講演情報
[JKS1-2]The Latest Preoperative Treatment for Locally Advanced Rectal Cancer and its Pros and Cons
Seung-Bum Ryoo (Seoul National University Hospital)

Neoadjuvant long-course chemoradiotherapy (CRT) followed by total mesorectal excision (TME) and adjuvant chemotherapy has been the standard treatment for locally advanced rectal cancer (LARC). This multimodal approach, established through landmark European and German trials, significantly reduced local recurrence and improved survival outcomes. However, despite local recurrence rates as low as 5-8% in modern practice, distant metastasis remains a major cause of treatment failure, with 10-year cumulative incidence approaching 30%. Adjuvant fluoropyrimidine-based chemotherapy failed to adequately prevent distant relapse, partly due to poor compliance and delayed initiation after CRT. To overcome these limitations, the concept of total neoadjuvant therapy (TNT) has emerged, aiming to deliver systemic chemotherapy earlier to eradicate micrometastases and increase pathologic complete response (pCR) rates. Recent randomized trials have demonstrated the benefits of TNT. The STELLAR and RAPIDO trials showed that short-course radiotherapy followed by CAPOX improved pCR and disease-related treatment failure compared with conventional CRT. The PRODIGE 23 trial using FOLFIRINOX followed by CRT significantly improved 3-year disease-free survival and doubled the pCR rate. These advances highlight TNT as a promising strategy for both oncological control and organ preservation. Nevertheless, the optimal regimen for standard-risk LARC remains unsettled. Key questions include the choice between short- and long-course radiotherapy, induction versus consolidation chemotherapy sequencing, and appropriate chemotherapy intensity. Ongoing randomized trials are expected to clarify these issues and establish a new standard of care.