P258 Early-onset colorectal cancer: clinical presentation, tumour characteristics and survival

IntroductionEarly-onset colorectal cancer (EOCRC) as defined by patients diagnosed at age 50 years and younger represent a distinctive group which present with different clinicopathological features and tumour biology compared to classical/late-onset CRC (LOCRC). While there has been a decline in the incidence of late-onset CRC due to improved detection and screening, there has been a surge of EOCRC often presenting with advanced disease at diagnosis and with largely unknown pathogenesis. We thus aimed to describe the clinical presentation, tumour characteristics and survival of EOCRC compared to LOCRC.MethodsWe retrospectively analysed all patients diagnosed with colorectal cancer from 2019 to 2022 at a single centre. EOCRC were defined as patients diagnosed with CRC at age 50 years and younger, while LOCRC included patients diagnosed at >50 years. Data collection included patient demographics, clinical information, as well as a detailed biochemical, radiological and histological review. Statistical analyses were performed using SPSS and p450x109/L) (24% vs 11%, p=0.038*) and tumour budding (12% vs 3%, p=0.006*) were significantly higher in the EOCRC group. There were no differences in the histological subtype, TNM staging and mutational profiling in each group. 28 (82%) vs 191 (70%) in the EOCRC and LOCRC group respectively remained alive over a median follow-up of 16 months, with no differences in survival between the groups (figure 1).ConclusionEOCRC represents an important and challenging subtype of CRC, which presents differently from classical LOCRC. The incidence of EOCRC is 11%, which is in keeping with published reports. Haematochezia was the most common presentation, while thrombocytosis and tumour budding were higher in the EOCRC group, suggesting a more advanced phenotype at diagnosis. However, the overall survival was similar in both groups. Prospective res