Nonoperative Management in Patients With Early-Onset Rectal Adenocarcinoma: A Retrospective Cohort Study

BACKGROUND: The incidence of rectal adenocarcinoma is rising in patients < 50 years old compared to those > 50. Nonoperative management and active surveillance have become a standard of care in rectal cancer treatment for those who achieve a complete response to neoadjuvant therapy; however, the use, safety and efficacy of this approach in different age groups has not been well described. OBJECTIVE: Examine oncological outcomes in patients with rectal adenocarcinoma managed by nonoperative management according to patient age. DESIGN: Retrospective cohort study. SETTING: Comprehensive cancer center in New York. PATIENTS: Patients with rectal adenocarcinoma diagnosed between January 2006 and December 2020. MAIN OUTCOME MEASURES: Local regrowth, recurrence-free survival, distant metastasis-free survival, overall survival rates. RESULTS: A cohort of 430 patients with rectal adenocarcinoma who were treated with neoadjuvant therapy and entered watch-and-wait were included. Patients were divided into 3 groups according to age at diagnosis: early-onset (age < 50, n = 98), middle-aged (50-64, n = 163), and late-onset (65+, n = 169). No differences were noted in tumor distance from the anal verge (p = 0.345) between groups. More patients in the early-onset cohort received induction chemotherapy with chemoradiation than late-onset patients, who more often received chemoradiation alone and had clinical stage I disease (p = 0.015). Median follow-up time was 4.0years (IQR 2.6-5.5). The 3-year local regrowth rates in each group were 23.8% (95% CI: 15.2-32.4), 33.0% (95% CI: 25.6-40.4), and 26.1% (95% CI: 19.4-32.8) in the early, middle-aged, and late-onset patients, respectively (p = 0.395). No associated differences in 5-year distant metastasis-free or recurrence-free survival rates were noted between the 3 age groups. The early-onset cohort had an associated superior disease-specific survival from the late-onset cohort. LIMITATIONS: Retrospective nature. CONCLUSIONS: Early-onset rectal cancer patients have at least similar oncological outcomes compared to those in older age groups when treated non-operatively. These data provide reassurance when offering a watch-and-wait approach to patients with early-onset rectal cancer. See Video Abstract.