The purpose of this study is to determine whether adding deep hyperthermia to neoadjuvant concurrent radiochemotherapy could improve T-downstaging rate for locally advanced rectal cancer (LARC).

The purpose of this study is to determine whether adding deep hyperthermia to neoadjuvant concurrent radiochemotherapy could improve T-downstaging rate for locally advanced rectal cancer (LARC). The sample size is 142. Patients with LARC (T3-4/N+) will be randomly divided into intervention group and control group. For intervention group, the neoadjuvant therapy is hyperthermia combined with concurrent radiochemotherapy. For control group, the neoadjuvant treatment is concurrent radiochemotherapy. T-downstaging rate will be used to evaluate the effectiveness of deep hyperthermia. T-downstaging is defined as the postoperative pathological T stage lower than the original T stage by imaging before treatment.

Inclusion Criteria:

• ≥18 years old
• Pathologically diagnosed as rectal adenocarcinoma
• Locally advanced rectal cancer (T3-4/N+) staging by CT, MRI and/or endoscopy
• Males with fertility and females of childbearing age must take effective contraceptive measures at least since signing informed consent until 180 days after the end of concurrent radiotherapy and chemotherapy. Childbearing age means pre-menopausal or within 2 years after menopause. Women of childbearing age must exclude pregnancy before concurrent radiotherapy and chemotherapy
• Patients with normal organ function prior to treatment, the following criteria are met:a) blood routine examination criteria : i) hemoglobin (HB) ≥90g/L; ii) absolute neutrophil count (ANC) ≥1.5×10e9/L; iii) platelet (PLT) ≥70×10e9/L; b) biochemical tests meet the following criteria: i) serum creatinine (Cr) ≤1.5 times of upper limit of normal (ULN) or creatinine clearance (CCr) ≥40ml/min; ii) total bilirubin (TBIL) ≤1.5 ULN; alanine aminotransferase (ALT) and aspartate aminotransferase (AST) ≤2.5 ULN, e）Coagulation test: International Normalized Ratio (INR)≤ 1.5 × ULN, Prothrombin Time ≤ 1.5 × ULN

Exclusion Criteria:

• Patients with signet ring cell carcinoma or mucinous adenocarcinoma.
• Patients who refuse to undergo hyperthermia or cannot cooperate with continuous follow-up.
• Patients with severe bleeding tendency, severe infection, wounds or infections on the skin of the hyperthermia area.
• Patients who have metal implants or pacemakers in their bodies who cannot tolerate excessively high temperatures.
• Other primary malignant tumors occurred within 5 years before concurrent radiotherapy and chemotherapy, except for malignant tumors that have undergone radical treatment and are locally curable (such as basal or squamous cell skin cancer, superficial bladder cancer or prostate, cervical or breast carcinoma in situ, etc.).
• Suffer from uncontrollable comorbid diseases, including but not limited to symptomatic congestive heart failure, uncontrollable hypertension, unstable angina, arrhythmia, active peptic ulcer or bleeding disease.
• Patients with a history of alcohol or drug abuse.
• Patients who do not agree to participate in this study or unable to complete the informed consent process.