Comparison of Clinicopathological Characteristics of Patients with Early and Late-onset Colorectal Adenocarcinoma: A Cross-sectional Study

Abstract

Introduction: Colorectal Cancer (CRC) has been primarily considered a disease of the elderly, but recent data have shown an alarming rise among young people. It has also been suggested that young age is associated with aggressive histopathological characteristics and advanced stages of the disease at diagnosis. Aim: To assess and compare the clinical and pathological characteristics of patients with rectal cancer diagnosed at ages over and below 45 years. Materials and Method: This prospective cross-sectional study was conducted between January 2020 and August 2022 in the Departments of Surgical, Medical, Radiation Oncology, Surgical Gastroenterology, and General Surgery at All India Institute of Medical Sciences (AIIMS) Rishikesh, Uttarakand, India. All patients underwent a biopsy from the representative site for histological documentation of the disease. They then underwent treatment (surgery/chemotherapy/radiotherapy) as required. All the data were categorised into two groups: an early-onset group (age <45 years) and a late-onset group (≥45 years). A comparison of the clinicopathological characteristics (age, gender, comorbidities, tumour subsite, clinical presentation, clinical stage, etc.), pathological data (grade and differentiation of tumour, as per World Health Organisation (WHO) grading system), and serum Carcinoembryonic Antigen (CEA) levels between the two groups was performed. The association between categorical variables was investigated using the Chi-square test. The mean difference was assessed using an independent t-test. A p-value of 0.05 or below was considered statistically significant. Results: A total of 51 patients with rectal cancer, 35 males and 16 females, were included in the study. The mean age was 44.73±16.47 years. Out of the total of 51 (100%) patients, lower rectum involvement was seen in 22 (43.1%) patients, followed by 7 (13.7%) patients each with ascending colon and sigmoid involvement resepectively. However, the Chi-square test showed no statistically significant association of location involved with age groups (χ2 =9.09; p=0.16). Out of 51 (100%) adenocarcinoma patients in total, three patients each under 45 years of age had signet cell adenocarcinoma and mucinous adenocarcinoma (χ2 =7.07; p=0.029). Among the total of 51 (100%) patients, moderately differentiated lesions were seen in 17 (33.3%) patients, poorly differentiated lesions were seen in 15 (29.4%) patients, and well-differentiated lesions were seen in 10 (19.6%) patients (χ2 =13.01; p=0.005). Conclusion: Younger patients tended to have larger tumours that were of a higher grade and had signet ring or mucinous histopathology. The social and clinical implications of these findings are to be explored.