The emerging breast cancer epidemic: early diagnosis and treatment.

Abstract

Breast cancer is the most common malignant tumour in women. Estimates for 2008 indicate that 1.38 million women were diagnosed and 0.46 million died from the disease worldwide [1]. Currently, the incidence in the developed and developing world is similar but, whereas incidence rates are tending to plateau or decline in the West, they are increasing in the developing world, presumably related to changes in dietary and reproductive behaviours and ageing populations [1]. Total mortality from breast cancer is already higher in the developing world [1]. Whilst mortality is declining in most western countries, it is estimated that it will increase by over 100% in developing countries by 2020 [2]. Whereas less than one-third of women diagnosed with breast cancer in developed countries die from the disease, this proportion reaches over two-thirds in developing countries and is directly related to income per capita (Figure ​(Figure1a)1a) [1,3]. Berry and colleagues [4] developed a series of independent statistical models of breast cancer incidence in order to determine the relative importance of the contribution of mammographic screening and adjuvant therapy to the marked decline in breast cancer mortality in the majority of developed countries. They estimated the mortality decline was related equally to screening and therapy and that mortality would increase in countries with limited facilities for screening and treatment (Figure ​(Figure1b1b). Figure 1 More deaths from breast cancer in the absence of early diagnosis and systemic treatment. (a) Income differences and differences between age-adjusted incidence and mortality (from [3] with permission). (b) Model of the estimates of the contribution of ... Early detection The analyses of Berry and colleagues and trials of screening indicate the importance of early detection by mammography. However, where mammographic screening is introduced into a country gradually, improvements in outcome are also seen in the non-screened group, which may, in part, be related to a general increase in awareness of the importance of early treatment [5,6]. Whilst randomised trials of breast self-examination versus no examination do not demonstrate the effectiveness of the intervention compared with women simply being made aware of breast examination [7], these studies do not address the issue of lack of awareness or of barriers to women presenting early rather than late. In many developing countries, the introduction of mammographic screening is currently not possible because of expense, the relatively low incidence of breast cancer and low age of diagnosis. Thus, the Early Resource Allocation Panel of the Breast Health Global Initiative (BHGI) produced guidelines suggesting a graded system of introduction for breast awareness and mammography based on whether the health care system was basic, limited, enhanced or maximal [8,9]. In countries with basic and limited resources they suggest the widespread introduction of culturally sensitive, linguistically appropriate, local education programmes to teach breast health awareness and awareness with mammography in countries with enhanced or maximal health care systems. An example is the Mumbai area in India, where mammography is not available but with education in the city two-thirds of women present with stage I and II breast cancer compared to only one-third in local rural populations (R Badwe, personal communication).