). All but 1 of the HRD cases harbored either a pathogenic BRCA1 variant or high somatic copy-number (SCN) losses of HR genes. Analysis of TCGA cases supported these results, with BRCA-associated genomic scars present in up to 48% (63/132) of NEEC versus 12% (37/312) of EEC (P < 0.001).

CONCLUSIONS

HRD occurs in endometrial cancers and is largely restricted to non-endometrioid, TP53-mutant endometrial cancers. Evaluation of HRD may help select patients that could benefit from treatments targeting this defect, including platinum compounds and PARP inhibitors.

The rise of a novel classification system for endometrial carcinoma; integration of molecular subclasses

Endometrial cancer is a clinically heterogeneous disease and it is becoming increasingly clear that this heterogeneity may be a function of the diversity of the underlying molecular alterations. Recent large-scale genomic studies have revealed that endometrial cancer can be divided into at least four distinct molecular subtypes, with well-described underlying genomic aberrations. These subtypes can be reliably delineated and carry significant prognostic as well as predictive information; embracing and incorporating them into clinical practice is thus attractive. The road towards the integration of molecular features into current classification systems is not without obstacles. Collaborative studies engaging research teams from across the world are working to define pragmatic assays, improve risk stratification systems by combining molecular features and traditional clinicopathological parameters, and determine how molecular classification can be optimally utilized to direct patient care. Pathologists and clinicians caring for women with endometrial cancer need to engage with and understand the possibilities and limitations of this new approach, because integration of molecular classification of endometrial cancers is anticipated to become an essential part of gynaecological pathology practice. This review will describe the challenges in current systems of endometrial carcinoma classification, the evolution of new molecular technologies that define prognostically distinct molecular subtypes, and potential applications of molecular classification as a step towards precision medicine and refining care for individuals with the most common gynaecological cancer in the developed world. Copyright © 2018 Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd.