Breast cancer has distinct causes, prognoses, and outcomes and effects in patients at premenopausal and postmenopausal ages. We sought to assess the global burden and trends in breast cancer by menopausal status. We did a population-based analysis of global breast cancer incidence and mortality among premenopausal and postmenopausal women. Menopausal status was defined using age as a proxy, whereby breast cancer cases or deaths at age 50 years or older were regarded as postmenopausal. Age-standardised breast cancer incidence and mortality in 2018 were calculated using GLOBOCAN data. Incidence trends for 1998-2012 were assessed in 44 populations from 41 countries using the Cancer in Five Continents plus database, by calculating the annual average percent change. Approximately 645 000 premenopausal and 1·4 million postmenopausal breast cancer cases were diagnosed worldwide in 2018, with more than 130 000 and 490 000 deaths occurring in each menopausal group, respectively. Proportionally, countries with a low UNDP human development index (HDI) faced a greater burden of premenopausal breast cancer for both new cases and deaths compared with higher income countries. Countries with a very high HDI had the highest premenopausal and postmenopausal breast cancer incidence (30·6 and 253·6 cases per 100 000, respectively), whereas countries with low and medium HDI had the highest premenopausal and postmenopausal mortality, respectively (8·5 and 53·3 deaths per 100 000, respectively). When examining breast cancer trends, we noted significantly increasing age-standardised incidence rates (ASIRs) for premenopausal breast cancer in 20 of 44 populations and significantly increasing ASIRs for postmenopausal breast cancer in 24 of 44 populations. The growth exclusively at premenopausal ages largely occurred in high-income countries, whereas the increasing postmenopausal breast cancer burden was most notable in countries under transition. We provide evidence of a rising burden of both premenopausal and postmenopausal breast cancer worldwide. Although early diagnosis and access to treatment remain crucial in low-income and middle-income countries, primary prevention efforts seeking to decrease exposure to known breast cancer risk factors are warranted in all world regions to curb the future breast cancer burden. None.

To date, the burden of cancer among young adults has rarely been studied in depth. Our aim was to describe the scale and profile of cancer incidence and mortality worldwide among 20-39 year-olds, highlighting major patterns by age, sex, development level, and geographical region. We did a population-based study to quantify the burden of young adult cancers worldwide. We defined young adult cancers as those occurring between the ages of 20 and 39 years because these individuals will have passed puberty and adolescence, but not yet experienced the effects of hormonal decline, immune response deterioration, or organ dysfunction associated with chronic health conditions. Global, regional, and country-specific (n=184) data estimates of the number of new cancer cases and cancer-associated deaths that occurred in 2012 among young adults were extracted in four 5-year bands from the International Agency for Research on Cancer's GLOBOCAN 2012 for all cancers combined and for 27 major types as defined by the International Classification of Disease, tenth revision. We report the number of new cancer cases and cancer-associated deaths overall and by sex alongside corresponding age-standardised rates (ASR) per 100 000 people per year. We also present results using four levels of the Human Development Index (HDI; low [least developed], medium, high, and very high [most developed]), which is a composite indicator for socioeconomic development comprising life expectancy, education, and gross national income. 975 396 new cancer cases and 358 392 cancer-associated deaths occurred among young adults worldwide in 2012, which equated to an ASR of 43·3 new cancer cases per 100 000 people per year and 15·9 cancer-associated deaths per 100 000 people per year. The burden was disproportionally greater among women and the most common cancer types overall in terms of new cases were female breast cancer, cervical cancer, thyroid cancer, leukaemia, and colorectal cancer; in terms of deaths, female breast cancer, liver cancer, leukaemia, and cervical cancer were the main contributors. When assessed by development level and geographical region, the cancer profile varied substantially; generally, the burden of infection-associated cancers was greater in regions under transition. Cancer incidence was elevated in very high-HDI regions compared with low-HDI regions (ASR 64·5 vs 46·2 cancer cases per 100 000 people per year); however, the mortality burden was 3 times higher in low-HDI regions (ASR 25·4 vs 9·2 cancer-associated deaths per 100 000 people per year), reflecting differences in cancer profiles and inferior outcomes. The global cancer burden among 20-39 year-olds differs from that seen in younger or older ages and varies substantially by age, sex, development level, and geographical region. Although the cancer burden is lower in this age group than that observed in older ages, the societal and economic effects remain great given the major effects of premature morbidity and mortality. Targeted surveillance, prevention, and treatment are needed to reduce the cancer burden in this underserved age group. International Agency for Research on Cancer (IARC) and European Commission's FP-7 Marie Curie Actions-People-COFUND.

Socioeconomic factors are associated with cancer incidence through complex and variable pathways. We assessed cancer incidence for all cancers combined and 27 major types according to national human development levels. Using GLOBOCAN data for 184 countries, age‐standardized incidence rates (ASRs) were assessed by four levels (low, medium, high, very high) of the Human Development Index (HDI), a composite index of life expectancy, education, and gross national income. A strong positive relationship between overall cancer incidence and HDI level was observed. When comparing the ASR in very high HDI regions with that in low HDI regions, we observed a positive association ranging from 2 to 14 and 2 to 11 times higher in males and females, respectively, depending on the cancer type. Positive dose–response relationships between the ASR and HDI level were observed in both sexes for the following cancer types: lung, pancreas, leukemia, gallbladder, colorectum, brain/nervous system, kidney, multiple myeloma, and thyroid. Positive associations were also observed for testicular, bladder, lip/oral cavity, and other pharyngeal cancers, Hodgkin lymphoma, and melanoma of the skin in males, and corpus uteri, breast, and ovarian cancers and non‐Hodgkin lymphoma in females. A negative dose–response relationship was observed for cervical and other pharyngeal cancers and Kaposi sarcoma in females. Although the relationship between incidence and the HDI remained when assessed at the country‐specific level, variations in risk within HDI levels were also observed. We highlight positive and negative associations between incidence and human development for most cancers, which will aid the planning of cancer control priorities among countries undergoing human development transitions.

Aims: This review examines the links between human development and cancer overall and for specific types of cancer, as well as cancer-related risk-factors and outcomes, such as disability and life expectancy. Methods: To assess human development, the Human Development Index was utilized continuously and according to four levels (low, medium, high, very high), where the low and very high categories include the least and most developed countries, respectively. All studies that assessed aspects of the global cancer burden using this measure were reviewed. Results: Although the present cancer incidence burden is greater in higher Human Development Index countries, a greater proportion of the global mortality burden is observed in less developed countries, with a higher mean fatality rate in the latter countries. Further, the future cancer burden is expected to disproportionally affect less developed regions; in particular, it has been estimated that low and medium Human Development Index countries will experience a 100% and 81% increase in cancer incidence from 2008 to 2030, respectively. Disparities were also observed in risk factors and average health outcomes, such as a greater number of years of life lost prematurely and fewer cancer-related gains in life expectancy observed in lower versus higher Human Development Index settings. Conclusions: From a global perspective, there remain clear disparities in the cancer burden according to national Human Development Index scores. International efforts are needed to aid countries in social and economic transition in order to efficiently plan, implement and evaluate cancer control initiatives as a means to reduce the widening gap in cancer occurrence and survival worldwide.

Background: Although adolescent and young adult (AYA) cancers represent a unique spectrum of malignancies, epidemiological studies of cancer incidence often group AYAs together with younger or older populations, obscuring patterns specific to this population. Methods: We examined AYA cancer incidence trends in 41 countries over a 15-year period using the CI5plus database. Truncated age-standardized incidence rates were calculated and the annual percentage change was assessed, with statistical significance corresponding to a 95% confidence interval that does not include zero. Results: From 1998 to 2012, the 41 included countries contributed a total of 1 846 588 cancer cases and 3.1 billion person-years among AYAs. Although statistically significant increases in the overall cancer burden were observed in 23 countries, the magnitude varied considerably, with the greatest increase in incidence observed in South Korea (annual percentage change2002–2012 = 8.5%, 95% confidence interval = 7.6% to 9.4%) due to thyroid cancer. Notable trends included sharp increases in the incidence of obesity-related malignancies among AYAs; indeed, statistically significant increases were observed among AYAs for 10 of 11 and 9 of 11 obesity-related cancer sites in the US and UK, respectively, with at least five obesity-related cancers statistically significantly increasing in Canada, Japan, South Korea, Australia, and the Netherlands. Other striking trends were noted for thyroid and testicular cancer, with statistically significantly increasing rates observed in 33 and 22 countries, respectively, whereas statistically significant declines in incidence were observed for smoking-related cancers, cervical cancer, and Kaposi sarcoma in many countries. Conclusions: Our results highlight the future health-care needs related to treatment as well as the urgency for public health initiatives that can mitigate the increasing burden of cancer in AYAs.