Mitogen-Activated Protein Kinase Inhibitor-Induced Inflammatory Alopecia in Woman With Ovarian Cancer.

Inflammatory alopecia is an increasingly reported side effect of targeted cancer therapies. Here we report one case of inflammatory alopecia secondary to mitogen-activated protein kinase kinase (MEK) inhibitor agent Trametinib in a woman with ovarian cancer. Biopsies of the scalp were consistent with early scarring alopecia compatible with drug-induced alopecia. Significant improvement in hair loss occurred after treatment with intralesional Kenalog (ILK) injections and oral isotretinoin. Though acute alopecia has been described in patients using MEK inhibitors, this is the first reported case of inflammatory alopecia.  J Drugs Dermatol. 2024;23(4):7802.     doi:10.36849/JDD.7802e  .

RETRACTED: Cost-effectiveness of chemotherapy and dostarlimab for advanced or recurrent endometrial cancer.

This article has been retracted: please see Elsevier Policy on Article Withdrawal (https://www.elsevier.com/about/policies/article-withdrawal). This article has been retracted at the request of the Authors. The authors have independently identified an error in the formula that was utilized to calculate the Quality Adjusted Life Years which invalidates the data and the conclusion of the paper. The authors have contacted the journal requesting to retract the article. Apologies are offered to the readers of the journal for any confusion or inconvenience that may have resulted from the publication of this article.

An SGO commentary: U.S. News and World Report gynecologic oncology procedural ratings-Do they reflect high-quality care?

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Learning to lead: The evolution of a pilot leadership curriculum for gynecologic oncology fellows at the Ohio State University.

•Leadership training is under-emphasized in traditional medical education.•An effective leadership curriculum must be dynamic and requires genuine investment from participants.•Through didactic education, self-reflection, and real-world perspective we can actively mold future leaders in gynecologic oncology.

Changes in prospectively collected patient-reported outcomes among women with incident endometrial cancer.

PURPOSE: We examined associations between patient and treatment characteristics with longitudinally collected patient-reported outcome (PRO) measures to provide a data-informed description of the experiences of women undergoing treatment for endometrial cancer. METHODS: We administered National Institutes of Health Patient Reported Outcomes Measurement Information System (PROMIS) questionnaires at the preoperative visit and at 6 and 12 months after surgery. Anxiety, depression, fatigue, sleep disturbance, pain, physical function, and ability to participate in social roles were assessed. Analysis of variance (ANOVA) and linear mixed models were used to examine associations between patient characteristics and PRO measures at baseline and through time. RESULTS: Of 187 women enrolled, 174 (93%) and 103 (69%) completed the 6- and 12-month questionnaires, respectively. Anxiety was substantially elevated at baseline (half of one population-level standard deviation) and returned to general population mean levels at 6 and 12 months. Younger age, Medicaid/None/Self-pay insurance, prevalent diabetes, and current smoking were associated with higher symptom burden on multiple PRO measures across the three time points. Women with aggressive histology, higher disease stage, or those with adjuvant treatment had worse fatigue at 6 months, which normalized by 12 months. CONCLUSIONS: We observed a high symptom burden at endometrial cancer diagnosis, with most PRO measures returning to general population means by 1 year. Information on risk factor-PRO associations can be used during the clinical visit to inform supportive service referral. IMPLICATIONS FOR CANCER SURVIVORS: These findings can inform clinicians' discussions with endometrial cancer survivors regarding expected symptom trajectory following diagnosis and treatment.

Does the choice of platinum doublet matter? A study to evaluate the impact of platinum doublet choice for treatment of platinum-sensitive ovarian cancer recurrence on the development of future PARP inhibitor and platinum resistance.

OBJECTIVES: The use of a platinum doublet for the treatment of platinum-sensitive epithelial ovarian cancer (EOC) recurrence is well established. The impact of the non­platinum chemotherapy used as part of a platinum doublet on PARP inhibitor (PARPi) and platinum sensitivity it not known. We aimed to describe oncologic outcomes in cases of recurrent EOC receiving PARPi as maintenance therapy based on preceding platinum doublet. METHODS: Retrospective study of patients with platinum-sensitive recurrent ovarian, fallopian tube or primary peritoneal cancer treated with platinum doublet followed by maintenance PARPi from 1/1/2015 and 1/1/2022. Comparisons were made between patients receiving carboplatin + pegylated liposomal doxorubicin (CD) versus other platinum doublets (OPDs). Descriptive statistics, Kaplan-Meier and univariate survival analyses were performed. RESULTS: 100 patients received PARPi maintenance following a platinum doublet chemotherapy regimen for platinum-sensitive recurrence. 25/100 (25%) received CD and 75/100 (75%) received OPDs. Comparing CD and OPDs, median progression-free survival was 8 versus 7 months (p = 0.26), median time to platinum resistance was 15 versus 13 months (p = 0.54), median OS was 64 versus 90 months (p = 0.28), and median OS from starting PARPi was 25 versus 26 months (p = 0.90), respectively. CONCLUSIONS: Using pegylated liposomal doxorubicin as part of a platinum doublet preceding maintenance PARPi for platinum-sensitive recurrence does not seem to hasten PARPi resistance or platinum resistance compared to OPDs. Although there was a non-significant trend towards increased OS among patients who received a platinum doublet other than CD prior to PARPi, the OS from PARPi start was similar between groups. Given the retrospective nature of this study and small study population, further research is needed to evaluate if the choice of platinum doublet preceding PARPi maintenance impacts PARPi resistance, platinum resistance and survival.

Characterization of mismatch-repair/microsatellite instability-discordant endometrial cancers.

BACKGROUND: Mismatch-repair (MMR)/microsatellite instability (MSI) status has therapeutic implications in endometrial cancer (EC). The authors evaluated the concordance of testing and factors contributing to MMR expression heterogeneity. METHODS: Six hundred sixty-six ECs were characterized using immunohistochemistry (IHC), MSI testing, and mut-L homolog 1 (MLH1) methylation. Select samples underwent whole-transcriptome analysis and next-generation sequencing. MMR expression of metastatic/recurrent sites was evaluated. RESULTS: MSI testing identified 27.3% of cases as MSI-high (n = 182), MMR IHC identified 25.1% cases as MMR-deficient (n = 167), and 3.8% of cases (n = 25) demonstrated discordant results. A review of IHC staining explained discordant results in 18 cases, revealing subclonal loss of MLH1/Pms 1 homolog 2 (PMS2) (n = 10) and heterogeneous MMR IHC (mut-S homolog 6 [MSH6], n = 7; MLH1/PMS2, n = 1). MSH6-associated Lynch syndrome was diagnosed in three of six cases with heterogeneous expression. Subclonal or heterogeneous cases had a 38.9% recurrence rate (compared with 16.7% in complete MMR-deficient cases and 9% in MMR-proficient cases) and had abnormal MMR IHC results in all metastatic recurrent sites (n = 7). Tumors with subclonal MLH1/PMS2 demonstrated 74 differentially expressed genes (determined using digital spatial transcriptomics) when stratified by MLH1 expression, including many associated with epithelial-mesenchymal transition. CONCLUSIONS: Subclonal/heterogeneous MMR IHC cases showed epigenetic loss in 66.7%, germline mutations in 16.7%, and somatic mutations in 16.7%. MMR IHC reported as intact/deficient missed 21% of cases of Lynch syndrome. EC with subclonal/heterogeneous MMR expression demonstrated a high recurrence rate, and metastatic/recurrent sites were MMR-deficient. Transcriptional analysis indicated an increased risk for migration/metastasis, suggesting that clonal MMR deficiency may be a driver for tumor aggressiveness. Reporting MMR IHC only as intact/deficient, without reporting subclonal and heterogeneous staining, misses opportunities for biomarker-directed therapy. PLAIN LANGUAGE SUMMARY: Endometrial cancer is the most common gynecologic cancer, and 20%-40% of tumors have a defect in DNA proofreading known as mismatch-repair (MMR) deficiency. These results can be used to guide therapy. Tests for this defect can yield differing results, revealing heterogeneous (mixed) proofreading capabilities. Tumors with discordant testing results and mixed MMR findings can have germline or somatic defects in MMR genes. Cells with deficient DNA proofreading in tumors with mixed MMR findings have DNA expression profiles linked to more aggressive characteristics and cancer spread. These MMR-deficient cells may drive tumor behavior and the risk of spreading cancer.

Deep learning-based segmentation of multisite disease in ovarian cancer.

PURPOSE: To determine if pelvic/ovarian and omental lesions of ovarian cancer can be reliably segmented on computed tomography (CT) using fully automated deep learning-based methods. METHODS: A deep learning model for the two most common disease sites of high-grade serous ovarian cancer lesions (pelvis/ovaries and omentum) was developed and compared against the well-established "no-new-Net" framework and unrevised trainee radiologist segmentations. A total of 451 CT scans collected from four different institutions were used for training (n = 276), evaluation (n = 104) and testing (n = 71) of the methods. The performance was evaluated using the Dice similarity coefficient (DSC) and compared using a Wilcoxon test. RESULTS: Our model outperformed no-new-Net for the pelvic/ovarian lesions in cross-validation, on the evaluation and test set by a significant margin (p values being 4 × 10-7, 3 × 10-4, 4 × 10-2, respectively), and for the omental lesions on the evaluation set (p = 1 × 10-3). Our model did not perform significantly differently in segmenting pelvic/ovarian lesions (p = 0.371) compared to a trainee radiologist. On an independent test set, the model achieved a DSC performance of 71 ± 20 (mean ± standard deviation) for pelvic/ovarian and 61 ± 24 for omental lesions. CONCLUSION: Automated ovarian cancer segmentation on CT scans using deep neural networks is feasible and achieves performance close to a trainee-level radiologist for pelvic/ovarian lesions. RELEVANCE STATEMENT: Automated segmentation of ovarian cancer may be used by clinicians for CT-based volumetric assessments and researchers for building complex analysis pipelines. KEY POINTS: • The first automated approach for pelvic/ovarian and omental ovarian cancer lesion segmentation on CT images has been presented. • Automated segmentation of ovarian cancer lesions can be comparable with manual segmentation of trainee radiologists. • Careful hyperparameter tuning can provide models significantly outperforming strong state-of-the-art baselines.

Delineating spatial cell-cell interactions in the solid tumour microenvironment through the lens of highly multiplexed imaging.

The growth and metastasis of solid tumours is known to be facilitated by the tumour microenvironment (TME), which is composed of a highly diverse collection of cell types that interact and communicate with one another extensively. Many of these interactions involve the immune cell population within the TME, referred to as the tumour immune microenvironment (TIME). These non-cell autonomous interactions exert substantial influence over cell behaviour and contribute to the reprogramming of immune and stromal cells into numerous pro-tumourigenic phenotypes. The study of some of these interactions, such as the PD-1/PD-L1 axis that induces CD8+ T cell exhaustion, has led to the development of breakthrough therapeutic advances. Yet many common analyses of the TME either do not retain the spatial data necessary to assess cell-cell interactions, or interrogate few (<10) markers, limiting the capacity for cell phenotyping. Recently developed digital pathology technologies, together with sophisticated bioimage analysis programs, now enable the high-resolution, highly-multiplexed analysis of diverse immune and stromal cell markers within the TME of clinical specimens. In this article, we review the tumour-promoting non-cell autonomous interactions in the TME and their impact on tumour behaviour. We additionally survey commonly used image analysis programs and highly-multiplexed spatial imaging technologies, and we discuss their relative advantages and limitations. The spatial organization of the TME varies enormously between patients, and so leveraging these technologies in future studies to further characterize how non-cell autonomous interactions impact tumour behaviour may inform the personalization of cancer treatment.​.

Intraluminal tumor cells and prognostic accuracy of endometrial cancer stage criteria: A multi-institution study.

OBJECTIVE: Endometrial cancer stage is a strong prognostic factor; however, the current stage classification does not incorporate transtubal spread as determined by intraluminal tumor cells (ILTCs). We examined relationships between ILTCs and survival outcomes according to histological subtype and stage and examined whether identification of ILTCs improves prognostic accuracy of endometrial cancer staging. METHODS: We conducted a retrospective cohort study of women diagnosed with endometrial cancer at five academic hospitals between 2007 and 2012. Pathologists determined ILTC presence (no vs. yes) and location (free in lumen vs. attached to epithelial surface) based on pathology review of hematoxylin and eosin-stained sections of fallopian tubes. Associations between ILTCs with time to recurrence (TTR) and overall survival (OS) were examined with Cox proportional hazards models adjusted for other prognostic factors. Model discrimination metrics were used to assess the addition of ILTCs to stage for prediction of 5-year TTR and OS. RESULTS: In the overall study population (N = 1303), ILTCs were not independently associated with TTR (HR = 0.95, 95% CI = 0.69-1.32) or OS (HR = 0.97, 95% CI = 0.72-1.31). Among 805 women with stage I disease, ILTCs were independently associated with worse TTR (HR = 2.31, 95% CI = 1.06-5.05) and OS (HR = 2.16, 95% CI = 1.14-4.11). Upstaging early-stage cases with ILTCs present did not increase model discrimination. CONCLUSION: While our data do not suggest that endometrial cancer staging guidelines should be revised to include ILTCs, associations between ILTCs and reduced survival observed among stage I cases suggest this tumor feature holds clinical relevance for subgroups of endometrial cancer patients.

The impact of antibiotic and proton pump inhibitor use at the time of adjuvant platinum-based chemotherapy on survival in patients with endometrial cancer.

OBJECTIVE: We sought to assess the impact of antibiotic (ABX) and proton-pump inhibitor (PPI) use on progression-free (PFS) and overall survival (OS) in patients treated with adjuvant platinum-based chemotherapy (PC) for endometrial cancer (EC). METHODS: A retrospective, single-institution cohort study of EC patients treated with ≥four cycles of adjuvant PC following surgical staging from 2014 to 2020. Demographics and clinicopathologic features, including ABX and PPI use, were compared using χ2 and Fisher's exact tests. Univariate and multivariable analyses were performed, and survival outcomes were compared using the log-rank test. RESULTS: Of 325 patients, 95 (29%) received ABX, and 80 (24.6%) received PPI. ABX were associated with decreased 3-year PFS (49.9% vs. 66%; p = 0.0237) but not 3-year OS (68.9% vs. 79.9%; p = 0.0649). ABX targeting gram-positive bacteria were associated with decreased 3-year PFS (21.2% vs. 66.0% vs. 55.4%; p = 0.0038) and 3-year OS (36.5% vs. 79.9% vs. 75.6%; p = 0.0014) compared to no ABX and other ABX, respectively. PPI use was associated with decreased 3-year PFS (46.9% vs. 66.0%; p = 0.0001) and 3-year OS (60.7% vs. 81.9%; p = 0.0041) compared to no PPI. On multivariable regression analysis controlling for confounders including stage, histology, grade, radiation, and co-morbidities, PPI use was independently associated with worse PFS (HR 1.96, 95% CI 1.25-3.08; p = 0.0041) and OS (HR 2.06, 95% CI 1.01-4.18, p = 0.04). CONCLUSION: In this retrospective cohort study, we demonstrate that PPI use is independently associated with worse PFS and OS in patients with EC treated with PC. ABX use was associated with worse PFS on univariate analysis only. There is an unmet need to understand how PPI, ABX, and, potentially, the microbiome impact the effectiveness of chemotherapy in EC patients.

Prevalence of type 2 diabetes diagnoses in the perioperative and survivorship periods following surgical management of endometrial cancer: An opportunity for screening and intervention?

OBJECTIVE: To determine the prevalence of Type 2 diabetes mellitus (T2DM) diagnoses during the peri-operative and survivorship periods in patients following surgical management of endometrial cancer (EC). METHODS: An IRB-approved, retrospective single-institution cohort study was performed in patients who underwent surgical management of EC from 2014 to 2020. The perioperative period was defined as the 30 days before and after surgery. T2DM diagnoses occurring during survivorship were recorded. T2DM diagnoses were defined by a HgbA1c ≥6.5% or a random blood glucose ≥200 mg/dL. Sequelae of peri-operative T2DM and predictors of future T2DM were examined utilizing univariate analysis. RESULTS: Of 519 patients meeting inclusion criteria, 37 (7.1%) were diagnosed with T2DM in the perioperative period. Patients diagnosed with T2DM in the perioperative period had significantly higher BMI (p = 0.006) compared to no T2DM, but there were no significant differences in age (p = 0.20), ethnicity/race (p > 0.05) or ECOG score (p = 0.19). The rates of intraoperative complications between groups did not significantly differ, except for vascular complications (p = 0.005), and the incidence of any postoperative complication was higher in the perioperative T2DM group (p = 0.01). With a median follow-up of 29 months [range 11.6-49.0 months], an additional 18.3% (n = 88) of the cohort met diagnostic criteria for T2DM. BMI (p < 0.001), perioperative glucose (p < 0.001), and HgbA1c (p = 0.002) demonstrate risk for a T2DM diagnosis during survivorship. CONCLUSION(S): In this retrospective cohort of EC patients, 25.4% were diagnosed with T2DM, with the majority diagnosed in the survivorship period. Surgical management and subsequent surveillance of EC presents an opportunity to diagnose at-risk patients with T2DM.

Assessment of the feasibility of same-day discharge following minimally invasive hysterectomy in the elderly population.

Objective: To determine the safety and feasibility of same-day discharge (SDD) following minimally invasive hysterectomy (MIH) for elderly patients and to evaluate associations between age, frailty, and postoperative outcomes. Methods: Retrospective review was conducted of patients aged ≥ 70 who underwent MIH within a single gynecologic oncology institution from 2018 to 2020. Demographics, peri-operative factors, postoperative complications, and 30-day readmission rates were collected. Frailty was determined by an 11-point modified frailty index ≥ 2. Outcomes were compared between SDD and observation groups using Fisher's exact and Wilcoxon rank-sum tests. Results: Of 169 patients included in the analysis, 8.9% (n = 15) underwent SDD, and 91.1% (n = 154) were admitted for OBS following MIH. Demographics, peri-operative factors, and frailty rates (33% SDD vs 43.5% observation; p = 0.59) were similar between groups. 86.7% (n = 13) of SDD cases were completed before 12PM, and none were completed after 6PM. No SDD patients had early post-operative complications or hospital readmissions. Early postoperative complications were diagnosed in 9 (5.8%) patients admitted for OBS, and the 30-day hospital readmission rate for patients who underwent OBS was 8.4% (n = 13). While elderly patients who met objective frailty criteria (n = 72) did not have a higher likelihood of early post-operative complications (44.4% vs 55.6%; p = 0.909), they did have a higher likelihood of ED visit within 30 days of discharge (15.3 vs 3.1%; p = 0.009), and a trend was noted toward a higher rate of 30-day hospital readmission (12.5% vs 4.1%; p = 0.080). Conclusions: Elderly patients undergoing SDD following MIH did not have increased morbidity or mortality. Elderly patients who meet objective criteria for frailty, however, represent a more vulnerable population.

Carboplatin dosing in the treatment of ovarian cancer: An NRG oncology group study.

OBJECTIVE: To determine the effects of using National Comprehensive Cancer Network (NCCN) guidelines to estimate renal function on carboplatin dosing and explore adverse effects associated with a more accurate estimation of lower creatinine clearance (CrCl). METHODS: Retrospective data were obtained for 3830 of 4312 patients treated on GOG182 (NCT00011986)-a phase III trial of platinum-based chemotherapy for advanced-stage ovarian cancer. Carboplatin dose per patient on GOG182 was determined using the Jelliffe formula. We recalculated CrCl to determine dosing using Modification of Diet in Renal Disease (MDRD) and Cockcroft-Gault (with/without NCCN recommended modifications) formulas. Associations between baseline CrCl and toxicity were described using the area under the receiver operating characteristic curve (AUC). Sensitivity and positive predictive values described the model's ability to discriminate between subjects with/without the adverse event. RESULTS: AUC statistics (range, 0.52-0.64) showed log(CrClJelliffe) was not a good predictor of grade ≥3 adverse events (anemia, thrombocytopenia, febrile neutropenia, auditory, renal, metabolic, neurologic). Of 3830 patients, 628 (16%) had CrCl <60 mL/min. Positive predictive values for adverse events ranged from 1.8%-15%. Using the Cockcroft-Gault, Cockcroft-Gault with NCCN modifications, and MDRD (instead of Jelliffe) formulas to estimate renal function resulted in a >10% decrease in carboplatin dosing in 16%, 32%, and 5.2% of patients, respectively, and a >10% increase in carboplatin dosing in 41%, 9.6% and 12% of patients, respectively. CONCLUSION: The formula used to estimate CrCl affects carboplatin dosing. Estimated CrCl <60 mL/min (by Jelliffe) did not accurately predict adverse events. Efforts continue to better predict renal function. Endorsing National Cancer Institute initiatives to broaden study eligibility, our data do not support a minimum threshold CrCl <60 mL/min as an exclusion criterion from clinical trials.

Tissue factor as a novel diagnostic target for early detection of ovarian cancer using ultrasound microbubbles.

INTRODUCTION: Ovarian cancer (OC) is the deadliest gynecologic malignancy, with an overall 5-year survival rate of less than 30%. The existing paradigm for OC detection involves a serum marker, CA125, and ultrasound examination, neither of which is sufficiently specific for OC. This study addresses this deficiency through the use of a targeted ultrasound microbubble directed against tissue factor (TF). METHODS: TF expression was examined in both OC cell lines and patient-derived tumor samples via western blotting and IHC. In vivo microbubble ultrasound imaging was analyzed using high grade serous ovarian carcinoma orthotopic mouse models. RESULTS: While TF expression has previously been described on angiogenic, tumor-associated vascular endothelial cells (VECs) of several tumor types, this is first study to show TF expression on both murine and patient-derived ovarian tumor-associated VECs. Biotinylated anti-TF antibody was conjugated to streptavidin-coated microbubbles and in vitro binding assays were performed to assess the binding efficacy of these agents. TF-targeted microbubbles successfully bound to TF-expressing OC cells, as well as an in vitro model of angiogenic endothelium. In vivo, these microbubbles bound to the tumor-associated VECs of a clinically relevant orthotopic OC mouse model. CONCLUSION: Development of a TF-targeted microbubble capable of successfully detecting ovarian tumor neovasculature could have significant implications towards increasing the number of early-stage OC diagnoses. This preclinical study shows potential for translation to clinical use, which could ultimately help increase the number of early OC detections and decrease the mortality associated with this disease.

The effect of older age on treatment outcomes in women with advanced ovarian cancer receiving chemotherapy: An NRG-Oncology/Gynecologic Oncology Group (GOG-0182-ICON5) ancillary study.

OBJECTIVE: To assess the effect of age on overall survival (OS) in women with ovarian cancer receiving chemotherapy. Secondary objectives were to describe the effect of age on treatment compliance, toxicities, progression free survival (PFS), time from surgery to chemotherapy, and rates of optimal cytoreduction. METHODS: Women enrolled in GOG 0182-ICON5 with stage III or IV epithelial ovarian cancer (EOC) who underwent surgery and chemotherapy between 2001 and 2004 were included. Patients were divided into ages <70 and ≥ 70 years. Baseline characteristics, treatment compliance, toxicities, and clinical outcomes were compared. RESULTS: We included a total of 3686 patients, with 620 patients (16.8%) ≥ 70 years. OS was 37.2 months in older compared to 45.0 months in younger patients (HR 1.21, 95% CI, 1.09-1.34, p < 0.001). Older patients had an increased risk of cancer-specific-death (HR 1.16, 95% CI, 1.04-1.29) as well as non-cancer related deaths (HR 2.78, 95% CI, 2.00-3.87). Median PFS was 15.1 months in older compared to 16.0 months in younger patients (HR 1.10, 95% CI, 1.00-1.20, p = 0.056). In the carboplatin/paclitaxel arm, older patients were just as likely to complete therapy and more likely to develop grade ≥ 2 peripheral neuropathy (35.7 vs 19.7%, p < 0.001). Risk of other toxicities remained equal between groups. CONCLUSIONS: In women with advanced EOC receiving chemotherapy, age ≥ 70 was associated with shorter OS and cancer specific survival. Older patients receiving carboplatin and paclitaxel reported higher rates of grade ≥ 2 neuropathy but were not more likely to suffer from other chemotherapy related toxicities. Clintrials.gov: NCT00011986.

Epigenetic MMR defect identifies a risk group not accounted for through traditional risk stratification algorithms in endometrial cancer.

Purpose: We sought to evaluate the contribution of mismatch repair (MMR) status to traditional risk stratification algorithms used to predict nodal involvement and recurrence in a large single-institution cohort. Methods: Endometrioid endometrial cancer (EC) cases from 2014-2020 were evaluated. MMR immunohistochemistry (IHC) was performed universally. Uterine factors assessed in the Mayo criteria were used to retrospectively classify patients as low or high risk for lymphatic spread. Patients were classified according to risk for recurrence using GOG 99 and PORTEC criteria. Associations were evaluated using chi-square and t-tests and contributing factors assessed using logistic regression models. Results: 1,514 endometrioid EC were evaluated; 392 (25.9%) were MMR (MMR) deficient of which 80.4% of MMR defects were associated with epigenetic silencing of MLH1. Epigenetic MMR defects were significantly more likely to be high risk for lymph node (LN) metastasis based on Mayo criteria (74.9% vs 60.6%, p=<0.001) and with the presence of LN metastasis (20.3 vs 10.5%, p=0.003) compared to MMR proficient tumors. Tumors with epigenetic MMR defects were significantly more likely to be classified as high or high intermediate risk using GOG99 and PORTEC criteria. Furthermore, cases with epigenetic MMR defects classified as low or low intermediate risk were significantly more likely to recur (GOG99 p=0.013; PORTEC p=0.008) and independently associated with worse disease-free survival (DFS). MMR status was found to be independently associated with worse DFS (HR 1.90; 95% CI 1.34-2.70; p=0.003) but not overall survival. Conclusion: While MMR deficient EC has been associated with poor prognostic features in prior reports; we demonstrate that only epigenetic MMR defects have poorer outcomes. Epigenetic MMR defect were independently associated with lymph node metastasis after controlling for risk criteria. Epigenetic MMR deficiency was found to be an independent predictor of recurrence beyond the factors considered in traditional risk stratification algorithms. Traditional uterine-based risk stratification algorithms may not fully reflect the risk for recurrence in MMR deficient tumors. Consideration should be given to implementing MMR status and MLH1 hypermethylation alongside traditional risk stratification algorithms. Performing MMR IHC on preoperative pathologic specimens may aid in risk stratification and patient counseling.