Inclusion Criteria:  Participant must provide written informed consent before any study-specific procedures or interventions are performed Participants aged >= 18 years  Pathologically-confirmed stage II or III primary adenocarcinoma of the rectum:  T3N0M0 - T4bN2M0  Exclusion Criteria:  Has radiologic evidence of distant metastases at the time of screening/enrollment Has received prior treatment for their rectal adenocarcinoma Requires or has received blood transfusion within 1 month of study enrollment