Elsevier

The Lancet

Volume 389, Issue 10071, 25 February–3 March 2017, Pages 847-860
The Lancet

Series
The global burden of women’s cancers: a grand challenge in global health

https://doi.org/10.1016/S0140-6736(16)31392-7Get rights and content

Summary

Every year, more than 2 million women worldwide are diagnosed with breast or cervical cancer, yet where a woman lives, her socioeconomic status, and agency largely determines whether she will develop one of these cancers and will ultimately survive. In regions with scarce resources, fragile or fragmented health systems, cancer contributes to the cycle of poverty. Proven and cost-effective interventions are available for both these common cancers, yet for so many women access to these is beyond reach. These inequities highlight the urgent need in low-income and middle-income countries for sustainable investments in the entire continuum of cancer control, from prevention to palliative care, and in the development of high-quality population-based cancer registries. In this first paper of the Series on health, equity, and women’s cancers, we describe the burden of breast and cervical cancer, with an emphasis on global and regional trends in incidence, mortality, and survival, and the consequences, especially in socioeconomically disadvantaged women in different settings.

Introduction

Cancer is a leading cause of premature death and disability worldwide, especially in women.1, 2 It is a rapidly growing crisis in low-income and middle-income countries (LMICs), where the epidemiological transition continues to shift the burden of disease from mainly infectious causes to chronic, non-communicable diseases (NCDs).3 Many countries, especially those with weak, under-resourced health systems, are struggling to cope with the rapid rise in NCDs while high maternal and child mortality rates, and high mortality rates from infectious diseases (including malaria, tuberculosis [TB], and HIV/AIDS) and malnutrition still persist.

Worldwide, more than 2 million women are diagnosed with breast or cervical cancer every year, but where a woman lives (ie, in which country, region, or setting in relation to the nearest health-care services) and how she lives (eg, poor or otherwise socially disenfranchised) largely determines whether or not she develops one of these cancers, how early she presents to health-care services, and her access to affordable, good-quality diagnostic and treatment services. This pattern is especially striking for cervical cancer, since around 85% of women diagnosed and 87% of women who die from cervical cancer live in LMICs.3 Proven approaches exist to reduce these gross inequities, yet most women have few opportunities to access these life-saving interventions. In many countries, and in many resource-poor regions within countries, implementation of human papillomavirus (HPV) vaccination is limited,4 as is the availability of—and access to—early detection programmes, cancer surgery,5 essential cancer medicines,6 radiotherapy,7 palliative care,8 and support for those who survive cancer, sometimes referred to as survivorship care.

Key messages

  • Worldwide, the majority of women who die from breast cancer and most who die from cervical cancer live in low-income and middle-income countries. This situation is a largely preventable tragedy for hundreds of thousands of women and their families every year.

  • Most women who develop breast or cervical cancer in a high-income country will survive; the opposite is true for women in most low-income and many middle-income countries. Where a woman lives, and her socioeconomic, ethnocultural, or migration status, should no longer mean the difference between life and death from these common cancers, for which cost-effective, life-saving interventions exist.

  • The incidence of breast cancer is expected to increase rapidly with human development. Although invasive cervical cancer should be predicted to fall in emerging economies, this is not yet the case in many countries where patterns of sexual behaviour are increasing the transmission of oncogenic human papillomavirus subtypes, and population-based organised human papillomavirus vaccination and cervical screening programmes are not yet widely implemented.

  • To understand the social, economic, and financial consequences of breast and cervical cancers, which take a disproportionate toll on women in low-income and middle-income countries in their prime of life, is of crucial importance. The efficacy and cost-effectiveness of interventions for breast and cervical cancer control must be critically evaluated to help inform and prioritise evidence-based, resource-appropriate programmes and policy making.

  • Global efforts, especially in recent years, have led to substantial improvements in maternal health outcomes. Similar efforts are urgently needed to address breast and cervical cancer, which take the lives of three times as many women each year than complications of pregnancy and childbirth (ie, maternal mortality).

Disability and premature death from breast or cervical cancer is a preventable tragedy for hundreds of thousands of women and their families every year. In 2012, breast and cervical cancer were responsible for the deaths of 522 000 and 266 000 women worldwide respectively;3 as such, around half a million more women died from these two cancers alone than from complications of pregnancy or childbirth (303 000 maternal deaths in 2015, according to the UN Population Fund).9 A further 152 000 women died from ovarian cancer and 76 000 from endometrial cancer.3 But where do women’s cancers fit in the global health agenda? In high-income countries, there is notable advocacy, media attention, and funding for research and treatment of cancer, but in many resource-poor settings, breast, cervical, and other gynaecological cancers are effectively neglected diseases.10 That these diseases cause substantial disability, premature death, disruption of family life, and loss to the national economy, thus exacerbating the cycle of poverty,11 has largely been ignored by the global health and development community.

Only 5% of global spending on cancer is directed toward the majority of countries (ie, LMICs) where the highest burden exists.12 Health inequities are differences in health “…that are unnecessary, avoidable, unfair and unjust”.13 Poor health within countries and inequities between countries represent an unequal distribution of power, income, goods, and services that result from “ineffective social policies, unfair economic arrangements, and bad politics”.14 Cancers that mainly affect women present particular challenges in terms of achieving health equity. Elevation of the status of women will be one of the key drivers in reducing disparities in cancer outcomes within and between countries.

The Lancet Series on health, equity, and women’s cancers seeks to provide an advocacy and action framework for radically improving progress toward closing the global cancer divide11 for women. The three papers in the Series will focus on the global burden of breast and cervical cancer, the untapped potential of proven and promising interventions, the challenges and opportunities to take these to scale while strengthening health systems, and the provision of recommendations for translating evidence to policy, to reduce inequities and improve cancer survival for women.

In this first paper of the Series, we describe the burden of breast and cervical cancer, with an emphasis on global and regional trends in incidence, mortality, and survival; the social and economic effects on women and their families; and the disparities in cancer survival in socioeconomically disadvantaged women. Endometrial, ovarian, and other gynaecological cancers are important contributors to cancer mortality, but this Series will focus mainly on breast and cervical cancer, since these are two of the greatest contributors to cancer mortality and morbidity in women worldwide. As highlighted in this paper, breast and cervical cancer will continue to pose particularly important challenges and create opportunities to strengthen health systems in the coming decades. Cervical cancer is largely preventable through public health interventions, such as HPV vaccination for girls aged 9–13 years, and screening with treatment of pre-cancerous lesions is among the few cancer-related so-called “best buys” or “very cost effective strategies” according to WHO’s Global Action Plan for the Prevention and Control of Noncommunicable Diseases (2013–20).15 Both HPV vaccination and screening and treatment of pre-cancerous cervical lesions are also included in the package of essential interventions for cancer control in LMICs, in the Cancer Volume of the World Bank Group’s Disease Control Priorities, Third Edition (DCP3).16 Although breast cancer screening continues to generate substantial debate regarding the magnitude of benefits and harms, opportune ages, screening intervals, cost-effectiveness, and relevance to resource-poor settings,17 improving access to early diagnosis and treatment for breast cancer can be cost effective, and promotion of breast cancer early diagnosis and treatment is listed in the DCP3 essential package.16 We therefore address only these two cancers in this Series, because they fall under the domains of public health and public policy most relevant to women’s cancers.

Section snippets

Causes and risk factors of breast and cervical cancer

The major known risk factors for breast cancer include female sex, age, and family history, and reproductive factors, including early age at menarche, later menopause, nulliparity, and first childbirth after age 30 years, all of which are independent risk factors.18 Breastfeeding is independently associated with a reduced risk, with longer duration associated with a greater reduction in risk of developing breast cancer.19 Overweight and obesity are associated with an increased risk for

Breast and cervical cancer: incidence, mortality, and survival

Every year, 1·7 million women are diagnosed with breast cancer, making it the most common cancer in women worldwide.3 Just over half of all cases (53%) occur in less developed regions.3 The highest incidence rates are reported from countries in northern and western Europe (eg, Denmark, Belgium, and the UK), North America, Australia, and New Zealand (figure 1A), but breast cancer is not confined to high-income countries and is the most commonly diagnosed cancer in women in 140 countries. With an

Women’s cancers and human development

Breast and cervical cancer are indicative of the late phase of the epidemiological transition that characterises the rise of NCDs in general. Increasing life expectancy and declines in infection-related diseases (including cervical cancer) are offset by an upsurge in cancers more common in wealthier countries and associated with a so-called western lifestyle,26, 27 referred to as the cancer transition.26 The Human Development Index (HDI) is a composite of three basic dimensions of human

Prediction of the future burden

Figure 4 shows the predicted global burden of breast and cervical cancers in 2030. Data available from long-standing high-quality population-based cancer registries from medium, high, or very high HDI countries65 suggest that if these average changes continue and were applicable to all countries of the world, the number of women diagnosed with breast cancer will increase to almost 3·2 million per year. Even if rates can be maintained at 2012 levels, a rise to 2·4 million new cases of breast

Wider effects on women, families, and society

Breast and cervical cancer are major contributors to the overall burden of disease in women worldwide. Breast cancer is the leading cause of life years spent with disability in 119 countries, whereas cervical cancer is the leading cause in 49 countries.2 However, as a cause of premature death (as estimated through years of life lost), cervical cancer leads breast cancer in 23 countries, mainly in sub-Saharan Africa and parts of Central and South America. As figure 5 shows, the

Conclusions

Huge global inequities exist in cancer survival for women. In low-resource settings, breast and cervical cancer disproportionately affect women in the prime of life, resulting in substantial economic and societal effects. A woman’s country, region of residence, income level, socioeconomic status, ethnocultural status, or migration status should no longer affect the likelihood of dying from these common cancers.

Several global initiatives are broadening their approach to women’s health along the

Search strategy and selection criteria

Studies for the economics analysis were retrieved through systematic searches on the following medical and social sciences electronic databases: Embase, Global Health, MEDLINE (OVID), Scopus, Web of Science, and Econlit. We combined variations of search terms related to “breast cancer”; “cervical cancer”; “low income”, “middle income”, and “developing” countries; the individually named countries of relevance; “economic burden” and “economic consequence”. We searched Google Scholar, scanned the

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