Biomedical subjects

Dora L W Kwong

Publications and source records attributed to Dora L W Kwong.

At least 19 recordsLinked to original sources

PubMed2006

Xerostomia and quality of life after intensity-modulated radiotherapy vs. conventional radiotherapy for early-stage nasopharyngeal carcinoma: initial report on a randomized controlled clinical trial.

PURPOSE: To compare directly the effect of intensity-modulated radiotherapy (IMRT) vs. conventional radiotherapy (CRT) on salivary flow and quality of life (QoL) in patients with early-stage nasopharyngeal carcinoma (NPC). METHODS AND MATERIALS: Fifty-one patients with T2, N0/N1, M0 NPC took part in a randomized controlled clinical study and received IMRT or CRT. Stimulated whole (SWS) and parotid (SPS) saliva flow were measured and Medical Outcomes Short Form 36 (SF-36), European Organization for Research and Treatment of Cancer (EORTC) core quetionnaire, and EORTC head-and-neck module (QLQ-H&N35) were completed at baseline and 2, 6, and 12 months after radiotherapy. RESULTS: Forty-six patients (88%) were in disease remission 12 months after radiotherapy. At 12 months postradiotherapy, 12 (50.0%) and 20 patients (83.3%) in the IMRT group had recovered at least 25% of preradiotherapy SWS and SPS flow respectively, compared with 1 (4.8%) and 2 patients (9.5%), respectively, in the CRT group. Global health scores showed continuous improvement in QoL after both treatments (p < 0.001). However, after 12 months subscale scores for role-physical, bodily pain, and physical function were significantly higher in the IMRT group, indicating a better condition (p < 0.05). Dry mouth and sticky saliva were problems in both groups 2 months after treatment. In the IMRT group, there was consistent improvement over time with xerostomia-related symptoms significantly less common than in the CRT group at 12 months postradiotherapy. CONCLUSIONS: IMRT was significantly better than CRT in terms of parotid sparing and improved QoL for early-stage disease. The findings support the case for assessment of health-related QoL in relation to head-and-neck cancer using a site-specific approach.

Adult↗

PubMed2006

Complementary activation of peripheral natural killer cell immunity in nasopharyngeal carcinoma.

NK cells and alphabeta- and gammadelta-CTL play important roles in cellular immunity against tumors. We previously demonstrated that NPC patients have a quantitative and qualitative deficit in gammadelta-CTL and EBV-specific alphabeta-CTL when compared to normal subjects and NPC long-term survivors. In this study we report further observations of a complementary activation of peripheral NK cells in NPC patients. The NK cells in these patients, compared to those of healthy subjects and NPC survivors, were preferentially activated in response to the stimulation of myeloma cell line XG-7 and expanded in the presence of exogenous IL-2. The production of IFN-gamma was lowest in the patient group, whereas IL-12, IL-15 and TNF-alpha were produced in higher levels in patients than in the donors and survivors. The cytolytic effect of the NK cells against NPC cells in the patient group was also higher than that of the donors and survivors. Furthermore, the patients at later stages of NPC had lower gammadelta-CTL activity but higher NK cytotoxicity towards NPC targets, with higher production of IL-12, IL-15 and TNF-alpha but lower production of IFN-gamma than in patients at earlier stages. This might be part of a triggered compensatory re-activation of the innate immunity, believed to be mediated through various cytokines and chemokines when adaptive T cell immunity is breached. Together, these data suggest complementary roles of innate and adaptive immune response in tumor immunity where NK cells, gammadelta- and alphabeta-CTL compensate for the deficits of one another at different stages of tumor invasion.

Asian People↗

PubMed2006

White matter anisotropy in post-treatment childhood cancer survivors: preliminary evidence of association with neurocognitive function.

PURPOSE: We aim to determine if the loss of white matter fractional anisotropy (FA), measured by diffusion tensor magnetic resonance imaging (DTI), in post-treatment childhood medulloblastoma (MED) and acute lymphoblastic leukemia (ALL) survivors correlate with intelligence quotient (IQ) scores. MATERIALS AND METHODS: MED and ALL survivors (n = 30; 20 male, 10 female; age range, 6.0 to 22.1 years; mean, 13.1 years) were recruited for DTI and IQ tests. In this cross-sectional study, age-matched normal control (n = 55; 32 male, 23 female; age range, 6.0 to 23 years; mean, 12.1 years) DTI was obtained to compute percentage difference in white matter FA (DeltaFA%) for each patient compared with the age-matched control group. Multivariate regression analysis was performed to determine the relationships between DeltaFA%, age at treatment, irradiation dose, time interval from treatment, and full-scale IQ (FSIQ), verbal IQ (VIQ), and performance IQ (PIQ). Receiver operating characteristics curves were used to determine the best DeltaFA% cutoffs for predicting FSIQ, VIQ, and PIQ of less than 85. RESULTS: DeltaFA% had a significant effect on FSIQ (adjusted r2 = 0.439; P < .001), VIQ (adjusted r(2) = 0.237; P = .028), and PIQ (adjusted r(2) = 0.491; P < .001) after adjusting for the effects of age at treatment, irradiation dose, and time interval from treatment. The best DeltaFA% value to predict less than 85 scores in FSIQ, VIQ, and PIQ was -3.3% with specificities of 100% and sensitivities ranging from 77.8% to 87.5%. CONCLUSION: Our preliminary findings suggest that white matter FA may be a clinically useful biomarker for the assessment of treatment-related neurotoxicity in post-treatment childhood cancer survivors.

Adolescent↗

PubMed2006

Mapping radiation dose distribution on the fractional anisotropy map: applications in the assessment of treatment-induced white matter injury.

We describe a method to map whole brain radiation dose distribution on to diffusion tensor MR (DT-MR) fractional anisotropy (FA) images and illustrate its applications for studying dose-effect relationships and regional susceptibility in two childhood medulloblastoma survivors. To determine the FA changes voxel-by-voxel in white matter, the post-treatment follow-up FA maps were coregistered to baseline pre-treatment FA maps and automatic segmentation for white matter was carried out. DeltaFA maps representing relative FA change in white matter were hence generated for visual inspection and quantitative analysis. The radiation dose distribution, calculated from radiotherapy plan and exported as images, was coregistered to baseline FA images. DT-MR imaging and processing noise was small with root mean square value of 1.49% for mean DeltaFA. We evaluated the mean DeltaFA changes of regions-of-interest according to radiation dose regions to provide an estimate of the dose-response and found increasing reduction in mean DeltaFA with increasing radiation dose up to 45 Gy after which there was a reversal in the mean FA trend and mean FA approached baseline value. We also found more severe mean FA reduction in the frontal lobes compared to the parietal lobes despite the same radiation dose, suggesting regional susceptibility in the frontal lobe, and mean FA increase in the brainstem after radiation in both patients. We conclude that the method described may be useful in estimating dose-effect relationships and studying regional susceptibility of the brain to radiation in medulloblastoma survivors.

Anisotropy↗

PubMed2006

Chemotherapy in locally advanced nasopharyngeal carcinoma: an individual patient data meta-analysis of eight randomized trials and 1753 patients.

OBJECTIVES: To study the effect of adding chemotherapy to radiotherapy (RT) on overall survival and event-free survival for patients with nasopharyngeal carcinoma. METHODS AND MATERIALS: This meta-analysis used updated individual patient data from randomized trials comparing chemotherapy plus RT with RT alone in locally advanced nasopharyngeal carcinoma. The log-rank test, stratified by trial, was used for comparisons, and the hazard ratios of death and failure were calculated. RESULTS: Eight trials with 1753 patients were included. One trial with a 2 x 2 design was counted twice in the analysis. The analysis included 11 comparisons using the data from 1975 patients. The median follow-up was 6 years. The pooled hazard ratio of death was 0.82 (95% confidence interval, 0.71-0.94; p = 0.006), corresponding to an absolute survival benefit of 6% at 5 years from the addition of chemotherapy (from 56% to 62%). The pooled hazard ratio of tumor failure or death was 0.76 (95% confidence interval, 0.67-0.86; p < 0.0001), corresponding to an absolute event-free survival benefit of 10% at 5 years from the addition of chemotherapy (from 42% to 52%). A significant interaction was observed between the timing of chemotherapy and overall survival (p = 0.005), explaining the heterogeneity observed in the treatment effect (p = 0.03), with the highest benefit resulting from concomitant chemotherapy. CONCLUSION: Chemotherapy led to a small, but significant, benefit for overall survival and event-free survival. This benefit was essentially observed when chemotherapy was administered concomitantly with RT.

Antineoplastic Agents↗

PubMed2006

Preservation of quality of life after intensity-modulated radiotherapy for early-stage nasopharyngeal carcinoma: results of a prospective longitudinal study.

BACKGROUND: Xerostomia is a ubiquitous complication after conventional radiotherapy for nasopharyngeal carcinoma (NPC) that seriously impairs patient quality of life (QOL). The effect on QOL of parotid-sparing intensity-modulated radiotherapy (IMRT) for early-stage NPC was assessed prospectively. METHODS: Thirty-two patients with T1-2,N0-1,M0 NPC received IMRT. Saliva flow was measured, and the Medical Outcomes Short Form 36 (SF-36), European Organization for Research and Treatment of Cancer (EORTC) core, and EORTC head and neck module (QLQ-H&N35) questionnaires were completed at baseline and 2, 6, and 12 months after IMRT. RESULTS: Saliva flow recovered to at least 25% of baseline in most cases after 1 year. Physical function, fatigue, and vitality were problems at 2 months and then resolved (p < or = .002). Global health scales showed continuous improvement in QOL after treatment (p < or = .004). Xerostomia and sticky saliva were problems 2 months after treatment; thereafter, continuous improvement occurred (p < or = .001). Xerostomia scores correlated with general aspects of QOL (p < or = .044). CONCLUSION: IMRT for early-stage disease preserved key aspects of QOL, and a reduction in xerostomia symptoms enhanced broader aspects of QOL.

Adult↗

PubMed2006

The effects of neoadjuvant chemoradiation on pTNM staging and its prognostic significance in esophageal cancer.

For esophageal cancer, it is not clear if pathologic TNM staging after chemoradiation and resection will have the same prognostic significance compared with patients who undergo resection only. From 1995 to 2004, prospectively collected data from 279 patients with intrathoracic squamous cell cancers were analyzed. Patients were given chemoradiation either as part of a randomized trial comparing neoadjuvant chemoradiation with surgical resection alone, or because of advanced disease at presentation. One hundred seventy patients had surgical resection only (surgery), and 109 had neoadjuvant chemoradiation (CRT plus surgery). In the surgery group, pT1, 2, 3, and 4 disease was found in 15, 17, 104, and 34 patients, respectively; their respective pN1 rates were 13.3%, 29.4%, 57.7%, and 64.7%, P < 0.01. In CRT plus surgery, pT0, T1, 2, 3, and 4 were found in 48, 12, 23, 21, and 5 patients, respectively; their respective pN1 rates were 31.3%, 16.7%, 21.7%, 52.4%, and 20%, P = 0.44. Logistic regression analysis of factors predictive of pN1 showed that pT stage correlated with pN1 status (P = 0.005) in the surgery group, but not for the CRT plus surgery group. Cox regression analysis demonstrated that in the surgery group, pT, pN, and R category, and overall pTNM stage, were independent prognostic factors, whereas pN, R category, and gender were identified as relevant for CRT plus surgery. After chemoradiation, pT and overall pTNM stage groupings were not as clearly prognostic as in patients without prior therapy. Nodal status remains an important prognostic factor.

Adult↗

PubMed2005

Preliminary results of radiation dose escalation for locally advanced nasopharyngeal carcinoma.

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. The prescribed dose was 76 Gy to gross tumor volume (GTV), 70 Gy to planning target volume (PTV), and 72 Gy to enlarged neck nodes (GTVn). All doses were given in 35 fractions over 7 weeks. Thirty-four patients also had concurrent cisplatin and induction or adjuvant PF (cisplatin and 5-fluorouracil). RESULTS: The average mean dose achieved in GTV, GTVn, and PTV were 79.5 Gy, 75.3 Gy, and 74.6 Gy, respectively. The median follow-up was 25 months, with 4 recurrences: 2 locoregional and 2 distant failures. All patients with recurrence had IMRT alone without chemotherapy. The 2-year locoregional control rate, distant metastases-free and disease-free survivals were 95.7%, 94.2%, and 93.1%, respectively. One treatment-related death caused by adjuvant chemotherapy occurred. The 2-year overall survival was 92.1%. CONCLUSIONS: Dose escalation to 76 Gy in tumor is feasible with T3-T4 NPC and can be combined with chemotherapy. Initial results showed good local control and survival.

Adult↗

PubMed2005

Treatment results for nasopharyngeal carcinoma in the modern era: the Hong Kong experience.

PURPOSE: To analyze the treatment results achievable for nasopharyngeal carcinoma in the modern era to identify the key failures for future improvement and to provide an updated baseline for future trials. METHODS AND MATERIALS: The results of 2687 consecutive patients treated at all public oncology centers in Hong Kong during 1996-2000 were retrospectively analyzed. The stage distribution (by American Joint Committee on Cancer and International Union Against Cancer staging system, 1997) was 7% Stage I, 41% Stage II, 25% Stage III, and 28% Stage IVA-B. All patients were irradiated with 6-MV photons and the median total dose was 66 Gy. Only 23% of patients had additional treatment with chemotherapy. RESULTS: The 5-year local, nodal, and distant failure-free rates were 85%, 94%, and 81%, respectively; patients with local failure had significantly higher risk of nodal and distant failures. The 5-year progression-free, overall, and cancer-specific survival rates were 63%, 75%, and 80%, respectively. The presenting stage was the most important prognostic factor for all endpoints: with overall survival decreasing from 90% for Stage I to 58% for Stage IVA-B. The results achieved by the 2070 patients treated by radiotherapy alone were almost identical to that of the whole series, the distant failure-free rate among patients with locoregional control was 89% for Stage I-II and 75% for Stage III-IVB. The 860 patients (32%) staged with magnetic resonance imaging achieved significantly better results than those staged by computed tomography, the overall survival being 93% vs. 83% for Stages I-II, and 72% vs. 63% for Stages III-IVB (p = 0.001). CONCLUSIONS: Treatment results for nasopharyngeal carcinoma have substantially improved in the modern era; future trials should be based on updated baseline results. Further reduction of distant failure is important for future breakthrough, particularly for patients with advanced disease.

Adolescent↗

PubMed2005

Cortical laminar necrosis in childhood intracranial germ cell tumor survivors.

We report two childhood germ cell tumor survivors treated for multifocal or large suprasellar tumors followed by the presentation of acute neurological deficits and extensive cortical laminar necrosis on magnetic resonance imaging (MRI), 7 and 34 months after cranial irradiation. This complication, though uncommon, represents another manifestation of delayed treatment-related brain injury that can be catastrophic and leads to significant morbidity.

Adolescent↗

PubMed2005

Comparative proteomic analysis of esophageal squamous cell carcinoma.

Ranking as the fourth commonest cancer, esophageal squamous cell carcinoma (ESCC) represents one of the leading causes of cancer death in China. One of the main reasons for the low survival rate is that neoplasms in esophagus are not detected until they have invaded into surrounding tissues or spread throughout the body at advanced stages. A better understanding of the malignant mechanism and early diagnosis are important for fighting ESCC. In this study, we used proteomics to analyze ESCC tissues, aiming at defining the proteomic features implicated in the multistage progression of esophageal carcinogenesis. Proteins that exhibited significantly different expressions were identified by peptide mass fingerprinting and validated by Western blotting and reverse transcriptase-polymerase chain reaction. The protein changes were then correlated to the different grades of disease differentiation. Compared to those in adjacent normal epitheliums, the expression of 15 proteins including enolase, elongation factor Tu, isocitrate dehydrogenase, tubulin alpha-1 chain, tubulin beta-5 chain, actin (cytoplasmic 1), glyceraldehyde-3 phosphate dehydrogenase, tropomyosin isoform 4 (TPM4), prohibitin, peroxiredoxin 1 (PRX1), manganese-containing superoxide dismutase (MnSOD), neuronal protein, and transgelin was up-regulated; and the expression of five proteins including TPM1, squamous cell carcinoma antigen 1 (SCCA1), stratifin, peroxiredoxin 2 isoform a, and alpha B crystalline was down-regulated in cancer tissues with a statistical significance (p < 0.05). In addition, the differential expression of SCCA1, PRX1, MnSOD, TPM4, and prohibitin can be observed in precancerous lesions of ESCC. The expression of stratifin, prohibitin, and SCCA1 dropped with increasing dedifferentiation of ESCC. These data may suggest that these proteins contribute to the multistage process of carcinogenesis, tumor progression, and invasiveness of ESCC.

Blotting, Western↗

PubMed2005

White matter anisotropy in childhood medulloblastoma survivors: association with neurotoxicity risk factors.

PURPOSE: To prospectively evaluate the relationships between change in white matter (WM) anisotropy and (a) patient age at craniospinal irradiation (CSI), (b) CSI dose, and (c) time of magnetic resonance (MR) imaging since CSI and to determine the effect of these neurotoxicity risk factors on WM anisotropy in posttreatment medulloblastoma survivors. MATERIALS AND METHODS: Informed consent was obtained from the patients, control subjects, or their parents, and the study was approved by the institutional review board. Twenty consecutive medulloblastoma survivors (14 male, six female; mean age, 11.0 years +/- 4.6 [standard deviation]) and 36 control subjects (14 male, 22 female; mean age, 10.7 years +/- 3.5) were examined. Control subjects were divided into four groups according to age: 5.0-7.9 years, 8.0-10.9 years, 11.0-13.9 years, and 14.0-18.9 years. The authors calculated the histogram-derived mean WM fractional anisotropy (FA) value for each patient and compared it with the mean WM FA value for the control subjects in the corresponding age group to evaluate the percentage change in WM FA (DeltaFA) in each patient. Spearman rank correlation analysis was used to analyze the relationships between DeltaFA and (a) age at CSI, (b) CSI dose, and (c) time of MR imaging since CSI. Then, multiple linear regression analysis was performed to study the simultaneous influence of these factors on DeltaFA. RESULTS: There were significant correlations between DeltaFA and both age at CSI (r = 0.631, P = .003) and CSI dose (r = -0.586, P = .007) but not between DeltaFA and time of MR imaging since CSI. Multiple linear regression analysis revealed age at CSI to be the only independent variable that significantly affected DeltaFA (adjusted r2= 0.391, P = .012). CONCLUSION: Loss of WM anisotropy is significantly affected by age at CSI, and there is a trend toward increasing anisotropy loss with larger CSI dose. Both age at CSI and CSI dose are known risk factors of neurotoxicity.

Adolescent↗

PubMed2004

Intensity-modulated radiotherapy for early-stage nasopharyngeal carcinoma: a prospective study on disease control and preservation of salivary function.

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. METHODS: Thirty-three patients with T1,N0-N1,M0 NPC were treated with IMRT from 2000 to 2002. The prescribed dose was 68-70 grays (Gy) in 34 fractions to gross tumor volume, 64-68 Gy to the planning target volume, and 70 Gy to enlarged cervical lymph nodes. Nineteen patients had stimulated whole salivary (SWS) flow assessment and stimulated parotid salivary (SPS) flow assessment at baseline and at 2 months, 6 months, 12 months, 18 months, and 24 months after the completion of IMRT. RESULTS: At a median follow-up of 2 years, only 1 neck failure was observed. The 2-year and 3-year local control, distant metastases-free, and overall survival rates all were 100%. The lymph node control and progression-free survival rates were 100% at 2 years and 92.3% at 3 years, respectively. The average mean dose to the parotid gland was 38.8 Gy. The SWS and SPS flow showed continuous recovery: 60% and 47.1% of patients recovered at least 25% of their baseline SPS flow and SWS flow, respectively, at 1 year after completion of IMRT, and the proportions rose to 85.7% and 71.4%, respectively, by 2 years. The pH and buffering capacity of saliva also improved with time. CONCLUSIONS: Parotid-sparing IMRT achieved good locoregional control, and there was continuous recovery of salivary flow, pH, and buffering capacity in the first 2 years after IMRT in patients with NPC.

Adult↗

PubMed2004

Concurrent and adjuvant chemotherapy for nasopharyngeal carcinoma: a factorial study.

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. AC comprised alternating cisplatin, fluorouracil, vincristine, bleomycin, and methotrexate for six cycles. There were four treatment groups: A, RT; B, CRT; C, RT and AC; D, CRT and AC. For CRT versus RT, groups B and D were compared with groups A and C. For AC versus no AC, groups C and D were compared with groups A and B. RESULTS: Three-year failure-free survival (FFS) and overall survival (OS) for CRT versus RT were 69.3% versus 57.8% and 86.5% versus 76.8%, respectively (P =.14 and.06; n = 110 v 109). Distant metastases rate (DMR) was significantly reduced with CRT (14.8% v 29.4%; P =.026). Locoregional failure rates (LRFR) were similar (20% v 27.6%; P =.39). Three-year FFS and OS for AC versus no AC were 62.5% versus 65% and 80.4% versus 83.1%, respectively (P =.83 and.69; n = 111 v 108). DMR and LRFR were not reduced with AC (P =.34 and.15, respectively). Cox model showed CRT to be a favorable prognostic factor for OS (hazard ratio, 0.42; P =.009). CONCLUSION: An improvement in OS with CRT was observed but did not achieve statistical significance. The improvement seemed to be associated with a significant reduction in DMR. AC did not improve outcome.

Administration, Oral↗

PubMed2004

Quantitative analysis of plasma cell-free Epstein-Barr virus DNA in nasopharyngeal carcinoma after salvage nasopharyngectomy: a prospective study.

BACKGROUND: The quantity of circulating cell-free Epstein-Barr virus (EBV) DNA in patients with nasopharyngeal carcinoma (NPC) managed by radiotherapy has prognostic relevance. We measured the copy number of EBV DNA in patients with early recurrent NPC before and after salvage nasopharyngectomy. METHODS: Nasopharyngectomy with the maxillary swing approach was performed for 28 patients. Serum blood samples were taken prospectively before nasopharyngectomy and on postoperative day 7. Plasma cell-free EBV DNA copies were measured with a real-time quantitative polymerase chain reaction for the BamHI-W fragment of the EBV genome. RESULTS: Cell-free EBV DNA was detected in 17 patients before nasopharyngectomy. Surgical resection reduced the copy number of EBV DNA significantly (p = .016). Negative surgical margins achieved during nasopharyngectomy is associated with a zero EBV DNA copy postoperatively (p = .022). CONCLUSION: Cell-free EBV DNA was detected in 61% of patients with recurrent NPC, and its quantity postoperatively reflects whether the salvage nasopharyngectomy has achieved a negative surgical margin.

Adult↗

PubMed2004

White-matter diffusion anisotropy after chemo-irradiation: a statistical parametric mapping study and histogram analysis.

The aim of the study was to evaluate white-matter (WM) diffusion anisotropy in medulloblastoma survivors after cranial irradiation and chemotherapy using voxel-based analysis with SPM99 and fractional anisotropy (FA) histogram-derived indices, and to identify quantitative indices for detecting and monitoring children with treatment-induced white-matter injury. Familywise error rate (FWE) that corrects for multiple comparisons was used to locate statistically significant regions of P < 0.05 in voxel-based analysis. Subsequently, the false discovery rate (FDR) controlling procedure (corrected P < 0.05) was used. FA map histogram analysis of histogram-derived indices, mean FA, mean FA peak height, and peak location was performed. Two-sample t test was used in all analyses. Using FWE-corrected P < 0.05, there was a cluster of reduced anisotropy in the periventricular white matter lateral to the left ventricular atrium. When FDR-corrected P < 0.05 was used, there were multiple clusters of reduced anisotropy in the periventricular white matter, the corpus callosum, and corona radiata. Simplified voxel-based morphometry (VBM)-like analysis of cerebrospinal fluid (CSF) did not show significant differences between patient and control subjects. 'White-matter FA map' histogram showed significant reduction in mean FA and mean FA peak location and significant increase in mean FA peak height in the patient group compared to control subjects (P = 0.003, P = 0.003, and P = 0.014, respectively). This approach of quantifying FA can be applied to characterize anisotropy in the white matter after cranial irradiation and chemotherapy and can potentially be used to detect and monitor treatment-induced neurotoxicity.

Adolescent↗

PubMed2004

Target dose conformity in 3-dimensional conformal radiotherapy and intensity modulated radiotherapy.

BACKGROUND AND PURPOSE: Dose conformity to the planning target volume is an important criterion in radiotherapy treatment planning, for which the conformity index is a useful assessment tool. The purpose of this study is to compare the differences in CI for the treatment planning of four cancers including the nasopharynx, oesophagus, lung and prostate. PATIENTS AND METHODS: Seventy patients with cancers of nasopharynx (30), oesophagus (15), lung (15) and prostate (10) were recruited. Each of these patients was planned with three sets of treatment plans using the FOCUS treatment planning system: the forward and inverse 3DCRT plans and the IMRT plan. The CI was generated for each treatment plan. The mean CI from each cancer patient group was calculated and compared with the other three cancer groups. The mean value of CI was also compared among the three planning methods. RESULTS: The oesophageal and lung cancers demonstrated relatively higher overall mean CI values (0.64 and 0.62, respectively), whereas that of the nasopharynx and prostate were lower (0.54 and 0.50, respectively). With regards to the planning method groups, the IMRT plans produced the highest overall mean CI (0.62), while those for the forward and inverse 3DCRT were similar (0.57 and 0.55, respectively). CONCLUSION: For the four selected cancers, oesophageal and lung cancers were easier to conform than the nasopharyngeal and prostate cancers. The IMRT plans were more effective in achieving better dose conformity than that of the 3DCRT.

Cohort Studies↗

PubMed2003

Salivary gland function and xerostomia in southern Chinese following radiotherapy for nasopharyngeal carcinoma.

Nasopharyngeal carcinoma (NPC) is rare among Caucasians but very common among southern Chinese. No information is presently available on the relationship between salivary gland function and xerostomia in irradiated southern Chinese. Salivary gland function and xerostomia were measured in irradiated NPC patients, recently diagnosed NPC patients, and a matched control group. Stimulated whole saliva was collected from each participant and flow rate, pH and buffer capacity measured. All participants completed a multi-item dry mouth questionnaire. Comparisons were made using Chi-square and Mann-Whitney tests and correlations assessed using Spearman's rank correlation coefficients. The mean saliva flow rate and pH were significantly lower and the buffer capacity impaired in irradiated NPC patients compared with the other groups ( P<0.01). Significantly more irradiated NPC patients had negative impacts associated with dry mouth generally, sticky saliva, and hoarse voice ( P<0.01). Subjective dry mouth symptoms and associated reduced saliva flow were also relatively common in non-irradiated participants. Salivary gland hypofunction and xerostomia were major complications in irradiated NPC patients. In irradiated and non-irradiated southern Chinese, subjective dry mouth symptoms appeared to be correlated with actual salivary gland function.

Analysis of Variance↗