Biomarkers in Patients With Rectal Cancer Undergoing Chemotherapy and Radiation Therapy

Capecitabine administration (where deemed appropriate by the treating medical oncologist) will commence on the second day of radiotherapy after the 24-hour biopsy has been performed. Dosing will be per current standard of care at the discretion of the treating Medical, Radiation and Surgical Oncologist

Administration of 5-fluorouracil (where deemed appropriate by the treating medical oncologist) will commence on the second day of radiotherapy after the 24-hour biopsy has been performed. Dosing and dose modification will be per current standard of care at the discretion of the treating Medical, Radiation and Surgical Oncologist.

Surgery will occur approximately 2-6 weeks after chemoradiation depending on clinical factors (i.e. resectability, presence or absence of metastatic disease).

Dosing and dose modification will be per current standard of care at the discretion of the treating Radiation Oncologist.