DESIGN: A Stock-and-Flow simulation model was used to project smoking prevalence and mortality from 2018 to 2050 under eight different scenarios: (1) maintaining the 2018 status quo, (2) implementation of smoke-free policies, (3) tobacco use cessation programmes, (4-5) health warning about the dangers of tobacco (labels, mass media), (6) enforcement of tobacco advertising bans or (7) tobacco taxation at the highest recommended level and (8) all these interventions combined.

RESULTS: Under the status quo, the smoking prevalence in Japan will decrease from 29.6% to 15.5% in men and 8.3% to 4.7% in women by 2050. Full implementation of MPOWER will accelerate this trend, dropping the prevalence to 10.6% in men and 3.2% in women, and save nearly a quarter million deaths by 2050. This reduction implies that Japan will only attain the current national target of 12% overall smoking prevalence in 2033, 8 years earlier than it would with the status quo (in 2041), a significant delay from the national government's 2022 deadline.

OBJECTIVE: To assess the global distribution of breast cancer stage by country, age group, calendar period, and socioeconomic status using population-based data.

DATA SOURCES: A systematic search of MEDLINE and Web of Science databases and registry websites and gray literature was conducted for articles or reports published between January 1, 2000, and June 20, 2022.

STUDY SELECTION: Reports on stage at diagnosis for individuals with primary breast cancer (C50) from a population-based cancer registry were included.

DATA EXTRACTION AND SYNTHESIS: Study characteristics and results of eligible studies were independently extracted by 2 pairs of reviewers (J.D.B.F., A.D.A., A.M., R.S., and F.G.). Stage-specific proportions were extracted and cancer registry data quality and risk of bias were assessed. National pooled estimates were calculated for subnational or annual data sets using a hierarchical rule of the most relevant and high-quality data to avoid duplicates.

MAIN OUTCOMES AND MEASURES: The proportion of women with breast cancer by (TNM Classification of Malignant Tumors or the Surveillance, Epidemiology, and End Results Program [SEER]) stage group.

RESULTS: Data were available for 2.4 million women with breast cancer from 81 countries. Globally, the proportion of cases with distant metastatic breast cancer at diagnosis was high in sub-Saharan Africa, ranging from 5.6% to 30.6% and low in North America ranging from 0.0% to 6.0%. The proportion of patients diagnosed with distant metastatic disease decreased over the past 2 decades from around 3.8% to 35.8% (early 2000s) to 3.2% to 11.6% (2015 onwards), yet stabilization or slight increases were also observed. Older age and lower socioeconomic status had the largest proportion of cases diagnosed with distant metastatic stage ranging from 2.0% to 15.7% among the younger to 4.1% to 33.9% among the oldest age group, and from 1.7% to 8.3% in the least disadvantaged groups to 2.8% to 11.4% in the most disadvantaged groups.

METHODS: This is a meta-analysis of seven prospective cohort studies participating in the CHANCES consortium including 18 668 men and 24 751 women with a mean age of 62 and 63 years, respectively. Harmonised individual participant data from all seven cohorts were analysed separately and alternatively for each anthropometric indicator using multivariable Cox proportional hazards models.

RESULTS: After a median follow-up period of 12 years, 1656 first-incident obesity-related cancers (defined as postmenopausal female breast, colorectum, lower oesophagus, cardia stomach, liver, gallbladder, pancreas, endometrium, ovary, and kidney) had occurred in men and women. In the meta-analysis of all studies, associations between indicators of adiposity, per s.d. increment, and risk for all obesity-related cancers combined yielded the following summary hazard ratios: 1.11 (95% CI 1.02-1.21) for BMI, 1.13 (95% CI 1.04-1.23) for WC, 1.09 (95% CI 0.98-1.21) for HC, and 1.15 (95% CI 1.00-1.32) for WHR. Increases in risk for colorectal cancer were 16%, 21%, 15%, and 20%, respectively per s.d. of BMI, WC, HC, and WHR. Effect modification by hormone therapy (HT) use was observed for postmenopausal breast cancer (Pinteraction<0.001), where never HT users showed an ∼20% increased risk per s.d. of BMI, WC, and HC compared to ever users.

METHODS: The number of new incident cases and deaths for all cancers combined and for leading cancers were extracted from the GLOBOCAN 2022 database developed by the International Agency for Research on Cancer for the 11 countries in southeast Asia. For comparison, we extracted estimates from China, India, Japan, Pakistan, South Korea, and the USA. We estimated age-standardised incidence rates (ASIRs) and age-standardised mortality rates (ASMRs) per 100 000 person-years; projections to 2050 were also estimated by multiplying ASIR and ASMR estimates for 2022 by the expected population for 2050. Data on race or ethnicity were not collected.

FINDINGS: Data were extracted on Dec 5, 2024. For the 11 countries in southeast Asia for all cancers combined, 545 725 (47·6%) of a total of 1 146 810 incident cases were estimated in men and 601 085 (52·4%) incident cases were estimated in women in 2022. In the same period, 385 430 (53·8%) of a total of 716 116 deaths were estimated in men and 330 686 (46·2%) deaths were estimated in women. The total cancer ASIR in men and women was highest in Singapore (235·89 per 100 000 and 231·01 per 100 000 respectively), while the corresponding ASMR was greatest in Laos for men (132·91 per 100 000) and Brunei for women (104·20 per 100 000). Breast cancer was the most common cancer among women in all countries (highest ASIRs in Singapore [72·61 per 100 000] and the Philippines [60·34 per 100 000]), and the most common cause of cancer mortality among women in the Philippines (ASMR 21·47 per 100 000), Malaysia (19·30 per 100 000), Singapore (17·82 per 100 000), Viet Nam (14·67 per 100 000), Indonesia (14·35 per 100 000), and Timor-Leste (10·24 per 100 000). Among men, lung cancer was the most frequently diagnosed cancer in the Philippines (ASIR 37·66 per 100 000), Malaysia (23·23 per 100 000), Myanmar (21·59 per 100 000), and Indonesia (21·30 per 100 000), and the leading cause of death due to cancer in the Philippines (ASMR 33·59 per 100 000), Singapore (31·94 per 100 000), Brunei (23·84 per 100 000), Malaysia (20·42 per 100 000), Myanmar (19·91 per 100 000), Indonesia (18·96 per 100 000), and Timor-Leste (12·95 per 100 000). Liver cancer contributed the greatest incidence and mortality in men in Cambodia, Laos, Viet Nam, and Thailand, and was also the leading cause of death due to cancer among women in Laos (ASMR 13·49 per 100 000), Cambodia (13·34 per 100 000), and Thailand (12·14 per 100 000). Cervical cancer was the leading cause of death due to cancer in women in Myanmar (ASMR 13·37 per 100 000); colorectal cancer was the most common cancer in men in Singapore (ASIR 39·41 per 100 00) and Brunei (37·70 per 100 000). By 2050, 2·03 million new cases of cancer are anticipated in southeast Asia annually, an 89·2% increase in men and a 65·6% increase in women, relative to 2022.

INTERPRETATION: The current patterns of cancer incidence and mortality in southeast Asia are primarily driven by breast cancer in women and lung cancer in men, but infection-related cancers (liver and cervix) are common in some countries. Regional collaborations must be strengthened to improve cancer prevention, diagnosis, care, and research in southeast Asia.

METHODS: This is an observational multi-country study set in low- and middle-income countries. We aim to recruit over 2000 women diagnosed with ovarian cancer across multiple hospitals in 24 countries in Asia, Africa and South America. Country sample sizes have been calculated (n = 70-96 participants /country), taking account of varying national five-year disease prevalence rates. Women within five years of their diagnosis, who are in contact with participating hospitals, are invited to take part in the study. A questionnaire has been adapted from a tool previously used in high-income countries. It comprises 57 multiple choice and two open-ended questions designed to collect information on demographics, women's knowledge of ovarian cancer, route to diagnosis, access to treatments, surgery and genetic testing, support needs, the impact of the disease on women and their families, and their priorities for action. The questionnaire has been designed in English, translated into local languages and tested according to local ethics requirements. Questionnaires will be administered by a trained member of the clinical team.