Breast cancer is the most frequent cancer among women, impacting 2.1 million women each year, and also causes the greatest number of cancer-related deaths among women. In 2018, it is estimated that 627,000 women died from breast cancer – that is approximately 15% of all cancer deaths among women. While breast cancer rates are higher among women in more developed regions, rates are increasing in nearly every region globally.
In order to improve breast cancer outcomes and survival, early detection is critical. There are two early detection strategies for breast cancer: early diagnosis and screening. Limited resource settings with weak health systems where the majority of women are diagnosed in late stages should prioritize early diagnosis programmes based on awareness of early signs and symptoms and prompt referral to diagnosis and treatment.
Early diagnosis strategies focus on providing timely access to cancer treatment by reducing barriers to care and/or improving access to effective diagnosis services. The goal is to increase the proportion of breast cancers identified at an early stage, allowing for more effective treatment to be used and reducing the risks of death from breast cancer. WHO Package of essential noncommunicable (PEN) disease interventions for primary health care in low-resource settings has guidance on the approach to assessment and referral for women with suspected breast cancer in the primary care setting.
Screening consists of testing women to identify cancers before any symptoms appear. Various methods have been evaluated as breast cancer screening tools, including mammography, clinical breast exam and breast self-exam.
Mammography: uses low-energy X-rays to identify abnormalities in the breast. It has been shown to reduce breast cancer mortality by approximately 20% in high-resource settings. WHO Position paper on mammography screening concluded that in well-resourced settings women aged 50-69 should undergo organized, population-based mammography screening if pre-specified conditions on programme implementation are met. In limited resource settings with weak health systems, mammography is not cost-effective, and early detection should focus on reducing stage at diagnosis through improved awareness. For women aged 40-49 years or 70-75 years, WHO recommends systematic mammography screening in women aged 40-49 years or 70-75 years only in the context of rigorous research and in well-resourced settings.
Clinical Breast Exam (CBE): is an examination of both breasts performed by a trained health professional. CBE seems to be a promising approach for low resource settings and could be implemented depending on the evidence from ongoing studies.
Because screening requires substantial investment and carries significant potential personal and financial costs, the decision to proceed with screening should be pursued only after (1) basic breast health services including effective diagnosis and timely treatment are available to an entire target group; (2) its effectiveness has been demonstrated in the region; and (3) resources are available to sustain the programme and maintain quality.
WHO Related links
WHO PEN Protocol 4.1 Assessment and referral of women with suspected breast cancer at primary health care
- WHO position paper on mammography screening
- IARC handbooks on breast cancer screening (2015)