The challenge of colorectal cancer (CRC) screening in low and middle-income countries (LMIC): The Brazilian ten year long experience.

Abstract

129 Background: The increasing incidence of CRC seen in LMIC and the high mortality rates compared to high-income countries points towards the difficult implementation of an effective screening strategy in LMIC. Brazil is one of the few Latin American countries and LMIC that have a population-based CRC screening program, targeting ages 50 to 74 and performing a fecal occult blood test (FT) every 2 years and colonoscopy/sigmoidoscopy as a confirmatory test. Methods: We performed a cross-sectional study, which evaluated the prevalence of every stage of CRC/carcinoma in situ (CIS) at the time of its diagnosis from 2013 to 2022. Similar data regarding the Brazilian breast and cervical cancer screening programs was obtained. Each stage was evaluated by age targeted by their respective screening program using the national database (DATASUS). Results: In the analyzed decade there was a total of 87507 CRC/CIS cases in the overall studied population, which only 11% was of Stage I or less and 70% was of stage III or IV at the time of diagnosis. In the subdivided age groups, the prevalence of each stage remained somewhat constant through all groups (In situ/Stage 0 = 8-9%; Stage I = 3%; Stage II = 20-21%; Stage III = 35-36%; Stage IV = 32-34%) and the majority of cases occurred from age 60 to 64 (20549 cases). In 2022, a total of 2128168 RT was performed - corresponding to only 4,6% of the targeted population - and 408489 colonoscopies. When compared to other cancer screening programs, CRC presents indifferent to age group, sustaining constant rate of regional/distant stages, with at least 32% of patients presenting a <17% 5-year survival rate (5-YSR), whereas cervical cancer presents approximately 80% of cases at >91% 5-YSR at the first age group, and breast cancer with 89% of cases at >86% 5-YSR at the first age group. Conclusions: Data suggests the inefficacy of CRC screening implementation, and literature sustains to be due to its poor acceptance by the population and the unavailability of confirmatory imaging tests due to long-waiting times and high cost, reducing its ability to detect early stage lesions, in contrast with the overall acceptance and high effectivity of cervical/breast cancer screening. The discrepancy between the guidelines and their implementation as a screening program in LMIC are in consonant. This study aims to be a launching point for new research and interventional studies evaluating the impact of better locally adjusted actions in the prevention of CRC such as screening invitations, in-community health education, and the developing of better cost-benefit confirmatory methods might hinder the advance of CRC in LMIC.[Table: see text]