Publications by authors named "Ashley C K Cheng"

Introduction: T4 nasopharyngeal carcinoma (NPC) with close proximity to critical organs at risk (OARs) is usually underdosed during radiotherapy in order to respect radiation constraints. N3 disease has high risk of distant metastasis. Induction chemotherapy (IC) provides advantages of sparing of OARs during subsequent chemoradiotherapy (CCRT) and early eradication of micrometastasis.

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Introduction: Previous studies have shown that the beam arrangement had significant influence on plan quality in intensity modulated radiotherapy (IMRT). This study aimed to evaluate the dosimetric performance of beam arrangement methods by employing equally spaced beams (ESB), beam angle optimization (BAO), and volumetric modulated arc therapy (VMAT) in the planning of five types of head and neck (H&N) cancers treated by IMRT.

Methods: Five plans of different beam arrangement methods were optimized for 119 H&N cancer patients with the prescription of 66-70 Gy for high-risk planning target volume (PTV), 60 Gy for intermediate risk PTV, 54 Gy for low-risk PTV using a simultaneously integrated boost method.

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Purpose The contribution of adjuvant chemotherapy after chemoradiation therapy (CRT) in nasopharyngeal cancer (NPC) remains controversial. Plasma Epstein-Barr virus (EBV) DNA is a potential biomarker of subclinical residual disease in NPC. In this prospective, multicenter, randomized controlled trial, we used plasma EBV DNA to identify patients with NPC at a higher risk of relapse for adjuvant chemotherapy.

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Purpose: To evaluate treatment outcomes, failure patterns and late toxicities in patients with nasopharyngeal carcinoma (NPC) treated by intensity modulated radiotherapy (IMRT) in 6 public hospitals in Hong Kong over a 10-year period from 2001 to 2010.

Material And Methods: Eligible patients were identified through the Hong Kong Cancer Registry data base. Clinical information was retrieved and verified by oncologists working in the individual centers.

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Background: This study investigated the associations of savoring with cancer-specific physical symptoms, psychological distress, and psychological well-being and the moderating effect of savoring in the associations between physical symptoms and psychological outcomes among cancer patients.

Methods: A total of 263 Chinese adults recently diagnosed with cancer (mean time since diagnosis = 43.72 days, SD = 38.

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Background: Recovery experience including psychological detachment from caregiving and savoring positive moments in life could be complementary coping processes for cancer caregivers. This study aims to examine the nature of their associations with caregiving burden and anxiety and depressive symptoms among Chinese cancer caregivers in Hong Kong.

Methods: A total of 155 Chinese caregivers of recently diagnosed cancer patients (mean time since diagnosis = 42.

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Background: This study aimed to investigate the sonographic appearances of the thyroid glands in nasopharyngeal carcinoma (NPC) patients whose cervical lymph nodes were treated with conventional radiotherapy (RT) or intensity-modulated radiotherapy (IMRT). The post-RT sonographic appearances of the thyroid glands in NPC patients were also correlated with the thyroid function.

Methods: One hundred and three NPC patients who had completed RT of cervical lymph nodes using the anterior cervical field, 30 NPC patients who had completed RT of cervical lymph nodes using IMRT, and 61 healthy subjects were included in the study.

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The purpose of this study was to investigate the potential benefits of using triple-arc volumetric-intensity modulated arc radiotherapy (RapidArc (RA)) for the treatment of early-stage nasopharyngeal carcinoma (NPC). A comprehensive evaluation was performed including plan quality, integral doses, and peripheral doses. Twenty cases of stage I or II NPC were selected for this study.

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We attempted to develop a method to compute the normal tissue complication probability (NTCP) of various critical organs from combined intensity-modulated radiotherapy (IMRT) and stereotactic radiotherapy (SRT) boost treatment of nasopharyngeal carcinoma (NPC), with the aid of a nonlinear image registration method. The SRT's planning computed tomography (CT) of a NPC patient treated with IMRT was warped to the IMRT's planning CT using a nonlinear image registration. Because CT and dose were inherently in-register, the entire dose distribution could be deformed using the same deformation field derived from the two CT sets.

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Background And Purposes: To develop a dose-volume-based Plan Quality Index for IMRT plans.

Materials And Methods: This study used a H(ealthy) Tissue Conformity Index to describe the overall plan conformity, a M(erit) function to describe the target coverage and a P(enalty) function to evaluate doses to critical organs. The Euclidean distance (PQI) between (H, M, P) and (1,1,1) represented the quality of a treatment plan.

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Purpose: To study the safety and efficacy of dose escalation in tumor for locally advanced nasopharyngeal carcinoma (NPC).

Methods And Materials: From September 2000 to June 2004, 50 patients with T3-T4 NPC were treated with intensity-modulated radiotherapy (IMRT). Fourteen patients had Stage III and 36 patients had Stage IVA-IVB disease.

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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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Background: Xerostomia is a uniform complication after radiotherapy (RT) for nasopharyngeal carcinoma (NPC). Dosimetric studies suggested that intensity-modulated RT (IMRT) can spare part of the parotid glands from high-dose radiation. Disease control and salivary function after IMRT for early-stage NPC was studied prospectively.

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Purpose: To study the efficacy of concurrent chemoradiotherapy (CRT) and adjuvant chemotherapy (AC) for nasopharyngeal carcinoma (NPC).

Patients And Methods: Patients with Ho's stage T3 or N2/N3 NPC or neck node > or = 4 cm were eligible. Patients were randomly assigned to have radiotherapy (RT) or CRT with uracil and tegafur and to have AC or no AC after RT/CRT.

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Background: To review the outcome and evaluate the prognostic factors in the treatment of synchronous locoregional failures of nasopharyngeal carcinoma (NPC).

Methods: We reviewed the records of 43 patients with synchronous locoregional failures of NPC who received salvage treatment or chemotherapy between November 1986 and January 2001. The recurrent disease was stage II in 61%, stage III in 30%, and stage IV in 9%.

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