# Radiomics in Gynaecological Imaging: A State-of-the-Art Review
## 3 Endomet Cancer  
Endometrial cancer (EC) is the most common gynaecological malignancy in industrialized countries, with an expected increasing incidence worldwide [19; 20; 21]. EC usually affects postmenopausal patients (75-80% of cases), with a peak between 55 and 65 years, and its most frequent clinical manifestation is abnormal postmenopausal bleeding [19; 22].  
Diagnosis is based on minimally invasive procedures (hystereoscopy, endometrial biopsy, dilatation, and curettage) and transvaginal ultrasound (TVUS) [22; 23]. However, MRI is considered the best technique for pre-operative staging [24; 25].  
EC is classified according to the recently updated International Federation of Gynaecology and Obstetrics (FIGO) staging system [26] and is traditionally grouped into two major prognostic groups (type I and type II), based on the histological type and FIGO histological grading system [27; 28; 29]. Type I tumours account for approximately 80% of endometrial neoplasms and include endometrioid histotypes with pathological grading G1 and G2. This category of EC is characterized by a good prognosis and is typically estrogen responsive. Type II represents approximately 20% of overall endometrial tumours and includes high-grade (G3) endometrioid and non-endometrioid forms (clear-cell, mucinous, carcinomas, undifferentiated forms). This group usually shows a more aggressive course and does not correlate with estrogenic exposure.  
In order to provide therapeutic management guidelines, the European Society of Gynaecological Oncology (ESMO), European Society for Radiotherapy and Oncology (ESTRO), and European Society of Gynaecological Oncology (ESGO) guidelines stratify EC into four risk categories (low, intermediate, high intermediate, and high risk) according to histology, grade, stage, and the presence of lymph vascular space invasion (LVSI), which describe tumour behaviour and the likelihood of recurrences, directing toward possible adjuvant therapy [22]. EC clinical behaviour is also influenced by its genomic features; therefore, a reclassification of EC based on genomics has been recently proposed considering four categories (POLE ultramutated, microsatellite instability hypermutated, copy-number low, and copy-number high) [30].  
Deep myometrial invasion (DMI) allows for the differentiation between the FIGO stages IA and IB, the most important morphological prognostic factor [31; 32]. Even if MRI is the most accurate technique for the evaluation of DMI, its detection is not always straightforward and has shown relatively high inter-observer variability, particularly when the endometrium is thinned (i.e., older patients, endometrial cavity distension), when the endometrial-myometrial interface is obscured by fibroids or adenomyosis, and when the lesion is located in uterine corneal regions [31; 32; 33; 34].  
Another key prognostic factor is the presence of pelvic or para-aortic nodes metastases (LNM), which is also essential in guiding the therapeutic approach. The principal criterion for suspecting nodes metastases is based on nodal size (short axis > 1 cm). However, this criterion has a low specificity because hyperplastic nodes can also be enlarged, which may lead to a high percentage of false-positive results. At the same time, it has been demonstrated that nodes with a short axis lower than 1 cm are sometimes proved as metastatic at pathology [24; 35].  
Many studies investigated the possible role of radiomics in improving the assessment of EC [36; 37]. The most common imaging modality employed in radiomics investigation studies for EC diagnosis and staging was MRI, using standard diagnostic MRI protocols. According to the latest guidelines of the European Society of Urogenital Radiology (ESUR),pelvic MRI protocol for EC assessment includes T2 WI, diffusion-weighted (DWI), and dynamic contrast-enhanced (DCE) imaging [24].  
Multicentric and prospective radiomic studies applied to EC are summarised in Table 1.