Analysis of CDO1, PITX2, and CDH13 Gene Methylation in Early Endometrial Cancer for Prediction of Medical Treatment Outcomes.

An observational cohort study of patients diagnosed with endometrial cancer (EC) stage IA G1, or atypical endometrial hyperplasia (AEH), undergoing organ-preserving treatment, was conducted. OBJECTIVE OF THE STUDY: To determine CDO1, PITX2, and CDH13 gene methylation levels in early endometrial cancer and atypical hyperplasia specimens obtained before organ-preserving treatment in the patients with adequate response and with insufficient response to hormonal treatment. MATERIALS AND METHODS: A total of 41 endometrial specimens obtained during diagnostic uterine curettage in women with EC (n = 28) and AEH (n = 13), willing to preserve reproductive function, were studied; 18 specimens of uterine cancer IA stage G1 from peri- and early postmenopausal women (comparison group) were included in the study. The control group included 18 endometrial specimens from healthy women obtained by diagnostic curettage for missed abortion and/or intrauterine adhesions. Methylation levels were analyzed using the modified MS-HRM method. RESULTS: All 13 women with AEH had a complete response (CR) to medical treatment. In the group undergoing organ-preserving treatment for uterine cancer IA stage G1 (n = 28), 14 patients had a complete response (EC CR group) and 14 did not (EC non-CR group). It was found that all groups had statistically significant differences in CDO1 gene methylation levels compared to the control group (p < 0.001) except for the EC CR group (p = 0.21). The p-value for the difference between EC CR and EC non-CR groups was <0.001. The differences in PITX2 gene methylation levels between the control and study groups were also significantly different (p < 0.001), except for the AEH group (p = 0.21). For the difference between EC CR and EC non-CR groups, the p-value was 0.43. For CDH13 gene methylation levels, statistically significant differences were found between the control and EC non-CR groups (p < 0.001), and the control and EC comparison groups (p = 0.005). When comparing the EC CR group with EC non-CR group, the p-value for this gene was <0.001. The simultaneous assessment of CDO1 and CDH13 genes methylation allowed for an accurate distinction between EC CR and EC non-CR groups (AUC = 0.96). CONCLUSION: The assessment of CDO1 and CDH13 gene methylation in endometrial specimens from patients with endometrial cancer (IA stage G1), scheduled for medical treatment, can predict the treatment outcome.

New staging of endometrial carcinoma - FIGO 2023.

AIM: To review the changes in the new version of the FIGO 2023 staging system for endometrial cancer. METHODS AND RESULTS: The new FIGO 2023 endometrial cancer staging system provides key updates for the diagnosis and treatment of endometrial cancer. An important step in diagnosis is molecular classification, which allows more accurate risk stratification for recurrence and the identification of targeted therapies. The new staging system, based on the recommendations of the international societies ESGO, ESTRO and ESP, incorporates not only the description of the pathological and anatomical extent of the disease, but also the histopathological characteristics of the tumour, including the histological type and the presence of lymphovascular space invasion. In addition, the staging system uses molecular testing to classify endometrial cancers into four prognostic groups: POLEmut, MMRd, NSMP and p53abn. Each group has its own specific characteristics and prognosis. The most significant changes have occurred in stages I and II, in which the sub-staging better reflects the biological behaviour of the tumour. This update increases the accuracy of prognosis and improves individualized treatment options for patients with endometrial cancer. CONCLUSION: The updated FIGO staging of endometrial cancer for 2023 incorporates different histologic types, tumour features, and molecular classifications to better reflect the current improved understanding of the complex nature of several endometrial cancer types and their underlying bio logic behaviour. The aim of the new endometrial cancer staging system is to better define stages with similar prognosis, allowing for more precise indication of individualised adjuvant radiation or systemic treatment, including the use of immunotherapy.

Tailoring postoperative management through sentinel lymph node biopsy in low- and intermediate-risk endometrial cancer - the SENTRY clinical trial.

BACKGROUND: While total hysterectomy and bilateral salpingo-oophorectomy without lymph node staging are standard for low- and intermediate-risk endometrial cancer, certain histopathologic factors revealed after surgery can necessitate additional interventions. Our study assessed the influence of sentinel lymph node biopsy on postoperative decision-making. MATERIALS AND METHODS: In the SENTRY trial (July 2021 - February 2023), we enrolled patients with International Federation of Gynaecology and Obstetrics (FIGO) stage IA-IB low-grade endometrioid endometrial cancer. Laparoscopic sentinel lymph node mapping using indocyanine green was performed alongside total hysterectomy with bilateral salpingo-oophorectomy. Subsequent management changes based on sentinel lymph node biopsy results were evaluated. The trial was registered at ClinicalTrials.gov (NCT04972682). RESULTS: Of the 100 enrolled participants, a bilateral detection rate of 91% was observed with a median detection time of 10 min (interquartile range 8-13 min). Sentinel lymph node metastases were found in 8% (N = 8) of participants. Postoperative FIGO staging increased in 15% (N = 15) and decreased in 5% (N = 5) of patients. Sentinel lymph node biopsy results altered the adjuvant treatment plan for 20% (N = 20): external beam radiotherapy was omitted in 12% (N = 12) while 6% (N = 6) had external beam radiotherapy +/- systemic chemotherapy added due to sentinel lymph node metastases. In 2% (N = 2), the external beam radiotherapy field was expanded with the paraaortic region. No intraoperative complications were reported and no 30-day major morbidity and mortality occurred. Throughout a median follow-up of 14 (95% CI 12-15 months, neither patient-reported lymphedema nor pelvic recurrence surfaced in the cohort. CONCLUSIONS: Sentinel lymph node biopsy using indocyanine green is a safe procedure and allows tailoring adjuvant therapy in presumed low- and intermediate-risk endometrial cancer. It assists in avoiding external beam radiotherapy overtreatment and introducing additional modalities when necessary.

A new perspective on Endometrial Carcinoma classification and management strategies in context of molecular subtypes.

Endometrial cancer is the most common gynecological cancer and the second most prevalent female malignancy in the developed world. It is typically diagnosed in postmenopausal women, presenting with the characteristic clinical symptom of uterine abnormal bleeding. In the past, only two histological types were considered. However, it has become increasingly evident that endometrial cancer is a clinically heterogeneous disease, and this heterogeneity is closely associated with the diversity of underlying molecular alterations. The Cancer Genome Atlas classification has significantly advanced the diagnosis, risk stratification, and management of endometrial cancer by categorizing it into four molecular subgroups, each characterized by distinct mutational burdens and copy number alterations.

Sociodemographic, clinical characteristics, and treatment patterns of endometrial cancer cases in Puerto Rico during the period 2009 to 2015: A retrospective study.

BACKGROUND: Over the past decades, the rising incidence rates of endometrial cancer have made it a significant public health concern for women worldwide. Treatment strategies for endometrial cancer vary based on several factors such as stage, histology, the patient's overall health, and preferences. However, limited amount of research on treatment patterns and potential correlations with sociodemographic characteristics among Hispanics is available. This study analyzes the treatment patterns for patients diagnosed with endometrial cancer in Puerto Rico. METHODS: A secondary database analysis was performed on endometrial cancer cases reported to the Puerto Rico Central Cancer Registry-Health Insurance Linkage Database from 2009 to 2015 (n = 2,488). The study population's sociodemographic and clinical characteristics were described, along with an overview of the therapy options provided to patients receiving care on the island. Logistic regression models were used to evaluate the association of sociodemographic/clinical characteristics with treatment patterns stratified by risk of recurrence. RESULTS: In our cohort, most patients were insured through Medicaid and had a median age of 60 years. Almost 90% of patients received surgery as the first course of treatment. Surgery alone was the most common treatment for low-risk patients (80.2%). High-risk patients were more likely to receive surgery with radiotherapy and chemotherapy (24.4%). Patients with Medicare insurance were five times (HR: 4.84; 95% CI: 2.45-9.58; p < 0.001) more likely to receive surgery when compared with patients insured with Medicaid. In contrast, those with private insurance were twice as likely to receive surgery (HR: 2.38; 95% CI: 1.40-4.04; p = 0.001) when compared to those with Medicaid. CONCLUSION: These findings provide insight into the treatment patterns for endometrial cancer in Puerto Rico and highlight the importance of considering factors such as disease risk when making treatment decisions. Addressing these gaps in treatment patterns can contribute to effective management of endometrial cancer.

Treatment of endometrial cancer from 2000 to 2020 in Germany: a retrospective population based cohort study.

PURPOSE: Endometrial cancer (EC) is one of the most common malignancies among women in western countries. This study aimed to assess data on patient treatment in Germany throughout two decades to evaluate the development and effect of surgery, radiation, and chemotherapy. METHODS: This retrospective registry study included 34,349 EC patients diagnosed between 2000 and 2020. Patients were classified into five risk groups. Overall survival was analyzed by Kaplan-Meier method as well as univariable and multivariable Cox regression to evaluate risk factors and treatment options. RESULTS: Over the study period, minimal invasive surgery was used more often compared to open surgery and was associated with better overall survival. Patients with advanced EC were more likely to receive multimodal therapy. Patients with intermediate risk EC had a good prognosis upon surgery, which further improved when radiotherapy was added. High-risk patients showed poorer prognosis but clearly benefited from additional radiotherapy. Survival of elderly high-risk patients with a non-endometrioid histology was improved when chemotherapy was added to surgery and radiotherapy. CONCLUSION: Our study includes a large analysis of data from German clinical cancer registries on the care of endometrial cancer during two decades. We observed an increase of minimal invasive surgery. There is evidence that minimal invasive surgery is not inferior to open surgery. Adjuvant radio- and chemotherapy further improves survival depending on risk group and age.

Neuroendocrine carcinoma of the endometrium: a retrospective analysis of data from a single center.

BACKGROUND: Neuroendocrine carcinoma (NEC) originating from the endometrium is rare, and there is limited knowledge regarding its diagnosis and optimal management. In this study, we present our experience with 11 patients with endometrial NEC, aiming to provide guidance for clinical practice. METHODS: We retrospectively collected the clinical, pathological, and treatment data of 11 patients with endometrial NEC who were treated at the First Affiliated Hospital of Zhengzhou University from January 2011 to July 2023. The clinicopathological characteristics, treatment and prognosis of these patients were analyzed. RESULTS: The median age of the patients was 55.0 (39.0-64.0) years, and the median tumor size was 40.0 (33.0-60.0) mm. Irregular vaginal bleeding was the most common symptom observed in 10 out of 11 patients, while metabolic syndrome occurred in only 2 out of 11 patients. Six out of the 11 patients were diagnosed at an early stage. Among the patients, 6 were diagnosed with endometrial NECs, while the remaining patients had a combination of endometrial NEC and other non-NEC endometrial carcinomas. All patients underwent surgery, except for one who received only chemotherapy due to multiple metastases. After surgery, adjuvant chemotherapy was administered to 5 patients, chemotherapy combined with radiotherapy was given to 3 patients, and 2 patients did not receive any adjuvant therapy. A total of 10 patients completed the follow-up, with a median follow-up time of 51.0 (14.3-81.0) months. Unfortunately, 2 patients died from the disease. CONCLUSION: NECs originating from the endometrium might not be affected by metabolic disorders. Preoperative diagnosis of these tumors was challenging. The primary approach for managing endometrial NEC can be multimodal treatment centered around surgery.

Pregnancy and obstetric outcomes after fertility-sparing management of endometrial cancer and atypical hyperplasia: a multicentre cohort study.

STUDY QUESTION: What are the pregnancy and obstetric outcomes in women with atypical hyperplasia (AH) or early-stage endometrial cancer (EC) managed conservatively for fertility preservation? SUMMARY ANSWER: The study found a live birth rate of 62% in patients with AH or EC after conservative treatment, with higher level of labour induction, caesarean section, and post-partum haemorrhage. WHAT IS KNOWN ALREADY: Fertility-sparing treatment is a viable option for women with AH or EC during childbearing years, but the outcomes of such treatments, especially regarding pregnancy and obstetrics, need further exploration. STUDY DESIGN, SIZE, DURATION: This retrospective cohort study analysed data from January 2010 to October 2022, involving 269 patients from the French national register of patients with fertility-sparing management of AH/EC. PARTICIPANTS/MATERIALS, SETTING, METHODS: Women above 18 years of age, previously diagnosed with AH/EC, and approved for fertility preservation were included. Patients were excluded if they were registered before 2010, if their treatment began <6 months before the study, or if no medical record on the pregnancy was available. MAIN RESULTS AND THE ROLE OF CHANCE: In total, 95 pregnancies in 67 women were observed. Pregnancy was achieved using ART in 63 cases (66%) and the live birth rate was 62%, with early and late pregnancy loss at 26% and 5%, respectively. In the 59 cases resulting in a live birth, a full-term delivery occurred in 90% of cases; 36% of cases required labour induction and 39% of cases required a caesarean section. The most common maternal complications included gestational diabetes (17%) and post-partum haemorrhaging (20%). The average (±SD) birthweight was 3110 ± 736 g; there were no significant foetal malformations in the sample. No significant difference was found in pregnancy or obstetric outcomes between ART-obtained and spontaneous pregnancies. However, the incidence of induction of labour, caesarean section, and post-partum haemorrhage appears higher than in the general population. LIMITATIONS, REASONS FOR CAUTION: The retrospective nature of the study may introduce bias, and the sample size might be insufficient for assessing rare obstetric complications. WIDER IMPLICATIONS OF THE FINDINGS: This study offers valuable insights for healthcare providers to guide patients who received fertility-sparing treatments for AH/EC. These pregnancies can be successful and with an acceptable live birth rate, but they seem to be managed with caution, leading to possible tendency for more caesarean sections and labour inductions. No increase in adverse obstetric outcomes was observed, with the exception of suspicion of a higher risk of post-partum haemorrhaging, to be confirmed. STUDY FUNDING/COMPETING INTEREST(S): No funding was received for this study. There are no conflicts of interest to declare. TRIAL REGISTRATION NUMBER: N/A.

Diagnostic and therapeutic challenges in a recurrent endometrial carcinoma in lung, 15 years after primary treatment.

Endometrial carcinoma (EC) is the sixth most common cancer in females. Most ECs are detected in stage 1 and have a 5-year survival rate of more than 90%. Recurrence rates are highest within 5 years after treatment and are exceptionally rare after 10 years. Here, we describe a woman in her late 70s with endometrial cancer who was treated in 2008 and was diagnosed with a relapse in her left lung in 2023. Due to her advanced age and comorbidities, she was deemed inoperable. However, she received sequential chemotherapy and radiotherapy with a good partial response. She has now been started on hormonal therapy with an alternate megestrol and tamoxifen regime. There is a lack of follow-up imaging guidelines to detect late relapse, a dilemma in preferred treatment sequencing at relapse and an enigma in selecting chemotherapy or hormonal therapy.

Prognostic impact of metabolic syndrome in patients with primary endometrial cancer: a retrospective bicentric study.

PURPOSE: Endometrial cancer (EC) is the most common gynaecological cancer. Its incidence has been rising over the years with ageing and increased obesity of the high-income countries' populations. Metabolic syndrome (MetS) has been suggested to be associated with EC. The aim of this study was to assess whether MetS has a significant impact on oncological outcome in patients with EC. METHODS: This retrospective study included patients treated for EC between January 2010 and December 2020 in two referral oncological centers. Obesity, arterial hypertension (AH) and diabetes mellitus (DM) were criteria for the definition of MetS. The impact of MetS on progression free survival (PFS) and overall survival (OS) was assessed with log-rank test and Cox regression analyses. RESULTS: Among the 415 patients with a median age of 64, 38 (9.2%) fulfilled the criteria for MetS. The median follow-up time was 43 months. Patients suffering from MetS did not show any significant differences regarding PFS (36.0 vs. 40.0 months, HR: 1.49, 95% CI 0.79-2.80 P = 0.210) and OS (38.0 vs. 43.0 months, HR: 1.66, 95% CI 0.97-2.87, P = 0.063) compared to patients without MetS. Patients with obesity alone had a significantly shorter median PFS compared to patients without obesity (34.5 vs. 44.0 months, P = 0.029). AH and DM separately had no significant impact on PFS or OS (p > 0.05). CONCLUSION: In our analysis, MetS in patients with EC was not associated with impaired oncological outcome. However, our findings show that obesity itself is an important comorbidity associated with significantly reduced PFS.

Effect of low uterine segment involvement on prognosis of early stage endometrial cancer.

AIM: Our aim is to investigate the effect of uterine lower segment involvement on prognosis of early-stage endometrial cancer cases diagnosed and treated in our clinic. MATERIALS AND METHODS: The file records of 316 cases reviewed retrospectively.Only stage I (a and b, n=209) cases were investigated, because they were more homogeneous group. RESULTS: The lymphovascular invasion rate was found to be higher in patients with stage Ia and uterine lower segment involvement (p < 0.001). Adjuvant treatment requirement was higher in patients with stage Ia and uterine lower segment involvement (p < 0.001). Among stage Ia cases, the recurrence rate between 1 and 3 years was found to be higher in cases with uterine lower segment involvement (p = 0.001). Among the stage Ib cases, lymphovascular invasion was found to be higher in cases with uterine lower segment involvement (p < 0.001). The recurrence rate between 1 and 3 years was found to be higher in stage Ib compared to Ia (p = 0.01). Uterine lower segment involvement was found to be associated with high lymphovascular invasion rate in all stage I cases (p < 0.001). It was determined that the need for adjuvant treatment was higher in cases with uterine lower segment involvement (p < 0.001). It was determined that the probability of recurrence between 1 and 3 years was higher in cases with uterine lower segment involvement (p = 0.007). CONCLUSION: Uterine lower segment involvement is associated with increased lymphovascular invasion even in the early stages. It is an important risk factor for systemic spread such as lymphovascular invasion, myometrial invasion, and lymph node involvement.

Disease progression, survival, and molecular disparities in Black and White patients with endometrioid endometrial carcinoma in real-world registries and GOG/NRG oncology randomized phase III clinical trials.

OBJECTIVE: Investigate racial disparities in outcomes and molecular features in Black and White patients with endometrioid endometrial carcinoma (EEC). METHODS: Black and White patients diagnosed with EEC who underwent hysterectomy ± adjuvant treatment in SEER, National Cancer Database (NCDB), the Genomics Evidence Neoplasia Information Exchange (GENIE) project (v.13.0), and eight NCI-sponsored randomized phase III clinical trials (RCTs) were studied. Hazard ratio (HR) and 95% confidence interval (CI) were estimated for cancer-related death (CRD), non-cancer death (NCD), and all-cause death. RESULTS: Black (n = 4397) vs. White (n = 47,959) patients in SEER had a HR (95% CI) of 2.04 (1.87-2.23) for CRD and 1.22 (1.09-1.36) for NCD. In NCDB, the HR (95% CI) for death in Black (n = 13,468) vs. White (n = 155,706) patients was 1.52 (1.46-1.58) dropping to 1.29 (1.23-1.36) after propensity-score matching for age, comorbidity, income, insurance, grade, stage, LVSI, and treatment. In GENIE, Black (n = 109) vs. White (n = 1780) patients had fewer PTEN, PIK3R1, FBXW7, NF1, mTOR, CCND1, and PI3K-pathway-related gene mutations. In contrast, TP53 and DNA-repair-related gene mutation frequency as well as tumor mutational burden-high status were similar in Black and White patients. In RCTs, Black (n = 187) vs. White (n = 2877) patients were more likely to have advanced or recurrent disease, higher grade, worse performance status and progressive disease. Risk of death in Black vs. White patients in RCTs was 2.19 (1.77-2.71) persisting to 1.32 (1.09-1.61) after matching for grade, stage, and treatment arm while balancing age and performance status. CONCLUSIONS: Differences exist in clinical presentation, outcomes, and molecular features in Black vs. White patients with EEC in real-world registries and RCTs. Targeted-drug development, strategies to modify social determinants, and diverse inclusion in RCTs are approaches to reduce disparities.

Reproductive and Oncologic Outcomes in Young Women with Stage IA and Grade 2 Endometrial Carcinoma Undergoing Fertility-Sparing Treatment: A Systematic Review.

BACKGROUND: Endometrial cancer (EC) is the most common gynecological malignancy in both Europe and the USA. Approximately 3-5% of cases occur in women of reproductive age. Fertility-sparing treatment (FST) options are available, but very limited evidence regarding grade 2 (G2) ECs exists in the current literature. This systematic review aimed to comprehensively evaluate reproductive and oncologic outcomes among young women diagnosed with stage IA or G2EC disease who underwent FST. METHODS: A comprehensive search of the literature was carried out on the following databases: MEDLINE, EMBASE, Global Health, The Cochrane Library (Cochrane Database of Systematic Reviews, Cochrane Central Register of Controlled Trials, Cochrane Methodology Register), the Health Technology Assessment Database, and Web of Science. Only original studies that reported the oncologic and reproductive outcomes of patients with stage IA and G2EC tumors who underwent FST were considered eligible for inclusion in this systematic review (CRD42023484892). Studies describing only the FST for endometrial hyperplasia or G1 EC were excluded. RESULTS: Twenty-two papers that met the abovementioned inclusion criteria were included in the present systematic review. Preliminary analysis suggested encouraging oncologic and reproductive outcomes after FST. CONCLUSIONS: The FST approach may represent a feasible and safe option for women of childbearing age diagnosed with G2EC. Despite these promising findings, cautious interpretation is warranted due to inherent limitations, including heterogeneity in study designs and potential biases. Further research with standardized methodologies and larger sample sizes is imperative for obtaining more robust conclusions.

MicroRNA Expression in Endometrial Cancer: Current Knowledge and Therapeutic Implications.

Background and Objectives: An extracellular vesicle is part of a class of submicron particles derived from cells, mediating cellular crosstalk through microRNA (miRNA). MiRNA is a group of RNA molecules, each of which consists of 15-22 nucleotides and post-transcriptionally modulates gene expression. The complementary mRNAs-onto which the miRNAs hybridize-are involved in processes such as implantation, tumor suppression, proliferation, angiogenesis, and metastasis that define the entire tumor microenvironment. The endometrial biopsy is a standard technique used to recognize cellular atypia, but other non-invasive markers may reduce patient discomfort during the use of invasive methods. The present study aims to examine the distribution and the regulation of the differentially expressed miRNAs (DEMs) and EV-derived substances in women with endometrial cancer. Materials and Methods: We systematically searched the PubMed, EMBASE, Scopus, Cochrane Library, and ScienceDirect databases in April 2023, adopted the string "Endometrial Neoplasms AND Exosomes", and followed the recommendations in the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) statement. We selected all the studies that included patients with endometrial cancer and that described the regulation of miRNA molecules in that context. The differences in molecule expression between patients and controls were evaluated as significant when the proteins had a fold change of ±1.5. Results: Seventeen records fulfilled the inclusion criteria: a total of 371 patients and 273 controls were analyzed. The upregulated molecules that had the widest delta between endometrial cancer patients and controls-relative expression ≥ 1 > 3 log2(ratio)-were miR-20b-5p, miR-204-5p, miR-15a-5p, and miR-320a. In particular, miR-20b-5p and miR-204-5p were extracted from both serum and endometrial specimens, whereas miR-15a-5p was only isolated from plasma, and miR-320a was only extracted from the endometrial specimens. In parallel, the most downregulated miRNA in the endometrial cancer patients compared to the healthy subjects was miR-320a, which was found in the endometrial specimens. Conclusions: Although their epigenetic regulation remains unknown, these upregulated molecules derived from EVs are feasible markers for the early detection of endometrial cancer. The modulation of these miRNA molecules should be assessed during different treatments or if recurrence develops in response to a targeted treatment modality.

Lymph Node Isolated Tumor Cells in Patients With Endometrial Cancer.

Importance: Isolated tumor cells (ITCs) are the histopathological finding of small clusters of cancer cells no greater than 0.2 mm in diameter in the regional lymph nodes. For endometrial cancer, the prognostic significance of ITCs is uncertain. Objective: To assess clinico-pathological characteristics and oncologic outcomes associated with ITCs in endometrial cancer. Design, Setting, and Participants: This retrospective cohort study using the National Cancer Database included patients with endometrial cancer who had primary hysterectomy and nodal evaluation from 2018 to 2020. Patients with microscopic and macroscopic nodal metastases and distant metastases were excluded. Data were analyzed from June to September 2023. Exposure: Regional nodal status with ITCs (N0[i+] classification) or no nodal metastasis (N0 classification). Main Outcomes and Measures: (1) Clinical and tumor characteristics associated with ITCs, assessed with multivariable binary logistic regression model, and (2) overall survival (OS) associated with ITCs, evaluated by nonproportional hazard analysis with restricted mean survival time at 36 months. Results: A total of 56 527 patients were included, with a median (IQR) age of 64 (57-70) years. The majority had T1a lesion (37 836 [66.9%]) and grade 1 or 2 endometrioid tumors (40 589 [71.8%]). ITCs were seen in 1462 cases (2.6%). In a multivariable analysis, ITCs were associated with higher T classification, larger tumor size, lymphovascular space invasion (LVSI), and malignant peritoneal cytology. Of those tumor factors, LVSI had the largest association with ITCs (7.9% vs 1.4%; adjusted odds ratio [aOR], 4.37; 95% CI, 3.87-4.93), followed by T1b classification (5.3% vs 1.3%; aOR, 2.62; 95% CI, 2.30-2.99). At the cohort level, 24-month OS rates were 94.3% (95% CI, 92.4%-95.7%) for the ITC group and 96.1% (95% CI, 95.9%-96.3%) for the node-negative group, and the between-group difference in expected mean OS time at 36 months was 0.35 (SE, 0.19) months, but it was not statistically significant (P = .06). There was a statistically significant difference in OS when the low-risk group (stage IA, grade 1-2 endometrioid tumors with no LVSI) was assessed per nodal status and adjuvant therapy use (P < .001): (1) among the cases treated with surgical therapy alone, 24-month OS rates were 95.9% (95% CI, 89.5%-98.5%) for the ITC group and 98.8% (95% CI, 98.6%-99.0%) for the node-negative group, and the between-group mean OS time difference at 36 months was 0.61 (SE, 0.43) months (P = .16); and (2) among the cases with ITCs, adjuvant therapy (radiotherapy alone, systemic chemotherapy alone, or both) was associated with improved survival compared with no adjuvant therapy (24-month OS rates, 100% vs 95.9%; between-group mean OS time difference at 36 months, 0.95 [SE, 0.43] months; P = .03). Conclusions and Relevance: In this cohort study of patients with surgically staged endometrial cancer, the results of exploratory analysis suggested that presence of ITCs in the regional lymph node may be associated with OS in the low-risk group. While adjuvant therapy was associated with improved OS in the low-risk group with ITCs, careful interpretation is necessary given the favorable outcomes regardless of adjuvant therapy use. This hypothesis-generating observation in patients with low-risk endometrial cancer warrants further investigation, especially with prospective setting.