Rethinking colorectal cancer prevention in Tanzania: High malignancy rates in colorectal polyps and health-system gaps revealed through colonoscopy data

Abstract

Colorectal cancer (CRC) is an important public health concern in sub-Saharan Africa; however, screening programs in many low-resource settings remain limited. Findings from colonoscopy-detected colorectal polyps at Tanzania’s national hospital highlight important gaps and opportunities in CRC prevention and health system preparedness. A substantial proportion of polyps were malignant, suggesting a delayed presentation in some patients. Malignancy was associated with tobacco exposure; moreover, similar proportions of malignant polyps were observed above and below 50 years of age, supporting reconsideration of age thresholds and targeted screening of high-risk individuals. The predominance of rectosigmoid lesions and the association between larger polyps and malignancy raise the possibility that lower-cost screening strategies, including faecal immunochemical testing and selective flexible sigmoidoscopy, may offer pragmatic interim approaches in areas where colonoscopy capacity is expanding. In settings such as Tanzania, where CT imaging is widely available than endoscopy, CT colonography may also serve as a complementary approach for CRC screening in selected populations. These findings also highlight important documentation and pathology reporting gaps that may undermine surveillance efforts. Together, these observations underscore the need for context-specific phased CRC preventive strategies in Tanzania.