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Iyer, Prasad G.

https://orcid.org/0000-0002-9822-1420

Mayo Clinic

Mayo Clinic in Arizona

Citations 113

Endoscopic Ultrasound/Fine Needle Aspiration Is Effective for Lymph Node Staging in Patients With Cholangiocarcinoma
Malikowski, Thomas, Levy, Michael J. , Gleeson, Ferga C. , Topazian, Mark , Iyer, Prasad G. , Rajan, Elizabeth , Roberts, Lewis R. , Abu Dayyeh, Barham K, Roberts, Lewis R , Levy, Michael J. , Storm, Andrew C. , Vargas, Eric J. , Dayyeh, Barham K. Abu , Gores, Gregory J. , Chandrasekhara, Vinay

Hepatology | December 20, 2019 | Volume: 72 | Issue: 3 | Pages: 940-948

10.1002/hep.31077 Get It

Background and Aims Presence of malignant regional lymph nodes (MRLNs) precludes curative oncological resection or liver transplantation for cholangiocarcinoma (CCA). Limited data support the utility of endoscopic ultrasound (EUS)/fine needle aspiration (FNA) for detection of MRLNs in extrahepatic CCA, but there are no data for its role in intrahepatic CCA (iCCA). The aim of this study is to evaluate the staging impact of EUS for CCA, including analysis by subtype. Approach and Results We identified consecutive patients with CCA who underwent EUS staging at a single tertiary care center from October 2014 to April 2018. Among this cohort, we abstracted clinical demographic, radiographical, procedural, cytopathological, and surgical data. STATA 15 software was used for comparative analysis calculations (StataCorp LP, College Station, TX). The study cohort included 157 patients; 24 (15%), 124 (79%), and 9 (6%) with intrahepatic, perihilar, and distal CCA, respectively. EUS was able to identify regional lymph nodes (RLNs) in a higher percentage of patients compared to cross‐sectional imaging (86% vs. 47%; P < 0.001). FNA was performed in 133 (98.5%) patients with RLNs, with a median of three passes per node. EUS‐FNA identified MRLN in 27 of 31 (87.1%) patients ultimately found to have MRLNs. For iCCA, EUS detected a higher percentage of RLN compared to cross‐sectional imaging (83% vs. 50%; P = 0.048), with MRLNs identified in 4 (17%) patients. Among the entire cohort, identification of at least one MRLN by EUS was associated with lower median survival (353 vs. 1,050 days; P < 0.001) and increased risk of death (hazard ratio = 4.1; P < 0.001). Conclusions EUS‐FNA is effective for identifying MRLN in patients with CCA, and should be routinely incorporated into staging of all CCA subtypes given the impact of MRLN on prognosis and management decisions.
415 External Validation of the Progression in Barrett’s Score in a Prospective Multicenter BE Cohort
Codipilly, Don C. , Kennedy, Kevin , Plevak, Matthew F., Dierkhising, Ross , Lansing, Ramona, Johnson, Michele L., Parasa, Sravanthi , Iyer, Prasad G. , Sharma, Prateek

American Journal of Gastroenterology | October 8, 2019 | Volume: 114 | Issue: 1 | Pages: S244-S244

10.14309/01.ajg.0000591192.18564.1c Get It

INTRODUCTION: Endoscopic surveillance guidelines in Barrett’s esophagus (BE) to detect progression to high grade dysplasia (HGD) or esophageal adenocarcinoma (EAC) are based solely on dysplasia grade. Given low rates of progression, identification of predictors (and scores) of progression may help to focus surveillance or intervention in those at higher risk. We aimed to assess predictors of progression and externally validate the Progression in Barrett’s (PIB) score in an independent multicenter prospective BE and EAC cohort. METHODS: The EA and Barrett’s esophagus (EABE) registry is a prospective cohort of patients recruited from three medical centers. Progressors were defined as those with the development of HGD or EAC more than 12 months after initial diagnosis. Demographic and clinical variables were abstracted. The annual incidence rate and predictors of progression were assessed using univariate and multivariable Cox proportional hazards analysis. The ability of the PIB score (incorporating weighted scores for male gender, smoking (ever versus never), BE length and confirmed LGD) to risk stratify the cohort into low (0-10 points), intermediate (11-20 points) and high risk (> 20 points) groups was assessed. RESULTS: 429 patients were included. 84% were men, with a mean (SD) age of 61.5 (9.9) years. 65% were ever smokers and most (76.7%), had NDBE at diagnosis. Mean (SD) maximal BE segment length was 5.9 (3.2) cm. Eighty-two patients (19.1%) progressed to HGD (n = 65) or EAC (n = 17) over a median (IQR) follow up of 7.5 (3.7, 12.5) years. Annual incidence rates of progression to EAC and EAC/HGD were 0.5% and 2.0% respectively. Univariate and multivariable predictors of progression are displayed in Table 1. The PIB score divided patients into three groups (Table 2) with progressively increasing rates of progression. The risk in the high risk group was three fold higher than the low risk group ( P = 0.024). The risk in the intermediate group was twofold higher but not statistically significantly higher ( P = 0.13). The PIB score had a c-statistic score of 0.76 in the original cohort. In this cohort the c-statistic value was lower at 0.64, suggesting moderate performance. CONCLUSION: Male sex and BE length predicted progression in this independent multicenter cohort. The PIB score was also able to risk-stratify patients in this validation cohort with the high risk cohort being 3x more likely to progress compared to the low risk cohort.
Discovery, Validation, and Application of Novel Methylated DNA Markers for Detection of Esophageal Cancer in Plasma
Qin, Yi , Wu, Chung Wah, Sawas, Tarek , Burger, Kelli N. , Yab, Tracy C. , Lidgard, Graham P. , Allawi, Hatim T. , Buttar, Navtej , Smyrk, Thomas C. , Iyer, Prasad G. , Katzka, David A. , Ahlquist, David A. , Wu, Chung W, Mahoney, Douglas W. , Buttar, Navtej S, Kisiel, John B , Qin, Y , Taylor, William R. , Sun, Zhifu , Kisiel, John B.

Clinical Cancer Research | September 16, 2019 | Volume: 25 | Issue: 24 | Pages: 7396-7404

10.1158/1078-0432.ccr-19-0740 Get It

Abstract Purpose: The burden of esophageal cancer continues to rise, and noninvasive screening tools are needed. Methylated DNA markers (MDM) assayed from plasma show promise in detection of other cancers. For esophageal cancer detection, we aimed to discover and validate MDMs in tissue, and determine their feasibility when assayed from plasma. Experimental Design: Whole-methylome sequencing was performed on DNA extracted from 37 tissues (28 EC; 9 normal esophagus) and 8 buffy coat samples. Top MDMs were validated by methylation specific PCR on tissue from 76 EC (41 adeno, 35 squamous cell) and 17 normal esophagus. Quantitative allele-specific real-time target and signal amplification was used to assay MDMs in plasma from 183 patients (85 EC, 98 controls). Recursive partitioning (rPART) identified MDM combinations predictive of esophageal cancer. Validation was performed in silico by bootstrapping. Results: From discovery, 23 candidate MDMs were selected for independent tissue validation; median area under the receiver operating curve (AUC) for individual MDMs was 0.93. Among 12 MDMs advanced to plasma testing, rPART modeling selected a 5 MDM panel (FER1L4, ZNF671, ST8SIA1, TBX15, ARHGEF4) which achieved an AUC of 0.93 (95% CI, 0.89–0.96) on best-fit and 0.81 (95% CI, 0.75–0.88) on cross-validation. At 91% specificity, the panel detected 74% of esophageal cancer overall, and 43%, 64%, 77%, and 92% of stages I, II, III, and IV, respectively. Discrimination was not affected by age, sex, smoking, or body mass index. Conclusions: Novel MDMs assayed from plasma detect esophageal cancer with moderate accuracy. Further optimization and clinical testing are warranted.
Interpretation of volumetric laser endomicroscopy in Barrett's esophagus using image enhancement software
Kamboj, Amrit K. , Hoversten, Patrick , Iyer, Prasad G. , Wang, K K, Leggett, Cadman L. , Leggett, Cadman L , Kahn, Allon , Trindade, Arvind J.

Diseases of the Esophagus | May 9, 2019 | Volume: 32 | Issue: 11 | Pages: No page available

10.1093/dote/doz037 Get It

SUMMARY Image interpretation of Barrett's esophagus (BE) with volumetric laser endomicroscopy (VLE) can be enhanced by image processing software that highlights established features using a color-graded scale (intelligent real-time image segmentation, IRIS). This study aims to provide a description of IRIS features of various gastroesophageal tissue types using histologic correlation. A database of 80 VLE laser-marked targets with histologic correlation was reviewed for various tissue types. IRIS was applied off-line to the VLE scans, laser-marked targets were identified, and feature review was performed. Squamous epithelium targets (N = 7) showed IRIS layered architecture with lack of surface hyper-reflectivity and epithelial glands. Gastric cardia targets (N = 10) showed absent layering (100%) and surface hyper-reflectivity with epithelial glands (40%). Nondysplastic BE targets (N = 39) showed surface hyper-reflectivity (64%), epithelial glands (51%), and lack of layering (74%). Targets of BE with early neoplasia (N = 24), showed surface hyper-reflectivity (96%), epithelial glands (67%), and lack of layering (96%). IRIS features that characterize each tissue type appear to mirror the nonenhanced VLE counterparts that define them.
Staging of T1 esophageal adenocarcinoma with volumetric laser endomicroscopy: a feasibility study
Kamboj, Amrit K. , Muppa, Prasuna, Sawas, Tarek , Lutzke, Lori S., Buras, Matthew , Golafshar, Michael A. , Katzka, David A. , Iyer, Prasad G. , Smyrk, Thomas C. , Wang, Kenneth T. , Kahn, Allon , Leggett, Cadman L. , Buras, Matthew R , Golafshar, Michael

Endoscopy International Open | March 22, 2019 | Volume: 07 | Issue: 04 | Pages: E462-E470

10.1055/a-0838-5326 Get It

Abstract Background and study aims Precise staging in T1 esophageal adenocarcinoma (EAC) is critical in determining candidacy for curative endoscopic resection. High-frequency endoscopic ultrasound (EUS) has demonstrated suboptimal accuracy in T1 EAC staging due to insufficient spatial resolution. Volumetric laser endomicroscopy (VLE) allows for high-resolution wide-field visualization of the esophageal microstructure. We aimed to investigate the role of VLE in staging T1 EAC. Patients and methods Patients undergoing endoscopic mucosal resection (EMR) were prospectively enrolled and only T1 EAC cases were included. EMR specimens were imaged using second-generation VLE immediately after resection. VLE images were analyzed for signal intensity by depth and signal attenuation (dB/mm) in both cross-sectional and en-face orientation. A decision tree model was constructed to combine measured VLE parameters and delineate diagnostic thresholds. Results Thirty EMR scans were obtained – 15 T1a specimens from 9 patients and 15 T1b specimens from 11 patients. T1b specimen VLE scans exhibited higher signal intensity (P < 0.0001) and higher signal attenuation compared to T1a specimens (P = 0.03). A combination of signal attenuation and signal intensity at 150 µm depth yielded optimal diagnostic thresholds and an area under the curve (AUC) of 0.77. VLE signal attenuation was significantly associated with grade of differentiation, irrespective of EAC stage. Conclusions VLE signal intensity and signal attenuation are quantitatively distinct in T1a and T1b EAC and associated with grade of differentiation. This is the first study examining the role of VLE for staging of T1 EAC and demonstrates promising diagnostic performance. With further in vivo validation, VLE may serve a role in staging superficial EAC.
Timeline and location of recurrence following successful ablation in Barrett’s oesophagus: an international multicentre study
Sami, Sarmed S. , Ravindran, Adharsh, Snyder, Diana L. , Santiago, José , Ortiz‐Fernández‐Sordo, Jacobo , Tan, Wei Keith , Dierkhising, Ross , Johnson, Michele L., Lansing, Ramona, Ragunath, Krish , Pietro, Massimiliano di , Wolfsen, Herbert C. , Ramirez, Francisco C. , Fleischer, David E., Wang, Kenneth K, Leggett, Cadman L. , Katzka, David A. , Iyer, Prasad G. , Kahn, Allon , Snyder, Diana, Dierkhising, Ross A, Crook, Julia E. , Wolfsen, Herbert, Ramirez, Francisco, Fleischer, David, Katzka, D A , Iyer, P G , Leggett, Cadman L , Santiago, Jose, Heckman, Michael G.

Gut | January 11, 2019 | Volume: 68 | Issue: 8 | Pages: 1379-1385

10.1136/gutjnl-2018-317513 Get It

Objective Surveillance interval protocols after complete remission of intestinal metaplasia (CRIM) post radiofrequency ablation (RFA) in Barrett’s oesophagus (BE) are currently empiric and not based on substantial evidence. We aimed to assess the timeline, location and patterns of recurrence following CRIM to inform these guidelines. Design Data on patients undergoing RFA for BE were obtained from prospectively maintained databases of five (three USA and two UK) tertiary referral centres. RFA was performed until CRIM was confirmed on two consecutive endoscopies. Results 594 patients achieved CRIM as of 1 May 2017. 151 subjects developed recurrent BE over a median (IQR) follow-up of 2.8 (1.4–4.4) years. There was 19% cumulative recurrence risk of any BE within 2 years and an additional 49% risk over the next 8.6 years. There was no evidence of a clinically meaningful change in the recurrence hazard rate of any BE, dysplastic BE or high-grade dysplasia/cancer over the duration of follow-up, with an estimated 2% (95% CI −7% to 12%) change in recurrence rate of any BE in a doubling of follow-up time. 74% of BE recurrences developed at the gastro-oesophageal junction (GOJ) (24.1% were dysplastic) and 26% in the tubular oesophagus. The yield of random biopsies from the tubular oesophagus, in the absence of visible lesions, was 1% (BE) and 0.2% (dysplasia). Conclusions BE recurrence risk following CRIM remained constant over time, suggesting that lengthening of follow-up intervals, at least in the first 5 years after CRIM, may not be advisable. Sampling the GOJ is critical to detecting recurrence. The requirement for random biopsies of the neosquamous epithelium in the absence of visible lesions may need to be re-evaluated.
Obesity and GERD impair esophageal epithelial permeability through 2 distinct mechanisms
Blevins, Christopher H. , Dierkhising, Ross , Geno, Debra M., Johnson, Michele L., Vela, Marcelo F. , Iyer, Prasad G. , Katzka, David A. , Blevins, C H , Ravi, Karthik

Neurogastroenterology & Motility | July 31, 2018 | Volume: 30 | Issue: 10 | Pages: No page available

10.1111/nmo.13403 Get It

AbstractBackgroundThe mechanism by which obesity leads to damage independent of reflux is unclear. We aimed to determine the influence of obesity on mean nocturnal baseline impedance (MNBI), a functional measure of the epithelial barrier, in the presence and absence of acid reflux, using ambulatory pH impedance measurements.MethodsTwenty‐four‐hour pH impedance studies performed off medications in Caucasian men with a normal endoscopic examination were assessed for level of acid exposure and MNBI. Four patient groups were studied: Group 1, Not obese and normal acid exposure; Group 2, Obese and normal acid exposure; Group 3, Not obese and increased acid exposure; and Group 4, Obese with increased acid exposure.ResultsOne hundred patients were studied (25 in each group). Mean esophageal mucosal impedance (MI) was substantially lower in obese patients without reflux (Group 2) and non‐obese patients with reflux (Group 3) compared to normal controls (non‐obese, no reflux, Group 1). MI was progressively lower in the distal (vs the proximal) esophagus in GER patients, compared to those without GER. This difference persisted in the presence or absence of obesity. In contrast, in obese patients, the mean MI was significantly lower throughout the esophagus when compared to the non‐obese patients and also persisted in the presence and absence of accompanying reflux. Obesity and reflux were both independently negatively correlated with MI.ConclusionObesity is associated with abnormal esophageal MNBI. In contrast to gastro‐esophageal reflux, this decrease is pan‐esophageal. These data may support a systemic mechanism by which obesity alters the esophageal barrier function.
Barrett Esophagus Length, Nodularity, and Low-grade Dysplasia are Predictive of Progression to Esophageal Adenocarcinoma
Solanky, Dipesh , Krishnamoorthi, Rajesh , Crews, Nicholas R. , Johnson, Michele L., Wolfsen, Herbert C. , Fleischer, David E., Ramirez, Francisco C. , Katzka, David A. , Buttar, Navtej , Iyer, Prasad G. , Crews, Nicholas, Johnson, Michele, Wolfsen, Herbert, Fleischer, David, Katzka, David, Wang, Kenneth

Journal of Clinical Gastroenterology | April 2, 2018 | Volume: 53 | Issue: 5 | Pages: 361-365

10.1097/mcg.0000000000001027 Get It

Goals: To investigate factors predictive of progression from nondysplastic Barrett esophagus (NDBE) or low-grade dysplasia (LGD) to high-grade dysplasia (HGD) or esophageal adenocarcinoma (EAC) using a large, prospective cohort of patients, wherein all esophageal biopsies undergo expert gastrointestinal pathologist review. Background: Efficacy and cost-effectiveness of endoscopic surveillance to detect incident EAC in the setting of Barrett esophagus (BE), particularly in NDBE patients, is questioned. Previous studies have reported factors predictive of progression to EAC to guide surveillance intervals, but their strength is limited by small sample size and absence of expert gastrointestinal pathologist involvement in esophageal biopsy review. Study: NDBE and LGD subjects were identified from a prospective registry in a tertiary care center. “Progressors” were BE subjects who developed HGD/EAC>12 months after the initial NDBE or LGD diagnosis. Cox proportional hazards model were used to identify predictors of progression. Results: In total, 318 with NDBE and 301 with BE-LGD (mean age, 62.6 y, 85% male) were included. The mean follow-up was 5.3 years. The 7 NDBE and 21 LGD subjects progressed to HGD/EAC. BE length [hazards ratio (HR), 1.16; 95% confidence interval (CI), 1.03-1.29], presence of nodularity (HR, 4.98; 95% CI, 1.80-11.7), and baseline LGD (HR, 2.57; 95% CI, 1.13-6.57) were significant predictors of progression on multivariate analysis. Conclusions: In this well-defined cohort of NDBE and BE-LGD subjects, BE length, presence of LGD, and nodularity were independent predictors of progression to HGD/EAC. These factors may aid in identifying high-risk patients who may benefit from closer endoscopic surveillance/therapy.
Association of sporadic and familial Barrett's esophagus with breast cancer
Chan, Megan , Blum, Andrew E., Chandar, Apoorva K., Emmons, Agnieszka, Shindo, Yuri, Brock, Wendy , Wang, J S, Iyer, Prasad G. , Shaheen, Nicholas J. , Thota, Prashanthi N. , Guda, Kishore , Chak, Amitabh , Falk, Gary W. , Canto, Marcia Irene , Grady, William M. , Abrams, Julian A

Diseases of the Esophagus | March 8, 2018 | Volume: 31 | Issue: 4 | Pages: No page available

10.1093/dote/doy007 Get It

Comparative Assessment of Patient Preferences and Tolerability in Barrett Esophagus Screening
Blevins, Christopher H. , Egginton, Jason S. , Shah, Nilay D., Johnson, Michele L., Iyer, Prasad G.

Journal of Clinical Gastroenterology | January 23, 2018 | Volume: 52 | Issue: 10 | Pages: 880-884

10.1097/mcg.0000000000000991 Get It

Goals: To determine patient preference for the Barrett esophagus (BE) screening techniques. Background: Sedated esophagogastroduodenoscopy (sEGD) and unsedated transnasal endoscopy (uTNE) are both potential techniques for BE screening. However, systematic assessment of patient preference for these 2 techniques is lacking. As part of a comparative effectiveness randomized trial of BE screening modalities, we measured short-term patient preferences for the following approaches: in-clinic uTNE (huTNE), mobile-based uTNE (muTNE), and sEGD using a novel assessment instrument. Study: Consenting community patients without known BE were randomly assigned to receive huTNE, muTNE, or sEGD, followed by a telephone administered preference and tolerability assessment instrument 24 hours after study procedures. Patient preference was measured by the waiting trade-off method. Results: In total, 201 patients completed screening with huTNE (n=71), muTNE (n=71), or sEGD (n=59), and a telephone interview. Patients’ preferences for sEGD and uTNE using the waiting trade-off method were comparable (P=0.51). Although tolerability scores were superior for sEGD (P<0.001) compared with uTNE, scores for uTNE examinations were acceptable. Conclusions: Patient preference is comparable between sEGD and uTNE for diagnostic examinations conducted in an endoscopy suite or in a mobile setting. Given acceptable tolerability, uTNE may be a viable alternative to sEGD for BE screening.