الفهرس 
Gross anatomy:
Risk factors:Only 14 pages are availabe for public view
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Abstract
Colorectal cancer is the second most common cancer in women and the third most common cancer in men. In recent years, mortality rates have decreased due to major changes in therapeutic management, in particular the standardization of the operative procedure and more important accurate pre operative strategy making depending on imaging ( Around 40 50% of colorectal cancers are l ocated in the rectum. Rectal cancer is defined as a tumor whose margin measured with the rigid rectoscope is 16 cm or less from the anocutaneous line (Rectal cancer staging has three crucial components: local staging, metastatic disease evaluation and investigation of other bowel segments for synchronous tumors (Preoperative imaging for rectal cancer staging is also useful to determine which surgical technique would be more appropriate. Ideal imaging modality should accurately assessthe depth of tu mor penetration (T), lymph node involvement (N), presence of distant metastatic disease (M), mesorectal fascia involvement, and anal sphincter involvement. Prognosis of rectal cancer is determined by depth of invasion, number of involved lymph nodes, and i nvolvement of circumferential resection margin .