Kwok Hung Yu

Prince of Wales Hospital, Hong Kong, Chiu-lung, Kowloon City, Hong Kong

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Publications (5)21.95 Total impact

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    ABSTRACT: To investigate the prognostic value of HER2 and p63 expression in head and neck squamous cell carcinoma (HNSCC). A case review of 186 HNSCCs from the oral tongue, palate, maxillary sinus, floor of mouth, oropharynx, hypopharynx, and larynx. All primary tumor specimens were evaluated by immunohistochemistry for HER2 and p63 expressions, which were correlated with clinical parameters including age, sex, grade, lymph node metastases, stage, and survival. One hundred forty-one patients had stage III-IV disease and 109 had lymph node metastases. For all cases, T and N stages were significant prognostic predictors for both overall and disease-free survivals. In the node-positive subgroup, T stage and HER2 expression were significant prognostic predictors for both overall and disease-free survivals. HER2 may be associated with longer survival in node-positive patients with HNSCC.
    Otolaryngology Head and Neck Surgery 10/2009; 141(4):467-73. · 1.73 Impact Factor
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    ABSTRACT: Our previous studies of tonsillar cancers from New South Wales, Australia, and Jilin Province in the north-east of China, provided evidence that the proportion of these cancers attributable to human papillomavirus (HPV) varies geographically. This study provides the first data on HPV in tonsillar cancers from Hong Kong. A total of 49 Hong Kong tonsillar cancers were analysed for HPV DNA by PCR/sequencing and for p16(INK4A), retinoblastoma (pRb) protein, cyclin D1 and p53 expression by semiquantitative immunohistochemistry as evidence of virus causality. Results were compared with those from New South Wales and Jilin Province. Of the 31 Hong Kong cancers with amplifiable DNA, nine (29%) were HPV positive by PCR compared with 46% from New South Wales and 0% from Jilin Province. HPV positivity correlated with female gender, young age, over-expression of p16(INK4A) and loss of pRb and cyclin D1. Five-year disease-specific survival for patients with HPV positive and HPV negative cancers was 82 and 42%, respectively. Relationships between HPV status and cell protein expression in Hong Kong cancers were consistent with those from New South Wales and Jilin Province. The proportion of HPV-associated cancers reflected the relative incidence of oropharyngeal cancer in these regions. HPV is responsible for a small proportion of tonsillar cancers in Hong Kong patients. Differences in the proportions of tumours attributable to HPV in Hong Kong, New South Wales and Jilin Province may be due to environmental, cultural or genetic factors in the different populations.
    Pathology 05/2007; 39(2):217-22. · 2.66 Impact Factor
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    ABSTRACT: 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. 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. The primary endpoint was local control. The prognostic significance of dose-escalation ('boost') after 66 Gy, T-stage, N-stage, use of chemotherapy, sex and age (< or =40 years vs >40 years) was studied. Both univariate and multivariate analyses were performed. On multivariate analysis, T-stage (P < 0.01; hazard ratio [HR], 1.58) and optimal boost (P = 0.01; HR, 0.34) were the only significant factors affecting local failure for the whole study population, and for the population of patients treated by radiotherapy alone, but not for patients who also received chemotherapy. The following were independent determinants of local failure for patient groups with different T-stages treated by radiotherapy alone: use of a boost in T1/T2a disease (P = 0.01; HR, 0.33); use of a boost (P < 0.01; HR, 0.60) and age (P = 0.01; HR, 1.02) in T3/T4 tumors. Among patients with T2b tumors treated by radiotherapy alone and given a boost, the use of a 20 Gy-boost gave a lower local failure rate than a 10 Gy-boost. There was no apparent excess mortality attributed to RT complications. Within the context of a multi-center retrospective study, dose-escalation above 66 Gy significantly improved local control for T1/T2a and T3/4 tumors when the primary RT course was based on the 2D Ho's technique without additional chemotherapy. 'Boosting' in NPC warrants further investigation. Caution should be taken when boosting is considered because of possible increase in radiation toxicity.
    Radiotherapy and Oncology 05/2006; 79(1):27-33. · 4.52 Impact Factor
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    ABSTRACT: We investigated the detectability of EBV DNA in the plasma of patients with non-nasopharyngeal head and neck carcinomas (NNHNC). Previous studies have shown that EBV is present in the tumor tissue of some NNHNC. We recruited 101 patients with NNHNC and 48 healthy controls. Blood samples were taken from controls and patients before treatment. Tumor tissue samples were tested for the presence of EBV in the first 69 patients by in situ hybridization for small EBV-encoded RNA (EBER). Plasma EBV DNA was measured by real-time quantitative PCR in patients and controls. Squamous cell carcinoma (SCC) was the commonest histology (78 patients) followed by lymphoepithelial carcinoma (8 patients). EBER was detected in tumor cells in 7 of 69 patients tested. All of the EBER-positive tumors were lymphoepithelial carcinoma. Two controls (2 of 48; 4.2%) had detectable plasma EBV DNA. Plasma EBV DNA was detected in all of the patients with EBER-positive tumors, and in 23 of 94 (24.5%) patients with tumors of EBER-negative or unknown status. The proportion of plasma EBV DNA-positive cases in either group was significantly higher than that in the control group (P < 0.0027). Plasma EBV DNA concentrations in patients with EBER-positive tumors (median, 3827 copies/ml) were significantly higher than those in the controls (median, 0 copy/ml; P = 0.0001). Of patients with SCC, 21 (26.9%) had detectable plasma EBV DNA (median concentration, 34 copies/ml). Plasma EBV DNA concentrations in the whole group of patients with SCC (median, 0 copy/ml; interquartile range, 0-4 copies/ml) were also significantly higher than those in the controls (P = 0.001). Our data indicate that plasma EBV DNA reflects tumoral EBER status, and it may be of use as a tumor marker for EBER-positive NNHNC. The biological and clinical significance of low levels of circulating EBV DNA in the minority of patients with EBER-negative tumors remain to be elucidated.
    Clinical Cancer Research 03/2004; 10(5):1726-32. · 7.84 Impact Factor
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    ABSTRACT: Topotecan (9-dimethylaminomethyl-10-hydroxycampthothecin) is a new topoisomerase I inhibitor with promising efficacy in the treatment of patients with small cell lung carcinoma (SCLC). Combination with a topoisomerase II inhibitor may potentate the therapeutic effect of topotecan, although there has been conflicting preclinical information on the combination. The objectives of this study were to establish the maximum tolerated dose and to determine the efficacy of the sequential combination of intravenous topotecan and oral etoposide in the treatment of patients with SCLC. Patients with histologically confirmed, limited or extensive stage SCLC were eligible. The dose escalation scheme of three cohorts (six patients per cohort) started at intravenous topotecan 0.5 mg/m(2) per day for 5 days and oral etoposide 50 mg twice daily for 7 days (21-day cycles). Subsequent dose levels involved escalation of topotecan to 0.75 mg/m(2) per day and 1.0 mg/m(2) per day for 5 days. A Phase II study was conducted at one dose level below the maximum tolerated dose. The authors alternated the drug sequence with each consecutive cycle and compared the hematologic toxicity between the two sequences. Thirty-six patients (21 patients with limited disease and 15 patients with extensive disease) received a total of 173 courses of sequential combination chemotherapy (topotecan --> etoposide, 88 courses; etoposide --> topotecan, 85 courses). The authors identified dose levels for the Phase II study as follows: topotecan, 0.75 mg/m(2) per day for 5 days; and etoposide, 50 mg twice daily for 7 days. The dose-limiting toxicity was neutropenia. At this dose level, the incidence of Grade 3-4 neutropenia and the incidence of Grade 3-4 thrombocytopenia were 25% and 10.9%, respectively. Two patients died from neutropenic sepsis. There was no significant difference in hematologic toxicities between the two sequences. Complete and partial response rates were 5.6% and 55.6%, respectively (limited disease, 9.5% and 66.75%; extensive disease, 0% and 40%, respectively). The median progression free survival was 31.9 weeks (limited disease, 36.1 weeks; extensive disease, 28.9 weeks; 95% confidence interval, 25.6-36.0 weeks), and the median overall survival was 52.4 weeks (limited disease, 54.9 weeks; extensive disease, 30.1 weeks; 95% confidence interval, 39.6-57.7 weeks). Combination therapy with topoisomerase I and II inhibitors is a safe and effective regimen for patients with SCLC. Future research on this combination should focus on an oral regimen for patients with extensive disease and poor tolerance to cisplatin. The authors recommend an oral dosage of topotecan at 1.2 mg/m(2) per day (equivalent to intravenous topotecan at 0.75 mg/m(2) per day) for 5 days followed by etoposide 50 mg twice daily for 7 days.
    Cancer 11/2002; 95(7):1511-9. · 5.20 Impact Factor