The study evaluates the addition of Chinese Herbal Compound Dendrobium Huoshanense Granules to capecitabine and irinotecan in neoadjuvant chemoradiation(CRT) in locally advanced rectal cancer. Half of participants will receive CRT with Dendrobium Huoshanense Granules, while the others will receive CRT with placebo. We will evaluate whether Dendrobium Huoshanense Granules can enhance the immune function and alleviate symptoms caused by the tumor and CRT .

Inclusion Criteria:

• pathological confirmed rectum adenocarcinoma
• clinical stage T3-4 and/or N+
• the distance from anal verge less than 10 cm
• without distance metastases
• performance status score: 0~1
• UGT1A1*28 6/6 or 6/7
• without previous anti-cancer therapy
• able to follow the protocol during the study period
• sign the inform consent

Exclusion Criteria:

• Pregnant or breastfeeding women
• Those with other history of malignant disease in the past 5 years, except for cured skin cancer and cervical carcinoma in situ
• If there is an uncontrolled history of epilepsy, central nervous system disease or mental disorder, the investigator may determine that the clinical severity may hinder the signing of informed consent or affect the patient's oral medication compliance.
• Clinically severe (ie, active) heart disease, such as symptomatic coronary heart disease, New York Heart Association (NYHA) class II or more severe congestive heart failure or severe arrhythmia requiring medication intervention (see appendix 12), or a history of myocardial infarction in the last 12 months
• Organ transplantation requires immunosuppressive therapy
• Severe uncontrolled recurrent infections, or other serious uncontrolled concomitant diseases
• Subject blood routine and biochemical indicators do not meet the following criteria: hemoglobin ≥ 90g / L; absolute neutrophil count (ANC) ≥ 1.5 × 109 / L; Alanine transaminase (ALT), aspartate aminotransferase (AST) ≤ 2.5 times the upper limit of normal; alkaline phosphatase (ALP) ≤2.5 times the normal upper limit; serum total bilirubin <1.5 times the normal upper limit; serum creatinine <1 times the normal upper limit; serum albumin ≥ 30g / L
• Anyone who is allergic to any research medication
• DPD deficiency
• UGT1A1*28 7/7