Screening Colonoscopy from a Large Single Center of Thailand - Something Needs to be Changed?

Aswakul, Pitulak,Prachayakul, Varayu,Lohsiriwat, Varut,Bunyaarunnate, Thirapol,Kachintorn, Udom Asian Pacific Journal of Cancer Prevention 2012 Asian Pacific journal of cancer prevention Vol.13 No.4

Background: Results of screening colonoscopy from Western countries reported adenoma detection rates (ADRs) of 30-40% while those from Asia had ADR as low as 10%. There have been limited data regarding screening colonoscopy in Thailand. The objectives of this study were therefore to determine polyp and adenoma detection rates in Thai people, to evaluate the incidence of colorectal cancer detected during screening colonoscopy and to determine the endoscopic findings of the polyps which might have some impact on endoscopists to perform polypectomy. Materials & Methods: This study was a retrospective electronic chart review of asymptomatic Thai adults who underwent screening colonoscopy in our endoscopic center from June 2007 to October 2010.Results: A total of 1,594 cases were reviewed. The patients had an average age of $58.3{\pm}10.5$ years (range 27-82) and 55.5% were female. Most of the cases (83.8%) were handled by staff who were endoscopists. A total of 488 patients (30.6%) were reported to have colonic polyps. Left-sided colon was the most common site (45.1%), followed by right-sided colon (36.5%) and the rectum (18%). Those polyps were removed in 97.5% of cases and 88.5 % of the polyps were sent for histopathology (data lost 11.5%). Two hundred and sixty three cases had adenomatous polyps, accounting for 16.5 % ADR. Advanced adenomas were detected in 43 cases (2.6%). Hyperplastic polyps were mainly located distal to the splenic flexure of the colon whereas adenomas were found throughout the large intestine. Ten cases (0.6%) were found to have colorectal cancer. Four advanced adenomas and two malignant polyps were reported in lesions ${\leq}$ 5 mm. Conclusion: The polyp detection rate, adenoma detection rate, advanced adenoma detection rate and colorectal cancer detection rate in the screening colonoscopy of Thai adults were 30.9%, 16.5%, 2.6% and 0.6% respectively. Malignant transformation was detected regardless of the size and location of the polyps. Therefore, new technology would play an important role indistinguishing polyps.

Clinical Characteristics and Treatment Outcomes of Patients with Unresectable Cholangiocarcinoma in Thailand: Are there Differences Dependent on Stent Type?

Prachayakul, Varayu,Chaisayan, Suthasinee,Aswakul, Pitulak,Deesomsak, Morakod Asian Pacific Journal of Cancer Prevention 2013 Asian Pacific journal of cancer prevention Vol.14 No.1

Cholangiocarcinoma, though very rare in Western countries, is one of the commonest liver malignancies in Southeast Asia, especially in Thailand. More than half of the patients present with advanced stage disease. Given the poor treatment outcomes of adjuvant therapeutic options, many patients undergo only biliary drainage for palliative treatment. Clinical characteristics and treatment outcomes after biliary stenting were here analyzed for a total of 224 uresectable cholangiocarcinoma cases, 58.9% in men. The mean age was 61.5 years. Hilar involvement was the most common location. The patients underwent biliary drainage using plastic and metallic stents equally, early stent occlusion being encountered in 21.4% and 10.7%, respectively. The median survival time was 4.93 months for patients who received plastic and 5.87 months for patients who received metallic stents.

Clinical, Radiologic, and Endoscopic Manifestations of Small Bowel Malignancies: a First Report from Thailand

Tangkittikasem, Natthakan,Boonyaarunnate, Thiraphon,Aswakul, Pitulak,Kachintorn, Udom,Prachayakul, Varayu Asian Pacific Journal of Cancer Prevention 2015 Asian Pacific journal of cancer prevention Vol.16 No.18

Background: The symptoms of small bowel malignancies are mild and frequently nonspecific, thus patients are often not diagnosed until the disease is at an advanced stage. Moreover, the lack of sufficient studies and available data on small bowel cancer makes diagnosis difficult, further delaying proper treatment for these patients. In fact, only a small number of published studies exist, and there are no studies specific to Thailand. Radiologic and endoscopic studies and findings may allow physicians to better understand the disease, leading to earlier diagnosis and improved patient outcomes. Objective: To retrospectively analyze the clinical, radiologic, and endoscopic characteristics of small bowel cancer patients in Thailand's Siriraj Hospital. Materials and Methods: This retrospective analysis included 185 adult patients (97 men, 88 women; mean age = $57.6{\pm}14.9$) with pathologically confirmed small bowel cancer diagnosed between January 2006 and December 2013. Clinical, radiologic, and endoscopic findings were collected and compared between each subtype of small bowel cancer. Results: Of the 185 patients analyzed, gastrointestinal stromal tumor (GIST) was the most common diagnosis (39.5%, n=73). Adenocarcinoma was the second most common (25.9%, n = 48), while lymphoma and all other types were identified in 24.3% (n = 45) and 10.3% (n = 19) of cases, respectively. The most common symptoms were weight loss (43.2%), abdominal pain (38.4%), and upper gastrointestinal bleeding (23.8%). Conclusions: Based on radiology and endoscopy, this study revealed upper gastrointestinal bleeding, an intra-abdominal mass, and a sub-epithelial mass as common symptoms of GIST. Obstruction and ulcerating/circumferential masses were findicative of adenocarcinoma, as revealed by radiology and endoscopy, respectively. Finally, no specific symptoms were related to lymphoma.

Centralized 3D Radio Resource Allocation and Scheduling for Multi-tier Control-/User-plane Split Architecture for 5G Mobile Network

Rony Kumer Saha,Chaodit Aswakul 대한전자공학회 2017 대한전자공학회 학술대회 Vol.2017 No.1

In this paper, we propose a centralized allocation and scheduling strategy for 3-dimensional radio resources (namely, time, frequency, and power) for a multi-tier control-plane and user-plane (C-/U-plane) split 5G mobile network architecture by considering schedulers of all base stations (BSs) located at a central station. We consider a multi-tier network comprises of a macrocell BS (MCBS) and a number of outdoor picocell BSs as well as indoor femtocell BSs (FCBSs) deployed within a multi-storage building. In contrast to the conventional almost blank subframe, we consider a fully blank subframe (FBS) based eICIC to split completely C-/U-plane such that control-plane can be served only by the MCBS and user-plane by each UE’s respective BS. The system bandwidth is reused in FCBSs, and frequency resources are allocated orthogonally per tier basis. We propose a simple FCBS power control mechanism by modeling a FCBS’s on-state and off-state power as on/off traffic source model, and derive an optimal value of average activation factor (AAF) of any FCBSs per FBS pattern period to trade-off its serving capacity and transmit power saving. With a system level simulation it is shown that the capacity of a FCBS increases whereas its power saving decreases linearly with an increase in its AAF because of serving increased traffic, and an optimal AAF of 0.5 for the capacity scaling factor k=1and greater than 0.5 for k<1is found.

Microwave and Millimeter-wave Enabled Small Cell for Non-uniform and Asymmetric Traffic in 5G Mobile Network

Rony Kumer Saha,Chaodit Aswakul 대한전자공학회 2017 대한전자공학회 학술대회 Vol.2017 No.1

In this paper, a multi-band, namely co-channel microwave and 60 GHz millimeter-wave bands, enabled femtocell base station (FCBS) architecture (MBFA) is proposed to address non-uniform and asymmetric traffic in 5G cellular mobile networks. All femtocells are deployed in a multi-storage building. For the co-channel microwave band, the interference between FCBSs and the macrocell base station is avoided using almost blank subframe based enhanced inter-cell interference coordination techniques. The coexistence of both bands architecture is studied, and the outperformance of millimeter-wave over co-channel microwave bands is shown in terms of system capacity and spectral efficiency. We analyze the use of MBFA to address non-uniform traffic and asymmetric traffic from splitting uplink/downlink as well as control-plane/user-plane. Finally, the outperformance of MBFA over the single band enabled FCBS architecture in terms of energy efficiency, system capacity, and spectral efficiency is shown.

A Novel Clustering, Frequency Reuse and Allocation Technique for 2D Regular Grid-based Dense Urban Femtocell Deployment for 5G Mobile Networks

Rony Kumer Saha,Chaodit Aswakul 대한전자공학회 2017 대한전자공학회 학술대회 Vol.2017 No.1

In this paper, we propose a technique for clustering, frequency reuse, and allocation to femtocells (FCs) deployed densely in a 2-dimensional (2D) space in urban environments to address the high capacity and spectral efficiency demands of 5G mobile networks. We model the 2D space to consist of a set of square-grid apartments with one FC per apartment. A region of exclusion (RoE) including a group of FCs over the space is formed based on satisfying an optimization constraint of a minimum aggregate interference per link between co-channel FCs of adjacent RoEs. The co-channel interference is modelled using the planar-Wyner model. The number of FCs within a RoE forms a cluster of FCs, and all FC clusters have the same size for a given constraint. We propose an adjacent channel interference avoided static resource reuse and allocation algorithm for FCs within each cluster where the whole system bandwidth is reused. For performance evaluation, we consider a floor of a multi-storage building as 2D space that consists of 5×5 squaregrid apartments, and a multi-tier network that consists of a macrocell, a number of outdoor picocells and indoor FCs on the floor. The almost blank subframe (ABS) based eICIC technique is used to avoid cross-tier interference between macro-tier and femto-tier. With a system level simulation, we demonstrate the number of clusters that can be formed for a given interference constraint and the outperformance of the proposed technique by manifold in terms of the capacity and spectral efficiency as compared to the conventional ABS based eICIC technique.

Capacity Analysis of Control-/User-plane Traffic of Different Small Cell Base Station Architectures for 5G Cellular

Rony Kumer Saha,Chaodit Aswakul 대한전자공학회 2017 대한전자공학회 학술대회 Vol.2017 No.1

In this paper, we present numerous small cell base station, i.e. femtocell base station (FCBS), architectures based on the number of transceivers (e.g., single or dual transceiver) and operating frequency bands (e.g., microwave and millimeter wave bands) existing in a FCBS for serving control-plane and user-plane (C-/U-plane) traffic in indoor environments under both traditional C-/U-plane coupled architecture (CUCA) as well as prospective C- /U-plane separation architecture (CUSA). With a system level simulation of a multi-tier network, we evaluate the performances of these FCBS architectures in terms of control-plane, user-plane, and an aggregate C-/U-plane traffic capacities. The simulation results show that because of serving only U-plane traffic by a FCBS in CUSA, CUSA outperforms CUCA for a single transceiver based FCBS in terms of user-plane traffic capacity irrespective of operating frequency. However, the presence of dual bands at a dual transceiver based FCBS results in higher aggregate C-/U-plane traffic capacity than that of a single transceiver based FCBS. Finally, we discuss a number of strengths and weaknesses, viability challenges, and open issues of these FCBS architectures.

Gastric Somatostatinoma: An Extremely Rare Cause of Upper Gastrointestinal Bleeding

Varayu Prachayakul,Pitulak Aswakul,Morakod Deesomsak,Ananya Pongpaibul 대한소화기내시경학회 2013 Clinical Endoscopy Vol.46 No.5

A 49-year-old woman presented with chronic abdominal discomfort, significant weight loss, and chronic intermittent diarrhea. She suddenly developed massive upper gastrointestinal bleeding and was referred for further treatment. Endoscopy indicated a large mass in the upper gastric body with antral and duodenal bulb involvement. Endosonography showed a large well-defined isoechoic gastric subepithelial mass with multiple intra-abdominal and peri-pancreatic lymphadenopathy, suspected to be malignant on the basis of fine needle aspiration cytology. The tumor was surgically removed, and histopathology showed typical characteristics of a neuroendocrine tumor. On the basis of immunohistochemical staining, somatostatinoma, a rare neuroendocrine tumor, was diagnosed. Gastrointestinal bleeding is a rare presentation and the stomach is an uncommon tumor location.

Emulated OpenFlow Based Experimental Study on Middle-Box Buffering Effect for Multi-Path Chunked Video Streaming

Phyo May Thet,Nattakarn Tientrakul,JongWon Kim,Chaodit Aswakul 대한전자공학회 2015 ITC-CSCC :International Technical Conference on Ci Vol.2015 No.6

In this paper, we have implemented the emulated multipath OpenFlow network with splitting and middle-box functionalities for investigating video buffering effects on packet delay and jitter performance for an RTP video streaming session. The mininet emulator is used to construct the multi-path OpenFlow network. The network consists of a video server, a video client, four Open vSwitches (OVSs), a remote controller and a middle-box. The POX controller is used for adding flow entries into switches and assigning periodic splitting function. The reported mean/ standard deviation of packet delay results show that the proper chunk size ratio and initial buffering time need to be considered carefully to improve the video packet delay and jitter performance.