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

Inclusion Criteria: 1. Middle rectum adenocarcinoma Tumor(T)x Node (N)+ or T3 /T4 N0 or N+ 2. Classification done on pelvic Magnetic Resonance Imaging (MRI) and rectal ultrasonography 3. Age ≥ 18 4. No contraindication to treatment with capecitabine 5. Able to receive radiotherapy 50 Grays in 5 weeks 6. No contraindication for surgery after chemoradiotherapy which will be 8 to 10 weeks after completion of chemoradiotherapy 7. Patient or legal representative provided with information and signature of informed consent Exclusion Criteria: 1. High rectum adenocarcinoma 2. Contraindication to rectal biopsy: including anti-coagulants or anti-platelet agents (vitamin K antagonists, clopidogrel, aspirin \> 160 grams) that cannot be interrupted 3. Pregnant woman or breastfeeding 4. Persons deprived of their liberty, or under guardianship 5. Impossibility of undergoing the trial's medical follow-up for geographical, social or psychological reasons. 6. Patient already included in another therapeutic trial with an experimental medication during the realization of protocol biopsies and surgery 7. Patient not covered by health insurance