Grade and Estrogen Receptor Expression Identify a Subset of No Specific Molecular Profile Endometrial Carcinomas at a Very Low Risk of Disease-Specific Death

Molecular classification of metastatic and recurrent endometrial endometrioid carcinoma: prognostic relevance among low- and high-stage tumours

AIMS

Molecular classification according to The Cancer Genome Atlas (TCGA) improves endometrial endometrioid carcinoma (EEC) prognostication and has specific treatment implications; however, original data were skewed towards low-grade and low-stage tumours. Herein, we molecularly classify EECs metastatic at the time of diagnosis or with subsequently documented recurrent/metastatic disease to examine correlation with clinical outcomes.

METHODS

TCGA categories include POLE-mutated, microsatellite instability (MSI), p53 abnormal (p53 abnl) and no specific molecular profile (NSMP). POLE targeted sequencing at exons 9, 11, 13 and 14 and immunohistochemistry (IHC) for PMS2, MSH6 and p53 were performed to establish molecular classification.

RESULTS

The distribution in our cohort of 141 EECs was similar to that generally reported in EEC, with nine POLE-mutated (6%), 45 MSI (32%), 16 p53 abnl (11%) and 71 NSMP (50%), with similar distributions between low- and high-stage cohorts. We demonstrate that when stratified by molecular subtype, disease-specific survival from the time of high-stage (stages III-IV) presentation or time of recurrence in low-stage (stages I-II) disease among metastatic and/or recurrent EEC is strongly associated with TCGA classification (high-stage P = 0.02, low-stage P = 0.017). Discordant molecular classification between primary and metastatic/recurrent tumours occurred in four of 105 (3.8%) patients, two related to PMS2/MSH6 IHC and two related to p53 IHC.

CONCLUSIONS

We demonstrate that molecular classification is prognostically relevant not only at the time of diagnosis, but also at the time of recurrence and in the metastatic setting. Rare subclonal alterations occur and suggest a role for confirming TCGA classification in recurrent/metastatic tumours.

The spectrum of oestrogen receptor expression in endometrial carcinomas of no specific molecular profile

AIMS

Decreased oestrogen receptor (ER) expression is a marker of poor prognosis in endometrial carcinomas (EC) of no specific molecular profile (NSMP), but the optimal cut-off to separate high-risk 'low ER' versus low-risk 'high ER' expression has not been defined. Here we characterised the distribution of ER staining in a cohort of ECs.

METHODS AND RESULTS

Biopsy specimens from 120 cases of NSMP EC were stained for ER and assigned an Allred score. In 66 additional cases ER staining of matched biopsy and hysterectomy were compared. Twelve of 120 tumours had an Allred score of 0-3, including three endometrioid carcinomas (EEA) (one G1, two G3), four clear cell carcinomas (CCC), two mesonephric-like adenocarcinoma (MLA) and one each of: gastric-type adenocarcinoma, carcinosarcoma and endometrial carcinoma NOS. Three had Allred scores of 4-5: two MLA and one high-grade carcinoma with yolk sac differentiation. Five had Allred scores of 6: four EEA (one G1, one G2, two G3) and one mixed clear cell and endometrioid carcinoma. The remaining 100 tumours with Allred scores ≥ 7 were all EEA (66 G1, 28 G2, five G3 and one grade unknown). Comparing the biopsy versus hysterectomy ER staining (n = 66), the results were within a single Allred score point, except two cases with strong diffuse expression in the biopsy (Allred 8) and moderate expression in the hysterectomy (Allred 5).

CONCLUSIONS

Most NSMP ECs (> 80%) show high ER expression (Allred score ≥ 7). All non-endometrioid carcinomas and a few endometrioid carcinomas had lower ER expression (Allred score ≤ 6) or were completely negative.

New clinicopathological concept of endometrial carcinoma with integration of histological features and molecular profiles

The dual-stratified pathway of endometrial carcinomas (ECs) has long been dominant. However, in 2013, The Cancer Genome Atlas (TCGA) defined four EC subgroups with distinctive prognoses. Inspired by TCGA, in 2018, the Proactive Molecular Risk Classifier for Endometrial Cancer (ProMisE) provided four pragmatic molecular classifiers to apply surrogate immunohistochemical markers to TCGA subgroup categorization. These trends prompted the revision of 2020 WHO Classification of Female Genital Tumors, 5th edition (2020 WHO classification), in which four molecular subtypes are recognized: POLE-ultramutated; mismatch repair-deficient; p53-mutant; and no specific molecular profile. In the 2020 WHO classification, the diagnostic algorithm is characterized by prioritizing POLEmut over other molecular abnormalities. Following the 2020 WHO classification, Federation of International Gynecology and Obstetrics (FIGO) proposed a new staging system in 2023. The updated system focuses on diagnostic parameters, such as histological type and grade, lymphovascular space invasion, and molecular alterations. These new histomolecular diagnostic concepts of ECs are being accordingly introduced into the routine pathology practice. For the first time, the 2020 WHO classification includes mesonephric-like adenocarcinoma (MLA) as a novel histological entity, mimicking the conventional mesonephric adenocarcinoma, but is considered of Müllerian ductal origin.

Impact of molecular classification on recurrence risk in endometrial cancer patients with lymph node metastasis: multicenter retrospective study

OBJECTIVE

To assess the distribution of molecular classes and their impact on the risk of recurrence in endometrial cancer patients with lymph node metastasis at the time of primary surgery.

METHODS

Endometrial cancer patients with lymph node micrometastasis or macrometastasis (International Federation of Gynecology and Obstetrics (FIGO) 2009 stage IIIC) after surgical staging at five referral centers worldwide from October 2013 to September 2022 who underwent molecular classification were identified. Endometrial cancers were categorized into four molecular classes: POLE mutated, mismatch repair deficient, p53 abnormal, and no specific molecular profile. Survival analyses using Kaplan-Meier and Cox models (univariate and multivariate) were conducted to evaluate the relationship between molecular class and 5-year recurrence free survival.

RESULTS

131 patients were included: 55 (42.0%) no specific molecular profile, 46 (35.1%) mismatch repair deficient, 1 (0.8%) POLE mutated, and 29 (22.1%) p53 abnormal. During a 5 year follow-up period, 50 (38.2%) patients experienced a recurrence with a median time of 1.2 years (interquartile range (IQR) 0.5-1.8). Median follow-up for the remaining 81 patients was 3.1 years (IQR 1.3-4.5). Survival analysis revealed a significant difference in recurrence-free survival between no specific molecular profile, mismatch repair deficient, and p53 abnormal classes (log rank p<0.01). In a model adjusted for type of lymph node metastasis and tumor grade, the molecular class did not retain significance (p=0.13), while in a model adjusted for type of lymph node metastasis and adjuvant therapy, the molecular class retained significance (p<0.01).

CONCLUSION

Among patients with stage IIIC endometrial cancer, POLE mutated tumors exhibited an extremely low prevalence, with no specific molecular profile emerging as the largest molecular subgroup. Despite the significant difference in recurrence-free survival between molecular classes, conventional histopathologic parameters retained crucial prognostic value. Our findings highlight the necessity of integrating molecular classes with pathological characteristics, rather than considering them in isolation as crucial prognostic factors in stage IIIC endometrial cancer.

Prognostic Significance of Disseminated Tumor Cells in Bone Marrow for Endometrial Carcinoma Patients

Background: Until now, limited clinical significance had been reported for disseminated tumor cells (DTCs) in gynecologic malignancies. DTCs were previously reported not to be associated with established risk factors, L1CAM immunoreactivity, and outcome in endometrial carcinoma (EC). This study's primary objective was to investigate potential correlations of DTCs in the bone marrow (BM) of EC patients with disease-related survival, and a secondary objective was to evaluate associations between molecular classification of EC and DTCs. Methods: Patients treated for primary EC at Tuebingen University women's hospital between 2003 and 2016 were identified. A total of 402 patients with a complete set of BM cytology, molecular, and clinical data were evaluable. Results: DTC occurrence was distributed equally among all four molecular groups (p = 0.651). DTC positivity was associated with a less favorable disease-free survival (HR: 1.86, 95% CI: 1.03-3.36, p = 0.036) and progression-free survival (HR: 1.86, 95% CI: 1.01-3.44, p = 0.045). Presence of DTCs was associated with a higher frequency of distant disease recurrence (p = 0.017). Conclusions: In line with our previous findings, tumor cell dissemination is not associated with molecular features in our large cohort of primary EC patients. Since DTCs seem to be associated with survival and location of disease recurrence, further studies are needed to decisively define their role in EC survival.

Guidelines of the Brazilian Society of Surgical Oncology for anatomopathological, immunohistochemical, and molecular testing in female tumors

INTRODUCTION

Precision medicine has revolutionized oncology, providing more personalized diagnosis, treatment, and monitoring for patients with cancer. In the context of female-specific tumors, such as breast, ovarian, endometrial, and cervical cancer, proper tissue collection and handling are essential for obtaining tissue, immunohistochemical (IHC), and molecular data to guide therapeutic decisions.

OBJECTIVES

To establish guidelines for the collection and handling of tumor tissue, to enhance the quality of samples for histopathological, IHC, genomic, and molecular analyses. These guidelines are fundamental in informing therapeutic decisions in cancer treatment.

METHOD

The guidelines were developed by a multidisciplinary panel of renowned specialists between June 12, 2013 and February 12, 2024. Initially, the panel deliberated on critical and controversial topics related to conducting precision medicine studies focusing on female tumors. Subsequently, 22 pivotal topics were identified within the framework and assigned to groups. These groups reviewed relevant literature and drafted preliminary recommendations. Following this, the recommendations were reviewed by the coordinators and received unanimous approval. Finally, the groups made the final adjustments, classified the level of evidence, and ranked the recommendations.

CONCLUSION

The collection of surgical samples requires minimum quality standards to enable histopathological, IHC, genomic, and molecular analyses. These analyses provide crucial data for informing therapeutic decisions, significantly impacting potential survival gains for patients with female tumors.

Unsolved Issues in the Integrated Histo-Molecular Classification of Endometrial Carcinoma and Therapeutic Implications

Endometrial carcinoma (EC) is the most frequent gynecological cancer, with an increasing incidence and mortality in recent times. The last decade has represented a true revolution with the development of the integrated histo-molecular classification of EC, which allows for the stratification of patients with morphologically indistinguishable disease into groups with different prognoses. Particularly, the POLE-mutated subgroup exhibits outstanding survival. Nevertheless, the indiscriminate application of molecular classification appears premature. Its prognostic significance has been proven mainly in endometrioid EC, the most common histotype, but it has yet to be convincingly confirmed in the other minor histotypes, which indeed account for a relevant proportion of EC mortality. Moreover, its daily use both requires a mindful pathologist who is able to correctly evaluate and unambiguously report immunohistochemical staining used as a surrogated diagnostic tool and is hampered by the unavailability of POLE mutation analysis. Further molecular characterization of ECs is needed to allow for the identification of better-tailored therapies in different settings, as well as the safe avoidance of surgery for fertility preservation. Hopefully, the numerous ongoing clinical trials in the adjuvant and metastatic settings of EC will likely produce evidence to refine the histo-molecular classification and therapeutic guidelines. Our review aims to retrace the origin and evolution of the molecular classification for EC, reveal its strengths and limitations, show clinical relevance, and uncover the desired future developments.

Selective utilization of circulating tumor DNA testing enables disease monitoring in endometrial and ovarian carcinomas

OBJECTIVE

Biomarkers reflecting real-time response to therapy and recurrence are lacking. We assessed the clinical value of detecting cell-free circulating tumor DNA (ctDNA) mutations in endometrial cancer (EC) and ovarian cancer (OC) patients.

METHODS

EC/OC patients undergoing primary surgery were consented for tissue banking and 2-year serial blood draws. Tumor tissue DNA and plasma ctDNA underwent next generation sequencing using a targeted gene panel to identify somatic mutations.

RESULTS

Of 44 patients (24 EC, 17 OC, 2 synchronous endometrial and ovarian carcinomas [SEOC] and 1 endocervical adenocarcinoma [EA]) at least one somatic mutation was identified in tumor tissue in 40 (91%, 20/24 EC, all OC/SEOC/EA), and in preoperative plasma ctDNA in 12 (27%) patients (6/24 [25%] EC and 6/17 [35%] OC). Detection of preoperative ctDNA mutations was associated with advanced stage, higher preoperative CA125, and disease recurrence. In 5/12 (42%) patients with preoperative ctDNA mutations, examination/imaging suggested clinical stage I however final pathology revealed stage II/III. In 11 patients where serial timepoints were assessed during treatment for ctDNA and CA125, ctDNA clearance preceded normalization of CA125. Thirteen patients developed recurrent disease (4 EC, 8 OC, 1 EA); 8 in whom ctDNA mutations were detected postoperatively, and 4 followed through time of recurrence with ctDNA mutations identified 2-5 months prior to clinical/radiologic/biomarker progression in 3.

CONCLUSION

ctDNA can reflect larger tumor volume/metastases, treatment response and recurrence in EC and OC. Careful patient selection is critical to direct resources to patients most likely to benefit, considering disease burden and risk group.

Prognostic value of molecular classification in stage IV endometrial cancer

OBJECTIVES

Multiple studies have proven the prognostic value of molecular classification for stage I-III endometrial cancer patients. However, studies on the relevance of molecular classification for stage IV endometrial cancer patients are lacking. Hypothetically, poor prognostic molecular subtypes are more common in higher stages of endometrial cancer. Considering the poor prognosis of stage IV endometrial cancer patients, it is questionable whether molecular classification has additional prognostic value. Therefore, we determined which molecular subclasses are found in stage IV endometrial cancer and if there is a correlation with progression-free and overall survival.

METHODS

A retrospective multicenter cohort study was conducted using data from five Dutch hospitals. Patients with stage IV endometrial cancer at diagnosis who were treated with primary cytoreductive surgery or cytoreductive surgery after induction chemotherapy between January 2000 and December 2018 were included. Exclusion criteria were age <18 years or recurrent disease. The molecular classification was performed centrally on all tumor samples according to the World Health Organization 2020 classification (including POLE and estrogen receptor status). The Kaplan-Meier method was used to calculate progression free and overall survival in the molecular subclasses, for the different histological subtypes and for estrogen receptor positive versus estrogen receptor negative tumors. Groups were compared using the log-rank test.

RESULTS

164 stage IV endometrial cancer patients were molecularly classified. Median age of the patients was 67 years (range 33-86). Most patients presented with a non-endometrioid histological subtype (58%). Intra-abdominal complete cytoreductive surgery was achieved in 60.4% of the patients. 101 tumors (61.6%) were classified as p53 abnormal, 35 (21.3%) as no specific molecular profile, 21 (12.8%) as mismatch repair deficient, and 6 (3%) as POLE mutated. Molecular classification had no significant impact on progression free (p=0.056) or overall survival (p=0.12) after cytoreductive surgery. Overall survival was affected by histologic subtype (p<0.0001) and estrogen receptor status (p=0.013).

CONCLUSION

The distribution of the molecular subclasses in stage IV endometrial cancer patients differed substantially from the distribution in stage I-III endometrial cancer patients, with the unfavorable subclasses being more frequently present. Although the molecular classification was not prognostic in stage IV endometrial cancer, it could guide adjuvant treatment decisions.

Predictive Value of Magnetic Resonance Imaging in Risk Stratification and Molecular Classification of Endometrial Cancer

This study evaluated the magnetic resonance imaging (MRI) findings of endometrial cancer (EC) patients and identified differences based on risk group and molecular classification. The study involved a total of 175 EC patients. The MRI data were retrospectively reviewed and compared based on the risk of recurrence. Additionally, the associations between imaging phenotypes and genomic signatures were assessed. The low-risk and non-low-risk groups (intermediate, high-intermediate, high, metastatic) showed significant differences in tumor diameter (p < 0.001), signal intensity and heterogeneity on diffusion-weighted imaging (DWI) (p = 0.003), deep myometrial invasion (involvement of more than 50% of the myometrium), cervical invasion (p < 0.001), extrauterine extension (p = 0.002), and lymphadenopathy (p = 0.003). Greater diffusion restriction and more heterogeneity on DWI were exhibited in the non-low-risk group than in the low-risk group. Deep myometrial invasion, cervical invasion, extrauterine extension, lymphadenopathy, recurrence, and stage discrepancy were more common in the non-low-risk group (p < 0.001). A significant difference in microsatellite stability status was observed in the heterogeneity of the contrast-enhanced T1-weighted images (p = 0.027). However, no significant differences were found in MRI parameters related to TP53 mutation. MRI features can be valuable predictors for differentiating risk groups in patients with EC. However, further investigations are needed to explore the imaging markers based on molecular classification.

Molecular profile is a strong predictor of the pattern of recurrence in patients with endometrial cancer

OBJECTIVES

To investigate the pattern of first recurrence of disease in patients with endometrial cancer according to molecular classification, and to assess the independent role of molecular profiling in each type of failure.

METHODS

Retrospective single-center study including patients diagnosed with endometrial cancer stage I-IVB (International Federation of Gynecology and Obstetrics 2009) between December 1994 and May 2022, who underwent primary surgical treatment and had a complete molecular profile. First recurrence was classified as isolated or multiple, and as vaginal, pelvic, peritoneal, nodal, and distant according to its location. The log-rank test and univariate and multivariate adjusted Cox regression models were used for comparison between groups.

RESULTS

A total of 658 patients were included. Recurrence was observed in 122 patients (18.5%) with a recurrence rate of 12.4% among mismatch-repair deficient tumors, 14.5% among non-specific molecular profile, 2.1% among POLE-mutated, and 53.7% among p53-abnormal tumors. Recurrences were found to be isolated in 80 (65.6%) and multiple in 42 (34.4%) patients, with no differences in molecular subtype (p=0.92). Patients with p53-abnormal tumors had a recurrence mainly as distant (28.4%) and peritoneal (21.1%) disease, while patients with non-specific molecular profile tumors presented predominantly with distant failures (10.3%), and mismatch-repair deficient tumors with locoregional recurrences (9.4%).On multivariate analysis, p53-abnormal molecular profile was the only independent risk factor for peritoneal failure (OR=8.54, 95% CI 2.0 to 36.3). Vaginal recurrence was independently associated with p53-abnormal molecular profile (OR=6.51, 95% CI 1.1 to 37.4) and lymphovascular space invasion. p53-abnormal and non-specific molecular profiles were independent predictors for distant recurrence (OR=3.13, 95% CI 1.1 to 8.7 and OR=2.35, 95% CI 1.1 to 5.0, respectively), along with lymphovascular space invasion and high-grade tumors. Molecular profile was not independently associated with pelvic and nodal recurrences.

CONCLUSIONS

Endometrial cancer featured different patterns of recurrence depending on the molecular profile. p53-abnormal molecular profiling was the only independent risk factor for peritoneal relapse, while non-specific molecular profile showed a strong association with distant failures.

Molecular features for timely cancer diagnosis and treatment - tumors of the ovary, fallopian tube and endometrium

Gynecologic pathology has moved, within only a few years, from being a diagnostic area devoid of molecular testing into a diagnostic discipline in which such analyses are becoming routine. The direct relevance of molecular characterization to the choice of treatment of patients with carcinomas originating in both the uterus and adnexae makes it likely that such testing will only expand along with our understanding of the molecular make-up of these tumors. As a consequence, gynecologic pathologists have become an integral part of patient management, rather than lab personnel providing external services.In parallel, molecular testing is expanding as a tool for diagnosing rare tumors affecting these organs, including soft tissue tumors, sex cord-stromal tumors and germ cell tumors, as well as other rare entities. Increased knowledge in this area bears directly on the ability to diagnose these tumors in a reproducible manner, as well as recognize and consult on genetic diseases. Hopefully, despite the inherent difficulty in studying rare cancers, it will also translate into new therapeutic options for the malignant ones among these rare cancers.

Mismatch Repair Deficiency as a Predictive and Prognostic Biomarker in Endometrial Cancer: A Review on Immunohistochemistry Staining Patterns and Clinical Implications

Among the four endometrial cancer (EC) TCGA molecular groups, the MSI/hypermutated group represents an important percentage of tumors (30%), including different histotypes, and generally confers an intermediate prognosis for affected women, also providing new immunotherapeutic strategies. Immunohistochemistry for MMR proteins (MLH1, MSH2, MSH6 and PMS2) has become the optimal diagnostic MSI surrogate worldwide. This review aims to provide state-of-the-art knowledge on MMR deficiency/MSI in EC and to clarify the pathological assessment, interpretation pitfalls and reporting of MMR status.

Moving into the modern era of molecular classification for endometrial cancer

The molecular subtypes of endometrial carcinoma (EC) were first described by The Cancer Genome Atlas (TCGA) a decade ago. Using surrogate approaches, the molecular classification has been demonstrated to be prognostic across EC patients and to have predictive implications. Starting in 2020, the molecular classification has been incorporated into multiple guidelines as part of the risk assessment and most recently into the International Federation of Gynecology and Obstetrics (FIGO) staging. This review article discusses the implementation of the EC molecular classification into clinical practice, the therapeutic implications, and the molecular and clinical heterogeneity of the EC molecular subtypes.

Characteristics and outcomes of surgically staged multiple classifier endometrial cancer

OBJECTIVE

The growing adoption of molecular and genomic characterization is changing the current landscape of treatment of endometrial cancer patients. Using the surrogate molecular classification, endometrial cancer patients can be classified in four subgroups: POLE mutated (POLEmut), MMRd/MSI-H, p53 abnormal (p53abn), and no specific mutational profile (NSMP). However, some patients can harbor two or more molecular features (defined as multiple classifier). Since the rarity of this occurrence, evidence regarding multiple classifiers is still limited. Here, we described characteristics and outcomes of multiple classifiers.

METHODS

This is a multi-institutional retrospective study. Data of consecutive patients having 2 or more molecular features were collected. Survival was assessed using the Kaplan-Meier and Cox proportional hazard methods.

RESULTS

Charts of 72 multiple classifiers were reviewed. Median (range) follow-up was 9.8 (1.2, 37.5) months. Overall, 31 (43%) patients had POLEmut. Patients with POLEmut-MMRd/MSI-H, POLEmut-p53abn, and POLEmut-MMRd/MSI-H-p53abn were 6 (8.3%), 20 (27.8%), and 5 (6.9%), respectively. Among those 31 patients, no recurrence occurred within a median follow-up of 10.5 months (only seven (22.6%) patients had at least 2-year follow-up). The remaining 41 (56.9%) patients were diagnosed with tumors harboring both p53 and MMRd/MSI-H. Among them, four (9.8%) recurrences occurred at a median follow-up time of 8.9 months. Adjuvant therapy (other than vaginal brachytherapy) was administered in 5/31 (16%) and 25/41 (61%) patients with and without POLEmut, respectively (p < 0.001).

CONCLUSIONS

Multiple classifiers endometrial cancer with POLEmut are characterized by good prognosis even in case of presence of MMRd/MSI-H and/or p53abn. Additional studies with long-term follow-up are needed.

New therapeutic targets for endometrial cancer: a glimpse into the preclinical sphere

INTRODUCTION

Endometrial cancer (EC) is the only gynecologic malignancy showing increasing trends in incidence and mortality. While standard treatment has been effective primarily for early-stage EC, precision medicine with tailored therapy has revolutionized the management of this disease. Genome sequencing analyses have identified four sub-types of EC. Treatments for primary and metastatic disease can now be tailored more accurately to achieve better oncologic results.

AREAS COVERED

This review provides an overview of the most relevant and updated evidence in the literature regarding EC molecular analysis and its role in risk classification, prognostication, and guidance for tailored and target therapies in early and advanced/metastatic stages. In addition, it provides updated information on optimal surgical management based on molecular classification and highlights key advances and future strategies.

EXPERT OPINION

EC molecular analysis yields the potential of tailoring adjuvant treatment by escalating or deescalating therapy, as shown for POLE-mutated and p53-mutated tumors. Moreover, the expression of specific molecular signatures offers the possibility to employ novel target therapies, such as immune-checkpoint inhibitors that have demonstrated a significant benefit on prognosis. New treatment guidelines are still being established, and ongoing studies are exploring the potential prognostic role of further sub-stratifications of the four molecular classes and treatment options.

Evolving treatment paradigms in metastatic or recurrent low-grade endometrial cancer: When is hormonal-based therapy the preferred option?

Endometrial cancer is the most common gynecologic malignancy in developed countries, with increasing incidence and mortality rates worldwide. While most cases are successfully treated with surgery, first-line treatment options for metastatic or recurrent endometrial cancer involve significant toxicities. Imprecise classification of heterogeneous subgroups further complicates treatment decisions and interpretation of clinical trial results. Recent advances in molecular classification are guiding treatment decisions for metastatic or recurrent endometrial cancers. Integrating molecular characteristics with traditional clinicopathology can both reduce overtreatment or undertreatment and help guide the appropriate choice of therapies and effective design of future studies. Here we discuss the treatment of metastatic or recurrent low-grade endometrioid adenocarcinoma of the uterine corpus, which is distinct from high-grade tumors histologically, molecularly, and in treatment response.

Molecular Classification of Endometrial Cancer and the 2023 FIGO Staging: Exploring the Challenges and Opportunities for Pathologists

This commentary explores the complexities of the FIGO 2023 staging system and the inclusion of The Cancer Genome Atlas's (TCGA) molecular classification in the management of endometrial cancer. It highlights the importance of histology as a prognostic tool, while scrutinizing the merits and demerits of its application to aggressive endometrial cancers. The commentary review sheds light on the recent introductions of lymphovascular space invasion (LVSI) and lymph node metastasis size in cancer staging. It outlines the difficulties in differentiating between synchronous and metastatic endometrial and ovarian cancers, underlining their implications on treatment strategies. Furthermore, the commentary discusses the integration of molecular classifications within the FIGO 2023 framework, emphasizing the pivotal yet challenging implementation of the pathogenic POLE mutation test. The commentary concludes by reaffirming the vital role of pathologists in executing the FIGO 2023 staging system.

FIGO staging of endometrial cancer: 2023

INTRODUCTION

Many advances in the understanding of the pathologic and molecular features of endometrial cancer have occurred since the FIGO staging was last updated in 2009. Substantially more outcome and biological behavior data are now available regarding the several histological types. Molecular and genetic findings have accelerated since the publication of The Cancer Genome Atlas (TCGA) data and provide improved clarity on the diverse biological nature of this collection of endometrial cancers and their differing prognostic outcomes. The goals of the new staging system are to better define these prognostic groups and create substages that indicate more appropriate surgical, radiation, and systemic therapies.

METHODS

The FIGO Women's Cancer Committee appointed a Subcommittee on Endometrial Cancer Staging in October 2021, represented by the authors. Since then, the committee members have met frequently and reviewed new and established evidence on the treatment, prognosis, and survival of endometrial cancer. Based on these data, opportunities for improvements in the categorization and stratification of these factors were identified in each of the four stages. Data and analyses from the molecular and histological classifications performed and published in the recently developed ESGO/ESTRO/ESP guidelines were used as a template for adding the new subclassifications to the proposed molecular and histological staging system.

RESULTS

Based on the existing evidence, the substages were defined as follows: Stage I (IA1): non-aggressive histological type of endometrial carcinoma limited to a polyp or confined to the endometrium; (IA2) non-aggressive histological types of endometrium involving less than 50% of the myometrium with no or focal lymphovascular space invasion (LVSI) as defined by WHO criteria; (IA3) low-grade endometrioid carcinomas limited to the uterus with simultaneous low-grade endometrioid ovarian involvement; (IB) non-aggressive histological types involving 50% or more of the myometrium with no LVSI or focal LVSI; (IC) aggressive histological types, i.e. serous, high-grade endometrioid, clear cell, carcinosarcomas, undifferentiated, mixed, and other unusual types without any myometrial invasion. Stage II (IIA): non-aggressive histological types that infiltrate the cervical stroma; (IIB) non-aggressive histological types that have substantial LVSI; or (IIC) aggressive histological types with any myometrial invasion. Stage III (IIIA): differentiating between adnexal versus uterine serosa infiltration; (IIIB) infiltration of vagina/parametria and pelvic peritoneal metastasis; and (IIIC) refinements for lymph node metastasis to pelvic and para-aortic lymph nodes, including micrometastasis and macrometastasis. Stage IV (IVA): locally advanced disease infiltrating the bladder or rectal mucosa; (IVB) extrapelvic peritoneal metastasis; and (IVC) distant metastasis. The performance of complete molecular classification (POLEmut, MMRd, NSMP, p53abn) is encouraged in all endometrial cancers. If the molecular subtype is known, this is recorded in the FIGO stage by the addition of "m" for molecular classification, and a subscript indicating the specific molecular subtype. When molecular classification reveals p53abn or POLEmut status in Stages I and II, this results in upstaging or downstaging of the disease (IICmp53abn or IAmPOLEmut ).

SUMMARY

The updated 2023 staging of endometrial cancer includes the various histological types, tumor patterns, and molecular classification to better reflect the improved understanding of the complex nature of the several types of endometrial carcinoma and their underlying biologic behavior. The changes incorporated in the 2023 staging system should provide a more evidence-based context for treatment recommendations and for the more refined future collection of outcome and survival data.

Back to the future: The impact of oestrogen receptor profile in the era of molecular endometrial cancer classification

PURPOSE

The aim of this study is to evaluate the impact of the oestrogen receptor (ER) profile on oncologic outcomes in the new endometrial cancer (EC) risk classification.

METHODS

Immunohistochemistry (IHC) analyses were performed in a retrospectively reviewed large series of ECs to assess the presence/absence of oestrogen receptors (ER0\1+ or ER2+\3+) and other molecular factors (i.e. p53 mutation, p53mut; and mismatch repair mutational status, MMRd (mismatch repair deficient) versus MMRp (mismatch repair proficient)), histopathologic and clinical outcomes. ER status was correlated with molecular, histologic, clinical and prognostic data.

RESULTS

891 EC patients were included in the study (211 ER0\1+ and 680 ER2+\3+). The ER0\1+ phenotype was associated with an unfavourable clinicopathological profile (i.e. grading, histotype, lymphovascular space invasion (LVSI), stages, etc.). Simple regression showed that risk class, p53mut, and ER0/1+ impacted on both disease-free survival (DFS) and overall survival (OS) (p < 0.05). In the ER0/1+ population, p53mut no longer influenced DFS and OS (p > 0.05). In multiple regression, age, high and advanced/metastatic risk classes influenced survival outcomes (p < 0.05), but lost significance in the ER0/1+ population (p > 0.05). ER-positivity retained a remarkable prognostic impact even after stratification of the population according to the European Society of Gynaecological Oncology, the European Society for Radiotherapy and Oncology, and the European Society of Pathology (ESGO/ESTRO/ESP) 2021 risk classes and molecular classification. ER0/1+ intermediate, high-intermediate, high and advanced risk versus ER2+/3+ intermediate, high-intermediate, high and advanced risk classes showed statistically different OS and DFS (p< 0.001). ER0/1+ status was associated with a worse prognosis when associated with MMRp, MMRd and p53mut compared to the same molecular classes associated with ER2+/3 (p < 0.001).

CONCLUSIONS

We demonstrated that ER status has a significant impact on oncologic outcomes, regardless of risk class and p53/MMR status. Based on our results, we recommend the inclusion of ER assessment in featured EC risk classification system.

Molecular subtype stratified outcomes according to adjuvant therapy in endometrial cancer

OBJECTIVES

Recent data support the predictive implications of molecular subtype assignment in endometrial cancer (EC). Our objective was to retrospectively assess clinical outcomes according to adjuvant treatment received within EC molecular subtypes.

METHODS

Clinical outcomes (disease-specific and progression-free survival DSS/PFS) of EC patients from a single institution and population-based cohorts that had undergone molecular classification were assessed with respect to adjuvant therapy received and 2016 ESMO risk group.

RESULTS

2472 ECs were assessed; 184 (7.4%) POLEmut, 638 (25.8%) MMRd, 1223 (49.5%) NSMP and 427 (17.3%) p53abn. N = 774 (34.6%) of the cohort were ESMO 2016 high risk and 109 (4.8%) were advanced or metastatic. In patients with MMRd EC, assessed across and within stage, there was no observed benefit in DSS or PFS with the addition of chemotherapy +/- radiation compared to radiation alone in ESMO high risk (p = 0.694) or ESMO high, advanced, metastatic risk groups combined (p = 0.852). In patients with p53abn EC, adjuvant chemotherapy given with radiation was associated with significantly longer DSS compared to radiation alone in ESMO high risk (p = 0.007) and ESMO high, advanced and metastatic risk groups combined (p = 0.015), even when restricted to stage I disease (p < 0.001) and when compared in serous vs. non-serous histotypes (p = 0.009).

CONCLUSIONS

Adjuvant chemotherapy is associated with more favorable outcomes for patients with p53abn EC, including stage I disease and non-serous histotypes, but does not appear to add benefit within MMRd ECs for any stage of disease, consistent with PORTEC-3 molecular subanalysis. Prospective trials, assessing treatment efficacy within molecular subtype are needed, however these 'real-world' data should be considered when discussing adjuvant treatment with patients.

Molecular Profiling of Endometrial Cancer From TCGA to Clinical Practice

Molecular classification provides an objective, reproducible framework for categorization of endometrial cancers (ECs), informing prognosis and selection of therapy. Currently, the uptake of molecular classification, integration in to EC management algorithms, and enrollment in molecular subtype-specific clinical trials lags behind what it could be. Access to molecular testing is not uniform, and subsequent management (surgical, adjuvant therapy) is unacceptably variable. We are in the midst of a critical landscape change in this disease site, with increasing emphasis on the integration of molecular features in EC care that can potentially improve standard of care globally. This article summarizes the rationale for molecular classification of ECs, strategies for implementation in low and high resource settings, and actionable opportunities based on this information.