Organ Preservation in Locally Advanced Rectal Cancer

After pathology confirmed rectal cancer patients with stage II and III (MRI, CT and endoscopy) will be identified in the first visit to Medical Oncology Department. Patients will receive the most appropriate neoadjuvant treatment according to clinical guidelines.

Response to neoadjuvant treatment will be assessed by MRI. Those patients with a complete response in MRI, confirmed by endoscopy, will be offered a "watch and wait" strategy. Patients with a complete response in MRI, with an almost complete response in endoscopy, will be offered transanal endoscopic microsurgery. All patients with complete or near complete response will sign an informed consent before study entry.

Radical surgery will be performed in patients without complete or almost complete response criteria after neoadjuvant treatment.

Patients in organ preserving strategy will be subjected to a more intensive follow up schedule, including MRI and endoscopy, compared to patients with radical surgery.

As the complete histopathologic response rate after neoadjuvant treatment in locally advanced rectal cancer is approximately 15-20%, considering that approximately 40 patients with locally advanced rectal cancer are diagnosed annually in our setting, approximately 6-8 patients per year could be potentially recruited for this project, until reaching an initial sample of 30 patients for evaluation.

The following results will be analyzed:

• Percentage of complete and almost complete responses.
• Percentage of watch and wait and transanal endoscopic microsurgery.
• Disease free survival.
• Overall survival.
• Local relapse rate.
• Distant relapse rate.
• Treatment and outcomes of relapses.
• Colostomy free survival.
• Quality of life.

All data will be obtained from patient's medical records

Inclusion criteria

• Patients with confirmed histopathological diagnosis of rectal adenocarcinoma.
• Patients treated with neoadjuvant chemoradiotherapy or neoadjuvant radiotherapy associated or not with induction chemotherapy.
• Patients with evidence of complete or near complete response criteria after completion of neoadjuvant treatment (approximately 8 weeks later). Response criteria should be based on digital rectal examination, flexible rectoscopy and MRI.

Exclusion criteria

• Evidence of distant metastases.