HIV-1-infected T cell clones are shared across cerebrospinal fluid and blood during ART.

The central nervous system HIV reservoir is incompletely understood and is a major barrier to HIV cure. We profiled people with HIV (PWH) and uninfected controls through single-cell transcriptomic and T cell receptor (TCR) sequencing to understand the dynamics of HIV persistence in the CNS. In PWH on ART, we found that most participants had single cells containing HIV-1 RNA, which was found predominantly in CD4 central memory T cells, in both cerebrospinal fluid (CSF) and blood. HIV-1 RNA-containing cells were found more frequently in CSF than blood, indicating a higher burden of reservoir cells in the CNS than blood for some PWH. Most CD4 T cell clones containing infected cells were compartment specific, while some (22%) - including rare clones with members of the clone containing detectable HIV RNA in both blood and CSF - were found in both CSF and blood. These results suggest that infected T cells trafficked between tissue compartments and that maintenance and expansion of infected T cell clones contributed to the CNS reservoir in PWH on ART.

Neurosyphilis is characterized by a compartmentalized and robust neuroimmune response but not by neuronal injury.

BACKGROUND: Neurosyphilis is increasing in prevalence but its pathophysiology remains incompletely understood. This study assessed for CNS-specific immune responses during neurosyphilis compared to syphilis without neurosyphilis and compared these immune profiles to those observed in other neuroinflammatory diseases. METHODS: Participants with syphilis were categorized as having neurosyphilis if their cerebrospinal fluid (CSF)-venereal disease research laboratory (VDRL) test was reactive and as having syphilis without neurosyphilis if they had a non-reactive CSF-VDRL test and a white blood cell count <5/µL. Neurosyphilis and syphilis without neurosyphilis participants were matched by rapid plasma reagin titer and HIV status. CSF and plasma were assayed for markers of neuronal injury and glial and immune cell activation. Bulk RNA sequencing was performed on CSF cells, with results stratified by the presence of neurological symptoms. FINDINGS: CSF neopterin and five CSF chemokines had levels significantly higher in individuals with neurosyphilis compared to those with syphilis without neurosyphilis, but no markers of neuronal injury or astrocyte activation were significantly elevated. The CSF transcriptome in neurosyphilis was characterized by genes involved in microglial activation and lipid metabolism and did not differ in asymptomatic versus symptomatic neurosyphilis cases. CONCLUSIONS: The CNS immune response observed in neurosyphilis was comparable to other neuroinflammatory diseases and was present in individuals with neurosyphilis regardless of neurological symptoms, yet there was minimal evidence for neuronal or astrocyte injury. These findings support the need for larger studies of the CSF inflammatory response in asymptomatic neurosyphilis. FUNDING: This work was funded by the National Institutes of Health, grants K23MH118999 (S.F.F.) and R01NS082120 (C.M.M.).

Longitudinal single-cell transcriptional dynamics throughout neurodegeneration in SCA1.

Neurodegeneration is a protracted process involving progressive changes in myriad cell types that ultimately results in the death of vulnerable neuronal populations. To dissect how individual cell types within a heterogeneous tissue contribute to the pathogenesis and progression of a neurodegenerative disorder, we performed longitudinal single-nucleus RNA sequencing of mouse and human spinocerebellar ataxia type 1 (SCA1) cerebellar tissue, establishing continuous dynamic trajectories of each cell population. Importantly, we defined the precise transcriptional changes that precede loss of Purkinje cells and, for the first time, identified robust early transcriptional dysregulation in unipolar brush cells and oligodendroglia. Finally, we applied a deep learning method to predict disease state accurately and identified specific features that enable accurate distinction of wild-type and SCA1 cells. Together, this work reveals new roles for diverse cerebellar cell types in SCA1 and provides a generalizable analysis framework for studying neurodegeneration.

Self-Reported Neuropsychiatric Post-COVID-19 Condition and CSF Markers of Neuroinflammation.

This case-control study assesses cerebrospinal fluid markers of neuroinflammation and blood-brain barrier disruption in individuals with post­COVID-19 condition who reported neuropsychiatric symptoms.

Reduction of nemo-like kinase increases lysosome biogenesis and ameliorates TDP-43-related neurodegeneration.

Protein aggregation is a hallmark of many neurodegenerative disorders, including amyotrophic lateral sclerosis (ALS). Although mutations in TARDBP, encoding transactive response DNA-binding protein 43 kDa (TDP-43), account for less than 1% of all ALS cases, TDP-43-positive aggregates are present in nearly all ALS patients, including patients with sporadic ALS (sALS) or carrying other familial ALS-causing (fALS-causing) mutations. Interestingly, TDP-43 inclusions are also present in subsets of patients with frontotemporal dementia, Alzheimer's disease, and Parkinson's disease; therefore, methods of activating intracellular protein quality control machinery capable of clearing toxic cytoplasmic TDP-43 species may alleviate disease-related phenotypes. Here, we identify a function of nemo-like kinase (Nlk) as a negative regulator of lysosome biogenesis. Genetic or pharmacological reduction of Nlk increased lysosome formation and improved clearance of aggregated TDP-43. Furthermore, Nlk reduction ameliorated pathological, behavioral, and life span deficits in 2 distinct mouse models of TDP-43 proteinopathy. Because many toxic proteins can be cleared through the autophagy/lysosome pathway, targeted reduction of Nlk represents a potential approach to therapy development for multiple neurodegenerative disorders.

A Complex Diagnosis of Ampullary Adenocarcinoma Presenting As Decompensated Cirrhosis.

Neoplasms arising from the ampulla of Vater are exceedingly rare, and there is a paucity of literature regarding their diagnosis and management. Ampullary cancer typically presents with jaundice and signs of biliary obstruction. We present a case of ampullary adenocarcinoma with concomitant choledocholithiasis that proved complex and diagnostically challenging.

A Phase 3b Study for Management of Ocular Side Effects in Patients with Epidermal Growth Factor Receptor-Amplified Glioblastoma Receiving Depatuxizumab Mafodotin.

INTRODUCTION: The Understanding New Interventions with GBM ThErapy (UNITE) study was designed to assess the effect of prophylaxis for ocular side effects (OSEs) in patients with glioblastoma receiving the antibody-drug conjugate (ADC) depatuxizumab mafodotin. UNITE (NCT03419403) was a phase 3b, open-label, randomized, exploratory study performed at 18 research sites in 5 countries. METHODS: The study enrolled adult patients with epidermal growth factor receptor-amplified, histologically confirmed, newly diagnosed supratentorial glioblastoma or grade IV gliosarcoma, and a Karnofsky Performance Status ≥70, receiving depatuxizumab mafodotin. All patients were administered depatuxizumab mafodotin during concurrent radiotherapy and temozolomide and with adjuvant temozolomide. Ninety patients were to be randomized (1:1:1) to OSE prophylactic treatments with each depatuxizumab mafodotin infusion: (a) standard steroid eye drops, (b) standard steroid eye drops plus vasoconstrictor eye drops and cold compress, or (c) enhanced steroids plus vasoconstrictor eye drops and cold compress. A Corneal Epitheliopathy Adverse Event (CEAE) scale was devised to capture symptoms, grade OSEs (scale of 0-5), and inform ADC dose modifications. The primary endpoint was the frequency of a required change in OSE management due to inadequate control of OSEs, defined as decline from baseline in visual acuity (using logarithm of the minimum angle of resolution [LogMAR] scale) or a Grade ≥3 CEAE event, in the worst eye in the first 8 weeks of treatment; unless otherwise specified, the treatment period refers to both the chemoradiation and adjuvant phases. RESULTS: The UNITE study was stopped early after interim analysis of separate phase III trial showed no difference in survival from depatuxizumab mafodotin. Forty patients were randomized (38 received depatuxizumab mafodotin). Overall, 23 patients experienced inadequate control of OSEs that required change in OSE management within 8 weeks of treatment, with 21 (70.0%) experiencing ≥+0.3 change on LogMAR scale in baseline-adjusted visual acuity and 12 reporting a grade ≥3 CEAE. There were no definitive differences among prophylactic treatments. CONCLUSIONS: The premature cessation of the study precludes definitive conclusions regarding the OSE prophylaxis strategies. No new clinically significant safety findings were noted. Despite these limitations, this study highlights the need for novel assessment tools to better understand and mitigate OSEs associated with ADCs.

Toxicity Profiles and Survival Outcomes Among Patients With Nonmetastatic Oropharyngeal Carcinoma Treated With Intensity-Modulated Proton Therapy vs Intensity-Modulated Radiation Therapy.

Importance: Patients with oropharyngeal carcinoma (OPC) treated with radiotherapy often experience substantial toxic effects, even with modern techniques such as intensity-modulated radiation therapy (IMRT). Intensity-modulated proton therapy (IMPT) has a potential advantage over IMRT due to reduced dose to the surrounding organs at risk; however, data are scarce given the limited availability and use of IMPT. Objective: To compare toxic effects and oncologic outcomes among patients with newly diagnosed nonmetastatic OPC treated with IMPT vs IMRT with or without chemotherapy. Design, Setting, and Participants: This retrospective cohort study included patients aged 18 years or older with newly diagnosed nonmetastatic OPC who received curative-intent radiotherapy with IMPT or IMRT at a single-institution tertiary academic cancer center from January 1, 2018, to December 31, 2021, with follow-up through December 31, 2021. Exposures: IMPT or IMRT with or without chemotherapy. Main Outcomes and Measures: The main outcomes were the incidence of acute and chronic (present after ≥6 months) treatment-related adverse events (AEs) and oncologic outcomes, including locoregional recurrence (LRR), progression-free survival (PFS), and overall survival (OS). Fisher exact tests and χ2 tests were used to evaluate associations between toxic effects and treatment modality (IMPT vs IMRT), and the Kaplan-Meier method was used to compare LRR, PFS, and OS between the 2 groups. Results: The study included 292 patients with OPC (272 [93%] with human papillomavirus [HPV]-p16-positive tumors); 254 (87%) were men, 38 (13%) were women, and the median age was 64 years (IQR, 58-71 years). Fifty-eight patients (20%) were treated with IMPT, and 234 (80%) were treated with IMRT. Median follow-up was 26 months (IQR, 17-36 months). Most patients (283 [97%]) received a dose to the primary tumor of 70 Gy. Fifty-seven of the patients treated with IMPT (98%) and 215 of those treated with IMRT (92%) had HPV-p16-positive disease. There were no significant differences in 3-year OS (97% IMPT vs 91% IMRT; P = .18), PFS (82% IMPT vs 85% IMRT; P = .62), or LRR (5% IMPT vs 4% IMRT; P = .59). The incidence of acute toxic effects was significantly higher for IMRT compared with IMPT for oral pain of grade 2 or greater (42 [72%] IMPT vs 217 [93%] IMRT; P < .001), xerostomia of grade 2 or greater (12 [21%] IMPT vs 68 [29%] IMRT; P < .001), dysgeusia of grade 2 or greater (16 [28%] IMPT vs 134 [57%] IMRT; P < .001), grade 3 dysphagia (4 [7%] IMPT vs 29 [12%] IMRT; P < .001), mucositis of grade 3 or greater (10 [53%] IMPT vs 13 [70%] IMRT; P = .003), nausea of grade 2 or greater (0 [0%] IMPT vs 18 [8%] IMRT; P = .04), and weight loss of grade 2 or greater (22 [37%] IMPT vs 138 [59%] IMRT; P < .001). There were no significant differences in chronic toxic effects of grade 3 or greater, although there was a significant difference for chronic xerostomia of grade 2 or greater (6 IMPT [11%] vs 22 IMRT [10%]; P < .001). Four patients receiving IMRT (2%) vs 0 receiving IMPT had a percutaneous endoscopic gastrostomy tube for longer than 6 months. Conclusions and Relevance: In this study, curative-intent radiotherapy with IMPT for nonmetastatic OPC was associated with a significantly reduced acute toxicity burden compared with IMRT, with few chronic toxic effects and favorable oncologic outcomes, including locoregional recurrence of only 5% at 2 years. Prospective randomized clinical trials comparing these 2 technologies and of patient-reported outcomes are warranted.

NMR-guided directed evolution.

Directed evolution is a powerful tool for improving existing properties and imparting completely new functionalities to proteins1-4. Nonetheless, its potential in even small proteins is inherently limited by the astronomical number of possible amino acid sequences. Sampling the complete sequence space of a 100-residue protein would require testing of 20100 combinations, which is beyond any existing experimental approach. In practice, selective modification of relatively few residues is sufficient for efficient improvement, functional enhancement and repurposing of existing proteins5. Moreover, computational methods have been developed to predict the locations and, in certain cases, identities of potentially productive mutations6-9. Importantly, all current approaches for prediction of hot spots and productive mutations rely heavily on structural information and/or bioinformatics, which is not always available for proteins of interest. Moreover, they offer a limited ability to identify beneficial mutations far from the active site, even though such changes may markedly improve the catalytic properties of an enzyme10. Machine learning methods have recently showed promise in predicting productive mutations11, but they frequently require large, high-quality training datasets, which are difficult to obtain in directed evolution experiments. Here we show that mutagenic hot spots in enzymes can be identified using NMR spectroscopy. In a proof-of-concept study, we converted myoglobin, a non-enzymatic oxygen storage protein, into a highly efficient Kemp eliminase using only three mutations. The observed levels of catalytic efficiency exceed those of proteins designed using current approaches and are similar with those of natural enzymes for the reactions that they are evolved to catalyse. Given the simplicity of this experimental approach, which requires no a priori structural or bioinformatic knowledge, we expect it to be widely applicable and to enable the full potential of directed enzyme evolution.

Variability of the Surface Area of the V1, V2, and V3 Maps in a Large Sample of Human Observers.

How variable is the functionally defined structure of early visual areas in human cortex and how much variability is shared between twins? Here we quantify individual differences in the best understood functionally defined regions of cortex: V1, V2, V3. The Human Connectome Project 7T Retinotopy Dataset includes retinotopic measurements from 181 subjects (109 female, 72 male), including many twins. We trained four "anatomists" to manually define V1-V3 using retinotopic features. These definitions were more accurate than automated anatomical templates and showed that surface areas for these maps varied more than threefold across individuals. This threefold variation was little changed when normalizing visual area size by the surface area of the entire cerebral cortex. In addition to varying in size, we find that visual areas vary in how they sample the visual field. Specifically, the cortical magnification function differed substantially among individuals, with the relative amount of cortex devoted to central vision varying by more than a factor of 2. To complement the variability analysis, we examined the similarity of visual area size and structure across twins. Whereas the twin sample sizes are too small to make precise heritability estimates (50 monozygotic pairs, 34 dizygotic pairs), they nonetheless reveal high correlations, consistent with strong effects of the combination of shared genes and environment on visual area size. Collectively, these results provide the most comprehensive account of individual variability in visual area structure to date, and provide a robust population benchmark against which new individuals and developmental and clinical populations can be compared.SIGNIFICANCE STATEMENT Areas V1, V2, and V3 are among the best studied functionally defined regions in human cortex. Using the largest retinotopy dataset to date, we characterized the variability of these regions across individuals and the similarity between twin pairs. We find that the size of visual areas varies dramatically (up to 3.5×) across healthy young adults, far more than the variability of the cerebral cortex size as a whole. Much of this variability appears to arise from inherited factors, as we find very high correlations in visual area size between monozygotic twin pairs, and lower but still substantial correlations between dizygotic twin pairs. These results provide the most comprehensive assessment of how functionally defined visual cortex varies across the population to date.

Outcomes and Toxicities of Nonmedullary Thyroid Tumors Treated with Proton Beam Radiation Therapy.

Purpose: Proton therapy is an emerging therapy for several malignancies owing to its favorable therapeutic ratio. There are very limited data on the use of proton therapy in the management of thyroid carcinoma. Our objective was to review the safety, feasibility, and outcomes of proton therapy for patients with thyroid cancer treated to the head and neck. Methods: From our institution's proton database from 2012 to 2021, we identified 22 patients with thyroid cancer treated with proton beam therapy. We evaluated outcomes and toxicities. Results: Median follow-up was 26 months. Of the 22 patients, 50% were female. The mean age was 65 years. Three patients had anaplastic cancer; 13, papillary carcinoma; 2, follicular carcinoma; and 2, poorly differentiated carcinoma. Forty-six percent had T4 disease. Primary targets were the central neck compartment, level VI, and upper mediastinum. Radiation dose was 60 GyRBE adjuvantly, and 70 GyRBE for gross disease (range, 6000-7600 GyRBE). Eight patients underwent upfront adjuvant radiation, and 3 received definitive radiation for unresectable disease upfront. Eleven patients received either salvage or palliative radiation. Fifty-nine percent of patients had extrathyroidal extension, and 64% of patients had gross disease in the neck before treatment. Fifty percent of patients had metastatic disease before treatment. Sixteen patients received concurrent chemotherapy, 63% of these patients received doxorubicin. For all patients, 1-year local regional recurrence (LRR) was 0%, and overall survival (OS) was 90%. Acute grade 3+ toxicities occurred in 27% of patients, the most frequent being dermatitis (27%). Three patients required a percutaneous endoscopic gastrostomy tube after radiation therapy (RT), 2 owing to progression. There were no grade 4+ toxicities. Conclusions: Proton therapy for thyroid cancer appears feasible and effective with minimal toxicities. Prospective studies comparing proton therapy with intensity-modulated RT, to evaluate the clinical efficacy of using proton therapy to reduce toxicities in patients undergoing radiation for thyroid cancer, are warranted.

Borrelia miyamotoi Meningoencephalitis in an Immunocompetent Patient.

Borrelia miyamotoi is an underdiagnosed cause of tick-borne illness in endemic regions and, in rare cases, causes neurological disease in immunocompetent patients. Here, we present a case of serologically confirmed Borrelia miyamotoi meningoencephalitis in an otherwise healthy patient who rapidly improved following initiation of antibiotic therapy.

IgG4-Related Hepatic Pseudotumor Masquerading as a Klatskin Tumor.

Immunoglobulin G subclass 4 (IgG-4)-related disease (IgG4-RD) is an uncommon immune-mediated, fibro-inflammatory disease which has garnered recognition as a systemic condition. One manifestation of the disease in the hepatobiliary system is the development of hepatic inflammatory pseudotumors. These benign tumors are often misdiagnosed as malignant tumors and undergo unnecessary hepatic resections. We present a case of IgG4-related hepatic inflammatory pseudotumor (IPT) mimicking a Klatskin tumor. A high degree of clinical suspicion and extensive workup is imperative in reaching the correct diagnosis. IgG4-related inflammatory pseudotumor is a rare entity, but an important consideration in evaluating hepatic tumors.

HIV viral transcription and immune perturbations in the CNS of people with HIV despite ART.

People with HIV (PWH) on antiretroviral therapy (ART) experience elevated rates of neurological impairment, despite controlling for demographic factors and comorbidities, suggesting viral or neuroimmune etiologies for these deficits. Here, we apply multimodal and cross-compartmental single-cell analyses of paired cerebrospinal fluid (CSF) and peripheral blood in PWH and uninfected controls. We demonstrate that a subset of central memory CD4+ T cells in the CSF produced HIV-1 RNA, despite apparent systemic viral suppression, and that HIV-1-infected cells were more frequently found in the CSF than in the blood. Using cellular indexing of transcriptomes and epitopes by sequencing (CITE-seq), we show that the cell surface marker CD204 is a reliable marker for rare microglia-like cells in the CSF, which have been implicated in HIV neuropathogenesis, but which we did not find to contain HIV transcripts. Through a feature selection method for supervised deep learning of single-cell transcriptomes, we find that abnormal CD8+ T cell activation, rather than CD4+ T cell abnormalities, predominated in the CSF of PWH compared with controls. Overall, these findings suggest ongoing CNS viral persistence and compartmentalized CNS neuroimmune effects of HIV infection during ART and demonstrate the power of single-cell studies of CSF to better understand the CNS reservoir during HIV infection.

Does the Use of BioZorb® Result in Smaller Breast Seroma Volume?

AIM: To evaluate the impact of BioZorb®, a 3D-bioabsorbable marker, on the tumor-bed boost volume and dosimetric parameters in adaptive boost planning for breast cancer. PATIENTS AND METHODS: Records were reviewed for 51 breast-cancer patients who underwent breast-conserving surgery and adjuvant whole-breast irradiation between January 2017 and October 2018. Changes in lumpectomy boost volume (LBV), doses to organs at risk, toxicity and cosmesis were compared between patients with and without BioZorb® Chi-square test and paired and independent t-tests were used for comparisons of variables. RESULTS: Median follow-up was 35.5 months. Mean LBV on initial CT (LBV1; 32.2 vs. 33.8 cc, p=0.74) and on boost computed tomography (CT) (LBV2; 25.3 vs. 24.8 cc, p=0.87) were similar with and without BioZorb® The mean decrease from LBV1 to LBV2 was 9.0 cc and 6.8 cc with and without BioZorb®, respectively (p=0.42). LBV1 was significantly positively correlated with a 20% reduction in LBV (p=0.02). Mean heart and lung doses on adaptive boost planning CT were slightly lower compared to initial planning CT in both groups. Acute breast pain was reported in 18/51 patients, 9 of whom had BioZorb® (p=0.24). Grade-2 pain was reported in 5/51 patients, 3 of whom had BioZorb® (p=0.11). Excellent or good cosmesis was reported in 36/41 patients. Fair cosmesis was reported in 5/41 patients, of whom 2 had BioZorb® (p=0.64). CONCLUSION: BioZorb® placement does not impact the tumor-bed boost volume nor the variation of seroma volume within the period of treatment. More data and longer follow-up are needed to identify a measurable clinical impact of BioZorb® placement.

A Novel Treatment of Postpartum Depression and Review of Literature.

Early-onset postpartum depression has been shown to have a unique neurobiological basis compared to major depressive disorder, implying a need for targeted treatments such as the recent Food and Drug Administration (FDA)-approved brexanolone. In this case report, a woman with a past medical history of major depressive disorder was diagnosed with postpartum depression due to worsening mood with suicidal and homicidal ideations. She was treated with vilazodone and aripiprazole with good effect after consideration of her past medication trials. Her regimen is unique in clinical practice and not reported in current literature for the treatment of postpartum depression. It may represent a safe and effective medication choice, especially in the context of current first-line treatments that have a high treatment failure rate. More research is needed to find treatments that address the unique challenges of postpartum women.

Peptide hydrogel with self-healing and redox-responsive properties.

We have rationally designed a peptide that assembles into a redox-responsive, antimicrobial metallohydrogel. The resulting self-healing material can be rapidly reduced by ascorbate under physiological conditions and demonstrates a remarkable 160-fold change in hydrogel stiffness upon reduction. We provide a computational model of the hydrogel, explaining why position of nitrogen in non-natural amino acid pyridyl-alanine results in drastically different gelation properties of peptides with metal ions. Given its antimicrobial and rheological properties, the newly designed hydrogel can be used for removable wound dressing application, addressing a major unmet need in clinical care.

Colonic adenocarcinoma with synchronous metastasis to the pancreas: A case report and literature review.

Metastatic lesions to the pancreas are a rare entity and make up about 0.5-5% of all pancreatic malignancies. Synchronous pancreatic metastasis is even less frequently reported. Before the widespread use of advanced endoscopic techniques, distinguishing between primary and secondary malignancies of the pancreas was diagnostically challenging. The accuracy of diagnosing metastatic lesions to the pancreas using endoscopic ultrasound with fine needle aspiration is around 91%. Distinguishing between primary and secondary lesions is crucial in determining disease management. We present a case of a young man who presented with synchronous pancreatic metastasis from colon adenocarcinoma.

Case Study: The Impact of Nursing Professional Practice during the COVID-19 Pandemic at a Large Community Hospital in Canada.

The COVID-19 pandemic posed numerous challenges experienced by healthcare organizations. Nursing professional practice plays a crucial leadership role in supporting nursing staff and leaders in developing policies, parameters and philosophical approaches for delivering safe patient care. The professional practice leadership at Humber River Hospital, a large Canadian community hospital, implemented three key interventions in this hospital-based case study: (1) proactive workforce planning, (2) increased nursing student placements and (3) novel "stretch model of care" in the intensive care unit (ICU). The overall results following the implementation of these interventions resulted in substantial improvements. For example, proactive nursing workforce planning supported both a 98% reduction in agency utilization and an accelerated ICU certification program with an 84% certificate completion rate. Through innovative strategies, there was a significant increase (33-67%) in the number of nursing student placements during the first two years of the pandemic compared with previous years. Within the ICU setting, we maintained optimum ICU capacity that resulted in stronger partnership-driven relationships between nurses and physicians through an interprofessional "stretch model of care." Finally, we avoided emergency department closures and Code Orange calls during peaks of the pandemic.

Does Prophylactic Paraortic Lymph Node Irradiation Improve Outcomes in Women With Stage IIIC1 Endometrial Carcinoma?

PURPOSE: To evaluate the impact of prophylactic paraortic lymph node (PALN) radiation therapy (RT) on clinical outcomes in patients with International Federation of Obstetrics and Gynecology 2018 stage IIIC1 endometrial cancer (EC). METHODS AND MATERIALS: A multi-institutional retrospective study included patients with International Federation of Obstetrics and Gynecology 2018 stage IIIC1 EC lymph node assessment, status postsurgical staging, followed by adjuvant chemotherapy and RT using various sequencing regimens. Overall survival (OS) and recurrence-free survival (RFS) rates were estimated by the Kaplan-Meier method. Univariable and multivariable analysis were performed by Cox proportional hazard models for RFS/OS. In addition, propensity score matching was used to estimate the effect of the radiation field extent on survival outcomes. RESULTS: A total of 378 patients were included, with a median follow-up of 45.8 months. Pelvic RT was delivered to 286 patients, and 92 patients received pelvic and PALN RT. The estimated OS and RFS rates at 5 years for the entire cohort were 80% and 69%, respectively. There was no difference in the 5-year OS (77% vs 87%, P = .47) and RFS rates (67% vs 70%, P = .78) between patients treated with pelvic RT and those treated with pelvic and prophylactic PALN RT, respectively. After propensity score matching, the estimated hazard ratios (HRs) of prophylactic PALN RT versus pelvic RT were 1.50 (95% confidence interval, 0.71-3.19; P = .28) for OS and 1.24 (95% confidence interval, 0.64-2.42; P = .51) for RFS, suggesting that prophylactic PALN RT does not improve survival outcomes. Distant recurrence was the most common site of first recurrence, and the extent of RT field was not associated with the site of first recurrence (P = .79). CONCLUSIONS: Prophylactic PALN RT was not significantly associated with improved survival outcomes in stage IIIC1 EC. Distant metastasis remains the most common site of failure despite routine use of systemic chemotherapy. New therapeutic approaches are necessary to optimize the outcomes for women with stage IIIC1 EC.