GEMCAD-REVEAL STUDY - Circulating Tumor DNA as a Predictor of Relapse in Patients With Locally Advanced Rectal Cancer.

The evaluation of the tumor response to chemoradiotherapy/total neoadjuvant therapy (CRT/TNT) remains a challenge. The integration of a blood-based biomarker such as ctDNA with clinico-radiological tools could offer the potential advantage of improving accuracy of assessment of tumor response to neoadjuvant therapy. Furthermore, data on functional outcomes and quality of life after total mesorectal excision (TME) and especially after " Watch And Wait" (WW) is scarce.REVEAL is a prospective, multicenter study in which the response to TNT in correlation with liquid biopsy (LB) of patients with rectal cancer in Spain will be evaluated. It is planned to include 120 patients. All patients will be aged 18 years or older, with histologically confirmed rectal adenocarcinoma, located in the mid or distal third (with the inferior margin within 12cm from the anal verge), clinically staged II and III (cT3-T4 and/or any TN+), scheduled to undergo TNT will be eligible. All cases and treatment decisions will be discussed by local Multidisciplinary Boards. Patients will be included consecutively when visiting the corresponding health centers for outpatient visits or hospitalization.The objective of the present study is to evaluate the role of ctDNA in the prediction of relapse in patients diagnosed with locally advanced rectal cancer (LARC) treated with TNT followed by WW or TME based on a clinical assessment of the local response

Inclusion Criteria:Legally capable patients ≥ 18 years of age.Histologically confirmed rectal adenocarcinoma.Any tumor located in the mid or distal rectum, clinically staged II-III (cT3/4 and/or any TN+).Willingness to be enrolled in the WW strategy if cCR or nCCR is achieved.Absence of metastases on imaging.Scheduled to undergo TNT followed by delayed surgery.Patients who have signed the informed consent for this study.Note: Decision was taken to treat the patient with a specific treatment prior and independently of patient inclusion in this non interventional study.Exclusion Criteria:Patients who do not meet inclusion criteria.Concomitant colorectal tumors.Intolerance or contraindication to planned TNT.Other concurrent malignant diseases. Pregnancy or breastfeeding.