Endometrial cancer is the most common gynaecological malignancy, with an increasing incidence in the developed world.1 Most endometrial carcinoma occur in post-menopausal women, however in rare cases they can also affect young women.2 In most cases it is diagnosed in early disease stages. With current therapeutic approaches, patients achieve an overall survival (OS) from 74% to 91%.1 Recently published data3 on 5-year OS of women with endometrial cancer in Slovenia shows a modest increase in survival between the years 2012–2016 (80.6%) as compared to between the years 1997–2001 (79.8%).3 Endometrial carcinoma are divided, based on their histopathological characteristics, into Type I and Type II carcinoma. Type I carcinomas represent the majority of EC and are of endometrioid subtype. Type II carcinomas are a more hetereogenous group of histopathological subtypes and include clear-cell, serous, mixed histology tumours and carcinosarcomas.4
There is a constant need to improve the risk assessment for improved precision in endometrial cancer treatment. An important aim is to identify patients that experience disease reccurrence regardless of the primary early stage endometrial cancer diagnosis. In the last decade, the molecular classification of endometrial cancer has emerged as a feasible possibility to stratify risk in women with endometrial cancer.5 The evaluated molecular classification showed, that determining the status of endometrial carcinoma tumours for: i) pathogenic variants of the exonuclease domain of DNA polymerase-epsilon
The molecular risk assessment has been applied for interventions and assessments of adjuvant therapy management decisions.9 Based on the current ESGO-ESTRO-ESP guidelines, women with low-risk EC do not need additional adjuvant therapy. For intermediate risk, radiotherapy has been suggested as the optimal course of treatment. In high-intermediate or some cases of intermediate risk, chemotherapy can be considered in addition to radiotherapy. The guidelines recommend for women with high risk EC to undergo radiotherapy with concurrent chemotherapy.4 Abdulfatah
Based on the currently available guidelines we aimed to assess the changes that clinical and integrated molecular risk assessment represent in terms of primary patient management.
This single centre study prospectively recruited consecutive women treated at the University Medical Centre Maribor (UMC Maribor), Slovenia. Participants were recruited from February 2020 to February 2021. Women were eligible to participate in this study if they had a biopsy-proven EC diagnosis and were candidates for surgical treatment.
Informed consent was obtained prior to surgical treatment from all study participants. This study was approved by the Slovenian Ethics Committee for Research in Medicine under the registration number 0120-40/2020/4 and was carried out in accordance to the Declaration of Helsinki.
All included women underwent complete diagnostic work-up at our centre, which routinely includes a comprehensive transvaginal ultrasound (TVUS) scan to assess for disease extent. Based on the clinical assessment of myometrial involvement and disease extent, as well as histopathological tumour assessment, a clinical risk prediction was made. Afterwards, they were presented to the interdisciplinary tumour board to plan the optimal treatment. Standard treatment of early stage endometrial cancer is surgical and is most commonly performed by minimally invasive surgery, but open surgical approach is also an option. This depends on the tumour type and patient characteristics. Surgical treatment usually consists of total hysterectomy with bilateral salpingo-oophorectomy. This is most commonly combined with sentinel lymph node biopsy (SLN) or pelvic/paraaortic lymph node dissection (LND).
The molecular risk-profile was determined according to current guidelines on endometrial cancer4, based on determining the tumour
MMRd status was determined by evaluating the immunohistochemical (IHC) markers (MLH1, MSH2, MSH6, PMS2). Previous research showed13, that IHC markers represent an appropriate surrogate for screening for MMRd. The p53 protein expression status was evaluated using IHC expression according to current recommendations.14
Based on genetic and IHC data, women were grouped, according to the ESGO/ESTRO/ESP guidelines5 into the following molecular classification groups:
Descriptive statistics were used to evaluate the distribution of each variable. Continuous variables were expressed as mean values with standard deviations. Categorical variables were reported as frequency or percentage. All statistical analyses were performed using SPSS software version 23.0 (IBM Corp., Armonk, NY, USA).
Molecular characterisation was performed in all 45 women enrolled. Among them, 39 women (86.7%) were classified according to the current recommendations in one of the four molecular classification groups. Their characteristics are presented in Table 1. Six women (13.3%) had multiple molecular classifiers. The characteristics of these women are presented in Table 2.
Patient characteristics
65.2 years (min 32 – max 86) | ||
31 (17–43) | ||
Parity (median, range) | 2 (0–5) | |
Spontaneuos abortion (median, range) | 0 (0–2) | |
Pre-menopausal | 5 (12.8%) | |
Post-menopausal | 34 (87.2%) | |
CA125 (n = 32) | 136.3 (min 2 – max 2084) | |
CEA (n = 32) | 3.4 (min 2 – max 17) | |
IA | 21 (54%) | |
IB | 8 (20.5%) | |
II | 1 (2.6%) | |
IIIA | 2 (5.1%) | |
IIIB | 2 (5.1%) | |
IIIC1 | 3 (7.7%) | |
IIIC2 | 1 (2.6%) | |
IV | 1 (2.6%) | |
Type 1 | 36 (92.3%) | |
Type 2 | 3 (7.7 %) | |
POLEmut | 1 (2.6%) | |
MMRd | 13 (33.3%) | |
NSMP | 22 (56.4%) | |
p53abn | 3 (7.7%) |
MMRd = mismatch repair deficient tumour; NSMP = non-specific molecular profile tumour; p53abn = p53 expression abnormal tumour; POLE = DNA polymerase-epsilon; POLEmut = POLE ultramutated tumour
Characteristics of patients with multiple molecular classifiers
Age at time of diagnosis | Multiple-classifier EC | POLE variant | Tumor type | FIGO stage | Lymphovascular invasion | Clinical risk assessment | |
---|---|---|---|---|---|---|---|
76 | POLEmut and p53abn | P286R | endometrioid | IIIC2 | Yes | High | |
75 | POLEmut and p53abn | P286R | carcinosarcoma | IB | Yes | High | |
70 | MMRd and p53abn | wild-type | endometrioid | IA | No | Low | |
87 | MMRd and p53abn | wild-type | endometrioid | IIIB | Yes | High | |
53 | POLEmut and p53abn | P286R | endometrioid | IA | No | Low | |
52 | POLEmut and p53abn | P286R | endometrioid | IA | No | Intermediate |
MMRd = mismatch repair deficient tumour; p53abn = p53 expression abnormal tumour; POLE = DNA polymerase-epsilon; POLEmut = POLE ultramutated tumour
Following the ESGO/ESTRO/ESP guidelines on risk assessment, women were classified according to the clinical risk assessment and the integrated molecular risk (Table 3). Most remained classified as low-risk endometrial cancer, reclassification changed for 4 women.
Risk assessment
Number of patients (%) | ||
---|---|---|
Low risk | 21 (53.8%) | |
Intermediate risk | 5 (12.8%) | |
High-intermediate risk | 2 (5.1%) | |
High risk | 10 (25.6%) | |
Advanced metastatic | 1 (2.6%) | |
Low risk | 22 (56.4%) | |
Intermediate risk | 4 (10.3%) | |
High-intermediate risk | 3 (7.7%) | |
High risk | 9 (23.1%) | |
Advanced metastatic | 1 (2.6%) |
ESGO = European Society of Gynaecological Oncology
The risk profiles of three women decreased after integrated molecular risk classification: one was reclassified from high risk to high-intermediate risk and two from intermediate to low-risk. The risk profile of women changed from: i) intermediate to low risk as one woman had a POLEmut tumour, ii) from intermediate to low risk since it was of NSMP and iii) from high to high-intermediate (HIR) risk due to the MMRd classification. In one case, the risk profile increased from low to intermediate risk due to the detected p53abn mutation.
Surgical treatment was performed in all patients included in the study. The specifics of the treatment are presented in Table 4. Thirty women (77%) underwent a laparoscopic procedure and 9 women (23%) an open surgical procedure. The multidisciplinary (MDT) recommendation in cases of pre-operatively persumed low-risk disease is to perform sentinel lymph node biopsy (SLN). If the lymph nodes are not visualized, further LND is generally omitted. In cases of persumed intermediate risk, the recommendation in case of SLN visualization failure is to perform LND.
Analysis of surgical treatment of women based on ESGO Clinical Risk Group assesment. SLN – sentinel lymph node biopsy, LND - lymphadenectomy
ESGO integrated molecular risk | Total number of women | Open surgery | Laparoscopic | SLN | LND | Unilateral SNB and contralateral LND | No LN treatment |
---|---|---|---|---|---|---|---|
Low risk | 22 (56.4%) | 2 (5.1%) | 20 (51.3%) | 18 (46.2%) | 0 | 0 | 4 (10.3%) |
Intermediate | 4 (10.3%) | 0 | 4 (10.3%) | 3 (7.7%) | 1 (2.6%) | 0 | 0 |
HIR | 3 (7.7%) | 1 (2.6%) | 2 (5.1%) | 0 | 2 (5.1%) | 1 (2.6%) | 0 |
High | 9 (23.1%) | 5 (12.8%) | 4 (10.3%) | 2 (5.1%) | 5 (12.8%) | 2 (5.1%) | 1 (2.6%) |
Advanced | 1 (2.6%) | 1 (2.6%) | 0 | 0 | 0 | 0 | 1 (2.6%) |
HIR = high-intermediate risk; LND = lymphadenectomy; SLN = sentinel lymph node biopsy
In the post-operative period two women (5.1%) died. Two women (5.1%) rejected the recommended adjuvant therapy. The final analysis was performed for 37 women as depicted in Figure 1.
Figure 1
Potential impact of risk shifts on adjuvant therapy. Depicted in circles are the absolute numbers of women with endometrial cancer and their adjuvant therapy recommendations. Arrows point to a potential risk shift impacting therapy with the use of the molecular classification.
CT = chemotherapy; RT = radiotherapy

Our study was observational and the molecular classification did not impact the MDT decision making. Two women which were re-classified from intermediate to low risk by the molecular classification received radiation therapy and one women that has been reclassified from high risk to HIR received radiotherapy and chemotherapy. One patient for whom the risk assesment increased from low to intermediate risk has been recommended no adjuvant treatment. In one patient of the intermediate risk group, the presence of co-morbidities led the MDT to suggest follow-up as the optimal strategy.
In this study we assessed the risk of endometrial cancer for women using the clinical classification and the integrated molecular classification as suggested by the recent ESGO/ESTRO/ESP guidelines. Out of 45 women enrolled in our study, the risk evaluation through integrated molecular risk groups was possible for 39 women. Six women had multiple molecular classifiers, which precluded further risk assessment using the current molecular classification. In the remaining group, assessment of molecular risk decreased in three and increased in one woman.
The classification of women with endometrial cancer into risk groups based on clinical and molecular data aims to improve individualised treatment according to the tumour biological potential. According to the currently valid guidelines4, histopathological characteristics, including lymphvascular space invasion (LVSI) are the cornerstone of risk stratification. This is one of the reasons that shifts in risk groups between clinical and integrated molecular groups were present, as LVSI has been identified as an important marker of prognosis in low-risk endometrial cancer and is associated with adverse outcomes.15 In comparison with a study of Oberndorfer
The nature of our study was observational and the molecular subtype was not taken into consideration for decision-making in regards to surgical or adjuvant therapy. Table 4 represents the surgical approach taken for women based on the pre-treatment assessment and the final ESGO Risk Group classification. The body of knowledge on using the integrated molecular classification for decision making on surgical treatment is scarce. Histopathological pre-operative evaluation might not always be concordant with post-operative diagnosis18,19 and could potentially impact the MDT to suggest less invasive surgical procedures. This is especially true in recognizing serous EC. In these instances based on the molecular characteristics such as
Considering the changes in risk assessment for patients within our study, if using the integrated molecular assessment, two patients would most likely been recommended follow-up instead of radiotherapy, thus de-escalating their therapy based on their individual biological features. One patient would have been, based on her biological characteristics upgraded from low to intermediate risk. Especially in the low-intermediate and intermediate-high risk group, it is important to identify the patients correctly. Without appropriate adjuvant therapy, these patients were found to be at a approximately 30% higher risk than if adjuvant therapy was offered.21 One of our patients was downgraded from high risk to the HIR risk group. While this individual has received radiotherapy and chemotherapy, this is also a valid strategy of treatment in the HIR risk group4 and the decision process most likely would have not changed for her. Participants in our study have been mostly classified as NSMP (56.4%). NSMP tumours are currently classified in the low-risk or intermediate risk4 based on a combination with other histopathological characteristics. As NSMP represents the largest group of currently classified tumours this shows the need for further refinements of molecular risk stratification.22,23 A potential additional marker which has shown potential prognostic value, especially in the intermediate risk groups, is L1CAM expression23,24 and in low risk endometrial cancer also mutation of
An important consideration in our study is how to evaluate and incorporate risk assessment for women with multiple classifiers. There were six women with multiple classifiers in which four tumours were p53abn and POLEmut. Multiple classifiers MMRd and p53abn were present in two women. Recently, Leon-Castilo
The strength of our study is that it is the first prospectively designed study to evaluate the implementation of molecular risk stratification to endometrial cancer patients in Slovenia. The limitation is the low number of patients included. The follow-up data is not yet available and the clinical implications of this approach are yet to be determined.
The introduction of molecular risk stratification in the management of women with endometrial cancer represents a significant shift from the established clinical practice. Several adjustments to the routine workflow and significant additional resources are necessary in order to implement this approach to the clinics. Our data shows that in comparison to the current clinical risk stratification based on clinical and histopathological data, this may lead to change in management in a small proportion of women. The clinical value of this remains to be proven in further prospective studies. It is also important to note that the molecular risk stratification is not applicable to all women and refinements of the current classification with additional biomarkers are likely to improve and further de-escalate treatment in certain subtypes of endometrial cancer in the future.
Figure 1

Analysis of surgical treatment of women based on ESGO Clinical Risk Group assesment. SLN – sentinel lymph node biopsy, LND - lymphadenectomy
ESGO integrated molecular risk | Total number of women | Open surgery | Laparoscopic | SLN | LND | Unilateral SNB and contralateral LND | No LN treatment |
---|---|---|---|---|---|---|---|
Low risk | 22 (56.4%) | 2 (5.1%) | 20 (51.3%) | 18 (46.2%) | 0 | 0 | 4 (10.3%) |
Intermediate | 4 (10.3%) | 0 | 4 (10.3%) | 3 (7.7%) | 1 (2.6%) | 0 | 0 |
HIR | 3 (7.7%) | 1 (2.6%) | 2 (5.1%) | 0 | 2 (5.1%) | 1 (2.6%) | 0 |
High | 9 (23.1%) | 5 (12.8%) | 4 (10.3%) | 2 (5.1%) | 5 (12.8%) | 2 (5.1%) | 1 (2.6%) |
Advanced | 1 (2.6%) | 1 (2.6%) | 0 | 0 | 0 | 0 | 1 (2.6%) |
Risk assessment
Number of patients (%) | ||
---|---|---|
Low risk | 21 (53.8%) | |
Intermediate risk | 5 (12.8%) | |
High-intermediate risk | 2 (5.1%) | |
High risk | 10 (25.6%) | |
Advanced metastatic | 1 (2.6%) | |
Low risk | 22 (56.4%) | |
Intermediate risk | 4 (10.3%) | |
High-intermediate risk | 3 (7.7%) | |
High risk | 9 (23.1%) | |
Advanced metastatic | 1 (2.6%) |
Characteristics of patients with multiple molecular classifiers
Age at time of diagnosis | Multiple-classifier EC | POLE variant | Tumor type | FIGO stage | Lymphovascular invasion | Clinical risk assessment | |
---|---|---|---|---|---|---|---|
76 | POLEmut and p53abn | P286R | endometrioid | IIIC2 | Yes | High | |
75 | POLEmut and p53abn | P286R | carcinosarcoma | IB | Yes | High | |
70 | MMRd and p53abn | wild-type | endometrioid | IA | No | Low | |
87 | MMRd and p53abn | wild-type | endometrioid | IIIB | Yes | High | |
53 | POLEmut and p53abn | P286R | endometrioid | IA | No | Low | |
52 | POLEmut and p53abn | P286R | endometrioid | IA | No | Intermediate |
Patient characteristics
65.2 years (min 32 – max 86) | ||
31 (17–43) | ||
Parity (median, range) | 2 (0–5) | |
Spontaneuos abortion (median, range) | 0 (0–2) | |
Pre-menopausal | 5 (12.8%) | |
Post-menopausal | 34 (87.2%) | |
CA125 (n = 32) | 136.3 (min 2 – max 2084) | |
CEA (n = 32) | 3.4 (min 2 – max 17) | |
IA | 21 (54%) | |
IB | 8 (20.5%) | |
II | 1 (2.6%) | |
IIIA | 2 (5.1%) | |
IIIB | 2 (5.1%) | |
IIIC1 | 3 (7.7%) | |
IIIC2 | 1 (2.6%) | |
IV | 1 (2.6%) | |
Type 1 | 36 (92.3%) | |
Type 2 | 3 (7.7 %) | |
POLEmut | 1 (2.6%) | |
MMRd | 13 (33.3%) | |
NSMP | 22 (56.4%) | |
p53abn | 3 (7.7%) |
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