Bulletin of the World Health Organization

Cervical and female breast cancers in the Americas: current situation and opportunities for action

Silvana Luciani a, Anna Cabanes a, Elisa Prieto-Lara a & Vilma Gawryszewski a

a. Pan American Health Organization, 525 23rd Street NW, Washington, DC 20037, United States of America.

Correspondence to Silvana Luciani (e-mail: [email protected]).

(Submitted: 19 December 2012 – Revised version received: 21 May 2013 – Accepted: 27 May 2013.)

Bulletin of the World Health Organization 2013;91:640-649. doi: http://dx.doi.org/10.2471/BLT.12.116699

Introduction

Cancer represents 30% of the burden posed by noncommunicable diseases in the Region of the Americas of the World Health Organization (WHO), where the leading causes of death have shifted from infectious diseases to noncommunicable diseases.1 Changes in demographic, social, economic and environmental factors, as well as life course changes – for example, changes in reproductive patterns – have contributed greatly to this epidemiological shift.2

Breast and cervical cancers are generally considered to be the most important cancers among women in the Americas, as they are among women worldwide.3 Globally, breast cancer incidence and mortality have increased over the past 30 years, at estimated annual rates of 3.1% and 1.8%, respectively. Over the same period, cervical cancer incidence and mortality have also increased, at estimated annual rates of 0.6% and 0.46%, respectively.4 The corresponding trends in the Americas have generally matched these global trends.5

These increases have occurred even though effective, population-based interventions are available for the control of breast and cervical cancers and the prevention of unnecessary deaths from these cancers. For cervical cancer, these interventions include vaccination against human papillomavirus (HPV) infection, screening based on cervical cytology, visual inspection of the cervix after applying acetic acid and testing for HPV DNA, and effective treatment for precancerous lesions and invasive cancer.6 WHO currently recommends the routine administration of HPV vaccine to girls – as part of a country’s national immunization programme – if cervical cancer is a public health priority in the country and if such HPV vaccination is programmatically feasible and sustainable and appears to be cost-effective in the country.7 If it is systematically applied with high coverage and quality assurance, cytological screening can reduce cervical cancer mortality by more than 50%.8 For breast cancer, the disease can be detected in its early stages through breast self-examination, clinical breast examination and mammography screening. The effectiveness of these strategies has been found to vary according to the resources available and the needs of the population involved.9 In general, however, mammography screening has led to a substantial reduction – estimated to be about 15% – in breast cancer mortality.10

The implementation of technologies that could reduce mortality from breast and cervical cancers continues to be a challenge in resource-constrained settings such as those often seen in the Caribbean and Latin America. This is especially true where several public health priorities compete for attention.

To assess the burden posed by breast and cervical cancers in the Americas and to understand the associated public health response, we reviewed the information on these cancers provided to the Pan American Health Organization (PAHO) by the relevant National Institutes of Vital Statistics and health ministry officials. We reviewed the temporal trends in mortality from breast and cervical cancers since 2000 and the results of a recent survey on the capacity of national programmes to prevent, screen for and treat noncommunicable diseases.

Methods

We extracted data – on mortality from breast and cervical cancers – from the PAHO Regional Mortality Database, which includes deaths that have been registered in national vital registration systems and reported annually to PAHO.11 The quality of the data from each country was evaluated by verifying the integrity and consistency of the data and validating selected variables (i.e. sex, age and underlying cause of death). An algorithm to correct for under-registration and ill-defined causes was applied to the data from countries that show more than 10% under-registration, more than 10% of deaths with an ill-defined cause, or both.12 For each of the 33 countries in WHO’s Region of the Americas with complete data, we included data from 2000 to the last year with reported data. This period was used because it was when each of the countries coded mortality using the International statistical classification of diseases and related health problems, 10th revision (ICD-10).

For breast cancer mortality, we extracted all deaths attributed to “female malignant neoplasm of breast” (i.e. ICD-10 code C50). For cervical cancer mortality, we extracted all deaths attributed to “malignant neoplasm of cervix uteri” (C53), “malignant neoplasm of corpus uteri” (C54) or “malignant neoplasm of uterus, part unspecified” (C55). We applied a reallocation algorithm – as used in similar analyses on trends and geographical comparisons13 – to reassign a proportion of the deaths coded as C55 to “malignant neoplasm of cervix uteri” (C53), based on the age- and time-specific distributions of the deaths. Eleven countries coded small proportions of their deaths among females (≤ 25% of the total number among women aged 30 years or older) as C55. For these countries – Brazil, Chile, Colombia, Costa Rica, Cuba, Mexico, Nicaragua, Panama, Suriname, Trinidad and Tobago and Venezuela – we reallocated the C55 deaths (unspecified) to C53 (cervix) or C54 (uterus), using the same ratio seen between the deaths coded C53 and those coded C54 – in the same data set – for the same country, year and age group. However, for the 13 countries that coded higher proportions of their deaths among women aged 30 years or older as C55 – Argentina, Belize, Canada, Dominican Republic, Ecuador, El Salvador, Guatemala, Guyana, Paraguay, Peru, Puerto Rico, Uruguay and the United States of America – the deaths coded C55 for each year were reallocated to C53 or C54 using the same ratio seen between the deaths coded C53 and those coded C54 in an appropriate reference country in the same year. The reference countries used were Chile for the data from Argentina, Ecuador, Paraguay, Peru and Uruguay; Mexico for the data from Belize, Canada, the Dominican Republic, El Salvador, Guatemala, Puerto Rico and the United States; and Trinidad and Tobago for the data from Guyana. The selection of the reference countries was based on the high quality of their vital statistics data, the consistently low proportions of their deaths that were coded C55, and their geographical, demographic and socioeconomic characteristics.

Age-standardized mortality rates were calculated using the world standard population.14 For those countries that did not have small populations and did not show large fluctuations in the time–series mortality data, annual changes in mortality rates were evaluated using Poisson regression models.

Information on the capacity of national public health programmes to deal with breast and cervical cancers was extracted – for the 25 countries in the Americas that provided the relevant data – from the PAHO Country Capacity Survey on noncommunicable diseases (S. Luciani, unpublished observations, 2013). This survey, which was conducted in April 2012, was based on a structured questionnaire which, for each targeted country, was sent to the health ministry staff members responsible for the national programme against noncommunicable diseases.

Results

In 2007, approximately 107 000 registered deaths in the Americas were attributed to female breast cancer (n = 82 370) or cervical cancer (n = 24 526),1 although another 12 240 deaths were reported as being from “cancer of the uterus, part unspecified” and some of these may have been from cervical cancer.

Breast cancer is the most common cause of cancer-related deaths among women in most countries in the Americas (Table 1). In Belize, El Salvador, Ecuador, Nicaragua, Paraguay and Peru, however, cervical cancer is the most common cause of cancer deaths among women (Table 2).

Within the Americas, mortality from female breast cancer is relatively high in the countries of the Southern Cone and the “English” Caribbean. According to the most recent data, the age-standardized annual rate of death from breast cancer is 22.8 deaths per 100 000 females in the Bahamas, 21.6 deaths per 100 000 females in Trinidad and Tobago and 22.0 deaths per 100 000 females in Uruguay (Table 1). The lowest rates of death from female breast cancer in recent years were observed in El Salvador and Guatemala, whereas Brazil, Canada and the United States showed intermediate values (Table 1).

Recent data on cervical cancer mortality (Table 2) show relatively high annual rates in El Salvador, Nicaragua and Paraguay – with 17.9, 19.4 and 20.5 deaths per 100 000 females, respectively – and relatively low rates in Canada, Puerto Rico and the United States – with 2.4, 3.4 and 3.1 deaths per 100 000 females, respectively.

In some countries the rate of death from female breast cancer is substantially greater than that from cervical cancer. One example is Brazil, which in 2009 recorded rates of 14.9 and 8.4 deaths per 100 000 females, breast and cervical cancer, respectively. In other countries the two types of cancer cause similar mortality. This applies to Mexico, which in 2009 recorded 9.0 deaths from breast cancer and 8.0 deaths from cervical cancer per 100 000 females. And there are still other countries where the rate of death from female breast cancer is much lower than that from cervical cancer. In Nicaragua in 2009, for example, the rate of death from female breast cancer was almost half as high as the rate of death from cervical cancer – 11.1 and 19.4 deaths per 100 000 females, respectively.

Two of the countries that we investigated had relatively high rates of death from both female breast cancer and cervical cancer. One was Paraguay, with 18.5 deaths from breast cancer and 20.5 deaths from cervical cancer per 100 000 females in 2009; the other was Venezuela, with corresponding rates of 15.1 and 14.9 deaths per 100 000 in 2007 for breast and cervical cancer, respectively.

Of the 19 countries included in the analysis of temporal trends in mortality from breast and cervical cancers, four showed substantial declines in breast cancer mortality since 2000, with annual percentage changes ranging from –1.21% (95% confidence interval, CI: –1.51 to –0.92) in Argentina to –2.25% (95% CI: –2.67 to –1.83) in Canada (Table 1). Another eight countries showed substantial increases in breast cancer mortality since 2000, with annual percentage changes as high as 3.52% (95% CI: 1.61 to 5.46) in El Salvador and 4.57% (95% CI: 1.80 to 7.42) in Trinidad and Tobago (Table 1).

Since 2000, mortality from cervical cancer has been decreasing in almost all of the countries included in the analysis of temporal trends, with the greatest annual percentage changes observed in Costa Rica (–6.65%; 95% CI: –8.44 to –4.82) and Panama (–5.43%; 95% CI: –7.01 to –3.83) (Table 2)

The trends for breast cancer mortality in relation to cervical cancer mortality followed three patterns: countries such as Brazil have maintained a higher rate of breast cancer mortality, whereas other countries, such as Mexico, have seen declines in cervical cancer mortality but increases in breast cancer mortality. Still others, such as Nicaragua, have maintained a higher rate of cervical cancer mortality (Fig. 1, Fig. 2 and Fig. 3).

Fig. 1. Temporal trends in mortality from cervical and female breast cancers, Brazil, 2000–2009
Fig. 1. Temporal trends in mortality from cervical and female breast cancers, Brazil, 2000–2009
ASMR, age-standardized mortality rate.
Fig. 2. Temporal trends in mortality from cervical and female breast cancers, Mexico, 2000–2009
Fig. 2. Temporal trends in mortality from cervical and female breast cancers, Mexico, 2000–2009
ASMR, age-standardized mortality rate.
Fig. 3. Temporal trends in mortality from cervical and female breast cancers, Nicaragua, 2000–2009
Fig. 3. Temporal trends in mortality from cervical and female breast cancers, Nicaragua, 2000–2009
ASMR, age-standardized mortality rate.

National policies and plans for the prevention and treatment of cancer exist in most of the countries we investigated and public health screening services for breast and cervical cancer are reported to be in place in 24 of the 25 countries that provided data for the PAHO Country Capacity Survey (Table 3). Cervical cancer screening is predominantly based on cytological testing in 24 countries, although 10 countries reported that they also offered testing for HPV DNA and 11 countries reported that they offered screening by visual inspection of the cervix after application of acetic acid. Although 24 countries reported that they offered free cytological screening for cervical cancer, only eight reported having free mammography-based screening services for breast cancer.

For cancer treatment, almost all of the 25 countries that provided data for the PAHO Country Capacity Survey reported the availability of chemotherapy, but eight countries, mainly in the Caribbean, reported that they had no radiotherapy available. In many countries, patients have to contribute financially to the costs of chemotherapy and – where available – radiotherapy. Although most of the countries reported having tamoxifen widely available, patients – even the poorest – were also charged for this drug. Most of the countries included in the survey reported having oral morphine available for palliative care. However, such medication was reportedly unavailable in seven of the countries, most of them in Central America.

Discussion

This brief descriptive analysis calls attention to the significant problem of breast and cervical cancers in all countries and territories of the Region of the Americas, and to the capacity that is available for the early detection and treatment of such cancers in the Region. It highlights the inequities represented by cervical cancer, which disproportionately affects women in the poorer countries, especially those with gross national incomes of less than 10 000 United States dollars per capita (Table 1 and Table 2). It also highlights the growing burden from breast cancer in several countries in Latin America and the Caribbean and the “double burden” of high mortality from both breast and cervical cancer faced by some of these countries.

Most of deaths from cervical cancer reported throughout the Americas were registered in Latin America or the Caribbean. This north–south divide can be seen in Appendix A (available at: http://www.paho.org/cancer/Appendix-A). The numbers of deaths from breast cancer in North America were, however, similar to the combined numbers for Latin America and the Caribbean (Appendix A). Within the countries and territories of Latin America and the Caribbean, the highest mortality rates from female breast cancer – seen in the countries of the Southern Cone – have been up to five times higher than the corresponding lowest rates – seen in Central America. Conversely, the highest rates of mortality from cervical cancer have been seen in Central America and have been up to three times higher than those recorded in the Southern Cone. These differences may be attributable to the level of socioeconomic development in each country and/or to geographical differences in access to screening, early diagnosis and treatment services.16–19

This review validates several recent reports on mortality from breast and cervical cancers in the Americas.5,16–25 In general, it has revealed temporal trends similar to those reported worldwide.4 However, several countries in the Americas have achieved important reductions in mortality from breast or cervical cancers over the last decade: Canada and the United States have achieved such reductions for breast cancer, whereas Chile, Costa Rica and Mexico have observed such reductions for cervical cancer. The relatively low annual numbers of deaths from both breast cancer and cervical cancer reported by the countries and territories of the Caribbean are potentially misleading, since they are reflections of small national populations and not of low mortality rates. The lack of radiotherapy in several of the small island nations of the Caribbean is a problem that needs to be resolved.

Progress in the development and implementation of policies, programmes and interventions against breast and cervical cancers have been seen in the Region of the Americas for several years.26–28 Since all the countries in the Region now have screening programmes for cervical cancer,25 several Latin American countries are now offering testing for HPV DNA in their national cervical cancer programmes26 and several report capacity for mammography screening.29 Effective screening for cervical cancer may partly explain recent declines in rates of mortality from such cancer. The continuing rise in mortality from breast cancer in several countries and territories of Latin America and the Caribbean is discouraging and probably a reflection of poor general access to health care and to a severe shortage of the resources needed to screen for such cancer.

According to some reports, in several countries in the Americas that have the capacity for screening and early detection, the main focus is still on treatment, with late-stage diagnosis and poor outcomes commonly observed.18 Such a focus can lead to low coverages in screening for both cervical cancer26 and breast cancer. In some countries mammography is limited to highly educated women or is unavailable to women who lack health insurance.30

The present analysis was based on deaths registered by national authorities and reported to PAHO, with corrections to account for any under-registration of mortality. Our mortality data differ from those presented in GLOBOCAN 2008,3 as they remain largely unchanged by estimation and prediction. There are, however, some limitations in using the mortality data reported to PAHO. First, PAHO has no mortality data from Bolivia, Haiti, Honduras or Jamaica, so these countries could not be included in this regional analysis. Second, PAHO only had incomplete mortality data for Anguilla, the British Virgin Islands, the Cayman Islands, Dominica, the Dominican Republic, French Guiana, Guadeloupe, Guatemala, Martinique, the former Netherlands Antilles, Saint Lucia, Turks and Caicos and Uruguay – although the data that were available for the Dominican Republic, Guatemala and Uruguay were sufficient for these three countries to be included in our analysis. As no subnational data for most countries in the Americas were available in the PAHO mortality database, no within-country comparisons of mortality rates were made. There is a general need to strengthen the vital statistics systems in most countries of Latin America and the Caribbean – to permit improvements in the quality, completeness and timeliness of the data collected on mortality – and to create or strengthen population-based cancer registries.

To enable comparisons between countries and take into consideration the substantial number of deaths recorded as being from “malignant neoplasm of uterus, parts unspecified” (i.e. ICD-10 code C55) we reassigned deaths attributed to C55 to a more specific cause of either cancer of the cervix or cancer of the uterus. This reassignment was possible for most of the countries included in our analyses; the exceptions were Caribbean countries and territories that reported small numbers of deaths from cervical cancer. As countries in the Region of the Americas do not apply a reallocation algorithm in reporting their national mortalities from cervical cancer, the data presented in this paper may vary from those presented in national reports by ministries of health. By applying the reallocation procedure, we tried to accommodate the underestimation of deaths from cervical cancer, adjust for any temporal improvements in data coding over the study period and improve the validity of any between-country comparisons. There were, however, limitations in using the procedure, particularly because there is no ideal reference population.

Low- and middle-income countries in the Americas are clearly making efforts – via screening and treatment programmes – to address the problems posed by breast and cervical cancers. In addition, by 2012 nine countries in the Region of the Americas – Argentina, Canada, Guyana, Mexico, Panama, Peru, Suriname, Trinidad and Tobago, and the United States – had introduced HPV vaccination into their national immunization programmes.28 The Region’s political and technical commitment to the control and treatment of cancer in general and cervical cancer in particular is demonstrated by the endorsement, by the Regions’ ministers of health, of a Regional Strategy and Plan of Action for Cervical Cancer Prevention and Control.31 Several countries in the Region have already implemented large-scale interventions that have demonstrated the feasibility and effectiveness of comprehensive programmes against cervical cancer and breast cancer.32,33 A network of South American cancer institutes known as RINC/UNASUR (for Red de Institutos Nacionales de Cáncer/Unión de Naciones Suramericanas) collaborates to strengthen programmes against breast and cervical cancer.34

The inequities represented by morbidity and mortality from breast and cervical cancers need to be reduced, perhaps by the use of existing health platforms, such as maternal and reproductive health programmes, to combat these women’s cancers.35,36 Although most countries in the Americas have some public health capacity for the control of breast and cervical cancers, the burden posed by these cancers could be reduced further by strengthening such capacity.

Competing interests:

None declared.

References