SCRT in TNT With or Without Chlorophyllin

Inclusion Criteria: * Age \> 18 years. * Histologically confirmed diagnosis of adenocarcinoma of the rectum. * Clinical Stage II/III (T2-3, 4b: adherent to prostate, SV or post vagina but not grossly invading, N0-2) based on MRI. * Non-circumferential tumours with craniocaudal length \<7 cm * The tumours of the lower rectum, or starting up to 7 cm from the anal verge. * No evidence of distant metastases on CT Chest and Abdomen. * No prior pelvic radiation therapy * No prior chemotherapy or surgery for rectal cancer * Eastern Cooperative Oncology Group (ECOG) Performance status 0-2 * Patients must read, agree to, and sign a statement of Informed Consent prior to participation in this study. * Eligible to receive one of the options of standard neoadjuvant chemotherapy as determined by the medical oncologist team. * Absolute neutrophil count (ANC) \> 1.5 cells/mm3, hemoglobin (HGB) \> 8.0 gm/dl, platelet (PLT) \> 150,000/mm3. * Total bilirubin ≤ 1.5 x ULN (except in patients with Gilbert's Syndrome who must have total bilirubin ≤ 3.0 x ULN), aspartate aminotransferase (AST) ≤ 3 x ULN, alanine transaminase (ALT) ≤ 3 x ULN. Exclusion Criteria: * Signet or mucinous histology cancer of rectum * Recurrent rectal cancer or previous pelvic radiotherapy * Primary unresectable rectal cancer. * Creatinine level greater than 1.5 times the upper limit of normal. * Patients who are unable to undergo an MRI. * Patients with a history of any arterial thrombotic event within the past 6 months. This includes angina (stable or unstable), MI, TIA, or CVA. * Ulcerative colitis or any other histologically confirmed inflammatory bowel disease. * Patients with a history of venous thrombotic episodes such as deep venous thrombosis, and pulmonary embolism occurring more than 6 months prior to enrollment may be considered for protocol participation, provided they are on stable doses of anticoagulant therapy. Similarly, patients who are anticoagulated for a trial fibrillation or other conditions may participate, provided they are on stable doses of anticoagulant therapy. * Patients with any other concurrent medical or psychiatric condition or disease which, in the investigator's judgment, would make them inappropriate candidates for entry into this study. * Poor reliability for follow up. * Ineligible as per eligibility criteria