Fibroblast Before and After Neoadjuvant Chemo-radiotherapy in Patient With Locally Advanced Rectal Adenocarcinoma

Patients included in the trial will have new biopsy performed before starting the Radiation Therapy and Chemotherapy (RT-CT). These biopsies will study the activity of fibroblasts in the tumor and away in the healthy rectal tissue. Within 8 to 10 weeks after the end of RT-CT, patients will have cancer surgery by proctectomy (with complete removal of the meso-rectum). On the resection specimen, new samples will be taken at the level of the tumor and away from the rectum.This study is single center interventional exploratory .

Inclusion criteria

• Middle rectum adenocarcinoma Tumor(T)x Node (N)+ or T3 /T4 N0 or N+
• Classification done on pelvic Magnetic Resonance Imaging (MRI) and rectal ultrasonography
• Age ≥ 18
• No contraindication to treatment with capecitabine
• Able to receive radiotherapy 50 Grays in 5 weeks
• No contraindication for surgery after chemoradiotherapy which will be 8 to 10 weeks after completion of chemoradiotherapy
• Patient or legal representative provided with information and signature of informed consent

Exclusion criteria

• High rectum adenocarcinoma
• Contraindication to rectal biopsy: including anti-coagulants or anti-platelet agents (vitamin K antagonists, clopidogrel, aspirin > 160 grams) that cannot be interrupted
• Pregnant woman or breastfeeding
• Persons deprived of their liberty, or under guardianship
• Impossibility of undergoing the trial's medical follow-up for geographical, social or psychological reasons.
• Patient already included in another therapeutic trial with an experimental medication during the realization of protocol biopsies and surgery
• Patient not covered by health insurance