Rectal Cancer, Adenocarcinoma

This prospective, single-center, single-arm phase II study will evaluate the efficacy, safety, and technical feasibility of an organ-preserving radiotherapy strategy for patients with localized rectal adenocarcinoma who are medically inoperable, decline radical surgery, or are considered technically unresectable without distant metastases. Participants will receive pelvic external beam radiotherapy followed by high-dose-rate (HDR) endorectal brachytherapy. Concurrent capecitabine may be given during external beam radiotherapy to participants who are considered able to tolerate chemotherapy. During HDR brachytherapy, all participants will be treated using a patient-specific 3D-printed guide template and individualized tungsten-alloy local shielding. The guide template is designed to improve applicator positioning and treatment reproducibility, while the local shielding is intended to reduce radiation exposure to non-target rectal wall. The study will enroll 50 participants. The primary objectives are to evaluate the 12-month clinical complete response rate and the technical completion rate of the HDR brachytherapy platform. Secondary assessments include organ preservation, local regrowth, survival outcomes, treatment-related toxicity, quality of life, and anorectal function.

This is a single-center, exploratory clinical study for patients with newly diagnosed, high-risk, locally advanced rectal cancer. The study aims to evaluate the effectiveness and safety of a comprehensive pre-surgery (neoadjuvant) treatment strategy. All participants will receive a short course of radiation therapy (25 Gy in 5 fractions) over one week. This will be followed by a combination of chemotherapy (Liposomal Irinotecan, Oxaliplatin, and Capecitabine) and immunotherapy (Sintilimab). This combined treatment is administered for six cycles. For patients who achieve a complete response, the option to avoid immediate surgery and enter a close monitoring program ("Watch and Wait") will be considered.

This prospective, single-center, randomized controlled trial aims to assessing the efficacy and safety of neoadjuvant chemoradiation plus Tislelizumab (PD-1 inhibitor) with or without Probio-M9 and subsequent TME surgery, by comparing assorted endpoints between two experiment groups (Experiment group 1: chemoradiation+PD-1 inhibitor+Probio-M9; Experiment group 2: chemoradiation+PD-1 inhibitor+placebo) with a control group (chemoradiation only).

The aim of this study is to evaluate the activity of first-line trastuzumab-deruxtecan, capecitabine and bevacizumab in terms of overall response rate for patients with HER-2 positive metastatic/locally advanced unresectable colorectal cancer

The goal of this clinical trial is to test a new combination treatment for locally advanced rectal cancer (cancer in the lower or middle part of the rectum that has not spread to distant organs). The study aims to increase the chance of making the tumor disappear completely (called "complete response") and improve the quality of life by increasing the rate of anal sphincter preservation (avoiding permanent colostomy bags). The main questions it aims to answer are: Does the combination of short-course radiation therapy, two types of immunotherapy drugs (Qibeian and Aike), and chemotherapy (XELOX) increase the complete response rate to over 50%? Is this combination treatment safe, and what are the side effects? Can this treatment help more patients keep their anal function and avoid permanent stomas? This is a single-arm study, meaning all participants will receive the experimental treatment (there is no placebo or control group). Participants will: Receive short-course radiation therapy (25 Gy total, given once daily for 5 consecutive days). The radiation will target only the tumor and visible lymph nodes, intentionally avoiding unaffected lymph node areas to protect the immune system. Receive Qibei'an (a dual immunotherapy drug targeting both PD-1 and CTLA-4) once, 2 days after completing radiation. Receive Camrelizumab (a PD-1 immunotherapy drug) three times, combined with XELOX chemotherapy. Receive XELOX chemotherapy (Oxaliplatin ivgtt on Day 1, plus Capecitabine pills taken twice daily for 14 days, for each cycle) for up to 3 cycles. Undergo detailed assessments after treatment, including MRI scans, colonoscopy with biopsies, and blood tests (including ctDNA tests), to determine if the tumor has disappeared or if surgery is needed. Attend regular follow-up visits for up to 5 years after treatment (or surgery) to monitor for recurrence and assess quality of life. The study will enroll approximately 19 patients at Beijing Friendship Hospital, Capital Medical University. An independent safety monitoring board will regularly review the data to ensure participant safety.

Colorectal cancer is the second most common malignancy worldwide and one-third of these tumors are located in the rectum. The treatment may involve up to three modalities: radiotherapy, chemotherapy, and surgery. For several years, thanks mainly to Brazilian researchers, subgroups of patients have been selected for non-surgical treatment when chemoradiotherapy induces a complete clinical response. These treatment regimens have reached a plateau leading researchers to seek strategies that can increase response rates. Intestinal microbiota studies have shown that an overpopulation of certain anaerobic bacteria is generally associated with poorer treatment response. No study has attempted to intervene in the gut microbiota to increase the complete response rate in rectal cancer. The proposal of the investigators aims to modulate the intestinal microbiota through a phase 2 clinical trial, with the use of metronidazole as the intervention .