Comparison of post-hepatectomy long-term survival outcome between non-colorectal non-neuroendocrine and colorectal liver metastases: A population-based propensity-score matching analysis

BACKGROUND

Hepatectomy is an established treatment for colorectal liver metastasis (CLM) or neuroendocrine liver metastasis. However, its role in non-colorectal non-neuroendocrine liver metastasis (NCNNLM) is controversial. This study aims to compare long-term survival outcomes after hepatectomy between NCNNLM and CLM in a population-based cohort.

METHODS

From 2009 to 2018, curative hepatectomy were performed in 964 patients with NCNNLM (n ​= ​133) or CLM (n ​= ​831). Propensity score (PS) matching was performed. Short-term and long-term outcomes were compared between PS-matched groups. Univariate and multivariate analyses were performed to identify prognostic factors affecting survival.

RESULTS

There were 133 patients in the NCNNLM group and 266 patients in the CLM group. The mortality (1.5 ​% vs 1.5 ​%) and morbidity (19.5 ​% vs 20.3 ​%) rates were comparable between the two groups. There was no statistically significant difference in 5-year overall (48.9 ​% vs 39.8 ​%) and recurrence-free (25.1 ​% vs 23.4 ​%) survival rates between NCNNLM and CLM groups. A high pre-operative serum bilirubin level, severe postoperative complications and multiple tumors were independent prognostic factors for poor survival.

CONCLUSION

Hepatectomy for selected patients with NCNNLM can achieve similar long-term oncological outcomes as those with CLM. High serum bilirubin, severe postoperative complication and multiple tumors are poor prognostic factors for survival.

Update on the Recommendations on Breast Cancer Screening by the Cancer Expert Working Group on Cancer Prevention and Screening

Breast cancer (BC) is the most common cancer among women in Hong Kong. The Food and Health Bureau commissioned The University of Hong Kong (HKU) to conduct the Hong Kong Breast Cancer Study (HKBCS) with the aim of identifying relevant risk factors for BC in Hong Kong and developing a locally validated BC risk assessment tool for Hong Kong Chinese women. After consideration of the most recent international and local scientific evidence including findings of the HKBCS, the Cancer Expert Working Group on Cancer Prevention and Screening (CEWG) has reviewed and updated its BC screening recommendations. Existing recommendations were preserved for women at high risk and slightly changed for women at moderate risk. The following major updates have been made concerning recommendations for other women in the general population: Women aged 44 to 69 with certain combinations of personalised risk factors (including presence of history of BC among first-degree relative, a prior diagnosis of benign breast disease, nulliparity and late age of first live birth, early age of menarche, high body mass index and physical inactivity) putting them at increased risk of BC are recommended to consider mammography screening every 2 years. They should discuss with their doctors on the potential benefits and harms before undergoing mammography screening. A risk assessment tool for local women (eg, one developed by HKU) is recommended to be used for estimating the risk of developing BC with regard to the personalised risk factors described above.

Recommendations on prevention and screening for colorectal cancer in Hong Kong

Colorectal cancer is the commonest cancer in Hong Kong. The Cancer Expert Working Group on Cancer Prevention and Screening was established in 2002 under the Cancer Coordinating Committee to review local and international scientific evidence, assess and formulate local recommendations on cancer prevention and screening. At present, the Cancer Expert Working Group recommends that average-risk individuals aged 50 to 75 years and without significant family history consult their doctors to consider screening by: (1) annual or biennial faecal occult blood test, (2) sigmoidoscopy every 5 years, or (3) colonoscopy every 10 years. Increased-risk individuals with significant family history such as those with a first-degree relative diagnosed with colorectal cancer at age ≤60 years; those who have more than one first-degree relative diagnosed with colorectal cancer irrespective of age at diagnosis; or carriers of genetic mutations associated with familial adenomatous polyposis or Lynch syndrome should start colonoscopy screening earlier in life and repeat it at shorter intervals.

Recommendations on prevention and screening for breast cancer in Hong Kong

In Hong Kong, breast cancer is the most common cancer among women and poses a significant health care burden. The Cancer Expert Working Group on Cancer Prevention and Screening (CEWG) was set up in 2002 by the Cancer Coordinating Committee to review and assess local and international scientific evidence, and to formulate recommendations for cancer prevention and screening. After considering the local epidemiology, emerging scientific evidence, and local and overseas screening practices, the CEWG concluded that it was unclear whether population-based breast cancer screening did more harm than good in local asymptomatic women at average risk. The CEWG considers that there is insufficient evidence to recommend for or against population-based mammography screening for such individuals. Women who consider breast cancer screening should be adequately informed about the benefits and harms. The CEWG recommends that all women adopt primary preventive measures, be breast aware, and seek timely medical attention for suspicious symptoms. For women at high risk of breast cancer, such as carriers of confirmed BRCA1/2 deleterious mutations and those with a family history of breast cancer, the CEWG recommends that they seek doctor's advice for annual mammography screening and the age at which the process should commence. Additional annual screening by magnetic resonance imaging is recommended for confirmed BRCA1/2 mutation carriers or women who have undergone radiation therapy to the chest between the age of 10 and 30 years. Women at moderate risk of breast cancer should discuss with doctors the pros and cons of breast cancer screening before making an informed decision about mammography screening every 2 to 3 years.

Best practices to prevent transmission and control outbreaks of hand, foot, and mouth disease in childcare facilities: a systematic review

INTRODUCTION

Hand, foot, and mouth disease continues to cause seasonal epidemics in the Asia-Pacific Region. Since the current Enterovirus 71 vaccines do not provide cross-protection for all Enterovirus species that cause hand, foot, and mouth disease, there is an urgent need to identify appropriate detection tools and best practice to prevent its transmission and to effectively control its outbreaks. This systematic review aimed to identify characteristics of outbreak and assess the impact and effectiveness of detection tools and public health preventive measures to interrupt transmission. The findings will be used to recommend policy on the most effective responses and interventions in Hong Kong to effectively minimise and contain the spread of the disease within childcare facilities.

METHODS

We searched the following databases for primary studies written in Chinese or English: MEDLINE, EMBASE, Global Health, WHO Western Pacific Region Index Medicus database, China National Knowledge Infrastructure Databases, and Chinese Scientific Journals Database. Studies conducted during or retrospective to outbreaks of hand, foot, and mouth disease caused by Enterovirus 71 from 1980 to 2012 within childcare facilities and with a study population of 0 to 6 years old were included.

RESULTS

Sixteen studies conducted on outbreaks in China showed that hand, foot, and mouth disease spread rapidly within the facility, with an outbreak length of 4 to 46 days, especially in those with delayed notification (after 24 hours) of clustered outbreak (with five or more cases discovered within the facility) to the local Center for Disease Control and Prevention and delayed implementation of a control response. The number of classes affected ranged from 1 to 13, and the attack rate for children ranged from 0.97% to 28.18%.

CONCLUSIONS

Communication between key stakeholders about outbreak confirmation, risk assessment, and surveillance should be improved. Effective communication facilitates timely notification (within 24 hours) of clustered outbreaks to a local Center for Disease Control and Prevention. Timely implementation of a control response is effective in minimising incidence and length of an outbreak in childcare facilities. The government should provide incentives for childcare facilities to train infection control specialists who can serve as the first contact, knowledge, and communication points, as well as facilitate exchange of information and provision of support across stakeholders during a communicable disease epidemic.

The contribution of charcoal burning to the rise and decline of suicides in Hong Kong from 1997-2007

BACKGROUND

There has been scant research exploring the relationship between choice of method (means) of self-inflicted death, and broader social or contextual factors. The recent emergence and growth of suicide using carbon monoxide poisoning resulting from burning charcoal in an enclosed space (hereafter, "charcoal burning") was related to an increase in the overall suicide rate in Hong Kong. The growth of this method coincided with changing economic conditions. This paper expands upon previous work to explore possible relationships further.

PURPOSE

This study aims to discern the role of charcoal burning in overall suicide rate transition during times of both economic recession and expansion, as captured in the unemployment rate of Hong Kong, and to examine whether there was evidence of an effect from means-substitution.

METHODS

Age and gender specific suicide rates in Hong Kong by suicide methods from 1997 to 2007 were calculated. To model the transition of suicide rate by different methods, Poisson regression analyses were employed.

RESULTS

Charcoal burning constituted 18.3% of all suicides, 88% of which involved individuals drawn from the middle years (25-59) of life. During both periods of rising and declining unemployment, charcoal burning played an important role in the changing suicide rates, and this effect was most prominent among for those in their middle years. Means-substitution was found among the married women during the period of rate advancement (1997-2003).

CONCLUSIONS

Compared to others, working-age adults preferentially selected carbon monoxide poisoning from charcoal burning.

Speedup of doping fronts in organic semiconductors through plasma instability

The dynamics of doping transformation fronts in organic semiconductor plasma is studied for application in light-emitting electrochemical cells. We show that new fundamental effects of the plasma dynamics can significantly improve the device performance. We obtain an electrodynamic instability, which distorts the doping fronts and increases the transformation rate considerably. We explain the physical mechanism of the instability, develop theory, provide experimental evidence, perform numerical simulations, and demonstrate how the instability strength may be amplified technologically. The electrodynamic plasma instability obtained also shows interesting similarity to the hydrodynamic Darrieus-Landau instability in combustion, laser ablation, and astrophysics.

Restricting the means of suicide by charcoal burning

We conducted an exploratory controlled trial to examine the efficacy of restricting access to charcoal in preventing suicides from carbon monoxide poisoning by charcoal burning in Hong Kong. All charcoal packs were removed from the open shelves of major retail outlets in the intervention region for 12 months; in the control region, charcoal packs were displayed as usual. The suicide rate from charcoal burning was reduced by a statistically significant margin in the intervention region (P<0.05) but not in the control region. We observed no significant change in the suicide rate using other methods in either location.

Evaluating the effectiveness of barrier installation for preventing railway suicides in Hong Kong

BACKGROUND

Railway suicide is a serious mortality issue. Most attempters are unmarried psychotic young men under psychiatric care having a high level of lethal intent. Installation of platform screen doors (PSDs) to limit access to the track has been suggested as an effective way for prevention. This study aims to examine the effectiveness of installing PSDs for preventing railway suicides; any sign of substitution of suicide location; and changes in psychiatric profile of suicide deceased after the PSD installation in the subway system of Hong Kong.

METHODS

Cases of railway suicide and related information from 1997 to 2007 were provided by the railway operators and the Coroner's Court. The effectiveness of installing PSDs was assessed through a quasi-experimental setting. Poisson regression and chi-squared test were used.

RESULTS

Over the 11-year study period, a total of 76 railway suicide cases (0.71% of all suicides) were reported. A significant reduction of 59.9% (p=0.0003) in railway suicides was found after the PSD installation. Analyses confirmed that there was no significant sign of substitution by displacing potential attempters to unsealed platforms (p=0.9051). Those having psychosis would be better protected as no suicide cases with such psychiatric background were reported after the installation of PSDs.

LIMITATIONS

It has not considered the potential economic benefits of PSD. It is difficult if not possible to examine whether the potential attempters would substitute to an alternative method of suicide.

CONCLUSIONS

This study shows that PSDs can effectively prevent suicides with no substitution by "delethalizing" the image and altering people's perception about the desirability of railway suicide. Railway operators should extend the coverage of PSD to all railway stations in Hong Kong without any delay.

Suicidal ideation and suicidal attempts in a population-based study of Chinese people: risk attributable to hopelessness, depression, and social factors

BACKGROUND

The population attributable fraction of hopelessness, depression and other risk factors for suicidal ideation and suicidal attempts in Asian population is unknown. Social support is often said to be a buffer against the effect of hopelessness and depression.

METHODS

Suicidal ideation, suicidal attempts as well as demographic and psychometric data were delineated in a random and representative population sample of 2,219 Chinese people in Hong Kong. The population attributable fraction was used to determine the contribution of hopelessness, depression and other risk factors to suicidal ideation and attempts.

RESULTS

Multivariate modelling shows that about 40% of suicidal ideation and attempts was attributable to depression and about 20% was attributable to hopelessness. Drug abuse and marital dissolution were also significant contributors to suicidality. The impact of hopelessness and depression was not affected by social support.

LIMITATIONS

Suicidality was self-reported.

CONCLUSIONS

Suicidal ideation and suicidal attempts were to a large extent attributable to depression and hopelessness, and, to a lesser extent, drug abuse and marital dissolution. Social support appeared to play little role as a buffer.

Thermochemical and Kinetic Analyses on Oxidation of Isobutenyl Radical and 2-Hydroperoxymethyl-2-propenyl Radical

In recognition of the importance of the isobutene oxidation reaction in the preignition chemistry associated with engine knock, the thermochemistry, chemical reaction pathways, and reaction kinetics of the isobutenyl radical oxidation at low to intermediate temperature range were computationally studied, focusing on both the first and the second O2 addition to the isobutenyl radical. The geometries of reactants, important intermediates, transition states, and products in the isobutenyl radical oxidation system were optimized at the B3LYP/6-311G(d,p) and MP2(full)/6-31G(d) levels, and the thermochemical properties were determined on the basis of ab initio, density functional theory, and statistical mechanics. Enthalpies of formation for several important intermediates were calculated using isodesmic reactions at the DFT and the CBS-QB3 levels. The kinetic analysis of the first O2 addition to the isobutenyl radical was performed using enthalpies at the CBS-QB3 and G3(MP2) levels. The reaction forms a chemically activated isobutenyl peroxy adduct which can be stabilized, dissociate back to reactants, cyclize to cyclic peroxide-alkyl radicals, and isomerize to the 2-hydroperoxymethyl-2-propenyl radical that further undergoes another O2 addition. The reaction channels for isomerization and cyclization and further dissociation on this second O2 addition were analyzed using enthalpies at the DFT level with energy corrections based on similar reaction channels for the first O2 addition. The high-pressure limit rate constants for each reaction channel were determined as functions of temperature by the canonical transition state theory for further kinetic model development.

Social and Economic Burden of Suicides in Hong Kong SAR

Abstract. The paper proposes to use the years-of-life-lost method (YLL) in assessing the social and economic burden of suicides in Hong Kong SAR. The YLL from suicide by age group in 1981-2002 is calculated based on the standard set by World Health Organization (WHO). It shows that the middle age group (25-39) contributed most to the burden of disease in Hong Kong. The proportion of older adults' suicides is about 25% of the total number of suicides but its disease burden is less than 6% in terms of the YLL. Though the group aged 25-39 contributed disproportionately to the total YLL from suicide, the prevention effort for this particular group has been very much neglected and needs to be strengthened. It illustrates that use of YLL could provide a new viewpoint for setting up public health policies.

Incidence and spectrum of non-Hodgkin lymphoma in Chinese migrants to British Columbia

The incidence and spectrum of non-Hodgkin lymphoma (NHL) differ between the Chinese and Caucasian populations. Using population-based registries, we studied the pattern of NHL in Chinese migrants to British Columbia (BC). The records of all NHL cases of Chinese descent diagnosed between 1980 and 1997 were retrieved. Age-standardized incidences were calculated by 5-year intervals in terms of age and calendar years and the relative rates were compared between the migrant, Hong Kong and BC populations. The histological distribution of NHL was compared with 4500 consecutive NHL cases diagnosed in the two populations. A total of 211 cases of migrant NHL were identified, with an age-standardized incidence rate of 7.11 per 100 000 per year, compared with the Hong Kong and BC rates of 7.91 [standardized incidence ratio (SIR) = 0.86, P = 0.01] and 11.88 (SIR = 0.56, P < 0.01). The standardized rates of follicular lymphoma remained low, but the incidence of gastric and nasal natural killer/T lymphomas in migrants were lower than expected. Genetic factors appeared to be stronger than environmental factors in governing the overall incidence of NHL in Chinese. However, certain subtypes of lymphoma may show decreased rates in migrants because of environmental factors.

Clinical Role of Circulating Epstein-Barr Virus DNA as a Tumor Marker in Lymphoepithelioma-Like Carcinoma of the Lung

Nineteen Chinese patients with lymphoepithelioma-like carcinoma (LELC) of the lung were tested for Epstein-Barr virus (EBV) DNA in their serum samples by a quantitative polymerase chain reaction (PCR) technique. There was prospective serial monitoring of the serum in seven patients with advanced inoperable or relapsing disease. Five other patients at first diagnosis and two patients at relapse had only a single serum sample available. Serum samples were also taken from three other patients who had prior curative surgery and two patients with prolonged disease remission. Measurable levels of EBV DNA were detected in 11 of 12 patients with a pre-therapy serum sample and a clinically evident tumor. A low level of EBV DNA was also detectable in one of the two other patients whose first serum samples were obtained after some chemotherapy. There was no detectable EBV DNA in the five patients without evidence of tumor. The longitudinal serum EBV DNA profile of seven patients showed consistent correlation with response to therapy and clinical outcome. Patients with a pre-therapy serum EBV DNA >10,000 copies/mL had significantly inferior overall survival. This study suggests that circulating serum EBV DNA can be used as a tumor marker in the clinical management of patients with LELC of the lung.

Analysis and interpretation of high transverse entanglement in optical parametric down conversion

Quantum entanglement associated with transverse wave vectors of down conversion photons is investigated based on the Schmidt decomposition method. We show that transverse entanglement involves two variables: orbital angular momentum and transverse frequency. We show that in the monochromatic limit high values of entanglement are closely controlled by a single parameter resulting from the competition between (transverse) momentum conservation and longitudinal phase matching. We examine the features of the Schmidt eigenmodes, and indicate how entanglement can be enhanced by suitable mode selection methods.

Suicide in Hong Kong: epidemiological profile and burden analysis, 1981 to 2001

OBJECTIVE

To describe changes of the epidemiological profile of suicides in Hong Kong, and the burden of suicides in terms of years of life lost between 1981 and 2001.

DESIGN

Retrospective study.

SETTING

Hong Kong.

PARTICIPANTS

Data on registered deaths of the Hong Kong population from 1981 to 2001 were retrieved from records of the Census and Statistics Department of the Government of the Hong Kong Special Administrative Region.

MAIN OUTCOME MEASURES

Crude, standardised, age- and sex-standardised suicide rates; years of life lost; suicide method used; and rank among leading causes of death.

RESULTS

Suicide ranked sixth in the leading cause of deaths and represented about 3% of all deaths each year. The suicide rate has increased from 9.6 per 100000 to 15 per 100000 between 1981 and 2001. The total years of life lost due to suicide increased by 96.0%, from about 9900 years in 1981 to 19 400 years in 2001, whereas the figure for all causes of death decreased by 14.0%, from 274600 years to 236700 years. The total share of years of life lost attributable to suicide deaths has increased from 3.6% to 8.1% and is still increasing, especially among the middle age-groups (30-59 years). The use of charcoal burning as a suicide method has increased from 6.0% before 1998 to more than 28.0% in 2001.

CONCLUSION

The burden on the years of life lost due to suicide is underestimated and overlooked. The increase of suicides in recent years has had a significant impact on the years of life lost and can be used as a useful indicator of performance in Hong Kong.

Control of entanglement and the high-entanglement limit

We examine two-particle entanglement and ways in which it might be coherently controlled. Control is desirable for successful implementation of quantum computing. As one result, we find that reaching very high entanglement may be feasible experimentally.

In-depth evaluation of the AJCC/UICC 1997 staging system of nasopharyngeal carcinoma: prognostic homogeneity and proposed refinements

PURPOSE

To critically evaluate the American Joint Commission on Cancer (AJCC)/International Union Against Cancer (UICC) 1997 staging system and look back on its achievements by comparing it with the AJCC/UICC 1992 and Ho 1978 staging systems. To identify areas for additional refinement, we analyzed the prognostic heterogeneity within each stage in depth, which provided important clues for the addition or better categorization of the different defining criteria.

METHODS AND MATERIALS

We performed a retrospective review of the data from 1294 consecutive biopsy-proven nonmetastatic nasopharyngeal carcinoma patients and staged the extent of disease according to the defining criteria of the three staging systems. All patients had undergone detailed pretreatment assessment by fiberoptic endoscopy and CT. Radical-intent radiotherapy was given using the Ho technique according to our standard protocol.

RESULTS

The AJCC/UICC 1997 staging system was superior to the other two staging systems, because it assigned patients to more uniform-size stage groupings and correlated better with prognosis. Parapharyngeal space involvement was not an independent predictor for survival, local control, or metastasis. On the other hand, carotid space involvement correlated with a greater likelihood of metastasis. Prognostic heterogeneity was found. Those with orbit, cranial nerve, or intracranial involvement fared worse within Stage T4; those with a maximal lymph node size >3 cm fared worse within Stage N2; and those with bilateral lymph node metastasis fared worse within Stage N3.

CONCLUSION

The prognostic accuracy of the AJCC/UICC 1997 staging system can be improved further by recategorization of the T, N, and group stage criteria.

Treatment of trichlorophenol by catalytic oxidation process

The oxidation of 2,4,6-trichlorophenol (TCP) by ferrous-catalyzed hydrogen peroxide was quantified and modeled in the study. TCP was effectively degraded by hydroxyl radicals that were generated by Fe(II)/H(2)O(2) in the oxidation process. The oxidation capacity (OC) of the process depends on the concentrations of oxidant (hydrogen peroxide) and oxidative catalyst (ferrous ion). Up to 99.6% of TCP removal can be achieved in the process, provided the doses of Fe(II) and H(2)O(2) are selected correctly. The OC of the process was successfully predicted through a kinetic approach in a two-stage model with some simple and measurable parameters, which makes the model useful for predicting, controlling and optimizing the catalyzed oxidation process in the degradation of TCP.

Healthy life expectancy in Hong Kong Special Administrative Region of China

Sullivan's method and a regression model were used to calculate healthy life expectancy (HALE) for men and women in Hong Kong Special Administrative Region (Hong Kong SAR) of China. These methods need estimates of the prevalence and information on disability distributions of 109 diseases and HALE for 191 countries by age, sex and region of the world from the WHO's health assessment of 2000. The population of Hong Kong SAR has one of the highest healthy life expectancies in the world. Sullivan's method gives higher estimates than the classic linear regression method. Although Sullivan's method accurately calculates the influence of disease prevalence within small areas and regions, the regression method can approximate HALE for all economies for which information on life expectancy is available. This paper identifies some problems of the two methods and discusses the accuracy of estimates of HALE that rely on data from the WHO assessment.

Acute care service utilisation and the possible impacts of a user-fee policy in Hong Kong

OBJECTIVES

To examine the utilisation pattern of accident and emergency services and to study the possible impact of a user-fee policy on non-emergency attendances in Hong Kong.

DESIGN

Retrospective study.

METHODS

Four different scenarios are postulated to examine the impact on the number of accident and emergency attendances of a user-fee policy from 2000 to 2029. Patient volume data of accident and emergency attendances for 2000 were made available by the Hospital Authority of Hong Kong.

RESULTS

Non-emergency use of the accident and emergency services is the main cause of over-utilisation and contributes to more than 70.0% of its use. Only 22.0% of patients attending accident and emergency departments were admitted to a ward for further treatment. By 2029, the number of accident and emergency attendances would increase by more than 47.0% if the present utilisation pattern prevails. However, if patients at triage levels 3, 4, and 5 were discouraged from using the accident and emergency services, the number of attendances would decrease by 76.4%.

CONCLUSION

The proposed user-fee policy would act as a deterrent by preventing unnecessary use of accident and emergency services. However, the use of out-patient services may be increased as a result and attendance should be carefully monitored. Community health education and civic education relating to abuse of accident and emergency services would be effective in reducing over-utilisation of these services.

Combination gemcitabine and cisplatin chemotherapy for metastatic or recurrent nasopharyngeal carcinoma: report of a phase II study

BACKGROUND

To evaluate the efficacy and toxicity of combination gemcitabine plus cisplatin (GC) chemotherapy in metastatic or recurrent nasopharyngeal carcinoma (NPC).

PATIENTS AND METHODS

Forty-four patients of Chinese ethnicity with metastatic or recurrent NPC received ambulatory GC chemotherapy every 28 days (gemcitabine 1000 mg/m(2) days 1, 8 and 15; cisplatin 50 mg/m(2) days 1 and 8). There were 40 male and four female patients with a mean age of 47.4 years. More than half (54.5%) of the patients had received either prior platinum-based chemotherapy and/or radiotherapy to target lesions.

RESULTS

There were nine complete responses and 23 partial responses in the 44 patients, achieving an overall response rate of 73% (78% for the 41 assessable patients). The mean duration of response was 5.3 months. Improved subjective symptom-control scores were found in 78% of patients with pre-existing symptoms, while 64% of patients experienced improved general well-being scores. Toxicity was mainly hematological: grade III/IV anemia, granulocytopenia and thrombocytopenia were found in 11, 37 and 16% of cycles, respectively. With a median follow-up of 17.2 months, 62% survived 1 year while 36% were alive and progression free.

CONCLUSIONS

Gemcitabine plus cisplatin chemotherapy offers a satisfactory overall response rate, subjective patient improvement and safety profile for metastatic and recurrent NPC.

Viability of the health protection account in Hong Kong

OBJECTIVE

To evaluate the viability of the Health Protection Account proposed by the Hong Kong Special Administrative Region Government.

DESIGN

Retrospective study.

SETTING

The Hospital Authority of Hong Kong.

MATERIALS AND METHODS

Data were obtained from hospital and specialist out-patient clinic admissions. The expected health cost for each patient from the age of 65 years to the average age of life expectancy (83 years) was estimated, as was the contribution to these health costs from the Health Protection Account.

RESULTS

If individuals contribute 1% of their salary to the Health Protection Account from age 40 to 65 years, the Account can only cover 4% of the actual health costs.

CONCLUSION

The Health Protection Account, as proposed, does not ease the financial burden of increasing health care costs in the elderly. Increasing the contribution rate or reducing the age at which contributions to the scheme are started are possible viable options for making the scheme sustainable. However, the current economic situation is such that the public would not favour either of these alternatives. It is envisaged that the Government will need to continue to finance the health care of its citizens by taxation. A gradual increase in user charges might be the only future option for controlling government health expenditure.

Assessment of the future resources and needs for hospitalization in Hong Kong SAR (Special Administrative District)

OBJECTIVES

To study the 'compression of morbidity' theory in the Hong Kong SAR by analysing the age and gender-specific hospitalization rates and the expected length of stay per patient for the period 1996-2000. 'Compression of morbidity' refers to the hypothesis that medical progress will reduce the duration of morbidity during life more significantly than increasing morbidity by extending life.

DESIGN

This is a retrospective study based on hospital admissions data from the Hospital Authority of Hong Kong which covers 93% of the patient population.

SETTING

Age and gender-specific hospitalization rates, expected length of stay and hospitalization needs for each specific age group in Hong Kong from 1996 to 2000, are estimated.

MAIN RESULTS

There is no empirical support for compression theory; and there is no significant change in the hospital admission rates for the period 1996-2000. The total number of patient days is expected to increase by 80% because of the ageing effect alone. It is projected that the geriatric service will account for more than 60% of the hospital patient days utilization in 2029. The elderly dependency ratio will increase and the social burden for the next generation will be increased, as the working populations size continues to decrease due to low fertility in the Hong Kong SAR.

CONCLUSION

The health care burden on the government is large and increasing. It is therefore essential to make plans to deal with the ageing population, which is predicted to be at its highest in 2020. The rising effect of public expectations on hospital services exerts further pressure on demand.

Localized single-photon wave functions in free space

We solve the joint open problems of photon localization and single-photon wave functions in the context of spontaneous emission from an excited atom in free space. Our wave functions are well-defined members of a discrete orthonormal function set. Both the degree and shape of the localization are controlled by entanglement mapping onto the atom wave function, even though the atom is remote from the photon.

Endovascular treatment of radiation-induced petrous internal carotid artery aneurysm presenting with acute haemorrhage. A report of two cases

Haemorrhage from rupture of petrous ICA aneurysm can be life threatening and emergency treatment is required. We report 2 cases of radiation-induced petrous internal carotid artery (ICA) aneurysm presenting with acute haemorrhage (epistaxis and otorrhagia) after radiotherapy (RT) for nasopharyngeal carcinoma (NPC). Both patients had a history of RT treatment for NPC. The first patient, a 54-year-old man, presented with sudden severe epistaxis and haemorrhagic shock. The second patient, a 35-year-old man, presented with episodes of severe otorrhagia. The first patient was immediately resuscitated. Obliteration of the aneurysm was performed by endovascular occlusion of the ICA with Guglielmi detachable coils and fibered platinum coils. For the second patient, the aneurysm was treated by deploying a self-expandable stent across the aneurysm neck. In an emergency situation, ruptured petrous ICA aneurysm can be treated with endovascular occlusion of the ICA with microcoils if there is a good collateral blood flow. Alternatively, the aneurysm can be treated by deployment of a stent, which can induce stasis and eventual thrombosis of the aneurysm.

Brain abscess formation in radiation necrosis of the temporal lobe following radiation therapy for nasopharyngeal carcinoma

BACKGROUND

Radiation necrosis is a known complication following radiation therapy for extracranial as well as intracranial tumours. However, brain abscess formation in radiation necrosis has not been reported in the literature. We report the clinical data of 6 patients suffering from this condition.

METHOD

Twenty-eight patients with radiation necrosis of the temporal lobe following radiotherapy for nasopharyngeal carcinoma were treated surgically at the Department of Neurosurgery, Queen Elizabeth Hospital, Hong Kong between January 1992 and July 1999. Of these, 6 cases were complicated by brain abscess formation. The clinical data of these 6 patients are retrospectively reviewed.

FINDINGS

The patients were 5 males and 1 female, ranging in age from 41 to 67 years. Three patients had previous treatment with steroids for the symptomatic radiation necrosis. A history of nasal infection or otitis media was recognised in all 6 patients. All patients were treated surgically by temporal lobectomy and excision of the necrotic tissue together with the abscess cavity. Intra-operatively, a bony defect was observed between the middle cranial fossa and the sphenoid sinus in 3 patients and the bony defect was repaired with a temporalis muscle flap. The species of organisms could only be identified in 3 patients. In 3 patients, the pus smear was positive but the culture was negative. Subsequently, 4 patients recovered and 2 patients died.

INTERPRETATION

Cerebral radiation necrosis is a predisposing cause of brain abscess formation. Surgical excision is recommended as the treatment of choice in this group of patients.

Acute hemorrhage in late radiation necrosis of the temporal lobe: report of five cases and review of the literature

Hemorrhage in late cerebral radiation necrosis is a rare complication after radiotherapy for intracranial and extracranial neoplasms. We report 5 cases of acute hemorrhage in late radiation necrosis of the temporal lobe following radiation therapy for nasopharyngeal carcinoma. In a review of the literature, the authors identified a total of 27 such cases. The interval period between the onset of hemorrhage and cranial irradiation is long (mean = 7.8 years). The most prominent histological feature was the proliferation of large, dilated and thin-walled new blood vessels in a background of gliosis and fibrinoid necrosis of vessels. Rupture of these thin-walled new blood vessels is the proposed mechanism of hemorrhage in this condition.

Motional dressed states in a bose-einstein condensate: superfluidity at supersonic speed

We present an exact analytic solution of a nonlinear Schrodinger field interacting with a moving potential (obstacle) at supersonic speed. We discover conditions under which the field can form a stable shape-invariant structure localized around the obstacle-a dressing effect that protects the field against excitations by the obstacle. Such an effect demonstrates the existence of frictionless motion beyond the conventionally defined critical velocity.

Continuous frequency entanglement: effective finite hilbert space and entropy control

We examine the quantum structure of continuum entanglement and in the context of short-pulse down-conversion we answer the open question of how many of the uncountably many frequency modes contribute effectively to the entanglement. We derive a set of two-photon mode functions that provide an exact, discrete, and effectively finite basis for characterizing pairwise entanglement. Our analysis provides a basis for entropy control in two-photon pulses generated from down-conversion.

Nasopharyngeal carcinoma---time lapse before diagnosis and treatment

This is a descriptive study of 168 patients with nasopharyngeal carcinoma who were referred to public oncology departments for primary treatment between July and September 1996. The mean duration from the onset of the symptoms to histological diagnosis was 5.0 months; the duration ranged from 6.1 months (for patients presenting with nasal symptoms) to 1.8 months (for those with cranial nerve dysfunction). The mean period between the onset of symptoms and the seeking of medical advice was 2.9months. For 54% of the patients, there was a further delay of up to 2.4 months between the initial medical consultation and referral to the appropriate specialist. The majority (84%) of patients attended public institutions for histological confirmation. The mean total time taken from the onset of symptoms to the commencement of radiotherapy was 6.5 months (range, 1.3-74.0 months)---45% of the delay was attributed to the patient, 20% to initial consultations, 14% to diagnostic arrangement, and 21% to preparation for radiotherapy. Concerted efforts are needed to minimise further the time between the onset of symptoms and treatment. A substantial reduction in this delay can be achieved if both public and primary care doctors were made more aware of the significance of relevant symptoms.

Weekly CAF chemotherapy for advanced breast cancer patients

In a prospective phase II study, 102 women with advanced breast cancer were treated with low doses of cyclophosphamide, Adriamycin and 5-fluorouracil (CAF) at weekly intervals by intravenous injection. Seventy-five patients were evaluable for treatment response and the overall response rate was 52% (95% confidence interval, 41-63%). Of the evaluable patients, 15% had complete response and 37% had partial response. The median survival after therapy was 15.6 months, the median time to progression was 6.8 months and the median duration of response was 9.1 months. The main toxicities were mild vomiting and moderate myelosuppression. There was only 1 patient who experienced heart failure. Weekly CAF appears to have an efficacy with tolerable side effects comparable to standard CAF with an every-3-week schedule.

A phase II study of carboplatin in nasopharyngeal carcinoma

This is a phase II study to evaluate the efficacy and toxicity of short-course carboplatin in advanced-stage nasopharyngeal carcinoma (NPC). Thirty-three previously untreated stage III-IV NPC patients were studied. Carboplatin was given as a rapid intravenous injection every 3 weeks. The dose of carboplatin was calculated according to the individual patient's creatinine clearance and desired platelet nadir of 75,000/microliter according to the Egorin formula. Response and toxicity were evaluated. Thirty-two patients were evaluated for response. The median age was 54 years, range 30-70 years. Twenty-four patients had local regional disease and 8 patients had metastatic disease. The median dose of carboplatin given was 415 mg/m2 (range 91-791 mg/m2). Fourteen (44%) patients had a partial response with a 95% confidence interval of 26-62%. Fifteen (47%) patients had stable disease and 3 (9%) progressive disease. The overall median survival rate was not reached at 43 months. Overall toxicity was tolerable. Grade III-IV myelosuppression occurred in 4 (12%) patients. There were no other major toxicity- or treatment-related deaths. We conclude that carboplatin has a significant anticancer effect in advanced NPC. Thus carboplatin combination chemotherapy for the treatment of NPC is worthy of future clinical investigations.

Staging of nasopharyngeal carcinoma: evaluation of N-staging by Ho and UICC/AJCC systems. Union Internationale Contre le Cancer. American Joint Committee for Cancer

To evaluate the prognostic accuracy of N-staging by Ho's and the UICC/AJCC systems, 5020 patients with undifferentiated or poorly differentiated squamous cell carcinoma of the nasopharynx treated at the Queen Elizabeth Hospital, Hong Kong in the period 1976-1985 were analysed retrospectively. They were initially staged with Ho's system, but detailed records of nodal involvement allowed accurate retrospective restaging with the UICC/ AJCC (1988) system. Staging assessment depended almost entirely on physical examination; only 14% of patients had additional investigations with computed tomography. To evaluate the independent significance of different nodal parameters, T-stage adjusted analyses of the 4730 patients presenting without distant metastases were performed. Both N-staging systems showed a strongly significant overall correlation with distant failures and cancer-specific deaths. A significant trend was also shown for nodal failures in node-positive patients. Ho's system was superior in predicting distant failures, while the UICC/AJCC system was superior for nodal failures. However, even with due adjustment for level, the independent significance of nodal size, laterality and fixity could be demonstrated. After adjustment for UICC/AJCC N-stage, both level and fixity were also significant. Furthermore, when adjusted for all other meaningful parameters, there were no significant differences between ipsilateral and contralateral involvement, upper and mid-level extent, and nodal size < or = 3 cm or > 3- < or = 6 cm. N-staging can be further optimized by a newly proposed system incorporating fixity (movable versus fixed), level (upper-mid versus lower), size (greatest diameter < or = 6 cm versus > 6 cm), and laterality (unilateral versus bilateral) as staging criteria.

N-staging of nasopharyngeal carcinoma: discrepancy between UICC/AJCC and Ho systems. Union Internationale Contre le Cancer. American Joint Committee for Cancer

To enable clinicians to have a better understanding of the limitations of the UICC/AJCC and Ho N-staging systems for nasopharyngeal carcinoma, 4730 patients without distant metastases at diagnosis were retrospectively analysed. The two systems agreed in 54% (1867/3451) of node-positive patients, and their treatment results were taken as the reference for comparison. To identify the most appropriate N-stage for the discrepant groups, their outcomes were measured against the respective reference. All patients with single, ipsilateral and small nodes, irrespective of their relative position in the upper-mid neck should be classified as N1, while those with multiple, bilateral/contralateral or medium-sized node(s) are effectively N2, even if nodal involvement is confined to the upper neck. All patients with extension to the supraclavicular fossa (irrespective of size) and those with nodes larger than 6 cm at the greatest diameter (irrespective of level) should be classified and treated as N3, especially as, in this group, half of the patients died of distant metastases and trials of adjuvant systemic therapy have to be considered. Areas of inaccurate prognostication by the respective system should be noted to avoid misguiding treatment strategy. The present analyses support our previous suggestions that both the level of extent and the bulk of nodal deposits are important prognostic factors. While supraclavicular involvement is a significant demarcation, there is little justification for further division into upper and mid-levels. The merits of both systems should be duly recognized and combined for the further improvement of prognostic accuracy.

Elimination of dose limiting toxicities of cisplatin, 5-fluorouracil, and leucovorin using a weekly 24-hour infusion schedule for the treatment of patients with nasopharyngeal carcinoma

BACKGROUND

Cisplatin, 5-flourouracil (5-FU), and leucovorin (PFL) chemotherapy has been reported to be effective in the treatment of cancers but severe mucositis or neutropenia are dose limiting toxicities. This Phase II study evaluated the anticancer effect and the toxicities of a new weekly 24-hour infusional PFL chemotherapy in patients with nasopharyngeal carcinoma (NPC).

METHODS

Forty-two patients with stage IV NPC were studied. Cisplatin 25 mg/m2/d, 5-FU 2200 mg/m2/d, and leucovorin 120 mg/m2/d were adminstered weekly by 24-hour intravenous continuous infusion in an outpatient setting. Clinical response and toxicity were evaluated weekly.

RESULTS

The complete response rate (CR) was 30% and the partial response (PR) rate 60% in the localized previously untreated group. The CR rate was 22.7% and PR rate 45.5% in local recurrent/metastatic group. The overall response rate was 79%. Eighty-one percent of patients who had no previous chemotherapy and 67% of patients who had previous chemotherapy responded to weekly PFL. There were no dose limiting toxicities. No patient had grade 3 or 4 mucositis or neutropenia. Thirty-two patients (76%) had no oral mucositis. Seven patients (17%) had grade 1 mucositis and 3 patients (7%) had grade 2 mucositis.

CONCLUSIONS

Elimination of dose limiting toxicities is possible using a weekly 24-hour infusion schedule of PFL chemotherapy while retaining significant anticancer activity as demonstrated in these patients with advanced NPC. To discover whether this schedule is superior to cisplatin and 5-FU or other PFL chemotherapy regimens requires further investigation.

Primary lymphoepithelioma-like carcinoma of the lung. A clinicopathologic study of 11 cases

BACKGROUND

Lymphoepithelioma-like carcinoma (LELC), best known to occur in the nasopharynx, can arise in a variety of sites, such as the salivary gland, thymus, lung, stomach, and skin. Primary LELC of the lung is very rare, with only limited information in the literature.

METHODS

The clinicopathologic features of 11 patients with pulmonary LELC collected from two regional hospitals in Hong Kong are described.

RESULTS

The patients, all Chinese, were aged 38 to 73 years (median, 54 years), with equal sex incidence. Two of the 8 patients were smokers. Four presented with coin lesions incidentally discovered on chest X-ray, five with cough and blood-stained sputum, and two with pleural effusion. The tumor formed a discrete (9 patients) or an ill-defined (1 patient) nodule in the lung, or, rarely, showed extensive bilateral pulmonary involvement (1 patient). The major bronchi were not involved except in 1 patient. Three patients had lymph node metastasis at presentation; two of them had bone metastasis, one at presentation and one after 9 months. The tumors had pushing margins, and grew in the form of anastomosing islands and sheets, comprising syncytial-appearing large cells with vesicular nuclei and prominent nucleoli. They were infiltrated by an appreciable number of small lymphocytes and plasma cells. Intratumoral amyloid globules were found in one tumor. In five patients, the tumor showed intraepithelial growth within the small bronchi; this could represent either the in-situ phase of the tumor or pagetoid spread into the bronchial epithelium. The neoplastic cells of all patients harbored Epstein-Barr virus (EBV) as demonstrated by in situ hybridization for EBV-encoded small nuclear RNAs. All eight Asian patients with pulmonary LELC previously reported in the literature similarly have been EBV-positive, whereas the four reported Caucasian patients all have been EBV-negative.

CONCLUSION

Lymphoepithelioma-like carcinoma of lung occurring in Asians is an EBV-associated neoplasm; it also appears to occur at a higher frequency in Asians than Caucasians. It usually presents as a solitary subpleural nodule, and there is no strong association with cigarette smoking. Most patients have early stage disease at presentation. From the limited available data, the behavior of LELC of lung is highly variable, ranging from apparent curability by excision (particularly for localized disease) to highly aggressive, extensive disease at presentation.

Pharmacokinetic and pharmacodynamic studies with mitoxantrone in the treatment of patients with nasopharyngeal carcinoma

The pharmacokinetics and pharmacodynamics of mitoxantrone were studied in 15 patients with advanced nasopharyngeal carcinoma (NPC) after single intravenous rapid infusion (12 to 14 mg/m2). Mitoxantrone plasma concentrations and urinary excretion were measured specifically with the use of a high-performance liquid chromatographic method with ultraviolet detection at 242 and 658 nm. The pharmacokinetic parameters are described adequately by a three-compartment model with a terminal half-life of 71.5 +/- 40.1 hours and a volume of distribution of 5037 +/- 2377 l. The total plasma clearance was 743 +/- 462 ml/minute, and the renal clearance was 18.8 +/- 8.49 ml/minute. Within 72 hours, 1.8 +/- 0.6% of the administration dose was excreted in urine as mitoxantrone parent compound. From the urinary excretion rate data, glomerular filtration and possible tubular reabsorption were the mechanisms involved in the urinary excretion of mitoxantrone. The values for unbound fraction (%) in plasma at time 0 and 5 minutes were 2.88 +/- 0.91% and 3.25 +/- 1.19%, with an average of 3.04 +/- 1.01%. The degree of protein binding of mitoxantrone was not affected by concentration (P greater than 0.05) in Chinese patients with NPC. The response rate for mitoxantrone was poor in this study. Clinical studies have demonstrated that mitoxantrone was generally well tolerated. Only very low incidences of nausea, vomiting, and alopecia were observed. The mild and rapidly reversible dose-limiting hematologic toxic effects have proven leukopenia. Although the toxicities reported here were tolerated for most patients, other combination regimens including mitoxantrone or other administration routes may be considered and need to be evaluated carefully.

Norms and alcohol consumption: Japanese in Japan, Hawaii and California

The study compared age/sex norms and alcohol consumption of a sample of Japanese from Japan and Japanese Americans in Hawaii and California. Age norms included acceptable drinking levels for the following age groups: 16, 21, 40 and 60, both male and female. There were significant differences in norms across the sites with the Japanese in Japan holding the most tolerant views of heavier drinking for men, followed by California and Hawaii. The Japanese-American samples were more tolerant of female drinking than were the Japanese. There was a high degree of similarity between Hawaii and California, whereas Japanese respondents in Japan differed in their responses. A correlation between drinking and norms by site indicated a high degree of congruence between drinking and more tolerant norms for drinking in all of the samples: Those who drank the most also had the most permissive norms toward drinking. The differences in norms between Japanese in Japan and Japanese Americans were explained in terms of enculturation and acculturation.