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Biomedical subjects

W I Wei

Publications and source records attributed to W I Wei.

At least 37 records · Page 2Linked to original sources
PubMed2001

Present status of management of nasopharyngeal carcinoma.

Contemporary imaging with endoscopic examination determines tumor extent and this is reflected in the revised staging system. Radiotherapy remains the primary treatment modality. The use of intensity-modulated radiotherapy aims at enhanced tumor control while reducing adverse effects. Concurrent chemotherapy has shown to improve survival, although its efficacy in endemic regions requires confirmation. Determination of circulating cell-free Epstein-Barr virus DNA might detect early recurrence. For patients who developed recurrence in the neck, surgery provides good salvage. For small tumor in the nasopharynx, good results can be obtained with reirradiation therapy, brachytherapy or surgery. The salvage option depends on the size and location of the tumor as well as the expertise available. The long-term effects of these treatment modalities might be significant.

DNA, Viral↗
PubMed2001

Correlation of endoscopic and histologic findings before and after treatment for nasopharyngeal carcinoma.

BACKGROUND: The endoscopic and histologic findings before and after radiotherapy (RT) for nasopharyngeal carcinoma (NPC) were correlated to study the sensitivity and specificity of endoscopic findings in predicting histologic results. The efficiacy of endoscopic examination and post-RT multiple site biopsies in detecting persistent disease was also evaluated. METHODS: Seven hundred forty-six patients were evaluated. Pre-RT, biopsies were taken from both sides of the nasopharynx to assess the extent of tumor. Four to 16 weeks after RT, routine six-site biopsy specimens were taken from both roofs, lateral, and posterior walls of the nasopharynx and repeated 2 weeks later. Endoscopic findings of exophytic growth, nodule, ulcer, and submucosal bulge were considered "residual tumor," others were considered "no residual tumor." Persistent disease was defined as positive histologic findings 12 weeks after RT. RESULTS: Before RT, sensitivity of endoscopic findings and biopsy specimens in detecting malignancy were 99.7% and 94.2%, respectively. After RT, sensitivity and specificity of endoscopic findings in predicting positive histologic findings were 29% and 85.8%, respectively, with a positive predictive value of 34.9% and a negative predictive value of 82.2%. Of positive histologic findings, 27.7% were missed in the first session of biopsies; 33.5% of those with positive histologic findings turned out to have persistent disease. For prediction of persistent disease, the sensitivity and specificity of endoscopic findings were 40.4% and 84.4%, with a positive predictive value of 16.3% and a negative predictive value of 95%, and that of histologic findings in the first session of biopsies were 59.6% and 88.3%, respectively, with a positive predictive value of 27.7% and a negative predictive value of 96.7%. CONCLUSIONS: Endoscopic findings alone have low sensitivity in predicting persistent disease, multiple sites biopsy specimens are indicated. Because only 1.9% of patients with endoscopic findings of "no residual tumor" and negative histologic findings in first session of biopsies had persistent disease, this group can be spared second biopsies. Repeat biopsies are indicated for those with endoscopic findings of "residual tumor" or positive histologic findings in first session of biopsies to improve detection of persistent disease.

Adolescent↗
PubMed2000

Carotid stenosis after radiotherapy for nasopharyngeal carcinoma.

OBJECTIVE: To determine the prevalence and risk factors for radiation-induced carotid stenosis in patients with malignant neoplasms of the head and neck. DESIGN: Prospective cross-sectional screening of extracranial carotid stenosis by color-flow duplex ultrasonography with an analysis of demographic and comorbid risk factors. SETTING: Tertiary oncology and vascular referral center. PATIENTS: The study included 96 consecutive patients (75 men and 21 women; mean age, 53.6 years) who had undergone cervical radiotherapy (RT) for nasopharyngeal carcinoma more than 12 months ago. The mean post-RT interval was 79.9 months. Fourteen patients had cerebrovascular symptoms. A group of 96 healthy individuals were used as controls. MAIN OUTCOME MEASURES: Internal carotid stenosis and common carotid artery stenosis were classified by duplex ultrasonography into moderate (30%-69%), severe (70%-99%), and totally occlusive. RESULTS: Internal carotid artery stenosis of 70% or more was detected in 14 arteries in 12 patients (6 occlusions). Common carotid artery stenosis of 70% or more was found in 11 arteries in 9 patients (4 occlusions). Overall, 15 patients (16%) had critical stenosis in their common or internal carotid arteries, and another 20 (21%) had stenosis in the moderate range. Critical carotid stenosis was not present in any of the control subjects. Severe post-RT carotid stenosis was associated with age (P = .003), smoking (P = .004), heart disease (P<.001), no prior oncological surgery (P<.001), cerebrovascular symptoms (P<.001), and interval from RT (P<.001). Smoking, interval from RT, cerebrovascular symptoms, and no head and neck surgery were significant independent predictors for severe carotid stenosis on multivariate logistic regression analysis. CONCLUSIONS: Patients who undergo irradiation of the head and neck for more than 5 years have a higher risk of developing significant carotid stenosis (relative risk, 15), and routine duplex ultrasound screening is recommended.

Carotid Artery, Common↗
PubMed2000

Preliminary study of in vivo autofluorescence of nasopharyngeal carcinoma and normal tissue.

BACKGROUND AND OBJECTIVE: In nasopharyngeal cancer, conventional white light endoscopy does not provide adequate information to detect the flat/small lesion and identify the margin of observable tumor. In the present study, we evaluate the potential of light-induced fluorescence spectroscopic imaging for the localization of cancerous nasopharyngeal tissue. STUDY DESIGN/MATERIALS AND METHODS: We built a multiple channel spectrometer specifically for the investigation of fluorescence collected by a conventional endoscopic system. Nasopharyngeal fluorescence were measured in vivo from 27 subjects during the routine endoscopy. The biopsy specimens for histologic analysis were taken from the tissue sites where the fluorescence were measured. RESULTS: Two algorithms to discriminate the nasopharyngeal carcinoma from normal tissue were created based on the good correlation between the tissue autofluorescence and histologic diagnosis. For the two-wavelength algorithm, carcinoma can be differentiated from normal tissue with a sensitivity and specificity of 93% and 92%, respectively. For the three-wavelength algorithm with compensation of variation of blood content in tissue, a sensitivity of 98% and specificity of 95% were achieved. CONCLUSION: Fluorescence endoscopic imaging used with the algorithms developed in this report is an efficient method for detecting the nasopharyngeal carcinoma.

Algorithms↗
PubMed2000

A comparison of the prognostic significance of tumor diameter, length, width, thickness, area, volume, and clinicopathological features of oral tongue carcinoma.

BACKGROUND: The present study aims at evaluation of the prognostic value of tumor size including diameter, length, thickness, width, area, and volume in the prediction of nodal metastasis, local recurrence, and survival of oral tongue carcinoma. The results will have important implications for the management of patients. METHODS: Eighty-five glossectomy specimens of oral tongue carcinoma were serially sectioned in 3 mm thickness for the tumor size evaluation with computer image analyzer. RESULTS: Among all the tumor size parameters being evaluated, tumor thickness was the only significant factor for the prediction of local recurrence, nodal metastasis, and survival. With the use of 3 mm and 9 mm division, tumor of up to 3 mm thickness has 10% nodal metastasis, 0% local recurrence, and 100% 5-year actuarial disease-free survival; tumor thickness of more than 3 mm and up to 9 mm has 50% nodal metastasis, 11% local recurrence, and 77% 5-year actuarial disease free survival; tumor of more than 9 mm has 65% nodal metastasis, 26% local recurrence, and 60% 5-year actuarial disease-free survival. CONCLUSIONS: Tumor thickness should be considered in the management of patients with oral tongue carcinoma.

Adolescent↗
PubMed2000

Thoracoscopic esophageal mobilization for pharyngolaryngoesophagectomy.

BACKGROUND: Pharyngolaryngoesophagectomy (PLE) for hypopharyngeal cancers and tumors of the cervical esophagus is a procedure of significant morbidity and mortality. Conventional esophageal mobilization is performed with the transhiatal dissection technique. Thoracoscopic esophageal mobilization is tested as an alternative to determine whether surgical outcome can be improved. METHODS: From 1994 to 1998, thoracoscopic mobilization was carried out in 30 consecutive patients who underwent PLE (PLE-TS). This was compared to a historical cohort of 30 patients who had PLE with transhiatal mobilization (PLE-TH). RESULTS: In PLE-TS, thoracoscopic esophageal mobilization was successful in 28 patients (93%). Median blood loss was 700 mL (range, 164 to 3,000 mL) compared to 1,000 mL (range, 400 to 2,200 mL) in group PLE-TH, p = 0.21. Thoracoscopy time was 90 minutes (range, 60 to 180 minutes). Total operating time were 392 minutes (range, 180 to 570 minutes) and 300 minutes (range, 150 to 550 minutes) in PLE-TS and PLE-TH, respectively (p = 0.03). Major pulmonary complications occurred in 7 (23%) and 8 (27%) patients in PLE-TS and PLE-TH, respectively (p = 0.77). Cardiac complications occurred in 7 (23%) and 5 (17%) patients in PLE-TS and PLE-TH, respectively (p = 0.52). Thirty-day mortality rates were 3.3% and 10% (p = 0.6) and hospital mortality rates were 13% and 17%, (p = 1.0). CONCLUSIONS: Thoracoscopy was safe and feasible. Morbidity and mortality after PLE was not significantly reduced. The theoretical advantage offered by thoracoscopy may be offset by the lengthened time of one-lung anesthesia.

Adult↗
PubMed2000

Salvage surgery for recurrent primary nasopharyngeal carcinoma.

Recurrent primary nasopharyngeal carcinoma after radiotherapy exhibits wide local extension [Uttley D, Moore A, Archer DJ. J Neurosurg 1989;71:705-10]. This wide exposure of the nasopharynx and its vicinity is essential for an oncological radical resection to be carried out. The resection should embrace the tumor with an adequate mucosal margin including the cartilaginous portion of the Eustachian tube. Paranasopharyngeal tissues should be included in the resection whenever indicated. The anterolateral approach to the nasopharynx and the paranasopharyngeal space provides adequate exposure required for an oncological resection. Morbidity associated with the operation is low and this is recommended for resection of most recurrent primary nasopharyngeal carcinoma after radiotherapy.

Carcinoma↗
PubMed2000

Chinese tonal language rehabilitation following cochlear implantation in children.

Cantonese language rehabilitation in 28 prelingually deaf children who underwent cochlear implantation was evaluated. All patients were implanted with multichannel devices and the operations went smoothly. They all had improved scores on audiological assessments and speech perception tests. The speech evaluation tests included the recognition of sounds, vowels, consonants and tone. Sentence recognition and story comprehension were both improved after training for 2 years. Cochlear implantation is a useful measure for the speech rehabilitation of prelingually profound deaf children when hearing aids are of no benefit. The multichannel implant device is of clinical significance in the rehabilitation of those patients using tonal language.

Child↗
PubMed2000

Clarithromycin attenuates mastectomy-induced acute inflammatory response.

Based on the observation that administration of clarithromycin led to an attenuation of the inflammatory response induced by surgical trauma in a guinea pig model, we investigated the potential beneficial effects of clarithromycin on the local and systemic inflammatory response in patients undergoing mastectomy in an open-label prospective study. During a 16-month period, 54 patients who underwent mastectomy were randomly divided into two groups. In one group, the patients received oral clarithromycin at a dose of 500 mg twice a day, from the day before to 3 days after mastectomy. There was no significant difference in the incidence of antibiotic prophylaxis-related toxicities or postoperative infections between the patients who received clarithromycin and those who did not. Clarithromycin treatment was significantly associated with an attenuation of febrile response, tachycardia, tachypnea, and an increase in monocyte counts (P, <0.0001, <0.01, <0.05, and <0.01, respectively). Clarithromycin also reduced the intensity and duration of postoperative pain (P, <0.05 and <0.005, respectively) and increased the range of motion of the involved shoulder (P < 0.05 for abduction and flexion). We conclude that clarithromycin effectively modulates the acute inflammatory response associated with mastectomy and produces a better clinical outcome.

Acute-Phase Reaction↗
PubMed2000

Correlation of pure tone audiogram results and hearing benefit of tympanoplasty for chronic suppurative otitis media.

The aim of this study was to evaluate the correlation between pure tone audiogram results and the subjective sensation of hearing benefit of patients who had tympanoplasty for chronic suppurative otitis media. This is a prospective study of 115 patients who had tympanoplasty between 1992 and 1994. The outcome, including a pure tone audiogram and the subjective sensation of hearing benefit, was evaluated at 1 year after operation. There were 63 (55%) patients with subjective hearing benefit after the tympanoplasty. The subjective sensation of hearing benefit correlated with the magnitude of the air conduction (AC) threshold reduction, and increased from 39% for an AC reduction of less than or equal to 10 dB to 100% for an AC reduction of more than 30 dB. The effect of the interaural AC threshold difference on the subjective sensation of hearing was not significant; improvement was felt by 92% of patients when the operated ear became the better hearing ear, and by 73% of patients when the operated ear remained the worse hearing ear. There was considerable discrepancy between the subjective hearing benefit and the pure tone audiogram results. A combination of parameters, including the air-bone gap, the AC threshold, and the subjective hearing change, is recommended in reporting the results of tympanoplasty.

Audiometry, Pure-Tone↗
PubMed2000

The training of otorhinolaryngologists in Asia.

Asian nations differ from one another in population, cultural background, ethnic tradition and economic situation. The training of otorhinolaryngologists in Asia is not in any way uniform. A questionnaire survey of 26 leading institutions in 12 countries/regions was carried out. The emphasis of investigation is towards the training programme for specialists in Otorhinolaryngology and continuous medical education (CME). The response rate of the survey was 100 per cent. The duration of training for otorhinolaryngologists ranges from three to seven years and an exit assessment is held in seven countries/regions. The training programmes are modifications of either the British or the American pattern depending on tradition. Documentation of CME is available in eight countries/regions while a defined cycle has been established in only three. Medical/health authorities or professional societies in each country contribute towards its monitoring. Better communication and sharing of experience will improve the training of otorhinolaryngologists in Asia.

Asia↗
PubMed2000

Effect of the external nasal dilator on nasal minimal cross-sectional area in orientals as assessed by acoustic rhinometry.

OBJECTIVE: This study aimed to evaluate the effect of the external nasal dilator on the dimension of the nasal valve in Orientals. DESIGN: A cohort study of normal subjects. SETTING: Academic institution. METHODS: The nasal fossae of normal subjects were assessed by acoustic rhinometry before and after application of the external nasal dilator. MAIN OUTCOME MEASURES: The minimal cross-sectional area of the nasal fossae and the total cross-sectional area of the nose. RESULTS: Nasal fossae of 25 normal subjects were evaluated. There was a significant increase of 0.10 cm2 (SD = 0.16) or a 17% increase in the minimal cross-sectional area of the 50 nasal cavities after application of the external nasal dilator (Wilcoxon's matched-pairs signed rank test, p = .0001). A significant increase in the total minimal cross-sectional area for the whole nose after application was also present (0.19 cm2, SD = .27, or 16%; Wilcoxon's matched-pairs signed rank test, p = .0032). CONCLUSIONS: The external nasal dilator results in an increase in the minimal cross-sectional area of the nasal airway in Orientals.

Cohort Studies↗
PubMed1999

Minimum graft size for successful living donor liver transplantation.

BACKGROUND: The extension of living donor liver transplantation to adult recipients is limited by the adequacy of the size of the graft. We evaluate the effect of the graft size on the survival of the recipient in order to establish a clinical guide for the minimum requirement. METHODS: The clinical records of 14 adults and 11 children (body weight 6.1-100 kg) who underwent living donor liver transplantation for chronic or acute liver failure were reviewed. The effect of the graft weight ratio (graft weight divided by standard liver weight of recipient) on graft function and survival was studied. RESULTS: The graft weight ratio ranged from 31 to 203%. The overall graft and patient survival rates were 84% at a median follow-up of 29 months. The survival rate was 95% for recipients with a graft weight ratio >40%, and 40% only for those with a ratio < or =40% (P = 0.016). It was 88% (7/8) when the ratio was >100%, 100% (5/5) when the ratio was 71 to 100%, 100% (7/7) when the ratio was 41 to 70%, and 40% (2/5) only when the ratio was < or =40%. When the graft weight ratio was < or =40%, early graft dysfunction was evident and contributed to the causes of death in three patients. CONCLUSIONS: Preoperative computed tomographic measurement of liver size of a living donor is essential. A graft that represented 40% or less of the recipient's standard liver weight should be regarded as a marginal graft with a lower success rate.

Acute Disease↗
PubMed1999

The time course of histologic remission after treatment of patients with nasopharyngeal carcinoma.

BACKGROUND: The objective of this study was to define the time course of histologic remission and to evaluate the prognostic significance of delayed histologic remission of patients with nasopharyngeal carcinoma (NPC). METHODS: Between 1986-1994, 803 patients underwent serial postradiotherapy nasopharyngeal biopsies. Patients with positive histology underwent repeated biopsies every 2 weeks until the biopsies were found to be negative or, if remission did not occur by the 12th week after radiotherapy, treatment was initiated for persistent disease. Patients with positive histology found after the fifth week but who achieved spontaneous remission before the twelfth week were considered to have delayed histologic remission. Negative histology by the sixth week was considered early histologic remission. The outcome of patients with delayed histologic remission, early histologic remission, and persistent disease were compared. RESULTS: Six hundred and seventeen patients (76.8%) had negative histology within 12 weeks of the completion of radiotherapy and 55 (6.9%) had persistent disease at Week 12. In 131 patients (16.3%) spontaneous remission was observed in repeat biopsies after initial positive histology. With increasing time after radiotherapy, the incidence of positive histology decreased but more patients were found to have persistent disease. Patients with early and delayed histologic remission had 5-year NPC control rates of 82.4% and 76.8%, respectively (P = 0.35) versus a 40% NPC control rate among patients with persistent disease (P < 0.001). The 5-year survival rates were 75.3%, 79.4%, and 54.2%, respectively, for the 3 groups (P < 0.001). CONCLUSIONS: A high proportion of early positive histology remitted spontaneously. Delayed histologic remission in NPC patients is not a poor prognostic factor and additional treatment is not necessary. A confirmatory biopsy at 10 weeks is recommended before the initiation of salvage treatment.

Biopsy↗
PubMed1999

Applicability of living donor liver transplantation to high-urgency patients.

BACKGROUND: Cadaveric liver donors are scarce in Hong Kong, and the application of liver transplantation to high-urgency patients is limited. We evaluated the use of grafts from living donors in this setting. METHODS: From July 1994 to January 1998, 49 consecutive adult patients who were intensive care unit-bound because of acute or chronic liver failure were put on a high-urgency list for liver transplantation. Family members were not solicited for living donation, and the initiation and decision for living donor liver transplantation (LDLT) was based on the donor's voluntary intent. Assessment of the living donor, including blood tests, computed tomographic volumetry, and angiography, was performed only after informed consent was executed. RESULTS: In 25 of 49 (51%) patients, no family member volunteered as living donor; 23 died awaiting donor organs, and 2 received a cadaveric graft. Twenty-four (49%) patients had 36 family members who volunteered as living donors. Before evaluation of living donor was completed, two patients received a cadaveric liver transplant. LDLT was not performed in nine patients because of recipient contraindications (n=4), ABO blood group incompatibility (n=3), and withdrawal of donor (n=2). Eight of these nine patients died, and one received a cadaveric liver graft. The remaining 13 (27%) patients received grafts from living donors. Four of 5 (80%) patients who underwent cadaveric liver transplantation and 11 of 13 (85%) who underwent LDLT survived. Thus, emergency transplantation from living donors increased the applicability of liver transplantation from 10% to 37%, and the survival rate after emergency LDLT (85%) was superior to that of the remaining patients (11%). CONCLUSIONS: When cadaveric organ donation is scarce, emergency liver transplantation from living donors can be applied to high-urgency adult patients.

Adolescent↗