Publications by authors named "Sing-Fai Leung"

Objective: Restrictive food avoidance behavior among Chinese cancer patients is common. Yet, to the authors' knowledge, no study has investigated factors associated with such behavior. This study attempted to validate a new measurement tool, the Cancer Patients Food Avoidance Behaviors Scale (CPFAB), that assessed cancer patients' belief regarding 5 perceived benefits of practicing food avoidance, and to test its applicability.

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Background: Circulating cell-free Epstein-Barr virus (EBV) DNA is a biomarker for nasopharyngeal carcinoma. We conducted a prospective study to investigate whether EBV DNA in plasma samples would be useful to screen for early nasopharyngeal carcinoma in asymptomatic persons.

Methods: We analyzed EBV DNA in plasma specimens to screen participants who did not have symptoms of nasopharyngeal carcinoma.

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Background: Single nucleotide polymorphism (SNP) of the excision repair cross-complementing group 1 (ERCC1) gene has been linked with sensitivity to platinum and radiation. The authors hypothesized that the ERCC1 genotype for the SNPs cytosine-to-thymine substitution at codon 118 (C118T) and cytosine-to-adenine substitution at codon 8092 (C8092A) is prognostic in patients with nasopharyngeal carcinoma (NPC) who receive either radiotherapy (RT) or cisplatin plus RT.

Methods: The authors tested their hypothesis using biomarker screening samples from the Hong Kong NPC Study Group 0502 trial, which was a prospective, multicenter clinical trial that used post-RT plasma Epstein-Bar virus (EBV) DNA (pEBV) levels to screen patients with high-risk NPC for adjuvant chemotherapy.

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Background: Nasopharyngeal carcinoma (NPC) is prevalent in Southeast Asia. Over the last decade, plasma Epstein-Barr virus (EBV) DNA has been developed as a tumor marker for NPC. In this study, the authors investigated whether plasma EBV DNA analysis is useful for NPC surveillance.

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Background And Purpose: Concurrent chemoradiotherapy (CRT) confers survival benefit over radiotherapy (RT) alone in the treatment of locoregionally advanced nasopharyngeal carcinoma (NPC). This study explored the prognostic significance of the total dose of cisplatin delivered during CRT.

Materials And Methods: A retrospective analysis was performed in patients with stage II to IVB NPC (AJCC 6th edition) who participated in 3 prospective studies.

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Background And Purpose: To evaluate the therapeutic benefits by adding chemotherapy (+C) and/or accelerated-fractionation (AF) for patients with T3-4N0-1M0 nasopharyngeal carcinoma.

Materials And Methods: From 1999 to 2004, 189 eligible patients were randomized to one of four treatment groups (CF/CF+C/AF/AF+C). The number of fractions/week was 5 for the CF groups and 6 for the AF groups.

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In this study, we investigated the expression of 14-3-3sigma tumor suppressor gene in a panel of NPC cell lines, xenografts and primary tumors. Our objective was to determine the correlation between 14-3-3sigma expression and clinical outcome in NPC. We detected reduced 14-3-3sigma expression in 5/6 NPC tumor lines by quantitative RT-PCR and Western blotting.

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Nasopharyngeal carcinoma (NPC) is rare in most of the world but common among southeast Asians. Since NPC is usually diagnosed at relatively young ages and most patients now survive, the issue of second primary tumors (SPTs) has become important. Previous studies of SPTs among NPC survivors have given conflicting results.

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Purpose: Locally recurrent nasopharyngeal carcinoma (NPC) patients can be salvaged by reirradiation with a substantial degree of radiation-related complications. Stereotactic radiotherapy (SRT) is widely used in this regard because of its rapid dose falloff and high geometric precision. The aim of this study was to examine whether the newly developed intensity-modulated stereotactic radiotherapy (IMSRT) has any dosimetric advantages over three other stereotactic techniques, including circular arc (CARC), static conformal beam (SmMLC), and dynamic conformal arc (mARC), in treating locally recurrent NPC.

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Objectives/hypothesis: To assess the contribution of laryngopharyngeal sensory deficits and impaired pharyngeal motor function to aspiration in patients irradiated for nasopharyngeal carcinoma.

Study Design: A retrospective study at a tertiary referral university teaching hospital.

Methods: One hundred consecutive patients who underwent radiotherapy for nasopharyngeal carcinoma referred to a dysphagia clinic underwent sensory testing of their laryngopharynx and endoscopic evaluation of their swallowing.

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Background: Radiation for patients who have nasopharyngeal cancer (NPC) often renders them hearing challenged and facing difficulties from treatment sequelae such as chronic suppurative otitis media and osteoradionecrosis. Conventional hearing aids aggravate otorrhea, and ear moulds traumatize osteoradionecrosis ulcers in the ear canal. The bone-anchored hearing aid (BAHA) hearing system might represent an excellent hearing solution.

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Purpose: To document the MRI appearances of radiation-induced abnormalities in the cervical spine following treatment for nasopharyngeal carcinoma (NPC).

Methods: Patients with radiation-induced abnormalities in the upper cervical spine were identified from a retrospective analysis of reports from patients undergoing MRI follow-up. Imaging and clinical records of these patients were reviewed.

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Purpose: To develop and validate adaptive dose-constraint templates in intensity-modulated radiotherapy (IMRT) planning for advanced T-stage nasopharyngeal carcinoma (NPC).

Method And Materials: Dose-volume histograms of clinically approved plans for 20 patients with advanced T-stage NPC were analyzed, and the pattern of distribution in relation to the degree of overlap between targets and organs at risk (OARs) was explored. An adaptive dose constraint template (ADCT) was developed based on the degree of overlap.

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The aim of this study was to document the sites and MRI features of radiation-induced tumors (RITs) in the head and neck following treatment for nasopharyngeal carcinoma (NPC). The MRI examinations and clinical records of 20 patients with 21 RITs were reviewed retrospectively. RITs developed 3-30 years after radiotherapy and included eleven squamous cell carcinomas, six sarcomas, two neuroendocrine carcinomas, one mucoepidermoid carcinoma and one meningioma.

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Purpose: Aberrations of circulating nucleic acid integrity have been observed in cancer patients. However, the clinical significance of such changes has not been completely elucidated. In this study, we investigated the plasma DNA integrity in nasopharyngeal carcinoma (NPC) patients and its association with patients' survival after radiotherapy.

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Purpose: This randomized trial compared the rates of delayed xerostomia between two-dimensional radiation therapy (2DRT) and intensity-modulated radiation therapy (IMRT) in the treatment of early-stage nasopharyngeal carcinoma (NPC).

Patients And Methods: Between November 2001 and December 2003, 60 patients with T1-2bN0-1M0 NPC were randomly assigned to receive either IMRT or 2DRT. Primary end point was incidence of observer-rated severe xerostomia at 1 year after treatment based on Radiotherapy Oncology Group /European Organisation for the Research and Treatment of Cancer late radiation morbidity scoring criteria.

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Purpose: To determine whether the standard techniques of measuring tumor size and change in size after treatment could be applied to the measurement of nasopharyngeal cancers, which are often irregular in shape.

Methods And Materials: The standard measurements of bidimensional (BDM) (World Health Organization criteria) and unidimensional (UDM) (Response Evaluation Criteria in Solid Tumors [RECIST] criteria), together with the maximum depth of the tumor perpendicular to the pharyngeal wall (DM), were acquired from axial magnetic resonance images of primary nasopharyngeal carcinoma in 44 patients at diagnosis and in 29 of these patients after treatment. Tumor volume measurements (VM), acquired from the summation of areas from the axial magnetic resonance images, were used as the reference standard.

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Purpose: To evaluate the effect of combining circulating Epstein-Barr viral (EBV) DNA load data with TNM staging data in pretherapy prognostication of nasopharyngeal carcinoma (NPC).

Patients And Methods: Three hundred seventy-six patients with all stages of NPC were studied. Pretreatment plasma/serum EBV DNA concentrations were quantified by a polymerase chain reaction assay.

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Objectives: Nasopharyngeal carcinoma (NPC) is a prevalent tumor in Hong Kong. The immune system of such patients could be adversely affected during the course of conventional chemotherapy or radiotherapy. We investigated the immunomodulatory effects of Traditional Chinese Medicine (TCM) Yunzhi-Danshen capsules in NPC patients treated with radiotherapy.

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Purpose: Recent research has shown the feasibility of detecting cell-free RNA markers in human subjects. As elevated RNase activity has previously been described in the circulation of cancer patients, we hypothesized that cancer patients may have reduced plasma RNA integrity. In this study, we used nasopharyngeal carcinoma (NPC) as a model system to test this hypothesis.

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Background And Purpose: To define the dose-response relationship of nasopharyngeal carcinoma (NPC) above the conventional tumoricidal dose level of 66 Gy when the basic radiotherapy (RT) course was given by the 2D Ho's technique.

Patients And Methods: Data from all five regional cancer centers in Hong Kong were pooled for this retrospective study. All patients (n = 2426) were treated with curative-intent RT with or without chemotherapy between 1996 and 2000 with the basic RT course using the Ho's technique.

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Background: The purpose of this article is to report the overall survival (OS) outcome of patients with nasopharyngeal carcinoma (NPC) with local failure who received salvage treatment and to identify prognostic factors for OS.

Methods: Between January 1996 and December 2000, 2915 patients received primary radiotherapy (RT) with or without chemotherapy for nonmetastatic NPC. At a median follow-up of 3.

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The aims of this study are (1) to establish a reliable and valid quality-of-life (QOL) questionnaire for Chinese patients with head and neck (H&N) cancer who are treated with radiation therapy and (2) to evaluate the impact of the immediate side effects of treatment on the QOL of these patients. The 39-item "Quality of Life Radiation Therapy Instrument with Head and Neck Companion Module" (QOL-RTI/H&N) was translated into Chinese. In the reliability evaluation phase (study module 1), the questionnaire was administered twice to 56 H&N cancer patients, 7 days apart, during the second and third week of radiation therapy.

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