Citations

Mayo Clinic

Clear

117 citation(s) found for "G Iyer, Prasad".

Predicting Progression in Barrett's Esophagus: Is the Holy Grail Within Reach?
Iyer, Prasad G. , Qin, Yi

American Journal of Gastroenterology | April 14, 2020 | Volume: 115 | Issue: 6 | Pages: 841-842

10.14309/ajg.0000000000000635 | PMID 32287139 Get It

Abstract Risk stratification in Barrett's esophagus may allow aggressive management of those at “high risk” and reduction in surveillance in at “low” risk. Davison et al. report the results of the independent validation of a multibiomarker panel (TissueCypher assay) performed on biopsy tissue, in a case control study. “High-risk” patients progressed 5 times more than those at “low risk.” Sensitivity and specificity for “high-risk” patients were 29% and 86% with a positive predictive value of 23%. A negative predictive value of a “low-risk” score was 96%. These findings may allow more intensive surveillance in those at “high risk.” Despite some limitations, this assay is a potentially major advance in the management of Barrett's esophagus patients without dysplasia.
Development and Pilot Testing of Decision Aid for Shared Decision Making in Barrett’s Esophagus With Low-Grade Dysplasia
Krishnamoorthi, Rajesh , Hargraves, Ian , Gopalakrishnan, Naveen, Blevins, Christopher H. , Priyan, Harshith, Johnson, Michele L., Maixner, Kristyn, Wang, Kenneth K, Katzka, David A. , Talwalkar, Jayant A., Iyer, Prasad G. , LeBlanc, Annie

Journal of Clinical Gastroenterology | February 10, 2020 | Volume: 55 | Issue: 1 | Pages: 36-42

10.1097/mcg.0000000000001319 | PMID 32040049 Get It

Goals: To develop an encounter decision aid [Barrett’s esophagus Choice (BE-Choice)] for patients and clinicians to engage in shared decision making (SDM) for management of BE with low-grade dysplasia (BE-LGD) and assess its impact on patient-important outcomes. Background: Currently, there are 2 strategies for management of BE-LGD—endoscopic surveillance and ablation. SDM can help patients decide on their preferred management option. Study: Phase-I: Patients and clinicians were engaged in a user-centered design approach to develop BE-Choice. Phase-I included review of evidence on BE-LGD management, observation of usual care (UC), creation, field-testing, and iterative development of BE-Choice in clinical settings. Phase-II: Impact of BE-Choice on patient-important outcomes (patient knowledge, decisional conflict, and patient involvement in decision making) was assessed using a controlled before-after study design (UC vs. BE-Choice). Results: Phase-I: Initial prototype was designed with observation of 8 clinical encounters. With field-testing, 3 successive iterations were made before finalizing BE-Choice. BE-Choice was paper based and fulfilled the qualifying criteria of International patient decision aid standards. Phase II: 29 patients were enrolled, 8 to UC and 21 to BE-Choice. Compared with UC, use of BE-Choice improved patient knowledge (90.4% vs. 70.5%; P =0.03), decisional comfort (89.6 vs. 71.9; P =0.01), and patient involvement (OPTION score: 27.1 vs. 19.2; P =0.01). Conclusions: BE-Choice is a feasible and effective decision aid to promote SDM in the management of BE-LGD. On pilot testing, BE-Choice had promising impact on patient-important outcomes. A larger multicenter trial is needed to confirm our results and promote widespread use of BE-Choice.
Approach to the Post-Ablation Barrett's Esophagus Patient
Shaheen, Nicholas J. , Iyer, Prasad G. , Kahn, Allon

American Journal of Gastroenterology | January 3, 2020 | Volume: 115 | Issue: 6 | Pages: 823-831

10.14309/ajg.0000000000000514 | PMID 31899706 Get It

Because of the rising incidence and lethality of esophageal adenocarcinoma, Barrett's esophagus (BE) is an increasingly important premalignant target for cancer prevention. BE-associated neoplasia can be safely and effectively treated with endoscopic eradication therapy (EET), incorporating tissue resection and ablation. Because EET has proliferated, managing patients after complete eradication of intestinal metaplasia has taken on increasing importance. Recurrence after complete eradication of intestinal metaplasia occurs in 8%–10% of the patients yearly, and the incidence may remain constant over time. Most recurrences occur at the gastroesophageal junction, whereas those in the tubular esophagus are endoscopically visible and distally located. A simplified biopsy protocol limited to the distal aspect of the BE segment, in addition to gastroesophageal junction sampling, may enhance efficiency and cost without significantly reducing recurrence detection. Similarly, research suggests that current surveillance intervals may be excessively frequent, failing to reflect the cancer risk reduction of EET. If validated, longer surveillance intervals could reduce the burden of resource-intensive endoscopic surveillance. Several important questions in post-EET management remain unanswered, including surveillance duration, the significance of gastric cardia intestinal metaplasia, and the role of advanced imaging and nonendoscopic sampling techniques in detecting recurrence. These merit further research to enhance quality of care and promote a more evidence-based approach.
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 | PMID 31860935 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 | PMID 31527170 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 | PMID 31069389 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 | PMID 30931378 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 | PMID 30635408 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.
FA02.07: BARRIER STRUCTURE AND FUNCTION OF THE NEO-SQUAMOUS EPITHELIUM FOLLOWING SUCCESSFUL BARRETT’S ENDOTHERAPY IS IMPAIRED
Ravindran, Adharsh, Blevins, Christopher H. , Johnson, Michele L., Lansing, Ramona, Katzka, David A. , Iyer, P. K. R., Wang, Kenneth , Iyer, Prasad

Diseases of the Esophagus | September 14, 2018 | Volume: 31 | Issue: Supplement_1 | Pages: 5-5

10.1093/dote/doy089.fa02.07 Get It

Abstract Background The neo-squamous epithelium that replaces columnar epithelium after successful endoscopic ablation of Barrett's esophagus (BE) has not been fully characterized in regard to its structural and functional integrity. Intercellular space is a surrogate marker for epithelial structural integrity and mucosal impedance (MI) is a surrogate for transepithelial resistance and thus epithelial functional integrity. Impairment of the structural and functional integrity may influence recurrence following successful ablation. We aimed to measure the esophageal epithelial intercellular space diameter and MI in the neo-squamous and normal squamous epithelium of patients who underwent successful radiofrequency ablation for dysplastic BE. Methods Forty patients with complete remission of intestinal metaplasia (CRIM) (defined as two negative surveillance endoscopies for intestinal metaplasia) were prospectively recruited. Patients were excluded if they had endoscopic evidence of esophagitis. MI measurements were taken at 1 cm above the GE junction and 2 cm above the prior BE segment (targeting uninvolved squamous epithelium), using a novel through the scope MI probe. Endoscopic biopsies were also taken at these corresponding sites to assess intercellular space diameter using transmission electron microscopy (TEM) using standard techniques. Results 80% of patients were male with a mean age of 69 years. Mean follow since achieving CRIM was 30 months. 39 patients underwent RFA for dysplasia. The mean intercellular space diameter was higher in the neo-squamous epithelium (1.01 μm) when compared to the untreated native squamous epithelium (0.96 μm) [Difference of 0.056 μm, 95% CI of -0.036 to 0.148, P = 0.228]. The mean MI was significantly lower in the neosquamous epithelium (4001.3 Ω) when compared to the untreated native epithelium (5168.1 Ω) [Difference of 1166.7 Ω, 95% CI 418.8 to 1914.6, P = 0.003]. Conclusion Neo-squamous epithelium that replaces BE epithelium following successful endoscopic therapy for BE appears to be functionally and likely structurally deficient with regards to acid reflux barrier function, when compared to native squamous esophageal epithelium. This impairment may be associated with recurrence following successful ablation. Disclosure All authors have declared no conflicts of interest.