Preoperative Sequential Short-course Radiation Therapy and FOLFOX for Locally Advanced Rectal Cancer

The treatment protocol proposed in this study is to perform short-term radiation therapy and 4 cycles of FOLFOX chemotherapy for neoadjuvant treatment of locally advanced rectal cancer. Compared to conventional chemoradiation therapy, the preoperative radiotherapy period is shortened, and the cure rate of rectal cancer patients can be improved by early treatment of micrometastasis using systemic chemotherapy. The patients who are assigned to the study group will received the short-course radiotherapy and 4 cycles of FOLFOX and patients in the control will received conventional chemoradiotherapy for preoperative treatment. All patients are recommended to receive total mesorectal excision (TME) after neoadjuvant treatment and adjuvant chemotherapy will be given according to the pathological stage.


Eligibility Criteria:
Inclusion Criteria:

* Asian
* ECOG (Eastern Cooperative Oncology Group) performance status 0-2
* Pathologically confirmed rectal cancer (rectal cancer located 10 cm or low from the anal verge in pelvis MRI)
* Histologic type: adenocarcinoma, mucinous carcinoma, and signet ring cell carcinoma
* Locally advanced rectal cancer with one or more of the following factors based on pelvis MRI: cTanyN1-2, cT3-4N0, or presence of extramural vascular invasion
* MRI findings such as pelvic lymph node metastasis, anal sphincter invasion, and T4b are not included in the exclusion criteria, which cases will be enrolled by the researcher's discretion
* Patients with appropriate organ (bone marrow, kidney, liver) function
* A person who understands the study and willing to provide informed consent

Exclusion Criteria: (one of the following criteria)

* Colon cancer or rectal cancer located more than 10 cm from the anal verge
* Stage I rectal cancer (clinical stage cT1-2N0)
* Clinically or pathologically diagnosed distant metastasis (cTanyNanyM1)
* Familial adenomatous polyposis
* Hereditary nonpolyposis colorectal cancer
* History of chemotherapy or radiotherapy within 6 months
* History of colorectal cancer or other type of malignancy within 5 years (except for cured nonmelanoma skin or in situ cervical cancer)
* Comorbidities that make it difficult to undergo chemotherapy or radiotherapy
* Bone marrow suppression with neutrophil count \<2 ×109/L or platelet count \<100 ×109/L prior to the first chemotherapy
* Peripheral sensory neuropathy with functional impairment (grade 2 or higher)
* Severe renal dysfunction (GFR ≤30ml/min by Wright or Cockroft formula)
* Severe hepatic dysfunction
* Genetic problems such as galactose intolerance, Lapp lactase deficiency or glucose-galactose malabsorption
* Taking tegafur, gimeracil, and oteracil potassium complex and those within 7 days of discontinuation
* Taking sorivudine or brivudine
* Significant heart disease or myocardial infarction within the last 6 months
* Hereditary diseases or history of coagulopathy
* Central nervous system disorders with disability or mental disorders
* Pregnant or lactating women
* Currently participating in other clinical trials or receiving research medication
* Unhealed wounds, fractures, peptic ulcer, abscesses in the abdominal cavity
* Active gastrointestinal bleeding
* Active infections requiring antibiotics for injection
* Emergency Surgery
* History of hypersensitivity to the drugs in study protocol
* Patients with non-malignant tumor diseases
* Dihydropyrimidine dehydrogenase deficiency
* Not willing to participate