In a study reported in The Lancet Oncology, Ward et al estimated the improvements in global overall survival for female breast cancer that could be achieved via increased availability of treatment and imaging modalities, as well as improvements in quality of care.
Study Details
The study used a microsimulation model of global breast cancer survival that accounted for availability and stage-specific survival impact of:
- Treatment modalities including chemotherapy, radiotherapy, surgery, and targeted therapy
- Imaging modalities including ultrasound, x-ray, computed tomography (CT), magnetic resonance imaging, positron-emission tomography, and single-photon emission CT
- Quality of cancer care.
Five-year survival for women with newly diagnosed breast cancer in 200 countries and territories in 2018 was estimated, with the model being calibrated to data on 5-year net breast cancer survival in 2010 to 2014 from the CONCORD-3 study; this study, published in 2018, reported data on 5-year net survival estimates for breast cancer from countries around the world.
The potential impact on survival of scaling up the treatment and imaging modalities and quality of care to the mean level of high-income countries was analyzed, with 1,000 simulations being performed for each scale-up element. The data are reported as means and 95% uncertainty intervals (UIs) for all model outcomes.
Key Findings
The overall estimated global 5-year net survival for women diagnosed with breast cancer in 2018 was 67.9% (95% UI = 62.9%–73.4%), including 3.5% (95% UI =0.4%–10.0%) in low-income countries and 87.0% (95% UI = 85.6%–88.4%) in high-income countries.
Among individual treatment modalities, the largest increase in global 5-year survival was estimated to occur with scaling up access to surgery, yielding an additional 2.7% (95% UI = 0.4%–8.3%). Among individual imaging modalities, the largest increase was associated with scaling up of CT, yielding an additional 0.5% (95% UI = 0.0%–2.0%).
Scaling up of surgery, chemotherapy, radiotherapy, ultrasound, and x-ray was estimated to increase global 5-year net survival to 75.6% (95% UI = 70.6%–79.4%); 5-year net survival in low-income countries was estimated to improve from 3.5% to 28.6% (95% UI = 4.9%–60.1%). Adding improvements in quality of care to the scaling up of these elements could improve global 5-year net survival to 78.2% (95% UI = 74.9%–80.4%), with improvement in low-income countries going up to 55.3% (95% UI = 42.2%–67.8%).
Comprehensive scale-up of access to all treatment and imaging modalities and concurrent improvement in quality of care could improve global 5-year net survival to as high as 82.3% (95% UI = 79.3%–85.0%).
The investigators concluded, “Comprehensive scale-up of treatment and imaging modalities and improvements in quality of care could improve global 5-year net breast cancer survival by nearly 15 percentage points. Scale-up of traditional modalities and quality-of-care improvements could achieve 70% of these total potential gains, with substantial impact in low- and middle-income countries, providing a more feasible pathway to improving breast cancer survival in these settings even without the benefits of future investments in targeted therapy and advanced imaging.”
Zachary J. Ward, PhD, of the Center for Health Decision Science, Harvard T. H. Chan School of Public Health, is the corresponding author for The Lancet Oncology article.
Disclosure: The study was funded by Harvard T. H. Chan School of Public Health and a National Cancer Institute grant to Memorial Sloan Kettering Cancer Center. For full disclosures of the study authors, visit thelancet.com.
