The aim of this clinical study is to increase the rate of pathological responses up to 70% by means of improved patient selection operated by a radiobiological index called ERI\_TCP and by an increase in the dose of radiotherapy in the final concomitant boost of preoperative radiochemotherapy treatment for rectal adenocarcinoma.
Histologically confirmed rectal adenocarcinoma
Microsatellite status: stable
Stage T2N0 if lower rectal lesions are candidates for subsequent intersphincteric resection or abdominoperineal amputation with permanent colostomy
Stage T3-T4N0 or any T with positive lymph nodes
Distant metastases
Previous cancer excluding non-melanoma skin cancer diagnosed less than 5 years before rectal cancer appearance
Previous chemotherapy or radiotherapy to the pelvis
Contraindications to radiotherapy: active ulcerative colitis