INCIDENCE OF COLORECTAL CANCER AND ITS HISTOPATHOLOGY GRADING IN YOUNG AGE

Background: Colorectal cancer (CRC) is the third most common cancer worldwide and the second leading cause of cancer-related mortality. While traditionally considered a disease of older adults, recent evidence indicates a concerning rise in early-onset CRC (EOCRC), with nearly 30–40% of cases now diagnosed in individuals younger than 50 years. These patients often present with advanced-stage disease and aggressive histological features, highlighting the need for timely diagnosis and targeted preventive strategies. Objective: To determine the incidence of colorectal cancer and describe its histopathological grading in young patients presenting to a tertiary care hospital in Karachi. Methods: A prospective cross-sectional study was conducted at the Department of Pathology and Oncology, Jinnah Postgraduate Medical Centre (JPMC), Karachi, from March 2024 to March 2025. A total of 203 patients aged 18–49 years presenting with clinical suspicion of CRC, including rectal bleeding, altered bowel habits, abdominal pain, weight loss, anemia, or other gastrointestinal symptoms, were enrolled. Colonoscopy was performed for definitive diagnosis, and biopsy samples were obtained from abnormal lesions. Only histologically confirmed cases were considered true CRC. Data were recorded on a structured proforma and analyzed using SPSS version 25.0. Results: The mean age of patients was 34.20 ± 8.67 years; 138 (68%) were male and 65 (32%) female. The overall incidence of CRC was 36.95% (75/203). The rectum was the most frequent tumor site, affecting 29 cases (38.67%), followed by the ascending colon (16%) and rectosigmoid region (14.67%). Histopathology revealed adenocarcinoma as the predominant subtype, with poorly differentiated tumors comprising 30.7%, moderately differentiated 25.3%, and well-differentiated 13.3%. Multivariate analysis showed age ≤30 years (AOR = 14.77, p = 0.0005) and 31–40 years (AOR = 18.11, p = 0.0005) as strong predictors, while family history (AOR = 2.33, p = 0.044), smoking (AOR = 5.18, p = 0.0005), red meat consumption (AOR = 3.33, p = 0.0004), and diabetes mellitus (AOR = 3.61, p = 0.045) were significant risk factors. Daily exercise conferred a protective effect (AOR = 0.27, p = 0.0009). Conclusion: Colorectal cancer is increasingly affecting young adults, with a substantial proportion presenting with aggressive histopathological subtypes. Younger age, smoking, red meat consumption, family history, and diabetes mellitus significantly increase risk, whereas daily physical activity appears protective. These findings reinforce the urgent need for early screening, risk-based preventive strategies, and lifestyle interventions in younger populations.