The study is a multicenter, randomized controlled, phase III clinical study, and the purpose of the study is to explore the complete response rate (CR, Defined as pathological complete response (pCR) + Clinical complete response (cCR) sustained for over one year) of patients with locally advanced rectal cancer(LARC) treated with personalized long-course radiotherapy plus chemotherapy with or without Serplulimab. A total of 184 patients were included in this study.
Age: ≥18 years old; sex is not limited.
Patients with stage II/III rectal cancer staged under MRI or endoscopic ultrasonography and have at least one risk factor: cT4a and invasion of intestinal lumen for more than 1/2 week (measured by MRI)；cT4b(resectable)；cT3c-d with EMVI+ (upper middle rectum)；cN2；MRF+ (≤2mm)；lower rectal cancer is located on the anterior wall and tumor reaching T3 and occupying the intestinal cavity for more than 1/2 week; lower rectal cancer is mainly located on the lateral posterior wall need invading the intestinal wall (anal sphincter) ≥ 5mm； tumor of lower rectal cancer invades the external anal sphincter or levator ani muscle (stage 4) . [According to the 8th edition of the 2018 AJCC Cancer Staging Manual and the 2008 ESMO Lower Segment Colorectal Cancer Staging Criteria] . The preoperative T stage is referred to endoscopic ultrasonography or rectal MRI. The N stage is referred to abdominal CT. The M stage is referred to abdominal and thoracic CT. If symptoms occur, other appropriate imaging examinations are needed (cranial MRI or ECT) . Patients with contraindications to MRI can be interpreted with caution based on CT and endoluminal ultrasound staging. MDT should review the staging of all patients.
The lower edge of lesion is less than 10cm from anal verge according to rigid sigmoidoscopy or rectal digital examination.
No distant metastasis after a thorough examination .
Patients who have previously received pelvic radiotherapy.
Presence of active or progressive infection requiring systemic treatment, such as active tuberculosis, active hepatitis, etc.
Presence of systemic diseases that are not stably controlled by the investigator, including diabetes mellitus, hypertension, liver cirrhosis, rheumatic immune diseases, and severe lung diseases.
Have had prior or concurrent cancer distinct in primary site or histology (including synchronous colon cancer) , except for curatively treated cervical cancer in situ, Basal cell carcinoma of skin.