Reducing Death from Breast Cancer by Mass Screening: Rethinking Strategies for LMICs
By Christabel Abewe and Vester Gunsaru
Breast cancer is the most common cancer diagnosed in women and the most common cause of death from cancer. Globally, breast cancer incidence, mortality, and survival rates vary considerably between the regions (approximately fourfold). However, what has been unequivocally consistent across the regions is that the incidence of breast cancer is increasing, and in regions without early detection programs, mortality is also increasing. The global trajectory is that breast cancer incidence is higher in the developed countries as compared with the developing countries, yet paradoxically; the breast cancer mortality in the developing countries is almost equal to that in the developed countries. This implies that breast cancer disproportionately affects women in developing countries. The high mortality in developing countries is largely attributed to the fact that about 75% of women diagnosed with breast cancer in low and middle income countries (LMICs) present with clinical stages III & IV of the disease. On the contrary, 70% of women with breast cancer in North America are diagnosed in stages 0 & I. Developing countries now face the challenge of effectively detecting and treating a disease that was previously considered too uncommon to warrant the allocation of finite health care resources.
Mammographic screening is the ONLY technique that has been found to sufficiently reduce breast cancer mortality and while mass screening using mammography has been well established and implemented in developed countries, it has not been replicated in LMICs due to the huge financial and human resources that are required for the technique. Aside from the huge financial resources needed for mammography, the appropriateness of this screening technique among women from sub-Saharan Africa has become a point of debate. The argument against considering mammography as the gold standard for screening for breast cancer is hinged on the fact that the bulk of the women who need screening for breast cancer in sub-Saharan Africa are between 30-45 years. This implies that the proportion of the demographic that requires screening in sub-Saharan Africa is composed of women who have dense breasts making it very difficult to tell abnormal and normal tissue apart on the X-ray film. Mammography is typically recommended and most effective when it is used to screen older women 50-69 years.
The use of Ultrasound scans has been advocated for in some LMICs such as Uganda as a stopgap measure to screen the most at risk women (30-45 years) of breast cancer in the absence of mammographic and other image screening services. Ultrasound scans are almost 50% cheaper than mammograms, easier to use, require less human resource expertise and are up to 10 fold more available than mammograms in most LMICs. Although ultrasonography is not up to par with the gold standard (i.e., lower specificity and sensitivity and higher false positives) it is still better than no screening at all. Breast cancer is and should be viewed as extremely fatal and yet can be cured if detected early and treated properly. The proposition to use ultrasonography for mass screening in LMICs where mammography is out of reach is therefore not to lower the standards of breast cancer diagnosis but rather an interim measure to fill the gap of unmet need until these countries have sufficient resources to afford more effective imaging screening tools. There is therefore need to investigate the efficacy of ultrasonography for breast cancer in LMICs and subsequently estimate the resource requirements for implementing population level screening using this method.