Establishment of an Asian Cancer Registry Network - problems and perspectives.

Cancer registration is the base for our understanding of the burden of neoplastic disease in our populations at the local, regional and national levels. Comparability of data is essential for interpretation and this in turn depends on standardization of methodology and the diagnostic and other criteria applied. If this is to be achieved across Asia, some form of international organization is clearly necessary. The question therefore should be whether the existing arrangement is adequate, and if this is not the case how a network in Asia might be established with due consideration of aims and attainable objectives. The present commentary focuses on the contributions made by the International Association of Cancer Registries (IACR) and individual country-based or region-based associations already active in Asia. Building on an analysis of the present status in Asia, as well as experience of the European Network of Cancer Registries (ENCR) and the North American Association of Central Cancer Registries (NAACCR), potential problems and possible solutions are here reviewed, with coverage of both organizational and financial constraints. An argument is presented here that there is a rationale for some form of an Asian Network of Cancer Registries, supported by the International Agency for Research on Cancer (IARC) and the UICC-Asian Regional Office, working alongside the IACR and existing national organizations and research institutes.

Development of a semi-quantitative food frequency questionnaire for dietary studies--focus on vitamin C intake.

The present work aimed to provide a basis for examination of intake of selected food items determined with a semi-quantitative food frequency questionnaire (SQFFQ) and planned-food selection (PFS). From February to July of 2003, ninety one cancer patients and 90 matched (same sex and age within 5 years) non-cancer patients were directly interviewed by trained interviewers using the designed questionnaire at the inpatient-department of Viet Duc hospital, Ha Noi City, Viet Nam. Study subjects consumed more SQFFQ-food items than PFS-food items, so that the latter method might not accurately reflect dietary habits regarding estimation of nutrient intake, especially vitamins. Because these are beneficial factors acting against cancer development at many sites, the absence of food items selected by SQFFQ may result in a poor database regarding possible confounding factors. For futher clarification we then focused on vitamin C contributions of Vietnamese food and analyzed data of the National Nutritional Household Survey in 2000: 7,686 households throughout the country (vitamin C intake status) and 158 households with 741 persons of the population of Hanoi city (individual food items contributing to vitamin C). Direct interview using a validated questionnaire with an album of current Vietnamese food items-recipes and weighing checks was conducted to obtain information regarding all types of food intake over the last 24-hours. Contribution analysis using the Nutritive Composition Table of Vietnamese Foods, revision 2000, and stepwise regression analysis was applied. Average intake adjusted by ages of vitamin C per person per day was estimated. In total, the study subjects were found to currently consume 184 food items. Average intake of vitamin C was 72.5 mg per person per day at the national level: 57.9% from leafy vegetables, 33.4% from fresh fruits, and 6.4% from non-leafy vegetables. For vitamin C contribution, the highest 25 food items contributed to a cumulative 95.3% of vitamin C intake with a cumulative R2=0.99.

Use of lay health workers in a community-based chronic disease control program.

The increasing burden of non-communicable diseases in the developing world, and in particular diabetes, cancer and circulatory diseases, is an unfortunate fact of life. At the same time infection-related diseases, including sexually transmitted HIV-AIDS and HPV-dependent cervical cancer, remain important. One approach to alleviating the resultant stress on national health provision is to expand the knowledge base at the community level with contributions by lay health workers (LHWs). Here we take a brief look at the available literature and propose a model for intervention incorporating two way dialogue with the general populace to find effective means to package expertise in the medical/research community for lay consumption. Our argument is that particular attention should be paid to socioeconomic and behavioural aspects and to disease surveillance at the local level in order to be able to accurately assess the impact of interventions. For this purpose, we need to marshal volunteers from within communities taking account of their problems and motivations. Included are provision of assistance in setting up physical exercise programs, quit tobacco campaigns, alcohol awareness programs, running disease screening exercises and general help by providing advice as to risk and protective factors and clinical treatments, with an special focus on palliative care.

Are there any real Helicobacter pylori infection-negative gastric cancers in Asia?

The great variability in gastric cancer rates across Asia, with very high incidences in Japan and Korea, and exceedingly low incidences in ethnic Malays, whether in Malaysia or Indonesia, appears largely due to variation in Helicobacter pylori infection rates. While between 2% and 10.6% of gastric cancers in a recent Japanese survey were considered to be negative for bacterial infection on the basis of seropositivity and H. pylori-dependent mucosal atrophy, it is notoriously difficult to preclude past infection. The situation is greatly complicated by reported differences in the etiology of gastric cardia and non-cardia cancers. In the Western world there do appear to be tumours arising close to the esophageal-gastric junction which are not related to H. pylori and associated inflammation, but in most Asian populations these appear to be very rare. Therefore preventive efforts, and particularly screening, should be focused on markers of bacterial infection, with avoidance of unnecessary exposure to X-ray radiation.

Impact of C-reactive protein on disease risk and its relation to dietary factors.

C-reactive protein (CRP) is one of the acute-phase proteins in inflammation and CRP serum concentrations are therefore of interest. Data for high-sensitivity CRP (hs-CRP) with a low detection limit of approximately 0.04 mg/L have become available over the past decade and research has shown a link between high concentrations of hs-CRP and obesity as well as smoking. Expanded adipose tissue is in fact known to secrete proinflammatory cytokines which enhance hepatic synthesis of CRP. Moderate alcohol consumption and high physical activity have been associated with low levels of hs-CRP, but the evidence in these cases is not conclusive. It has been suggested that hs-CRP is an independent marker of the risk of cardiovascular disease, but the predictive capacity remains controversial. However, many prospective studies have observed increased risk of type 2 diabetes mellitus associated with high concentrations of hs-CRP, independent of obesity and other cardiovascular risk factors. On the other hand, no measurable increase in the risk associated with high levels of hs-CRP was observed with multivariate adjustment in several studies. A number of authors have reported that high concentrations of hs-CRP are associated with increased risks of colorectal and other cancers, but the findings again are inconsistent. Diet and hs-CRP are also of increasing research interest. High intakes of carotenoids and vitamin C, but not of vitamin E, seem to decrease the level of circulating hs-CRP. In addition, high consumption of vegetables and fruit are associated with lower levels of circulating hs-CRP, perhaps by exerting anti-inflammatory effects. Both mechanistic and epidemiologic studies regarding dietary factors and low-grade inflammation are necessary to add to our knowledge of dietary influence on chronic disease development.

The 5th Conference on Asian Trends in Prostate Cancer Hormone Therapy.

The Conference on Asian Trends in Prostate Cancer Hormone Therapy is an annual forum for Asian urologists now in its 5th year. The 2006 conference, held in Bali, Indonesia, was attended by 27 leading urologic oncologists from China, Indonesia, Japan, Korea, Singapore, and Taiwan and featured a packed program of presentations and discussions on a wide range of topics such as relationships among clinicians and the newly opened Asia Regional Office for Cancer Control of the International Union Against Cancer (UICC), detection rates of prostate cancer by biopsy in each of the 6 Asian countries, and favored treatment modalities for hormone-refractory prostate cancer (HRPC) in each country. The first session of the conference kicked off with a keynote lecture entitled "Activities of the UICC ARO". UICC's new office will be the nerve center for its activities in the Asia region. Along with the Asian Pacific Organization for Cancer Prevention (APOCP), UICC aims to shift the focus of attention to cancer control. As such APOCP's long-running publication the APJCP is to be re-launched as the Asian Pacific Journal of Cancer Control. Although UICC is primarily concerned with cancer, several risk factors for cancer are common also to other non-communicable diseases such as diabetes and heart disease, and an important strategy is to implement measures to control these various pathologic conditions as a whole. Apart from contributing to an Asian prostate cancer registry the UICC-ARO will provide training courses, working groups, and assistance in collecting and processing data. The keynote lecture was followed by a roundtable discussion on possible ways in which clinicians from each Asian country can work with UICC. A number of suggestions were put forth including better registration, epidemiology research, possible implementation of UICC prostate cancer guidelines, early detection and screening, and roles of diet and phytotherapy. The underlying reasons for the large but dwindling difference in incidence rates of prostate cancer in various regions of Asia should be studied while the opportunity lasts. Session 2 was devoted to 6 presentations on detection rates by biopsy in each country. Although biopsy is the gold standard for detecting prostate cancer in most areas, indications for conducting biopsy are different in each country. For example, in Indonesia doctors may use PSAD 0.15 as the cutoff level. TRUS-guided biopsy is most widely used in Asian countries. Traditional sextant biopsy is often performed, although multiple-core biopsy is commonly available and associated with better detection rates, especially in men with large prostate volume. Positive DRE, high PSA, and older age were identified as factors associated with high biopsy detection rate, although elevated PSA has limited specificity. First biopsy in men with elevated PSA had a positive detection rate of approximately 30% in all countries. Community-based screening in some countries has an overall detection rate of approximately 1%.The favorable treatment modality for HRPC was the subject of the final session. First priority for doctors in all 6 countries is to maintain serum testosterone at castration level. Many therapeutic options are available, from cytotoxic drugs to traditional herbal medicines Chemotherapeutic agents such as estramustine, docetaxel, cyclophosphamide, and mitoxantrone are often given to patients with HRPC although not all are available in every country. Prednisone and dexamethasone are used for secondary hormonal therapy. External beam radiotherapy, radioisotopic drugs such as strontium 89, and bisphosphonates are common choices to control bone pain.

Prostate cancer control--aims of the UICC Asia Regional Office Consortium.

Cancer of the prostate remains at relatively low incidence in Asia but rates are increasing rapidly in some countries and specific populations so that measures for control need our attention. Little is known about risk factors, although vegetables and phytoestrogens may be protective and fat, meat and dairy products may increase the risk. Physical exercise may have preventive effects, while tobacco and alcohol appear to have no consistent relationship. The lack of clear lifestyle targets means that emphasis needs to be placed on screening for various prostate specific antigen parameters and clinical treatment, whether hormonal, radio or surgical, alone or in combination. While there is a massive literature for the Western world, the limited literature available for Asia means that cooperation to obtain a standardized data base is a high priority if the most effective measures for the specific populations of Asian countries are to be identified and put into practice.

Do cross-registry comparisons of Black and White Americans provide support for N-acetylation as an important determinant for urinary bladder and other tobacco-related cancers?

Tobacco smoking is an unequivocal risk factor for cancers of the larynx, lung, pancreas and urinary bladder. Whereas African-Americans demonstrate higher laryngeal, lung and pancreatic cancer rates than their Caucasian-American counterparts, they paradoxically have only approximately half of the urinary bladder incidences. One possible explanation is their N-acetyltransferase (NAT) status, since this enzyme is responsible for metabolism of arylamines in smoke and blacks are reported to have a higher rate for rapid acetylation than whites. However, other tobacco-related cancers are also linked to slow acetylation so that African-Americans might therefore also be expected to have lower incidences of other tobacco-related cancers. The present investigation was conducted with data from Cancer Incidence in Five Continents Vol VIII to assess whether there might be correlations between incidence rates for four major cancers across registries in the United States. Cluster analysis demonstrated clear separation of the white and black populations for all states, and significant correlations were observed between bladder and laryngeal cancers, and also for lung and laryngeal cancers, for both Blacks and Whites. Striking similarities in the plots for urinary bladder incidence against all three of the other cancers suggests the existence of a factor specific to the bladder. A review of black-white ratios for cancer incidences in all major body sites in both sexes and the published literature for NAT polymorphisms provided evidence that this might indeed be arylamine exposure, although other factors could also be involved.

Overview of existing networks--is there a rationale for an Asian Cancer Registry Network?

Cancer registration is the base for our understanding of the burden of neoplastic disease in our populations at the local level. Comparability of data is essential for interpretation and this in turn depends on standardization of methodology and diagnostic and other criteria applied. If this is to be achieved across Asia, some form of international organization is clearly necessary. The question therefore should be whether the existing arrangement is adequate, and if this is not the case how a network in Asia might be established with due consideration of aims and attainable objectives. The present commentary focuses on the contributions made by the International Agency for Research on Cancer (IARC), the International Association of Cancer Registries (IACR), the European Network of Cancer Registries (ENCR), the North American Association of Central Cancer Registries (NAACCR) and individual country-based or region-based associations already active in Asia. An argument is presented here that there is a rationale for an Asian Network of Cancer Registries, working alongside and learning from the existing international organizations to promote effective cancer registration and disease prevention in Asia.

What do cancer registry and household expenditure data in Japan tell us about variation in tumour burden ?

Data from the total of six Japanese Cancer Registries presently reporting to Cancer Incidence in Five Continents demonstrate marked variation in relative prevalence of cancers at particular sites, despite the genetic homogeneity of the Japanese population. Thus either major differences in registry procedures or local environment must be playing an important role and since the variation is clearly changing with time, the former must be considered likely. Over the last 25 year period, incidence rates for the esophagus have been generally increasing in Japan, except in Miyagi where they have been persistently high. Stomach cancer rates are on the decrease, although the trend is not so clear in Yamagata and Hiroshima, while colon and rectal cancers have both demonstrated consistent increment throughout the period surveyed, with a remarkable correlation between the two sites evident on cross-registry comparisons. Continued increases have also been apparent in lung, kidney, urinary bladder and prostate cancers in males and in breast, endometrium and thyroid neoplasms in females. Cervical cancer, in contrast, is decreasing, although a plateau may now have been reached in Miyagi. In the hepatopancreatic axis, patterns have generally showed elevation followed by a recent reduction, although without correlations among liver, gallbladder and pancreas rates at the cross-registry level. Common lifestyle factors may to some extent underly the increases seen in colon, breast, urinary bladder and thyroid incidence rates, given the significant relations apparent for these in the latest data across registries. Whether analysis of variation in dietary intake and exposure to other risk factors, for example using data for household expenditure, may provide clues to explaining the variation apparent across Japan is a question warranting further consideration. If so an expanded role for the cancer registry could well be envisaged.

The metabolic syndrome is associated with increased risk of colorectal adenoma development: the Self-Defense Forces health study.

The metabolic syndrome, a cluster of metabolic abnormalities linked to insulin resistance, has attracted much interest as a risk factor for cardiovascular disease and type 2 diabetes. Hyperinsulinemia is also a postulated biological risk factor for colorectal carcinogenesis. We therefore here examined the relation between the metabolic syndrome and colorectal adenoma development. The study subjects were 756 cases of colorectal adenoma and 1751 controls with no polyps who underwent total colonoscopy during the period January 1995 to March 2002 at two Self Defense Forces (SDF) hospitals in Japan. The metabolic syndrome was defined with reference to abdominal obesity in combination with any two of the following conditions: elevated triglycerides (150 mg/dL); lowered HDL cholesterol (<40 mg/dL); elevated blood pressure (systolic blood pressure 130 mmHg and/or diastolic blood pressure 85 mmHg); and raised fasting glucose (110 mg/dL). Abdominal obesity was defined as a waist circumference of 85 cm or more(Japanese criterion) or 90 cm (Asian criterion). Statistical adjustment was made for age, hospital, and rank in the SDF. The metabolic syndrome was found to be associated with a moderately increased risk of colorectal adenomas whether either of the Japanese and Asian criteria was used; adjusted odds ratios with the Japanese and Asian criteria were 1.38 (95% confidence interval [CI] 1.13-1.69) and 1.48 (95% CI 1.13-1.93), respectively. Increased risk was more evident for proximal than distal colon or rectal adenomas, and was almost exclusively observed for large lesions (5 mm in diameter). Thus the metabolic syndrome appears to be an important entity with regard to the prevention of colorectal cancer, as well as cardiovascular disease and type 2 diabetes.

Comparison of Japanese, American-Whites and African-Americans--pointers to risk factors to underlying distribution of tumours in the colorectum.

Relative incidence rates for colon and rectal cancer vary greatly between populations in the world. While Japanese have historically had low prevalence, immigration to the United States has now resulted in equal if not higher rates than in Caucasian- or African-Americans. Furthermore, recent data from some population-based registries in Japan itself are also pointing to particularly high susceptibility. Of particular interest is the fact that Japanese in both the home country and the US in fact have far higher rates for rectal cancer than the other two ethnic groups. An intriguing question is whether they might also demonstrate variation from Caucasian- and African-Americans in the relative incidence rates for proximal and distal colon cancers, given the clear differences in risk factors like diabetes, physical exercise, smoking, alcohol consumption, meat and fish intake and calcium exposure which have been shown to operate in these two sites. A comprehensive epidemiological research exercise is here proposed to elucidate ethnic variation in colorectal cancer development, based on cross-cancer registry descriptive and case control approaches. It is envisaged that additional emphasis on screened populations should further provide important insights into causal factors and how primary and secondary prevention efforts can be optimized.