2.An approach to the ethical evaluation of innovative surgical procedures.
Veronique K M TAN ; Pierce K H CHOW
Annals of the Academy of Medicine, Singapore 2011;40(1):26-29
While there is an ethical obligation to improve clinical outcomes by developing better therapies, surgical innovation has largely progressed without the strict regulations required of novel pharmaceutical products. We explore the reasons why new surgical techniques are frequently introduced without the benefit of randomised controlled trials, and present an approach to the ethical evaluation of novel surgical procedures.
Biomedical Research
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ethics
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Clinical Competence
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Diffusion of Innovation
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Ethics, Medical
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General Surgery
;
ethics
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methods
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standards
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Humans
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Informed Consent
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Medical Audit
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Medicine
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Singapore
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Specialty Boards
3.Conflict of Interest in Research--The Clinician Scientist's Perspective.
Nicole H Y KONG ; Pierce K H CHOW
Annals of the Academy of Medicine, Singapore 2013;42(11):623-628
Conflict of interest (COI) in research represents situations that pose risks of undue influence on scientific objectivity and judgment because of secondary interests. This is complex but is inherent to biomedical research. The role of a clinician scientist can be conflicted when scientific objectivity is perceived to compete with scientific success (publications, grants), partiality to patients (clinical trials), obligations to colleagues (allowing poor scholarship to pass), research sponsors (industry), and financial gains (patents, royalties). While there are many ways which COIs can occur in research, COI mitigations remain reliable. Collaborations between investigators and industry are valuable to the development of novel therapies and undue discouragement of these relationships may inadvertently harm the advancement of healthcare. As a result, proper management of COI is fundamental and crucial to the maintenance of long-term, mutually beneficial relationships between industry and academia. The nature of COI in research and methods of mitigation are discussed from the perspective of a clinician scientist.
Biomedical Research
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Conflict of Interest
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Humans
4.Image-guided radiofrequency ablation of liver malignancies: experience at Singapore General Hospital.
Shoen C S LOW ; Richard H G LO ; Te-Neng LAU ; London Lucien P J OOI ; Chee-Keong HO ; Bien-Soo TAN ; Alexander Y F CHUNG ; Wen-Hsin KOO ; Pierce K H CHOW
Annals of the Academy of Medicine, Singapore 2006;35(12):851-857
UNLABELLEDThe aim of this paper was to study the efficacy, side effects and complications of radiofrequency (RF) ablation of primary and metastatic liver malignancies.
MATERIALS AND METHODSWe retrospectively reviewed 57 patients (39 men, 18 women; mean age, 63 years; age range, 44 to 83 years) who underwent RF ablation for liver malignancies from January 2002 to December 2004. A total of 87 tumours were ablated - 71 (81.6%) hepatocellular carcinomas and 16 (18.4%) metastases (from primaries in the colon, stomach and pancreas). RF ablation was performed either percutaneously (n = 71) under conscious sedation or intraoperatively (n = 16) under general anaesthesia. Follow-up ranged from 1 month to 41 months (mean, 15.2) and included computed tomography (CT) 1 day, 1 month and 3 months after ablation, and half-yearly thereafter. Patients were observed for local tumour progression and for the emergence of new tumours.
RESULTSFour patients with a total of 5 tumours were lost to follow-up. Of the remaining 82 tumours treated, complete ablation was attained in 66 tumours after a single procedure, giving a primary effectiveness rate of 80.5%. Seven (8.5%) required 2 procedures to achieve complete ablation, giving a secondary effectiveness rate of 89% after 2 ablations. One tumour (1.2%) required 3 procedures to achieve complete ablation. One tumour required 4 procedures to date, with the latest follow-up CT still demonstrating incomplete ablation. Two tumours (2.4%) had an initial RF ablation and subsequent transarterial chemoembolisation (TACE). One tumour had an initial RF ablation followed by 32Phosphorus-biosilicon (BrachySil) injection, the latter as part of a Phase IIA trial. One tumour required 2 RF ablations and a subsequent TACE. Lastly, 3 tumours received initial RF ablation but subsequent local tumour progression was not treated as the patients were deemed unfit for repeat ablation. No procedure-related deaths or major complications were encountered. Minor complications were reported in 2 patients (3.8%) - subcapsular haematoma and thermal injury to the adjacent gastric antrum, both not necessitating surgical intervention.
CONCLUSIONSRF ablation is an effective, safe and relatively simple procedure for the treatment of unresectable liver malignancies.
Adult ; Aged ; Aged, 80 and over ; Carcinoma, Hepatocellular ; mortality ; secondary ; surgery ; therapy ; Catheter Ablation ; Chemoembolization, Therapeutic ; Combined Modality Therapy ; Female ; Hospitals, General ; Humans ; Liver Neoplasms ; mortality ; secondary ; surgery ; therapy ; Male ; Middle Aged ; Retreatment ; Retrospective Studies ; Singapore ; Surgery, Computer-Assisted
5.Infected pancreatic necrosis--an evaluation of the timing and technique of necrosectomy in a Southeast Asian population.
Victor T W LEE ; Alexander Y F CHUNG ; Pierce K H CHOW ; Choon-Hua THNG ; Albert S C LOW ; London-Lucien P J OOI ; Wai-Keong WONG
Annals of the Academy of Medicine, Singapore 2006;35(8):523-530
INTRODUCTIONAcute pancreatitis appears to be less prevalent in multi-ethnic Southeast Asia, where the aetiology also appears to be influenced by ethnicity. As with acute pancreatitis elsewhere, however, pancreatic necrosis is a cause of significant mortality and the aim of this study was to review our institutional experience with pancreatic necrosectomy.
MATERIALS AND METHODSThe records of all patients who underwent pancreatic necrosectomy from January 2000 to December 2004 were analysed. Indications for surgery were the presence of infected necrosis, unresolving sepsis attributable to ongoing pancreatitis or the presence of gas in the pancreatic bed on imaging. Surgical debridement was achieved by debridement with closure over drains or by debridement with open packing.
RESULTSThe cohort comprised 14 of 373 patients admitted for acute pancreatitis (3.8%), with an overall mortality rate of 29%. All patients had infected necrosis with positive bacteriological cultures. Eight patients (57%) underwent debridement with closure over drains and 6 patients (43%) underwent debridement with open packing. All mortalities occurred in patients who underwent open packing, who were also associated with a higher mean Acute Physiology and Chronic Health Evaluation (APACHE) II score. The mortality rate in patients who underwent debridement less than 4 weeks after admission was 33% (2 of 6), compared with 25% (2 of 8) in patients who underwent debridement after 4 weeks. There were no mortalities in patients operated on after 6 weeks.
CONCLUSIONSurgical debridement with closure of drains and a policy of performing delayed necrosectomy are viable in our population.
APACHE ; Adult ; Aged ; Asia, Southeastern ; epidemiology ; Cohort Studies ; Debridement ; methods ; Drainage ; Female ; Humans ; Male ; Middle Aged ; Pancreatectomy ; methods ; Pancreatitis, Acute Necrotizing ; diagnosis ; mortality ; surgery ; Time Factors ; Tomography, X-Ray Computed
6.Atypical enhancement pattern of hepatocellular carcinoma with portal vein thrombosis on multiphasic CT.
Yee Liang THIAN ; Albert S C LOW ; Pierce K H CHOW ; London L OOI ; Alexander Y F CHUNG ; Shoen C S LOW ; Wanying XIE ; Choon Hua THNG
Annals of the Academy of Medicine, Singapore 2011;40(10):454-459
INTRODUCTIONThe 2005 American Association for Study of Liver Diseases (AASLD) diagnostic criteria allow non-invasive diagnosis of hepatocellular carcinoma (HCC) based on their enhancement pattern but we have observed a high incidence of atypical enhancement characteristics in HCC associated with portal vein thrombosis. This study seeks to examine the radiological features of this particular subgroup.
MATERIALS AND METHODSPatients with HCC and portal vein thrombosis who underwent pre-treatment multiphasic CT imaging were drawn from a surgical database. The arterial, portal venous and delayed phase images were assessed qualitatively and quantitatively (with region of interest [ROI] analysis) for lesion hypervascularity and washout. The background enhancement of the left and right lobes of the liver was also quantifi ed by ROI analysis.
RESULTSTwenty-fi ve lesions in 25 patients were selected for analysis. Qualitative analysis showed that 10/25 (40%) lesions demonstrated arterial hypervascularity while 16/25 (64%) lesions showed washout. Ten out of 25 (40%) lesions demonstrated both arterial hypervascularity and washout. Quantitative analysis showed that the average absolute lesion enhancement from precontrast to arterial phases was 49.1 (± 17.1) HU for hypervascular lesions compared to 23.8 (± 16.6) HU for non-hypervascular lesions (P <0.01). The mean absolute enhancement of the background liver parenchyma in the arterial phase was 13.79 (± 7.9) HU for hypervascular lesions compared to 36.6 (± 30.6) HU for non-hypervascular lesions (P = 0.03).
CONCLUSIONA large proportion of HCC with portal vein thrombosis lack characteristic arterial hypervascularity, which may be secondary to compensatory increased arterial supply to the background liver. This is a potential pitfall when applying imaging criteria for diagnosis of HCC.
Adult ; Aged ; Aged, 80 and over ; Carcinoma, Hepatocellular ; complications ; diagnostic imaging ; Female ; Humans ; Liver Neoplasms ; complications ; diagnostic imaging ; Male ; Middle Aged ; Pattern Recognition, Automated ; Portal Vein ; diagnostic imaging ; physiopathology ; Retrospective Studies ; Tomography, X-Ray Computed ; methods ; Venous Thrombosis ; diagnostic imaging ; etiology
7.Portobiliary fistula: successful transcatheter treatment with embolisation coils.
Jendana CHANYAPUTHIPONG ; Richard Hoau Gong LO ; Bien Soo TAN ; Pierce Kah Hoe CHOW
Singapore medical journal 2014;55(3):e34-6
Although portobiliary fistula is a recognised complication of percutaneous transhepatic biliary drainage, it is extremely uncommon and can result in haemobilia. Herein, we present a case of complicated transhepatic biliary drainage catheter insertion in a patient with underlying hepatitis B liver cirrhosis, which resulted in a portobiliary fistula. The patient had a preoperative transhepatic biliary drainage procedure done prior to a Whipple's operation for a large, obstructive, gastrointestinal stromal tumour of the duodenum. To the best of our knowledge, this is the first case in the English medical literature reporting the successful treatment of portobiliary fistula by embolisation of its tract with embolisation coils, without compromising the portal vein or bile ducts.
Anemia
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complications
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Bile Ducts
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pathology
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Catheterization
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Cholangiography
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methods
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Embolization, Therapeutic
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methods
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Fistula
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etiology
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therapy
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Hepatitis B
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complications
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Humans
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Liver
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pathology
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Liver Cirrhosis
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complications
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Male
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Middle Aged
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Portal Vein
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pathology
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Tomography, X-Ray Computed
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Treatment Outcome
8.Utility of combining PIVKA-II and AFP in the surveillance and monitoring of hepatocellular carcinoma in the Asia-Pacific region
Do Young KIM ; Bao Nguyen TOAN ; Chee-Kiat TAN ; Irsan HASAN ; Lyana SETIAWAN ; Ming-Lung YU ; Namiki IZUMI ; Nguyen Nguyen HUYEN ; Pierce Kah-Hoe CHOW ; Rosmawati MOHAMED ; Stephen Lam CHAN ; Tawesak TANWANDEE ; Teng-Yu LEE ; Thi Thanh Nguyen HAI ; Tian YANG ; Woo-Chang LEE ; Henry Lik Yuen CHAN
Clinical and Molecular Hepatology 2023;29(2):277-292
Even though the combined use of ultrasound (US) and alpha-fetoprotein (AFP) is recommended for the surveillance of hepatocellular carcinoma (HCC), the utilization of AFP has its challenges, including accuracy dependent on its cut-off levels, degree of liver necroinflammation, and etiology of liver disease. Though various studies have demonstrated the utility of protein induced by vitamin K absence II (PIVKA-II) in surveillance, treatment monitoring, and predicting recurrence, it is still not recommended as a routine biomarker test. A panel of 17 experts from Asia-Pacific, gathered to discuss and reach a consensus on the clinical usefulness and value of PIVKA-II for the surveillance and treatment monitoring of HCC, based on six predetermined statements. The experts agreed that PIVKA-II was valuable in the detection of HCC in AFP-negative patients, and could potentially benefit detection of early HCC in combination with AFP. PIVKA-II is clinically useful for monitoring curative and intra-arterial locoregional treatments, outcomes, and recurrence, and could potentially predict microvascular invasion risk and facilitate patient selection for liver transplant. However, combining PIVKA-II with US and AFP for HCC surveillance, including small HCC, still requires more evidence, whilst its role in detecting AFP-negative HCC will potentially increase as more patients are treated for hepatitis-related HCC. PIVKA-II in combination with AFP and US has a clinical role in the Asia-Pacific region for surveillance. However, implementation of PIVKA-II in the region will have some challenges, such as requiring standardization of cut-off values, its cost-effectiveness and improving awareness among healthcare providers.
9.Wash-out of hepatocellular carcinoma: quantitative region of interest analysis on CT.
Cher Heng TAN ; Choon Hua THNG ; Albert S C LOW ; Veronique K M TAN ; Septian HARTONO ; Tong San KOH ; Brian K P GOH ; Peng Chung CHEOW ; Yu Meng TAN ; Alexander Y F CHUNG ; London L OOI ; Arul EARNEST ; Pierce K H CHOW
Annals of the Academy of Medicine, Singapore 2011;40(6):269-275
INTRODUCTIONThis study aims to determine if the quantitative method of region-of-interest (ROI) analysis of lesion attenuation on CT may be a useful adjunct to the conventional approach of diagnosis by visual assessment in assessing tracer wash-out in hepatocellular carcinomas.
MATERIALS AND METHODSFrom a surgical database of 289 patients from 2 institutions, all patients with complete surgical, pathological and preoperative multiphasic CT scans available for review were selected. For each phase of scanning, HU readings of lesion obtained (Lesion(arterial), Lesion(PV) and Lesion(equilibrium)) were analysed using receiver operating curves (ROC) to determine the optimal method and cut-off value for quantitative assessment of tumour wash-out (Lesion(arterial - equilibrium), Lesion(PV - equilibrium) or Lesion(peak - equilibrium)).
RESULTSNinety-four patients with one lesion each met the inclusion criteria. The area under the curve (AUC) values for Lesion(arterial - equilibrium) (0.941) was higher than the AUC for Lesion(pv - equilibrium) (0.484) and for Lesion(peak - equilibrium) (0.667). Based on ROC analysis, a cut-off of 10HU value for Lesion(arterial - equilibrium) would yield sensitivity and specificity of 91.5% and 80.9%, respectively. ROI analysis detected 9/21 (42.9%) of lesions missed by visual analysis. Combined ROI and visual analysis yields a sensitivity of 82/94 (87.2%) compared to 73/94 (77.7%) for visual analysis alone.
CONCLUSIONUsing a cut-off of 10 HU attenuation difference between the arterial and equilibrium phases is a simple and objective method that can be included as an adjunct to visual assessment to improve sensitivity for determining lesion wash-out on CT.
Adult ; Aged ; Aged, 80 and over ; Carcinoma, Hepatocellular ; diagnosis ; pathology ; surgery ; Confidence Intervals ; Databases, Factual ; Female ; Humans ; Liver ; pathology ; Liver Neoplasms ; diagnosis ; pathology ; surgery ; Male ; Middle Aged ; Preoperative Period ; ROC Curve ; Retrospective Studies ; Sensitivity and Specificity ; Tomography, X-Ray Computed ; instrumentation ; Young Adult
10.Interval increase in the prevalence of symptomatic cholelithiasis-associated non-alcoholic fatty liver disease over a ten-year period in an Asian population.
Kevin Beng Chin KHAW ; Rachel Huiyi CHOI ; Juinn Huar KAM ; Bibhas CHAKRABORTY ; Pierce Kah Hoe CHOW
Singapore medical journal 2017;58(12):703-707
INTRODUCTIONNon-alcoholic fatty liver disease (NAFLD) is frequently associated with cholelithiasis. The prevalence of NAFLD in Asia has been on the rise, but the magnitude of this increase had not been studied previously.
METHODSA retrospective cohort study was conducted on consecutive patients who underwent laparoscopic or open cholecystectomy from November 2001 to November 2004 (Cohort 1) and from November 2011 to November 2014 (Cohort 2) at Singapore General Hospital. Preoperative diagnostic scans (e.g. ultrasonography, computed tomography and magnetic resonance imaging) and clinical data were reviewed for the presence of fatty liver. Statistical analysis was performed.
RESULTSIn Cohorts 1 and 2, 127 patients and 99 patients were operated on, respectively. Cohort 2 had significantly higher proportions of patients with NAFLD (56.6% vs. 40.2%; p < 0.015) and hyperlipidaemia (45.5% vs. 18.9%; p < 0.001) as compared to Cohort 1. Binary logistic regression analysis showed that hypertension (odds ratio [OR] 2.558; p < 0.004) and Indian ethnicity (OR 5.448; p < 0.043) were significantly associated with NAFLD.
CONCLUSIONSimilar to other international studies, we found a significant increase in the prevalence of patients with NAFLD presenting symptomatically for cholecystectomy over an interval of ten years in Singapore. Hypertension and Indian ethnicity were significantly associated with NAFLD in both time periods. This trend supports the need for concerted public health intervention to stem the increasing incidence of NAFLD and prevent its progression to more advanced liver disease.