Total Neoadjuvant Treatment

This study hypothesizes that approximately 50% of rectal cancer patients can preserve their rectum using a watch-and-wait strategy if they achieve a complete or near-complete clinical response to total neoadjuvant therapy (TNT). The objective is to determine whether the complications, quality of life, and survival rates of rectal cancer patients who have achieved a complete or near-complete clinical response to TNT, followed by a watch-and-wait approach, are comparable to those of patients who undergo surgery first. Additionally, the study aims to identify potential prognostic and predictive markers for rectal cancer and examine survival rates and factors influencing responses to chemoradiotherapy (CRT) or TNT. The study is divided into two parts: \*\*Part One:\*\* Participants with cT1N1, T2-T3 N0-1 rectal cancer, MRF-, and EMVI-, with surgery as one of the possible first-line treatment options, will be randomized into two groups. The experimental group will consist of participants receiving TNT, including CRT and consolidation chemotherapy (Ch). If these participants achieve a complete or near-complete clinical response, they will be observed using a watch-and-wait strategy, which is a non-operative approach. The control group will consist of participants who undergo surgical treatment initially. \*\*Part Two:\*\* All participants with rectal cancer who have received CRT or TNT will be included. Additionally, participants diagnosed with rectal cancer who are scheduled for CRT or TNT but declined to participate in Part One or do not meet the inclusion criteria will also be included.

Safety and Efficacy of Organ Preservation Treatment for Stage I Rectal Cancer: Optimization of Consolidation Chemotherapy Before Local Excision After Neoadjuvant Chemoradiotherapy (OPTION); A Multi-center, Prospective, Randomized Trial The goal of this clinical trial is to find out if adding consolidation chemotherapy with capecitabine after total neoadjuvant chemoradiotherapy (TNT) works to improve oncologic outcomes in patients with stage I rectal cancer. It will also comparethe safety of adding consolidation chemotherapy before local excision. The main questions it aims to answer are: * Does adding consolidation chemotherapy increase the rate of pathologic complete response? * What medical problems or side effects do participants have during and after treatment? Researchers will compare TNT followed by local excision to TNT followed by consolidation chemotherapy with capecitabine and then local excision to see if adding consolidation chemotherapy improves tumor response and treatment outcomes. Participants will: * Receive TNT for stage I rectal cancer * Be randomly assigned to one of two treatment groups * Undergo local excision after preoperative treatment * Visit the clinic for checkups and tests to evaluate tumor response, side effects, recurrence, survival, quality of life, bowel function, urinary function, sexual function, circulating tumor DNA, and treatment-related costs

Effective systemic therapy such as nivolumab as an adjuvant therapy has been demonstrated to improve the outcomes of patients receiving neoadjuvant chemoradiotherapy (CRT) for locoregional esophageal cancer. A more effective systemic therapy with anti-PD-1 or anti-PD-L1 immune checkpoint inhibitors (ICIs) plus cisplatin-based doublet chemotherapy, which has shown with high tumor response rate and improved survivals in patients with late-stage ESCC, may provide crucial benefit to patients with locally advanced disease by improving the systemic control, downstaging the locoregional tumor burden and reducing recurrence and metastasis. Collectively, the investigators hypothesize that total neoadjuvant therapy (TNT) approach-consisting of induction immunochemotherapy followed by CRT-is a promising strategy to enhance the outcomes for participants with locally advanced esophageal squamous cell carcinoma.

This study aims to evaluate the efficacy and safety of short-course radiotherapy combined with CAPOX plus bevacizumab with or without a PD-1 inhibitor in patients with locally advanced rectal cancer (LARC). The hypothesis is that the addition of immunotherapy (PD-1 inhibitor) can significantly improve the complete response (CR) rate and enhance local control while reducing the incidence of distant metastasis. This study will compare the effects of sequential chemoradiotherapy and targeted therapy with or without immunotherapy following short-course radiotherapy, aiming to explore the optimal regimen for total neoadjuvant therapy.

Previously, preliminary results, from a subgroup analysis of STARS-RC03 (NCT04906044) conducted by our research team, showed that the 6-cycles consolidation chemotherapy combining with anti-PD-1 therapy had a better tumor regression advantage with a restricted safety profile contrasted with 3-cycle counterparts. Herein, we designed this study to further evaluate the short-term efficacy (such as pCR rate, R0 resection rate, etc.) and long-term survival (including DFS, OS, etc.) of 6-cycles consolidation therapy.