Ideas in this flowchart

• Radiation has precise roles in rectal and advanced colorectal cancer.
• Radiation acts most precisely on rectal cancer.
• Preoperative radiation is delivered before surgery.
• It shrinks the tumor before surgery.
• It reduces the risk of local recurrence in the pelvic region.
• When disease progresses beyond curative intent.
• Radiation manages what surgery and systemic therapy cannot reach.
• The symptoms include bleeding, obstruction, and localized pain.
• These symptoms arise in tissue already claimed by advanced colorectal cancer.