Reply to “Interpreting projected gastrointestinal cancer burden in Africa: The case of liver cancer”

We appreciate Njei and Al-Ajlouni for their insightful comments regarding our article on global gastrointestinal cancer projections and for highlighting the critical distinction between age-standardized rates (ASRs) and the absolute burden of liver cancer in sub-Saharan Africa.1 We strongly concur that favorable trends in age-standardized incidence rates can paradoxically coexist with a rapidly expanding absolute disease burden. As reported in our study using the GLOBOCAN database, Africa is projected to experience the largest increases in both incidence and mortality for gastrointestinal cancers by 2050 among six World Health Organization regions.1 This divergence in comparison with decreasing ASRs is primarily driven by the region’s unique demographic transition—specifically its rapid population growth and aging population structure—which threatens to outpace gains in reducing age-specific risks.2 Njei and Al-Ajlouni correctly note that although vaccination efforts against hepatitis B and improvements in viral hepatitis treatment are reducing ASRs, these interventions alone are insufficient to curb the absolute rise in cases. Neonatal vaccination programs take decades for associated declines in hepatocellular carcinoma incidence to be observed among adult populations, and existing efforts are not on track to meet the World Health Organization’s 2030 elimination goals.3 Globally, only about 36 million of an estimated 257.5 million people living with chronic hepatitis B virus have been diagnosed, and just 6.8 million of the 83.3 million who are eligible for treatment are receiving it.4 Furthermore, as we noted in our discussion, the epidemiological landscape of liver cancer is shifting alongside economic development. The rising prevalence of steatotic liver disease in low- and middle-income countries, which is confirmed by another large-scale database, adds a growing layer of complexity to the existing burden of chronic liver disease and liver cancer.5 The implications for health policy are profound. We agree that resource allocation based solely on ASRs may lead to a dangerous underestimation of clinical needs. Primary prevention strategies must focus on hepatitis B vaccination and antiviral treatment, as these interventions significantly reduce the risk of liver cancer.6 In addition, public health initiatives should promote maintaining a healthy lifestyle through weight control and smoking cessation to mitigate risks associated with metabolic syndrome6. Health systems in sub-Saharan Africa also must prepare for demand for screening and diagnostic infrastructure, including abdominal ultrasound and cross-sectional imaging, as well as various treatment capacities involving hepatobiliary surgery, interventional radiology, medical/radiation oncology, and palliative care services. Establishing robust surveillance programs and centers of excellence is vital for early detection and improved treatment outcomes and for generating the high-quality data needed to drive advocacy and resource allocation.7 We appreciate the complementary analysis and insightful comments from Njei and Al-Ajlouni. Their observations reinforce our conclusion that region-specific strategies, which account for both demographic forces and evolving risk factors, are urgent and essential to mitigate the impending burden of gastrointestinal cancers, including liver cancer, in Africa. Ju Dong Yang consults for AstraZeneca, Eisai, Exact Sciences, and FujiFilm Medical Sciences. Amit G. Singal has served as a consultant or on advisory boards for Genentech, AstraZeneca, Eisai, Exelixis, Bayer, Elevar, Boston Scientific, Sirtex, FujiFilm Medical Sciences, Exact Sciences, Helio Genomics, Roche, Abbott, Glycotest, DELFI, ImCare, Universal Diagnostics, and Curve Biosciences. Michael B. Wallace declares the following conflicts of interest: consulting for Cosmo/Aries Pharmaceuticals, Verily, Boston Scientific, Endiatx, InterVenn, AlphaMed UAE, and FujiFilm Medical Sciences; research grants from FujiFilm Medical Sciences, Boston Scientific, Olympus, Medtronic, NinePoint Medical, and Cosmo/Aries Pharmaceuticals; stock/stock options in Virgo Inc; consulting on behalf of the Mayo Clinic for Boston Scientific and Microtek; and general payments/minor food and beverage from Boston Scientific and Cook Medical. The other author declares no conflicts of interest. Ju Dong Yang’s research is supported by the National Institutes of Health (K08CA259534). Amit G. Singal’s research effort is also supported in part by the National Institutes of Health (R01 CA256977).