CT and MRI features of sarcomatoid urothelial carcinoma of the bladder and its differential diagnosis with conventional urothelial carcinoma.

BACKGROUND: Sarcomatoid urothelial carcinoma (SUC) is a rare and highly malignant form of bladder cancer with a poor prognosis. Currently, there is limited information on the imaging features of bladder SUC and reliable indicators for distinguishing it from conventional urothelial carcinoma (CUC). The objective of our study was to identify the unique imaging characteristics of bladder SUC and determine factors that aid in its differential diagnosis. MATERIALS AND METHODS: This retrospective study enrolled 22 participants with bladder SUC and 61 participants with CUC. The clinical, pathologic, and CT/MRI data from both groups were recorded, and a comparison was conducted using univariate analysis and multinomial logistic regression for distinguishing SUC from CUC. RESULTS: The majority of SUCs were located in the trigone of the bladder and exhibited large tumor size, irregular shape, low ADC values, Vesical Imaging-Reporting and Data System (VI-RADS) score ≥ 4, the presence of necrosis, and an invasive nature. Univariate analysis revealed significant differences in terms of tumor location, shape, the maximum long-axis diameter (LAD), the short-axis diameter (SAD), ADC-value, VI-RADS scores, necrosis, extravesical extension (EVE), pelvic peritoneal spread (PPS), and hydronephrosis/ureteral effusion (p < .001 ~ p = .037) between SUCs and CUCs. Multinomial logistic regression found that only SAD (p = .014) and necrosis (p = .003) emerged as independent predictors for differentiating between SUC and CUC. The model based on these two factors achieved an area under curve (AUC) of 0.849 in ROC curve analysis. CONCLUSION: Bladder SUC demonstrates several distinct imaging features, including a high incidence of trigone involvement, large tumor size, and obvious invasiveness accompanied by necrosis. A bladder tumor with a large SAD and evidence of necrosis is more likely to be SUC rather than CUC.

[Several key and difficult issues related to the grading of urothelial carcinoma of urinary bladder].

Grading and staging are the most important prognostic factors for both non-invasive and invasive urothelial carcinomas, and are also one of the most common difficulties encountered by pathologists in the daily diagnostic practice of urothelial carcinoma. Recently, the International Society of Urological Pathology organized a survey and questionnaire conference on various issues related to the diagnosis, grading, and staging of urothelial carcinoma, and ultimately formed a series of consensus opinions. This article briefly summarizes the consensus opinions of this series, and combines them with the current pathological diagnosis status of urothelial carcinoma in China. It briefly comments on how to apply this series of consensus opinions in the daily diagnostic practice of pathologists, deeply understand relevant diagnostic problems, and carry out relevant clinical pathological research to further solve problems.

No difference in oncological outcomes and perioperative complications between patients with ESRD with unilateral and bilateral UTUC receiving radical nephroureterectomy.

Patients with end stage renal disease (ESRD) are at high risk of developing upper tract urothelial carcinoma (UTUC). Due to high recurrence rate of UTUC in contralateral kidney and ureter, and high risk of complications related to surgery and anesthesia, whether it's necessary to remove both kineys and ureters at one time remains in debate. We utilized Taiwanese UTUC Registry Database to valuate the difference of oncological outcomes and perioperative complications between patients with ESRD with unilateral and bilateral UTUC receiving surgical resection. Patients with ESRD and UTUC were divided into three groups, unilateral UTUC, previous history of unilateral UTUC with metachronous contralateral UTUC, and concurrent bilatetral UTUC. Oncological outcomes, perioperative complications, and length of hospital stays were investiaged. We found that there is no diffence of oncological outcomes including overall survival, cancer specific survival, disease free survival and bladder recurrence free survival between these three groups. Complication rate and length of hospital stay are similar. Adverse oncological features such as advanced tumor stage, lymph node involvement, lymphovascular invasion, and positive surgical margin would negatively affect oncological outcomes.

Urinary Tract Cytopathology: Current and Future Impact on Patient Care.

Urine cytology is a non-invasive, cost-efficient, and sensitive test to detect high-grade urothelial carcinoma. The Paris System (TPS) for Reporting Urinary Cytology is an evidence-based system that uses the risk of malignancy to guide patient management. Since its inception, TPS has standardized urine cytology reports, facilitating communication among pathologists and between pathologists and clinicians. It is imperative to correlate the urine cytology findings with the concurrent tissue sample to avoid false-negative and false-positive results when possible. Several ancillary tests and artificial intelligence algorithms are being developed to increase the accuracy of urine cytology interpretation.

Three-dimensional imaging of upper tract urothelial carcinoma improves diagnostic yield and accuracy.

Upper tract urothelial carcinoma (UTUC) is a rare form of urothelial cancer with a high incidence of recurrence and a low survival rate. Almost two-thirds of UTUCs are invasive at the time of diagnosis; therefore, improving diagnostic methods is key to increasing survival rates. Histopathological analysis of UTUC is essential for diagnosis and typically requires endoscopy biopsy, tissue sectioning, and labeling. However, endoscopy biopsies are minute, and it is challenging to cut into thin sections for conventional histopathology; this complicates diagnosis. Here, we used volumetric 3-dimensional (3D) imaging to explore the inner landscape of clinical UTUC biopsies, without sectioning, revealing that 3D analysis of phosphorylated ribosomal protein S6 (pS6) could predict tumor grade and prognosis with improved accuracy. By visualizing the tumor vasculature, we discovered that pS6+ cells were localized near blood vessels at significantly higher levels in high-grade tumors than in low-grade tumors. Furthermore, the clustering of pS6+ cells was associated with shorter relapse-free survival. Our results demonstrate that 3D volume imaging of the structural niches of pS6 cells deep inside the UTUC samples improved diagnostic yield, grading, and prognosis prediction.

Primary exophytic urothelial carcinoma of the bladder: A case report.

RATIONALE: Bladder urothelial carcinoma (UC) is a common urinary system tumor that is generally diagnosed by cystoscopy combined with pathological biopsy. However, complete exophytic UC of the bladder is very rare and difficult to diagnose. Early diagnosis and accurate identification of such tumors, followed by aggressive surgical treatment, is essential for the management of these patients. PATIENT CONCERNS: An 84-year-old man was admitted to the hospital with dysuria, a poor diet, and significant weight loss. DIAGNOSIS: Pelvic computed tomography and magnetic resonance imaging revealed an exteriophytic round mass on the right lateral wall of the bladder. Cystoscopy revealed a necrotic mass on the right lateral wall of the bladder cavity, and no tumor cells were found following the biopsy. The tumor was removed via partial cystectomy, and the pathological result indicated high-grade muscle-invasive UC. INTERVENTIONS: The patient refused radical cystectomy and underwent laparoscopic partial cystectomy plus pelvic lymph node dissection followed by cisplatin plus gemcitabine chemotherapy. OUTCOMES: The patient's mental state and appetite were significantly improved after the urinary tube was removed 1 week after surgery. His general state was significantly improved after 1 month of follow-up but died of acute cerebral infarction 3 months after surgery. LESSONS: UC of the bladder may grow completely out of the bladder without symptoms such as gross hematuria; thus, early diagnosis is difficult. For high-risk individuals, regular imaging tests may help to detect tumors early. Partial cystectomy is a reliable surgical modality for bladder preservation in such patients.

Do we need a re-TUR after en bloc resection of T1 stage bladder cancer?

BACKGROUND: A second look trans-urethral resection of the bladder (re-TUR) is recommended after the diagnosis of T1 high grade (T1HG) bladder cancer. Few studies have evaluated the results of re-TUR after a first en bloc resection (EBR) and none of them have specifically reported the pathological results on the field of previous T1 disease. OBJECTIVE: To report the rate of upstaging and the rate of residual disease (RD) on the field of T1HG lesions resected with EBR. MATERIALS AND METHODS: Between 01/2014 and 06/2022, patients from 2 centers who had a re-TUR after an EBR for T1HG urothelial carcinoma were retrospectively included. Primary endpoint was the rate of RD including the rate of upstaging to T2 disease on the scar of the primary resection. Secondary endpoints were the rate of any residual disease outside the field. RESULTS: Seventy-five patients were included. No muscle invasive bladder cancer lesions were found after re-TUR. Among the 16 patients who had a RD, 4 were on the resection scar. All of these lesions were papillary and high grade. RD outside the field of the first EBR was observed in 12 patients. CONCLUSION: After EBR of T1HG disease, none of our patients had an upstaging to MIBC. However, the rate of RD either on and outside the field of the EBR remains quite significant. We suggested that predictive factors of residual papillary disease (number of tumors at the initial TUR and concomitant CIS) might be suitable to select patient who will benefit of the re-TUR.

Differential effect of surgical technique on intravesical recurrence after radical nephroureterectomy in patients with upper tract urothelial cancer: a systematic review and Meta-analysis.

CONTEXT: Radical nephroureterectomy (RNU) with bladder cuff resection is the standard treatment in patients with high-risk upper tract urothelial cancer (UTUC). However, it is unclear which specific surgical technique may lead to improve oncological outcomes in term of intravesical recurrence (IVR) in patients with UTUC. OBJECTIVE: To evaluate the efficacy of surgical techniques and approaches of RNU in reducing IVR in UTUC patients. EVIDENCE ACQUISITION: Three databases were queried in January 2024 for studies analyzing UTUC patients who underwent RNU. The primary outcome of interest was the rate of IVR among various types of surgical techniques and approaches of RNU. EVIDENCE SYNTHESIS: Thirty-one studies, comprising 1 randomized controlled trial and 1 prospective study, were included for a systematic review and meta-analysis. The rate of IVR was significantly lower in RNU patients who had an early ligation (EL) of the ureter compared to those who did not (HR: 0.64, 95% CI: 0.44-0.94, p = 0.02). Laparoscopic RNU significantly increased the IVR compared to open RNU (HR: 1.28, 95% CI: 1.06-1.54, p < 0.001). Intravesical bladder cuff removal significantly reduced the IVR compared to both extravesical and transurethral bladder cuff removal (HR: 0.65, 95% CI: 0.51-0.83, p = 0.02 and HR: 1.64, 95% CI: 1.15-2.34, p = 0.006, respectively). CONCLUSIONS: EL of the affected upper tract system, ureteral management, open RNU, and intravesical bladder cuff removal seem to yield the lowest IVR rate in patients with UTUC. Well-designed prospective studies are needed to conclusively elucidate the optimal surgical technique in the setting of single post-operative intravesical chemotherapy.

The impact of double-J ureteral stenting before radical cystectomy on the development of upper tract urothelial carcinoma.

BACKGROUND: It is controversial whether the use of a double-J stent (DJ) in patients with bladder cancer before radical cystectomy (RC) increases the risk of tumour seeding in the upper tract and thus the risk of metachronous upper tract urothelial carcinoma (UTUC). The aim of our study is to investigate the risk of upper tract recurrence after RC in patients previously managed with a DJ stent. METHODS: A total of 699 patients who had undergone RC between January 2003 and March 2022 with complete perioperative data and pathological outcome were included in our study. Patients treated preoperatively with a DJ stent were identified and compared for development of metachronous UTUC with those who did not receive prior internal stenting. Multivariable Cox regression analysis was used to determine predictors of UTUC occurrence among the possible pathological features; risk factors for mortality after RC were also examined. RESULTS: Of 699 patients, 117 (16.7%) were managed preoperatively with a DJ stent. The overall probability of metachronous UTUC was 1%, 4% and 6% at 1, 3 and 5 years, respectively. The groups with and without DJ stenting were comparable regarding their clinicopathologic features, except for the higher incidence of hydronephrosis in the DJ group. At similar follow-up periods (median follow-up 32 months), metachronous UTUC was detected in four (3.4%) patients in the DJ group and in 13 (2.2%) in the non-stented group (P=0.44). The median interval (IQR) from cystectomy to UTUC was 40.5 (20-49) months in the DJ group and 37 (24-82) in the non-stented group (P=0.7). In the multivariable analysis, only presence of CIS (HR 3.83, 95% CI 1.19-12.29, P=0.024) and positive ureteral margin (HR=5.2, 95% CI 1.38-19.57, P=0.015) were predictors of metachronous UTUC. The study is limited by the retrospective nature and relatively short follow-up. CONCLUSIONS: Ureteral stenting for management of hydronephrosis in patients with bladder cancer undergoing RC is a viable option, without higher risk for UTUC or mortality. Patients with positive ureteral margin and CIS are considered high-risk groups for upper tract recurrence and should receive long-term, rigorous follow-up.

Grading urothelial carcinoma with probe-based confocal laser endomicroscopy during flexible cystoscopy.

PURPOSE: Urothelial bladder cancer (UCB) care requires frequent follow-up cystoscopy and surgery. Confocal laser endomicroscopy (CLE) is a probe-based optical technique that can provide real-time microscopic evaluation with the potential for outpatient grading of UCB. This study aims to investigate the diagnostic accuracy and interobserver variability for the grading of UCB with CLE during flexible cystoscopy (fCLE). METHODS: Participants scheduled for transurethral resection of papillary bladder tumors were prospectively included for intra-operative fCLE. Exclusion criteria were flat lesions, fluorescein allergy or pregnancy. Two independent observers evaluated fCLE, classifying tumors as low- or high-grade urothelial carcinoma (LGUC/HGUC) or benign. Interobserver agreement was calculated with Cohens kappa (κ) and diagnostic accuracy with 2 × 2 tables. Histopathology was the reference test. RESULTS: Histopathology of 34 lesions revealed 14 HGUC, 14 LGUC and 6 benign tumors. Diagnostic yield for fCLE was 80-85% with a κ of 0.75. Respectively, sensitivity, specificity, NPV and PPV were: for benign tumors 0-20%, 96-100%, unmeasureable-50% and 87%, for LGUC 57-64%, 41-58%, 44-53% and 54-69% and for HGUC 38-57%, 56-68%, 38-57% and 56-68%, with an interobserver agreement of κ 0.61. CONCLUSION: fCLE is currently insufficient to grade UCB.

A review of urinary bladder microbiome in patients with bladder cancer and its implications in bladder pathogenesis.

PURPOSE: The recent discovery of the urinary microbiome has led to an emerging field of investigation about the potential role of microorganisms in the pathogenesis of urinary bladder cancer. Few preliminary data have been reported so far implicating urobiome as causative and prognostic factor of bladder tumorigenesis. In the present study, a review of the current evidence is presented about microbiome composition among patients with bladder cancer and healthy individuals as well as possible implications of microbiome on urothelial carcinoma of the bladder. METHODS: A literature review was conducted using PubMed/MEDLINE, Scopus, and the Cochrane library until December 2023. Search algorithm was constructed using the following terms and their associated Mesh terms and Boolean operators: "urinary microbiome" and "urinary microbiota". Studies written in English language, identifying, and comparing urinary microbiome among bladder cancer patients and healthy control group were included in the review. RESULTS: A total of 2,356 reports were identified. From this total 16 articles complied with the inclusion criteria were selected for analysis. These articles represent a total of about 486 bladder cancer patients. CONCLUSION: Recent studies revealed the colonization of the urinary tract and the bladder by micro-organisms using both enhanced culture- and molecular-based techniques for microbial characterization. However, several limitations exist in the literature decreasing the reliability of the current reports. As a result, urinary microbiome consist an ambitious era in bladder cancer research with an increasing number of evidence about its potential pathogenetic, prognostic and therapeutic role.

A histopathological and epidemiological study of urothelial carcinoma at a tertiary care centre in Peshawar, Pakistan.

Bladder cancer is the ninth leading cause of death worldwide and 14th leading cause of death in Pakistan. The objective of this study was to determine the frequency of urothelial carcinoma in various age groups, its gender distribution, and grades. A total of 131 cases of urothelial carcinoma, received at Department of Pathology, Peshawar Medical College, Peshawar, between January 2017 to December 2022, were included in the study; of them 107 (81.6%) were males while 24 (18.3%) were females with a mean age of 62±13 years. The most common histological subtype was papillary urothelial carcinoma in 117(89.3%) cases, followed by Squamous and Glandular in 5(3.8%) cases. Majority of the urothelial carcinoma with high grade showed a statistically significant relation with muscle invasion 38 (50.66%). Males were four times more likely to have urothelial carcinoma while older age groups were more likely to have high grade urothelial carcinoma.

Clinical, Pathological Characteristics and Progression of Urothelial Bladder Cancer in Young Adult Patients. Our Experience and Literature Review.

BACKGROUND: Bladder cancer is highly prevalent even though its incidence is considerably lower in patients younger than 40 years, thus raising the issue of the influence of age at diagnosis on the natural history of this disease. This study aimed to evaluate the characteristics and progression of young patients with urothelial bladder carcinoma with at least 10 years of follow-up and to compare the results with those of previously reported studies. MATERIAL AND METHODS: A retrospective study between 1990 and 2007 was conducted. The medical records and tissue samples of patients with urothelial bladder tumours were reviewed, and patients with a first diagnosis of urothelial carcinoma of the bladder at age 40 years or younger were selected. Their clinical and pathological data and disease-free survival were analysed. RESULTS: This study included 43 patients, with a median follow-up of 152 months (interquartile range (IQR): 96-222) and a mean age at diagnosis of 34 years (SD: 4.6). Thirty-five patients (81.4%) had non-muscle invasive tumours at diagnosis, and 53.5%, 27.9% and 18.6% had tumour grades of G1, G2 and G3, respectively. Fifteen patients (34.9%) experienced recurrence, and eight (18.6%) progressed. At 24 and 60 months, the recurrence-free survival rates were 84.8% (95% confidence interval (CI): 69.2%-92.9%) and 68.9% (95% CI: 51.7%-81%), respectively, and the progression-free survival rates were 94.9% (95% CI: 81%-98.7%) and 92.2% (95% CI: 77.8%-97.4%), respectively. CONCLUSIONS: Bladder cancer is an uncommon disease in young patients. In most cases, it consists of non-muscle-invasive tumours, with a low rate of recurrence and progression. The prognosis is based on the tumour's characteristics and not on the patient's age.

[A real-world study of the clinical application of the Paris system for reporting urinary cytology in cancer hospital].

Objectives: To evaluate the clinical value of the Paris system for reporting urinary cytology (TPS) in the diagnosis of urothelial carcinoma (UC). Methods: A total of 1 744 cytological diagnostic records (from 751 cases) were collected retrospectively. All specimens were voided urines and histopathology as the gold standard. The sensitivity and specificity of urinary cytological diagnosis of UC and risk of high grade malignant (ROHM) in each diagnostic category were compared. Results: There were 360 cases with histopathology. The percentage of negative for high-grade urothelial carcinoma (NHGUC) was 30.1% (226/751), atypical urothelial cells (AUC) was 29.8% (224/751), suspicious for high-grade urothelial carcinoma (SHGUC) was 16.8% (126/751), high grade urothelial carcinoma (HGUC) was 21.2% (159/751), and non-urothelial malignancy (NUM) was 2.1% (16/751). The histpathologic ROHM corresponding to each cytological diagnosis category were 27.3% for NHGUC, 32.7% for AUC, 74.7% for SHGUC, 96.6% for HGUC and 100.0% for NUM, respectively. ROHM of SHGUC was significantly higher than that of AUC group, and the difference between the two groups was statistically significant (P＜0.001). ROHM of HGUC group was significantly higher than that of SHGUC group, and the difference was statistically significant (P＜0.001). With SHGUC as the cut-off value, the sensitivity and specificity of cytological diagnosis of HGUC were 76.7% (165/215) and 85.7% (18/21), and with HGUC as the cut-off value, the sensitivity and specificity of cytological diagnosis of HGUC were 53.0% (114/215) and 100.0% (21/21), respectively. Conclusions: Urine cytology has high sensitivity and specificity in the diagnosis of HGUC. The malignant risk of TPS varies with different diagnosis category. The high malignant risk population in cancer hospital leads to the relatively high malignant proportion and ROHM in each diagnosis category. Urinary cytology TPS reporting system is helpful to clinical management and has good clinical application value.

Analysis of preoperative nutrition, immunity and inflammation correlation index on the prognosis of upper tract urothelial carcinoma surgical patients: a retrospective single center study.

BACKGROUND: SII, PNI, SIRI, AAPR, and LIPI are prognostic scores based on inflammation, nutrition, and immunity. The purpose of this study was to examine the prognostic value of the SII, PNI, SIRI, AAPR, and LIPI in patients with UTUC who underwent radical nephroureterectomy with bladder cuff excision. MATERIALS AND METHODS: Data of UTUC patients in Sichuan Provincial People's Hospital from January 2017 to December 2021 were collected. The optimal critical values of SII, PNI, SIRI, and AAPR were determined by ROC curve, and LIPI was stratified according to the dNLR and LDH. The Kaplan-Meier method was used to draw the survival curve, and Cox proportional hazard model was used to analyze the factors affecting the prognosis of UTUC patients. RESULTS: A total of 81 patients with UTUC were included in this study. The optimal truncation value of PNI, SII, SIRI and AAPR were determined to be 48.15, 596.4, 1.45 and 0.50, respectively. Univariate Cox proportional hazard regression showed that low PNI, high SII, high SIRI, low AAPR and poor LIPI group were effective predictors of postoperative prognosis of UTUC patients. Multivariate Cox proportional hazard regression showed that high SII was an independent risk factor for postoperative prognosis of UTUC patients. According to ROC curve, the prediction efficiency of fitting indexes of PNI, SII, SIRI, AAPR and LIPI is better than that of using them alone. CONCLUSIONS: The SII, PNI, SIRI, AAPR, and LIPI was a potential prognostic predictor in UTUC patients who underwent radical nephroureterectomy with bladder cuff excision.

A Fatal Case of Immune Checkpoint Inhibitor-Mediated Myasthenia Gravis, Myositis, and Cardiomyopathy Overlap Syndrome in Urothelial Carcinoma.

BACKGROUND: Immune checkpoint inhibitors (ICIs) have led to improved outcomes for many cancer types. However, their use can also precipitate immune-related adverse events (irAEs) that can affect any organ system. While irAEs are often mild, they rarely affect multiple organ systems concurrently and can be fatal. CASE: We report a fatal case of myasthenia gravis, myositis, and cardiotoxicity overlap syndrome precipitated by the ICI pembrolizumab along with a brief review of available literature. CONCLUSION: Early recognition of high grade irAEs and prompt intervention is essential. Despite the poor prognosis of these overlap syndromes, current recommendations offer little guidance for severe cases and warrant a call for increased awareness and expansion of available therapeutics.

Epacadostat plus pembrolizumab versus placebo plus pembrolizumab for advanced urothelial carcinoma: results from the randomized phase III ECHO-303/KEYNOTE-698 study.

BACKGROUND: Indoleamine 2,3-dioxygenase 1 (IDO1) levels correlate with poor outcomes in urothelial carcinoma (UC). IDO1 and programmed death-ligand 1 (PD-L1) are often co-expressed. Epacadostat is a potent and highly selective inhibitor of IDO1. In a subgroup analysis of patients with advanced UC participating in a phase I/II study, epacadostat-pembrolizumab treatment produced an objective response rate (ORR) of 35%. METHODS: ECHO-303/KEYNOTE-698 was a double-blinded, randomized phase III study of adults with metastatic or unresectable locally advanced UC with recurrence or progression following first-line platinum-based chemotherapy. Participants were randomized to epacadostat 100 mg twice daily (BID) plus pembrolizumab or placebo plus pembrolizumab until completion of 35 pembrolizumab infusions, disease progression, or unacceptable toxicity. The primary endpoint was investigator-assessed ORR per Response Evaluation Criteria in Solid Tumors version 1.1. RESULTS: Target enrollment was 648 patients; enrollment was halted early based on efficacy results from the phase III ECHO-301/KEYNOTE-252 study in metastatic melanoma. Forty-two patients were randomized to each treatment arm. Median duration of follow-up was 62 days in each arm. The investigator-assessed ORR (unconfirmed) was 26.2% (95% CI 16.35-48.11) for epacadostat plus pembrolizumab and 11.9% (95% CI 4.67-29.50) for placebo plus pembrolizumab. Two complete responses were reported, both in the placebo-plus-pembrolizumab arm. Circulating kynurenine levels increased from C1D1 to C2D1 in the placebo-plus-pembrolizumab arm and numerically decreased in the epacadostat-plus-pembrolizumab arm. The safety profile of epacadostat plus pembrolizumab was similar to that of pembrolizumab monotherapy, although a numerically greater proportion of patients in the combination vs. control arm experienced treatment-related grade ≥ 3 adverse events (16.7% vs. 7.3%). One patient in each arm died due to cardiovascular events, which were not deemed drug-related. No new safety concerns were identified for either agent. CONCLUSIONS: Epacadostat plus pembrolizumab demonstrated anti-tumor activity and was generally tolerable as second-line treatment of patients with unresectable locally advanced or recurrent/progressive metastatic UC. Epacadostat 100 mg BID, when administered with pembrolizumab, did not normalize circulating kynurenine in most patients. Further study of combined IDO1/PD-L1 inhibition in this patient population, particularly with epacadostat doses that result in durable normalization of circulating kynurenine, may be warranted. TRIAL REGISTRATION: ClinicalTrials.gov, NCT03374488. Registered 12/15/2017.