Local Tumor Regrowth after Nonoperative Management Following Neoadjuvant Therapy for Rectal Cancer

Abstract Nonoperative management (NOM) is increasingly being adopted as a treatment strategy for rectal cancer, offering the possibility of organ preservation and avoidance of surgical morbidity for patients who achieve an excellent response to neoadjuvant therapy. However, the risk of local tumor regrowth remains a critical concern and raises questions about its impact on oncologic outcomes. Emerging data suggest that local regrowth may be associated with an increased risk of distant metastasis, highlighting the importance of timely detection and intervention. Although salvage surgery is generally feasible and effective, the technical challenges it presents and the potential implications for surgical quality necessitate careful consideration. Clinical factors such as tumor stage and treatment response may help identify patients at higher risk of regrowth, but predictive biomarkers and molecular profiling remain underexplored. As NOM continues to evolve, further studies are needed to clarify the oncologic safety, refine patient selection criteria, and develop optimal surveillance strategies to maximize the benefits while minimizing risks. This review summarizes current evidence on local tumor regrowth in the context of NOM and discusses the clinical implications of local regrowth and future directions for NOM.