Long-term recurrence patterns in rectal cancer after neoadjuvant therapy: Insights from 25-years of real-world data.

239 Background: The management of locally-advanced rectal cancer has significantly evolved over recent years with the adoption of total neoadjuvant therapy (TNT). However, a lot of uncertainty remains regarding the selection of the optimal TNT regimen for the individual patient. We aimed to assess recurrence patterns in rectal cancer to improve patient risk stratification and neoadjuvant treatment decision-making. Methods: We conducted a cohort study of 850 rectal cancer patients treated with neoadjuvant radio- and chemotherapy over a 25-year period at the Leuven University Hospitals. Results: After a median follow-up of 12 years, the 5-year overall survival (OS) and disease-free survival (DFS) were 86.8% and 75.5% respectively. Overall, 167 (19.6%) patients developed a recurrence of which 31 (3.6%) patients had a locoregional recurrence (LRR), while 158 (18.6%) patients developed distant metastases (DM), and 22 (2.6%) patients experienced both LRR and DM. At 5 years, recurrence-free survival (RFS) was 76.9% (95% CI: 74.1%-79.9%), distant metastasis-free survival (DMFS) was 77.8% (95% CI: 75.0%-80.7%) and locoregional recurrence-free survival (LRFS) was 85.1% (95% CI: 82.7%-87.7%). Independent predictors of distant recurrence included lymphovascular invasion (LVI) (p