Patients with early-onset rectal cancer aged 40 year or less have similar oncologic outcomes to older patients despite presenting in more advanced stage; A retrospective cohort study.

Background: Early-onset colon and rectal cancer has increased in alarming rates. The present study reviewed the characteristics and outcome of early-onset rectal cancer in patients aged ≤40 years.

Methods: This was a retrospective cohort study on rectal cancer patients who were treated in a tertiary center in the Middle East. Baseline characteristics and outcomes of patients ≤40 years were compared with patients >40 years. Main outcome measures were patients' and tumor characteristics, local recurrence, distance metastasis, overall survival (OS), and disease-free survival (DFS).

Results: Among 244 patients with rectal cancer, 81 (33.2%) aged 40 years or less. 56.8% of patients ≤40 years and 49.7% of patients >40 years presented with stage III/IV disease (p = 0.36). Local recurrence and distant metastasis were detected in 10.3% and 13.2% of patients ≤40 years and in 16.9% and 13.9% of patients >40 years (p = 0.29 and 0.88). The 3-year OS and DFS rates of patients ≤40 years were 75% and 80.9% versus 74.2% and 76.5% in patients >40 years (p = 0.9 and 0.59). Patients ≤40 years presented with ulcerative carcinoma (38.3% vs 21.5%, p = 0.01) and signet-ring carcinoma (12.3% vs 2.5%, p = 0.008) more than patients > 40 years.

Conclusion: Early-onset rectal cancer accounted for one-third of all patients presenting with rectal cancer. Patients younger than 40 years had higher incidence of mucinous and signet-ring rectal carcinoma, and presented more with advanced stage. The age of patients did not have a significant impact on the oncologic outcome of rectal cancer.