Understanding the Epidemiology and Pathways to Care of Gastric Cancer in South Africa

Abstract

Introduction Globally gastric cancer (GC) is the 5th most common and deadliest cancer. In sub-Saharan Africa (SSA) GC is the 10th most common and 9th deadliest cancer. In South Africa (SA), GC is the 14th and 10th most common cancer in females and males respectively. The aim of this thesis is to understand the epidemiology of GC in SSA and SA from available published literature, to determine the incidence and mortality rates for GC in the SA adult population from South African data registries and to explore the SA GC care pathway via primary data collection from healthcare professionals’ (HCP) interviews. Methodology This explanatory mixed methods study comprises 3 research papers. Paper 1 is a systematic review (SR) on GC in SSA. Paper 2 is a cross-sectional study design using secondary data from cancer and death registries. Paper 3 is a qualitative study design using in-depth interviews. The study population for the paper 1 is primary SSA GC studies published between 1995 and 2022. In paper 2, data from the SA National Cancer Registry (NCR) from 2002 to 2020 were used for GC incidence rates and from Statistics South Africa (STATS-SA) from 2002 to 2018 for GC mortality rates. The study population for paper 3 comprises of 30 anonymised SA healthcare professionals (HCPs) that participated in a cancer care interview, across a variety of disciplines in the SA private and public healthcare sectors. Results The SR showed the overall crude pooled incidence was 1.20 GC cases per 100 000 (95%CI 1.15-1.26) people with 99.83% variability (I2 p<0.001). From the 29 high-quality population- based registry studies the crude pooled incidence was 1.71 GC cases per 100 000 people (95%CI 1.56-21.88) with 99.60% variability (I2 p<0.001). Paper 2 showed 22 391 GC cases and 20 212 GC deaths over the study period, with incidence increasing from the age of 40. Men had more than twice the GC ASIR than females at 0.39 and 0.15 GC cases per 100 000 people respectively in 2020. Men had more than twice the GC ASMR than females at 0.31 and 0.14 GC deaths per 100 000 people respectively in 2018. The average annual percentage change (AAPC) for ASIR (-0.8) and ASMR (-1.55) in the SA GC population was decreasing without statistical significance. Themes identified in paper 3 were referral and coordination processes in the GC care pathway, public versus private sector healthcare system differences, and the GC 14 care pathway challenges. The flow of GC care employs a multidisciplinary team (MDT) approach from diagnosis to treatment. Challenges include a low index of suspicion for GC by primary care clinicians (PCC) and Helicobacter pylori (H. pylori) detection. Conclusion This thesis demonstrated the high variability of GC incidence across SSA. Differential exposure to risk factors may explain the incidence and mortality differences observed among the SA population groups. There is a need for further primary data collection and exploration, and cancer care studies in SSA. Accurate estimation of the SA GC burden is crucial for public health policies and GC control measures. Thorough staging upon GC diagnosis provides a basis for a vigorous treatment plan, enhanced decision making on surgery and treatment administration. These steps will facilitate the effective flow of the GC care pathway and provide patients with a solid understanding of their disease and prognosis. An effective care pathway may assist in identifying a potential for cure or increased quality of life early in the patients’ treatment plan. A national consensus for a MDT GC care, emphasising early diagnosis to aid in a robust treatment plan for improved patient outcomes is warranted. This consensus will aid in public health strategies for a uniform and patient-specific approach for GC care in SA.