Characterization of tumor evolution by functional clonality and phylogenetics in hepatocellular carcinoma.

Hepatocellular carcinoma (HCC) is a molecularly heterogeneous solid malignancy, and its fitness may be shaped by how its tumor cells evolve. However, ability to monitor tumor cell evolution is hampered by the presence of numerous passenger mutations that do not provide any biological consequences. Here we develop a strategy to determine the tumor clonality of three independent HCC cohorts of 524 patients with diverse etiologies and race/ethnicity by utilizing somatic mutations in cancer driver genes. We identify two main types of tumor evolution, i.e., linear, and non-linear models where non-linear type could be further divided into classes, which we call shallow branching and deep branching. We find that linear evolving HCC is less aggressive than other types. GTF2IRD2B mutations are enriched in HCC with linear evolution, while TP53 mutations are the most frequent genetic alterations in HCC with non-linear models. Furthermore, we observe significant B cell enrichment in linear trees compared to non-linear trees suggesting the need for further research to uncover potential variations in immune cell types within genomically determined phylogeny types. These results hint at the possibility that tumor cells and their microenvironment may collectively influence the tumor evolution process.

Knowledge and Attitudes toward Colorectal Cancer among Healthcare Workers: A Pilot Cross-Sectional Survey in Thailand.

BACKGROUND: Colorectal cancer is an important public health problem in Thailand. The health workforce is one of the key strategies to reduce the burden of cancer. They are not only involved in patient care, but they can improve public knowledge of cancer within their community. This study aimed to explore the knowledge and attitudes toward colorectal cancer among Thai healthcare workers. METHODS: A cross-sectional pilot study was conducted from October 2021 to March 2022. Convenience sampling was used to recruit study participants who worked in selected primary healthcare units or hospitals located in different regions across the country. The data on demographics and health behavior, knowledge of using the Fecal Immunochemical Test (FIT), and knowledge and attitudes toward colorectal cancer were collected using self-administered questionnaires. Descriptive statistics were used for data analysis. RESULTS: A total of 300 healthcare workers were recruited in the study. The majority of participants presented a healthy lifestyle: 74% were in the healthy weight range, 68% had never consumed alcohol, and 99.3% were never smokers. More than 70% of participants provided correct answers to questions about the use of a FIT kit. The mean score for knowledge of colorectal cancer was 12.16 + 2.16 (out of 14) and 240 (80%) participants were considered to have adequate knowledge. Also, colorectal cancer knowledge was associated with age of participants (p<0.05). Most of the participants (76.2-92.3%) had positive attitudes toward colorectal cancer screening, however about half of them thought that a colonoscopy could be painful, uncomfortable, and embarrassing. CONCLUSIONS: Overall, the majority of participants had adequate knowledge of colorectal cancer and positive attitudes toward its screening. The present study provided overview information on practical guidance for undertaking a nationwide survey in the future.

Pan-viral serology uncovers distinct virome patterns as risk predictors of hepatocellular carcinoma and intrahepatic cholangiocarcinoma.

This study evaluates the pan-serological profiles of hepatocellular carcinoma (HCC) and intrahepatic cholangiocarcinoma (iCCA) compared to several diseased and non-diseased control populations to identify risk factors and biomarkers of liver cancer. We used phage immunoprecipitation sequencing, an anti-viral antibody screening method using a synthetic-phage-displayed human virome epitope library, to screen patient serum samples for exposure to over 1,280 strains of pathogenic and non-pathogenic viruses. Using machine learning methods to develop an HCC or iCCA viral score, we discovered that both viral scores were positively associated with several liver function markers in two separate at-risk populations independent of viral hepatitis status. The HCC score predicted all-cause mortality over 8 years in patients with chronic liver disease at risk of HCC, while the viral hepatitis status was not predictive of survival. These results suggest that non-hepatitis viral infections may contribute to HCC and iCCA development and could be biomarkers in at-risk populations.

REPCAN: Guideline for REporting Population-based CANcer Registry Data.

Background: The objective of this study was to develop a guideline on how to report result of a population-based cancer registry. Methods: The guideline's development involved a core working committee and a scientific committee comprising experts from diverse domains. The process comprised three steps: 1) a comprehensive review of existing tools and guidelines and the development of the initial draft of the guideline based on a review of literature, 2) refinement items through several rounds of focus group discussion among the core group, and development initial draft, and 3) Evaluation of the initial draft by scientific committee members. Items in the guideline were organized to accommodate reports of population-based cancer registries as a scientific manuscript. Results: The core committee developed 47 items distributed in the major heading of a scientific manuscript presented as a checklist. The evaluation of the scientific committee led to a consensus on the majority of the items included in the checklist. Among 10 committee members, 7 provided unreserved approval, validating each item's necessity, applicability, and comprehensibility in the checklist. Feedback from the remaining 3 members was carefully analyzed and integrated to enhance the guideline's robustness. Incorporating feedback, a first final draft was presented in a meeting of scientific and core working committee members. Collaborative discussion ensured clarity of expression for each items and a final checklist was developed. Conclusion: The guideline abbreviated as REPCAN offers a standardized framework for reporting population-based cancer registry, fostering transparency, comparability, and comprehensive data presentation. The guideline encourages flexibility while promoting comprehensive and robust reporting practices.

Agreement between Self- and Physician­Sampling for Detection of High­Risk Human Papillomavirus Infections in Women Attending Cervical Screening at National Cancer Institute, Thailand.

BACKGROUND: We determined testing of self-sampling vagina swabs for Human Papilloma Virus (HPV) can be used to screen for cervical disease in outpatient clinics. METHODS: In this study, women attending cervical cancer screening clinic and gynecology clinic of the National Cancer Institute were invited to take a vaginal self-sampling and physician-collected cervical sampling. RESULTS: Of 268 participants, 20 (7.5%) were HPV-positive on the physician-collected samples. Among these screen-positive women, only two (0.7%) had HPV 18 and/or 45 and none had HPV 16 infections. For the self-collected samples, 4 participants had invalid HPV test results. Of the remaining 264 women with valid test results on self-collected samples, 29 (11.0 %) were HPV-positive, of whom, two (0.8%) were infected with HPV 16 and one (0.4%) with HPV 18 and/or 45 infections. The agreement between self-sampling and physician-sampling HPV test results (when two HPV results categories were considered) was 92. 8% with a moderate Kappa value of 0.57. CONCLUSION: Overall, self-sampling seems to be a reliable alternative to health-provider collection. However, instructions on proper procedures for sample collection to the women are important step before general roll out.

Quantification of impact of COVID-19 pandemic on cancer screening programmes - a case study from Argentina, Bangladesh, Colombia, Morocco, Sri Lanka, and Thailand.

It is quite well documented that the COVID-19 pandemic disrupted cancer screening services in all countries, irrespective of their resources and healthcare settings. While quantitative estimates on reduction in volume of screening tests or diagnostic evaluation are readily available from the high-income countries, very little data are available from the low- and middle-income countries (LMICs). From the CanScreen5 global cancer screening data repository we identified six LMICs through purposive sampling based on the availability of cancer screening data at least for the years 2019 and 2020. These countries represented those in high human development index (HDI) categories (Argentina, Colombia, Sri Lanka, and Thailand) and medium HDI categories (Bangladesh and Morocco). No data were available from low HDI countries to perform similar analysis. The reduction in the volume of tests in 2020 compared to the previous year ranged from 14.1% in Bangladesh to 72.9% in Argentina (regional programme) for cervical screening, from 14.2% in Bangladesh to 49.4% in Morocco for breast cancer screening and 30.7% in Thailand for colorectal cancer screening. Number of colposcopies was reduced in 2020 compared to previous year by 88.9% in Argentina, 38.2% in Colombia, 27.4% in Bangladesh, and 52.2% in Morocco. The reduction in detection rates of CIN 2 or worse lesions ranged from 20.7% in Morocco to 45.4% in Argentina. Reduction of breast cancer detection by 19.1% was reported from Morocco. No association of the impact of pandemic could be seen with HDI categories. Quantifying the impact of service disruptions in screening and diagnostic tests will allow the programmes to strategize how to ramp up services to clear the backlogs in screening and more crucially in further evaluation of screen positives. The data can be used to estimate the impact on stage distribution and avoidable mortality from these common cancers.

Acceptability and Preference for Human Papilloma Virus Self-Sampling among Thai Women Attending National Cancer Institute.

BACKGROUND: Cervical cancer screening is an important public health strategy to reduce cervical cancer incidence and mortality. Human papillomavirus (HPV) self-sampling is the alternative method that can potentially increase participation in cervical cancer screening. This study aimed to evaluate the acceptability of HPV self-sampling as a primary cervical cancer screening among Thai women. METHODS: A cross-sectional study was conducted at National Cancer Institute, Thailand, between March and September 2021. Eligible women were invited to collect their own samples with a vaginal cotton swab for cervical screening. The data on demographics, acceptability, and preference for HPV self-sampling were collected via a self-administered questionnaire. A Likert scale was used to assess the response of self-sampling acceptability. The multivariable logistic regression determined factors that influence preference for HPV self-sampling. RESULTS: A total of 265 participants were recruited. Over 70% agreed that self-sampling was easy, less embarrassing, and not painful. They also felt confident in their ability to self-sample correctly and would recommend this method to a friend or relative. For their next screening round, 66.4% preferred self-sampling whereas 33.6% preferred clinician-collected samples as routine screening. The factors that influence preference for self-sampling were age, marital status, feeling less embarrassed, and confidence in performing the tests. CONCLUSIONS: Most of the study participants accepted HPV self-sampling. This suggests that the self-sampling method will be an additional option to increase cervical cancer screening coverage which leads to improving the effectiveness of the national program.

Cancer survival in Thailand from 1997 to 2012: Assessing the impact of universal health coverage.

BACKGROUND: In recent decades, many countries worldwide have implemented some form of Universal Health Coverage (UHC). We sought to evaluate incidence and survival trends of breast, cervical, and colorectal cancer before and after the implementation of UHC in Thailand. METHODS: The age-standardized incidence rate and 1- and 5-year net survival (NS) were calculated for five Thai provinces, namely Bangkok, Chiang Mai, Khon Kaen, Lampang, and Songkhla for breast, cervix, and colorectal cancer in three study periods (1997-2012): before, during, and after the implementation of UHC. RESULTS: The incidence of breast and colorectal cancer has increased over time, while the incidence of cervical cancer has decreased (17.9-29.9, 9.0-13.6, and 19.6-12.3 per 100,000, respectively). Larger proportion of breast cancer were diagnosed with localized stage after UHC implementation compared to the period prior to UHC (31.5 % vs 19.0 %). Overall, The improvement in survival by cancer site varied in magnitude with a 5-year NS increase from 61.3 % to 75.1 % for breast, 55.4-59.5 % for cervical, and 39.9-47.6 % for colorectal cancer. The amount of increase slightly differed across provinces. CONCLUSION: Rising incidence for breast and colorectal, and declining cervical cancer may partly be attributable to improved awareness and early detection programs. Additionally, improvement in survival may partly be attributable to increased access to healthcare, availability of treatment, and increased access to cancer screening after UHC was implemented. Thus, continued expansion of UHC package on cancer could potentially contribute to further improvement of cancer control in Thailand. POLICY SUMMARY: This study provides important evidence on the impact of UHC in cancer burden and survival for breast, cervical, and colorectal cancer in Thailand. This study serves as an example for other countries where UHC has been recently implemented and guide policymakers in allocating resources towards UHC and cancer control programs.

Antitumor Effects of Cannabinoids in Human Pancreatic Ductal Adenocarcinoma Cell Line (Capan-2)-Derived Xenograft Mouse Model.

Background: Pancreatic cancer is considered a rare type of cancer, but the mortality rate is high. Cannabinoids extracted from the cannabis plant have been interested as an alternative treatment in cancer patients. Only a few studies are available on the antitumor effects of cannabinoids in pancreatic cancer. Therefore, this study aims to evaluate the antitumor effects of cannabinoids in pancreatic cancer xenografted mouse model. Materials and Methods: Twenty-five nude mice were subcutaneously transplanted with a human pancreatic ductal adenocarcinoma cell line (Capan-2). All mice were randomly assigned into 5 groups including negative control (gavage with sesame oil), positive control (5 mg/kg 5-fluorouracil intraperitoneal administration), and cannabinoids groups that daily received THC:CBD, 1:6 at 1, 5, or 10 mg/kg body weight for 30 days, respectively. Xenograft tumors and internal organs were collected for histopathological examination and immunohistochemistry. Results: The average tumor volume was increased in all groups with no significant difference. The average apoptotic cells and caspase-3 positive cells were significantly increased in cannabinoid groups compared with the negative control group. The expression score of proliferating cell nuclear antigen in positive control and cannabinoids groups was decreased compared with the negative control group. Conclusions: Cannabinoids have an antitumor effect on the Capan-2-derived xenograft mouse model though induce apoptosis and inhibit proliferation of tumor cells in a dose-dependent manner.

Out-of-pocket payments for complementary medicine following cancer and the effect on financial outcomes in middle-income countries in southeast Asia: a prospective cohort study.

BACKGROUND: Complementary medicine, which refers to therapies that are not part of conventional medicine, comprising both evidence-based and non-evidence-based interventions, is increasingly used following a diagnosis of cancer. We aimed to investigate out-of-pocket spending patterns on complementary medicine and its association with adverse financial outcomes following cancer in middle-income countries in southeast Asia. METHODS: In this prospective cohort study, data on newly diagnosed patients with cancer were derived from the ASEAN Costs in Oncology (ACTION) cohort study, a prospective longitudinal study in 47 centres located in eight countries in southeast Asia. The ACTION study measured household expenditures on complementary medicine in the immediate year after cancer diagnosis. Participants were given cost diaries at baseline to record illness-related payments that were directly incurred and not reimbursed by insurance over the 12-month period after study recruitment. We assessed incidence of financial catastrophe (out-of-pocket cancer-related costs ≥30% of annual household income), medical impoverishment (reduction in annual household income to below poverty line following subtraction of out-of-pocket cancer-related costs), and economic hardship (inability to make necessary household payments) at 1 year. FINDINGS: Between March, 2012, and September, 2013, 9513 participants were recruited into the ACTION cohort study, of whom 4754 (50·0%) participants were included in this analysis. Out-of-pocket expenditures on complementary medicine were reported by 1233 households. These payments constituted 8·6% of the annual total out-of-pocket health costs in lower-middle-income countries and 42·9% in upper-middle-income countries. Expenditures on complementary medicine significantly increased risks of financial catastrophe (adjusted odds ratio 1·52 [95% CI 1·23-1·88]) and medical impoverishment (1·75 [1·36-2·24]) at 12 months in upper-middle-income countries only. However, the risks were significantly higher for economically disadvantaged households, irrespective of country income group. INTERPRETATION: Integration of evidence-supported complementary therapies into mainstream cancer care, along with interventions to address use of non-evidence-based complementary medicine, might help alleviate any associated adverse financial impacts. FUNDING: None.

An analysis of the incidence and survival rates of bone sarcoma patients in thailand: reports from population-based cancer registries 2001-2015.

BACKGROUND: Epidemiology data from population-based cancer registries (PBCR) can be very valuable in the development of health policy and for improving the quality of cancer control strategies. METHODS: This study analyzed the incidence of bone sarcomas in Thailand during 2001 - 2015 by analyzing data obtained from 5 PBCRs across country. Incidence rates per million person-years by sex, histological subtype, primary site and 5-year age group were calculated. Age-standardized incidence rates (ASR) were adjusted using the WHO's World Standard Population and comparisons between populations were done using standardized rate ratios (SRR). Incidence trends were evaluated using Joinpoint Trend Analysis. Survival rates were analyzed using STATA. RESULTS: The ASR of bone sarcomas in Thailand was 5.1/106 person-years, with an estimated 328 newly diagnosed bone sarcomas per year for the country overall. Osteosarcoma (52.5%), chondrosarcoma (18%), Ewing's sarcoma (11.6%), giant cell tumor (4.8%) and chordoma (4.7%) were the most common malignant bone tumors, representing 91.5% of all bone sarcomas. Bone sarcoma has a predilection for males (1.29:1) and an age-specific bimodal rate pattern closely related to the major histological subtypes, osteosarcoma. One- and five-year survival rates of Thai patients with bone sarcoma were 74% and 52%, respectively. Survival rates of bone sarcomas, particularly osteosarcoma, were lower than the rates reported from the United States, Europe and Japan. CONCLUSION: The lower overall survival rate of bone sarcoma represented the gap of bone sarcoma control program in Thailand. That indicates the need for improvement in health promotion, treatment process and chemotherapy for bone sarcoma patients in the future.

National Cervical Cancer Screening in Thailand.

BACKGROUND: Cervical cancer is an important public health problem in Thailand. It was the most common cancer in Thai women with the incidence rate of 23.4 per 100,000 women in 1990. OBJECTIVE: The aim of this study was to share the experiences and summary the outcome of cervical cancer screening program in Thailand. METHODS: The Ministry of Public Health in cooperation with the National Health Security Office, launched the National Cervical Cancer Screening Program, covering 76 provinces nationwide under Universal Coverage Scheme in 2005. The screening method are Pap smear and Visual Inspection with Acetic acid (VIA) for women aged 30-60 and 35-45 respectively with a 5-year screening interval. Detecting cervical pre-cancerous lesions will follow by day care treatment such as cryotherapy, Loop Electrosurgical Excision Procedure, etc. Results: The first phase (2005-2009), was carried out on 3,124,855 women, the coverage reached 77.5%. For the second phase (2010-2014), 7,637,226 women were screened, reaching 53.9% coverage of target women. However, we have few data of follow up examination after abnormal screening. Therefore, we conducted new system to get more follow up data in 2019. Under the coordination of many related partners, 10,762,081 women have been screened during 2005-2014. The incidence rate declined to 11.7 per 100,000 women which is ranked as the third most common in women in 2014. CONCLUSION: This article briefly reviews the challenge of implementing an efficient cervical cancer screening in Thailand. In 2020, HPV testing has been introduced as a primary screening test for all Thai women attending public health sector instead of conventional Pap test.

Breast cancer in Thailand: policy and health system challenges to universal healthcare.

Thailand has successfully implemented Universal Health Coverage (UHC) and embedded the 2030 Agenda for Sustainable Development into its Thailand 4.0 policy. Breast cancer is a growing challenge in Thailand, as it is globally. It serves as a perfect medium through which to interrogate UHC and demonstrate areas of the health system which require further strengthening if UHC is to be sustainable in the longer term. We conducted a situation analysis and used a Systemic Rapid Assessment (SYSRA) framework to examine the challenges posed to UHC through the lens of breast cancer. We identified a number of challenges facing UHC including (1) continued political commitment; (2) the need for coordinated scale-up of strategic investments involving increased financing and fine-tuning of the allocation of resources according to health needs; (3) reducing inequities between health insurance schemes; (4) investing in innovation of technologies, and more critically, in technology transfer and capacity building; (5) increasing capacity, quality and confidence in the whole primary healthcare team but especially family medicine doctors. This would subsequently increase both efficiency and effectiveness of the patient pathway, as well as allow patients wherever possible to be treated close to their homes, work and family; (6) developing and connecting information systems to facilitate understanding of what is working, where needs are and track trends to monitor improvements in patient care. Our findings add to an existing body of evidence which suggest, in light of changing disease burden and increasing costs of care, a need for broader health system reforms to create a more enabling platform for integrated healthcare as opposed to addressing individual challenging elements one vertical system at a time. As low- and middle-income countries look to realize the 2015 Sustainable Development Goals and sustainable UHC this analysis may provide input for policy discussion at national, regional and community levels and have applicability beyond breast cancer services alone and beyond Thailand.

Cancer incidence and cancer control in Bangkok, Thailand: Results from the cancer registry 2011-15 and projections to 2035.

BACKGROUND: With considerable diversity in the patterns of cancer in different regions of Thailand and between urban vs. rural areas, this report focuses on cancer incidence burden in the Bangkok Metropolis 2011-15. METHODS: Incidence rates in Bangkok were derived as the mean annual number of new cancer cases per 100,000 inhabitants for the period 2011-2015 stratified by 5-year age group and sex. Age-standardized incidence rates (ASR) were calculated using the world standard population. RESULTS: The five most frequent cancers in Bangkok correspond to close to 60 % of the total burden in both males and females. In males, cancers of the lung, liver and colorectum each comprised 14-16 % of the burden, while breast cancer was responsible for three in 10 cancers in women (or 29.4 %), with colorectal and cervical cancer ranking second and third (10.0 % and 8.5 % respectively). respectively. Under three different scenarios of trends in all-cancer incidence rates, demographic changes mean that the incidence burden will rise over the next two decades. CONCLUSIONS: The critical relevance of this information in the context of the planning and evaluation of national cancer control policies in Thailand is discussed. Evidently, the Bangkok and other Thai population-based cancer registries are essential in measuring the population-level impact of tobacco control, HBV and HPV vaccination, cervical and colorectal cancer screening, and via survival estimation, the effectiveness of cancer care.

National Cancer Control Program of Thailand.

Since 2000 cancer has been the leading cause of death in Thailand. In response to this challenge, the National Cancer Institute of Thailand (NCI), in collaboration with other bodies, has developed and promoted the National Cancer Control Program (NCCP) to provide appropriate policies and practice for the prevention, early detection and treatment of cancer, with optimal supportive care. With plans strongly supported by the Ministry of Public Health, the NCCP envisages integration into the health care system in 6 strategic areas: (1) cancer informatics; (2) primary prevention; (3) early detection; (4) treatment; (5) palliative care; and (6) cancer control research. For this purpose 7 regional cancer hospitals have been established to aid the NCI in conducting the NCCP. Cancer registration is a high priority, with 31.2% of the population now covered by quality registries. In primary prevention, there is a focus on awareness, lifestyle improvement, anti-smoking and alcohol control programs, vaccination, and Opisthorchis viverrini (OV) control. Screening programs for cervical, breast and colorectal cancer are underway to increase early detection. Priority is being given to facilities for chemotherapy and radiotherapy, as well as palliative care. Cancer control research encompasses international cooperation and participation in training programs, especially for development of cancer registration and other aspects of cancer control programs in South-East Asia, not least as an IARC Collaborating Center.

The functional ALDH2 polymorphism is associated with breast cancer risk: A pooled analysis from the Breast Cancer Association Consortium.

BACKGROUND: Epidemiological studies consistently indicate that alcohol consumption is an independent risk factor for female breast cancer (BC). Although the aldehyde dehydrogenase 2 (ALDH2) polymorphism (rs671: Glu>Lys) has a strong effect on acetaldehyde metabolism, the association of rs671 with BC risk and its interaction with alcohol intake have not been fully elucidated. We conducted a pooled analysis of 14 case-control studies, with individual data on Asian ancestry women participating in the Breast Cancer Association Consortium. METHODS: We included 12,595 invasive BC cases and 12,884 controls for the analysis of rs671 and BC risk, and 2,849 invasive BC cases and 3,680 controls for the analysis of the gene-environment interaction between rs671 and alcohol intake for BC risk. The pooled odds ratios (OR) with 95% confidence intervals (CI) associated with rs671 and its interaction with alcohol intake for BC risk were estimated using logistic regression models. RESULTS: The Lys/Lys genotype of rs671 was associated with increased BC risk (OR = 1.16, 95% CI 1.03-1.30, p = 0.014). According to tumor characteristics, the Lys/Lys genotype was associated with estrogen receptor (ER)-positive BC (OR = 1.19, 95% CI 1.05-1.36, p = 0.008), progesterone receptor (PR)-positive BC (OR = 1.19, 95% CI 1.03-1.36, p = 0.015), and human epidermal growth factor receptor 2 (HER2)-negative BC (OR = 1.25, 95% CI 1.05-1.48, p = 0.012). No evidence of a gene-environment interaction was observed between rs671 and alcohol intake (p = 0.537). CONCLUSION: This study suggests that the Lys/Lys genotype confers susceptibility to BC risk among women of Asian ancestry, particularly for ER-positive, PR-positive, and HER2-negative tumor types.

Accounting for Immigrant Status when Calculating Cancer Incidence Rates for Bangkok

Objective: Cancer-registry data are crucial for definingcancer incidence rates for use in setting service priorities and monitoringservice effects. This applies in Thailand where cancer is the leading cause of death and service needs are high. The Bangkok Cancer Registry (population-based) was established in 1990to determine cancer incidence rates for Bangkok. This proved difficult, however, because the Bangkokpopulation (>8million) fluctuates with numbers of temporary visitors, many of whom visit Bangkok temporarily for services. If these visitors are mis-categorized as usual residents, cancer incidence rateswould be inflated. During 2013-2015, residential addresses on the Registry were cross-checked against official addresses on the National Civil Registration records of the Ministry of Interior. The effectsof this cross-checking on incidence rates are discussed. Methods: Residential addresses recorded on the Registry for cancer diagnoses in 2013-2015 were corrected using official Ministry data. Effects on numbers of recorded cancers and crude and directly age-standardized rates (World Population) were determined. Results: Of 44,813 cancer casesdiagnosed and recorded on the Registryduring 2013-2015, 36,327 (81.1%) had an official Bangkok address. When limiting analyses to these cases, the crude incidencefor all cancer sites combined reduced by 18.9% (19.7% for males and 18.3% for females). Corresponding reductions in age-standardized incidence rates were 20.0% for males and 18.8% for females. These reductions varied for common cancer sites:in males,from 14.8% for lung to 25.9% for colorectal cancer; and in females, from 12.9% for lung to 24.0% for cervical cancer. Conclusions: These differences are considered sufficient in magnitude to justifyroutine use of official residential data when calculating cancer incidence rates for Bangkok. If these rates are to be compared with comparable rates for other Asian citiesthat serve broader populations, equivalent methodologies for determining residential status would be needed for all cities.