Clinicopathological features of colorectal cancer in adolescents and young adults (AYA) at a tertiary referral centre in Nigeria.

3629 Background: Colorectal cancer (CRC) is traditionally considered a disease of older adults; however, its incidence among AYA has been rising globally. In sub-Saharan Africa, including Nigeria, there is limited data on the clinicopathological characteristics of CRC in this age group. Understanding the patterns of CRC in AYA in Nigeria is crucial for developing targeted screening, early detection, and treatment strategies in this population. This study aims to investigate the clinicopathological features of CRC in AYA at a tertiary referral centre in Nigeria. Methods: A retrospective review of the ARGO-OAUTHC database was conducted to identify adolescents and young adults (age less than 40) diagnosed with colorectal cancer between 2013 and 2024. We compared AYA patients with middle-aged adults (ages 40-65) to assess differences in clinical presentation and histopathological features. Only patients with complete histopathology were included in the analysis while patients older than 65 years were excluded. Descriptive statistics were used to summarize the data, and statistical tests were performed to assess significant differences between the two groups. Results: 866 patients diagnosed with CRC were identified. Of these, 150 (18%) were AYA, with a median age of 33 years, and 448 (54%) were middle-aged adults (ages 40-65). The presenting symptoms were similar between the AYA and middle-aged groups, however, AYA patients were less likely to be diagnosed by colonoscopy (14.9% vs 29.4%, p = 0.002). Additionally, more AYA patients presented with symptoms that did not limit their daily activities , leading to a delay in seeking medical attention (9.3% vs 2.8%, p = 0.016). AYA patients were less likely to present with early-stage disease (Stages I and II) compared to middle-aged patients, (13.1% vs 20.9%, p = 0.045). Histopathological features were similar between the two groups overall, though mucin production was more prevalent in AYA patients (64.1% vs 45.2%, p = 0.044). Lung metastasis was less common in AYA patients (8.3% vs 23.5%, p = 0.011), the pattern of metastasis to other organs was however similar between the two groups. Conclusions: AYA patients in Nigeria tend to present at more advanced stages, partly due to the non-restrictive nature of their symptoms. They were less likely to be diagnosed via colonoscopy and were more likely to exhibit mucin production in their tumors. These findings underscore the need for increased awareness and early screening efforts for colorectal cancer in AYA populations to facilitate earlier diagnosis.