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Featured researches published by Thomas W.T. Leung.


The Lancet | 1999

Adjuvant intra-arterial lipiodol-iodine-131 for resectable hepatocellular carcinoma: a prospective randomised trial

W. Y. Lau; Thomas W.T. Leung; S. Ho; M. Chan; David Machin; Joseph Lau; Anthony T.C. Chan; Winnie Yeo; Tony Mok; Simon C.H. Yu; Nancy Leung; Philip J. Johnson

Summary Background Resection of hepatocellular carcinoma is potentially curative, but local recurrence is common. In this prospective randomised trial, we aimed to find out if one dose of postoperative adjuvant intra-arterial iodine-131-labelled lipiodol could reduce the rate of local recurrence and increase disease-free and overall survival. Methods Patients who underwent curative resection for hepatocellular carcinoma and recovered within 6 weeks were randomly assigned one 1850 MBq dose of 131 I-lipiodol or no further treatment (controls). We compared rates of recurrence and disease-free and overall survival (the primary endpoints) between the two groups by intention to treat. We planned an interim analysis when 30 patients (both groups together) had been followed up for a median of 2 years, with the intention of stopping early if the between-group difference in disease-free survival was significant (p=0·029). Findings Between April, 1992, and August, 1997, we recruited 43 patients: 21 received intra-arterial 131 I-lipiodol and 22 received no adjuvant treatment. During a median follow-up of 34·6 (range 14·1–69·7) months, there were six (28·5%) recurrences among the 21 patients in the adjuvant treatment, compared with 13 (59%) in the controls (p=0·04). Median disease-free survival in the treatment and control groups was 57·2 (0·4–69·7) and 13·6 (2·1–68·3) months, respectively (p=0·037). 3-year overall survival in the treatment and control groups was 86·4% and 46·3%, respectively (p=0·039). The interim analysis showed a significant increase in disease-free survival in the treatment group compared with the controls (p=0·01), so we closed the trial early. 131 I-lipiodol had no significant toxic effects. Interpretation In patients with hepatocellular carcinoma, one 1850 MBq dose of intra-arterial 131 I-lipiodol given after curative resection significantly decreases the rate of recurrence and increases disease-free and overall survival.


Journal of Clinical Oncology | 2002

Concurrent Chemotherapy-Radiotherapy Compared With Radiotherapy Alone in Locoregionally Advanced Nasopharyngeal Carcinoma: Progression-Free Survival Analysis of a Phase III Randomized Trial

Anthony T.C. Chan; Peter M.L. Teo; R.K. Ngan; Thomas W.T. Leung; Wan-Yee Lau; Benny Zee; Sing Fai Leung; F.Y. Cheung; Winnie Yeo; H.H. Yiu; K. H. Yu; K. W. Chiu; D.T. Chan; Tony Mok; K.T. Yuen; F. Mo; Maria Lai; W. H. Kwan; Paul Cheung-Lung Choi; Philip J. Johnson

PURPOSE Nasopharyngeal carcinoma (NPC) is highly sensitive to both radiotherapy (RT) and chemotherapy. This randomized phase III trial compared concurrent cisplatin-RT (CRT) with RT alone in patients with locoregionally advanced NPC. PATIENTS AND METHODS Patients with Hos N2 or N3 stage or N1 stage with nodal size > or = 4 cm were randomized to receive cisplatin 40 mg/m(2) weekly up to 8 weeks concurrently with radical RT (CRT) or RT alone. The primary end point was progression-free survival (PFS). RESULTS Three hundred fifty eligible patients were randomized. Baseline patient characteristics were comparable in both arms. There were significantly more toxicities, including mucositis, myelosuppression, and weight loss in the CRT arm. There were no treatment-related deaths in the CRT arm, and one patient died during treatment in the RT-alone arm. At a median follow-up of 2.71 years, the 2-year PFS was 76% in the CRT arm and 69% in the RT-alone arm (P =.10) with a hazards ratio of 1.367 (95% confidence interval [CI], 0.93 to 2.00). The treatment effect had a significant covariate interaction with tumor stage, and a subgroup analysis demonstrated a highly significant difference in favor of the CRT arm in Hos stage T3 (P =.0075) with a hazards ratio of 2.328 (95% CI, 1.26 to 4.28). For T3 stage, the time to first distant failure was statistically significantly different in favor of the CRT arm (P =.016). CONCLUSION Concurrent CRT is well tolerated in patients with advanced NPC in endemic areas. Although PFS was not significantly different between the concurrent CRT arm and the RT-alone arm in the overall comparison, PFS was significantly prolonged in patients with advanced tumor and node stages.


International Journal of Radiation Oncology Biology Physics | 1998

Selective internal radiation therapy for nonresectable hepatocellular carcinoma with intraarterial infusion of 90yttrium microspheres

Wan-Yee Lau; S. Ho; Thomas W.T. Leung; M. Chan; R. Ho; Philip J. Johnson; A. K. C. Li

PURPOSE To evaluate the efficacy of intraarterial 90yttrium (90Y) microspheres in nonresectable hepatocellular carcinoma (HCC). METHODS AND MATERIALS Patients with nonresectable HCC, but without extrahepatic disease, who also had lung shunting < 15% and tumor-to-normal ratio > or =2, as determined by simulation using (99m)technetium macroaggregated albumin, were entered into the study. The radiation dose delivered to the lungs, tumor, and normal liver was estimated by a partition model. 90Y microspheres were infused into the hepatic artery at the time of hepatic angiography or through an implanted arterial portacatheter under fluoroscopy. Repeated treatments were given for residual or recurrent tumor. Response to treatment was monitored by serum alpha-fetoprotein or ferritin levels, together with serial computed tomography. RESULTS Seventy-one patients, including 20 patients with postoperative recurrence, were initially treated with an activity of 0.8 to 5.0 Giga-Becquerel (GBq) (21.6-135.1 mCi) (median 3.0 GBq or 81.1 mCi) of 90Y microspheres. There was a 50% reduction in tumor volume in 19 (26.7%) patients after the first treatment. However, the overall objective response in terms of changes in alpha-fetoprotein levels was 89% [partial response (PR) 67%, complete response (CR) 22%] among the 46 patients with raised pretreatment levels. The serum ferritin level in the other 25 patients dropped by 34 to 99% after treatment. Treatment was repeated in 15 patients. The maximum number of treatments was 5 and the maximum total activity was 13.0 GBq (351.4 mCi), given in 3 treatments. The estimated radiation doses to the nontumorous liver ranged from 25 to 136 Gy (median 52 Gy) in the first treatment and the highest total radiation dose was estimated to be 324 Gy. For the tumors, the estimated radiation doses ranged from 83 to 748 Gy (median 225 Gy) in the initial treatment and the highest cumulative dose reached was 1580 Gy. The residual tumors were resected in 4 patients. Two of these had complete histological remission, but only occasional viable tumor cells were found in the necrotic centers of the tumors resected from the other 2 patients. The median survival of the 71 patients was 9.4 months (range 1.8 to 46.4 months). Treatment was well tolerated and there was no bone-marrow toxicity, or clinical evidence of radiation hepatitis or pneumonitis. CONCLUSIONS Selective internal radiation therapy using 90Y microspheres is effective for selected cases of nonresectable HCC and is well tolerated. The objective response rate in terms of drop in tumor marker levels is higher than that based on reduction in tumor volume shown by computed tomography. The nontumorous liver appears more tolerant to internal radiation than external beam radiation. Selective internal radiation treatment may convert nonresectable tumors to resectable ones.


International Journal of Radiation Oncology Biology Physics | 1995

A prospective randomized study of chemotherapy adjunctive to definitive radiotherapy in advanced nasopharyngeal carcinoma

Anthony T.C. Chan; Peter M.L. Teo; Thomas W.T. Leung; Sing F. Leung; Wai Y. Lee; Winnie Yeo; Peter H.K. Choi; Philip J. Johnson

PURPOSE A prospective randomized trial was conducted to compare chemoradiotherapy against radiotherapy alone in the treatment of locoregionally advanced nasopharyngeal carcinoma. METHODS AND MATERIALS Eighty-two patients with histologically proven nasopharyngeal carcinoma who had either Hos N3 staging or any N stage with a nodal diameter of > or = 4 cm were entered. Seventy-seven patients were evaluated for tumor response and survival. The patients were randomized to receive two cycles of cisplatin 100 mg/m2 Day 1,5-fluorouracil 1000 mg/m2 24-h infusion Days 2, 3, and 4 before radical radiotherapy, and four cycles of postradiotherapy chemotherapy (37 patients) or radiotherapy alone (40 patients). All patients received radical radiotherapy to the nasopharynx and neck. The nasopharynx and upper neck were treated to 66 Gy by conventional fractionation and the lower neck to 58 Gy. Booster radiotherapy (7.5 Gy/two fractions/week) was given to any residual nodes after standard radiotherapy. RESULTS The patient characteristics, including staging, were similar in both arms. The overall response rate to neoadjuvant chemotherapy was 81% (19% complete response, 62% partial response). The rates of radiotherapy for boosting parapharyngeal disease or residual lymph nodes were not significantly different in the two arms. The overall complete response rate to chemoradiotherapy was 100%, and to radiotherapy alone, 95%. Toxicities in the chemoradiotherapy arm were mainly myelosuppression, nephrotoxicity, and nausea and vomiting. The degree of mucositis was not significantly different in the two arms. There was no treatment-related death. The median follow up was 28.5 months. The 2-year overall survival was 80% in the chemoradiotherapy arm and 80.5% in the radiotherapy arm. The 2-year disease-free survival was 68% in the chemoradiotherapy arm and 72% in the radiotherapy arm, without significant difference between the two arms. The locoregional relapse rate, distant metastatic rate, and median time to relapse were also not significantly different between the two arms. CONCLUSION Despite promising tumor response rates from Phase II trials, this prospective randomized trial has demonstrated no benefit from adjunctive chemotherapy to radiotherapy in the treatment of locoregionally advanced nasopharyngeal carcinoma.


Annals of Surgery | 2003

Percutaneous Local Ablative Therapy for Hepatocellular Carcinoma: A Review and Look Into the Future

W. Y. Lau; Thomas W.T. Leung; Simon C.H. Yu; S. Ho

ObjectiveTo review and compare treatment result for percutaneous local ablative therapy (PLAT) with surgical resection in the treatment of small hepatocellular carcinoma (HCC). Summary Background DataPLAT is indicated for small unresectable HCC localized to the liver. From the use of ethanol to the latest technology of radiofrequency ablation, ablative techniques have been refined and their role in the management of HCC established. This review aims to give an overview of various ablative methods, including their efficacy, indications, and limitations, and also tries to look into the future of clinical trials in PLAT. MethodsThe authors reviewed recent papers in the English medical literature about the use of local ablative therapy for HCC. Focus was given to the results of treatment in terms of local control, progression-free survival, and overall survival, and to compare treatment results with those of surgery. ResultsPLAT for small HCC (<5 cm) with thermal ablation (radiofrequency ablation or microwave coagulation) can achieve effective local control of disease and is superior to ethanol injection. Progressive disease in untreated areas is a common reason for failure. Overall progression-free survival is similar to that of surgical resection. ConclusionsThermal ablation gives good local control of small HCC, is superior to ethanol, and may be comparable to surgical resection in long-term outcome.


International Journal of Radiation Oncology Biology Physics | 1995

Radiation pneumonitis after selective internal radiation treatment with intraarterial 90Yttrium-microspheres for inoperable hepatic tumors

Thomas W.T. Leung; Wan-Yee Lau; S. Ho; Simon C. Ward; John Chow; Michael S.Y. Chan; Con Metreweli; Philip J. Johnson; A. K. C. Li

PURPOSE To investigate the clinical, histopathological, and radiological features of radiation pneumonitis arising as a complication of selective internal radiation treatment for liver tumors. To correlate the development of radiation pneumonitis with the degree of lung shunting as assessed by 99mTechnetium-labeled macroaggregated albumin (Tc-MAA) scan. METHODS AND MATERIALS Five out of 80 patients who had inoperable hepatic tumors and underwent treatment with intraarterial 90Yttrium- (90Y)-microspheres, developed progressive restrictive ventilatory dysfunction without an infective or cardiovascular cause. Histopathological evidence of a pneumonitis and the presence of microspheres in the lung tissue suggested a diagnosis of radiation pneumonitis. The clinical course, radiological and histopathological findings, percentage tumor shunting to the lungs (lung shunting, as predicted by gamma camera scanning after intraarterial Tc-MAA), and the estimated radiation dose to the lungs were analyzed. In an attempt to reduce pulmonary shunting of the microspheres, three patients received partial hepatic embolization with inert particles before selective internal radiation therapy. RESULTS In the five patients who developed radiation pneumonitis, lung shunting percentages (as predicted by Tc-MAA scan) ranged from 13.1 to 45.6% (median 23.7%). The estimated whole lung radiation dose ranged from 10.43 Gy to 36.44 Gy (median 25.04 Gy). Among 75 patients who did not develop radiation pneumonitis, the percentage lung shunting ranged from less than 1% to 15% (median 6%). Nine patients had lung shunting greater than 13% and five of them developed radiation pneumonitis, whereas this developed in none of those in whom shunting was below 13%. The onset of radiation pneumonitis ranged from 1 to 6 months after internal radiation treatment. All five patients exhibited characteristic plain radiographic and computerized tomographic changes comprising extensive consolidation with well-defined lateral margins. Clinical improvement after corticosteroid treatment was seen in two patients. Three patients died from respiratory failure and two from other causes. Partial hepatic arterial embolization reduced the degree of lung shunting to less than 13%, but did not prevent the development of radiation pneumonitis. CONCLUSION Radiation pneumonitis may become a complication after intraarterial 90Y-microspheres treatment when lung shunting, as assessed by Tc-MAA scan, is high (above 13%). Prescribed activity of 90Y and lung shunting of Tc-MAA should be considered together before giving selective internal radiation (SIR) therapy for hepatic tumors, and preferably avoided if the lung shunting is above 13%.


Clinical Chemistry | 2003

Comprehensive Proteomic Profiling Identifies Serum Proteomic Signatures for Detection of Hepatocellular Carcinoma and Its Subtypes

Terence C.W. Poon; Tai Tung Yip; Anthony T.C. Chan; Christine Yip; Victor Yip; Tony Mok; Conrad Lee; Thomas W.T. Leung; S. Ho; Philip J. Johnson

BACKGROUND Detection of hepatocellular carcinoma (HCC) in patients with chronic liver disease (CLD) is difficult. We investigated the use of comprehensive proteomic profiling of sera to differentiate HCC from CLD. METHODS Proteomes in sera from 20 CLD patients with alpha-fetoprotein (AFP) <500 microg/L (control group) and 38 HCC patients (disease group) were profiled by anion-exchange fractionation (first dimension), two types (IMAC3 copper and WCX2) of ProteinChip Arrays (second dimension), and time-of-flight mass spectrometry (third dimension). Bioinformatic tests were used to identify tumor-specific proteomic features and to estimate the values of the tumor-specific proteomic features in the diagnosis of HCC. Cross-validation was performed, and we also validated the models with pooled sera from the control and disease groups, serum from a CLD patient with AFP >500 microg/L, and postoperative sera from two HCC patients. RESULTS Among 2384 common serum proteomic features, 250 were significantly different between the HCC and CLD cases. Two-way hierarchical clustering differentiated HCC and CLD cases. Most HCC cases with advanced disease were clustered together and formed two subgroups that contained significantly more cases with lymph node invasion or distant metastasis. For differentiation of HCC and CLD by an artificial network (ANN), the area under the ROC curve was 0.91 (95% confidence interval, 0.82-1.01; P <0.0005) for all cases and 0.954 (95% confidence interval, 0.881-1.027; P <0.0005) for cases with nondiagnostic serum AFP (<500 microg/L). At a specificity of 90%, the sensitivity was 92%. Both cluster analysis and ANN correctly classified the pooled serum samples, the CLD serum sample with increased AFP, and the HCC patient in complete remission. CONCLUSION Tumor-specific proteomic signatures may be useful for detection and classification of hepatocellular cancers.


Journal of Clinical Oncology | 2004

Lamivudine for the Prevention of Hepatitis B Virus Reactivation in Hepatitis B s-Antigen Seropositive Cancer Patients Undergoing Cytotoxic Chemotherapy

Winnie Yeo; Paul K.S. Chan; Wing M. Ho; Benny Zee; Kwok Chi Lam; Kenny I. K. Lei; Anthony T.C. Chan; Tony Mok; Jam J. Lee; Thomas W.T. Leung; Sheng Zhong; Philip J. Johnson

PURPOSE For cancer patients receiving cytotoxic chemotherapy, hepatitis B virus (HBV) reactivation is a well described complication resulting in varying degrees of liver damage. The objectives of this study were to assess the efficacy of the antiviral agent lamivudine in reducing the incidence of HBV reactivation and diminishing morbidity and mortality of cancer patients with chronic HBV infection during chemotherapy. PATIENTS AND METHODS Two groups were compared in this nonrandomized study. The prophylactic lamivudine group consisted of 65 patients in a phase II study who were treated with lamivudine before and until 8 weeks after discontinuing chemotherapy. The historical controls consisted of 193 consecutive patients who underwent chemotherapy without prophylactic lamivudine. Significant prognosticators for the development of HBV reactivation were determined based on data from the controls. Potential confounding factors were identified between the two groups. The outcomes were compared. RESULTS In the controls, lymphoma and anthracycline usage were factors identified to be associated with reactivation. The two groups were comparable in most baseline characteristics, although in the prophylactic lamivudine group, there were significantly more patients with lymphoma and receiving anthracyclines. In the prophylactic lamivudine group, there was significantly less HBV reactivation (4.6% v 24.4% in the controls; P <.001), fewer incidences of hepatitis (17.5% v 44.6%; P <.0001) that were less severe (4.8% v 18.7%; P =.0005), and less disruption of chemotherapy (15.4% v 34.6%; P =.0029). The reduction in overall mortality was not statistically different. CONCLUSION Prophylactic lamivudine significantly reduced the incidence of HBV reactivation and the overall morbidity of cancer patients undergoing chemotherapy.


European Journal of Nuclear Medicine and Molecular Imaging | 1997

Clinical evaluation of the partition model for estimating radiation doses from yttrium-90 microspheres in the treatment of hepatic cancer

S. Ho; W. Y. Lau; Thomas W.T. Leung; M. Chan; Philip J. Johnson; A. K. C. Li

Radiation doses to the tumour and non-tumorous liver compartments from yttrium-90 microspheres in the treatment of hepatic cancer, as estimated by a partition model, have been verified by correlation with the actual doses measured with a beta probe at open surgery. The validity of the doses to the lungs, the tumour and non-tumorous liver compartment as estimated by the partition model was further evaluated in clinical settings. On the basis of the observation that one of three patients who received more than 30 Gy from a single treatment and one of two patients who received more than 50 Gy from multiple treatments developed radiation pneumonitis, it was deduced that an estimated lung dose <30 Gy from a single treatment and a cumulative lung dose <50 Gy from multiple treatments were probably the tolerance limits of the lungs. Three of five patients who received lung doses >30 Gy as estimated by the partition model and were predicted to develop radiation pneumonitis, did so despite the use of partial hepatic embolization to reduce the degree of lung shunting. Furthermore, a higher radiological response rate and prolonged survival were found in the group of patients who received higher tumour doses, as estimated by the partition model, than in the group with lower estimated tumour doses. Thus the radiation doses estimated by the partition model can be used to predict (a) complication rate, (b) response rate and (c) duration of survival in the same manner as the actual radiation doses measured with a beta probe at open surgery. The partition model has made selective internal radiation therapy using90Y microspheres safe and repeatable without laparotomy.


European Journal of Nuclear Medicine and Molecular Imaging | 1996

Partition model for estimating radiation doses from yttrium-90 microspheres in treating hepatic tumours

S. Ho; W. Y. Lau; Thomas W.T. Leung; M. Chan; Y. K. Ngar; Philip J. Johnson; A. K. C. Li

A uniform distribution of yttrium-90 (90Y) microspheres throughout the entire liver has always been assumed for dose calculation in treating hepatic tumours. A simple mathematical model was formulated which allows estimation of the activities of a therapeutic dose of90Y microspheres partitioned between the lungs, the tumour and the normal liver, and hence the radiation doses to them. The doses to the tumour and normal liver were verified by intra-operative direct beta-probing. The percentage of activity shunted to the lung and the tumour-to-normal tissue ratio (T/N) were obtained from gamma scintigraphy using technetium-99m-labelled macroaggregated albumin (MAA) which simulates the90Y microspheres used in subsequent treatment. The intrahepatic activity was partitioned between the tumour and the normal liver based on the T/N and their masses determined from computerized tomography slices. The corresponding radiation doses were computed using the MIRD formula. The estimated radiation doses were correlated with the doses directly measured using a calibrated beta-probe at laparotomy by linear regression. The radiation doses to the tumour and the normal liver, estimated using the partition model, were close to that measured directly with coefficients of correlation for linear regression: 0.862 for the tumours and 0.804 for the normal liver compartment (P<0.001). The partition model permits a distinction between the radiation doses received by the tumour and the normal liver to be made and the doses thus estimated are close to the actual doses received. The optimal doses to the tumour and normal liver and hence the required quantity of90Y microspheres to be administered can be easily predetermined.

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Anthony T.C. Chan

The Chinese University of Hong Kong

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Tony Mok

The Chinese University of Hong Kong

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Winnie Yeo

The Chinese University of Hong Kong

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S. Ho

The Chinese University of Hong Kong

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Simon C.H. Yu

The Chinese University of Hong Kong

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W. Y. Lau

The Chinese University of Hong Kong

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A. K. C. Li

The Chinese University of Hong Kong

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Benny Zee

The Chinese University of Hong Kong

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Paul B.S. Lai

The Chinese University of Hong Kong

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