Colorectal Carcinoma (CRC)

  • Risk factors for development of CRC:
  • Age:
  • – 90% CRC develop > 50 years age
  • – Peak age: 7th decade
  • Adenomatous Polyp:
  • Macroscopic lesion made up of dysplastic epithelium
  • – Histological type: Tubular, Villous, Tubulovillous
  • – Risk factor for adenoma to carcinoma is related to polyp size and histologic characteristics:
  •          • Large and villous polyps are more prone to CRC
  • – Evolution of colon cancer may take as long as decade and as much as 5 years for progression  from adenoma to invasive carcinoma
  • – Adenomas often occur in anatomic proximity to colon cancer (Sentinel polyp) and cancer risk is proportional to the number of adenomas present synchronously
  • Family History:
  • Sporadic Cancer
  • – FAP
  • – HNPCC
  • – Other Hereditary Syndromes:
  •            • Peutz –jeghers syndrome
  •            • Juvenile Polyposis Syndrome
  •            • Torre’s Syndrome (Muir-toir Syndrome)
  •            • Turcoat’s Syndrome
  •                                              
  •                              IBD:
  •                                                
  •    UC
  • – In general population (without UC) dysplasia occur in polyps
  • – In UC dysplasia often occur in flat mucosa
  • – Risk factor of CRC increase 7-10 years after initial diagnosis
  • – Risk of cancer is highest when dysplasia arise in visible plaque or masses (DALM)
  • – Dysplasia in UC
  •            • High Grade: significant risk of synchronous CRC or subsequent Cancer development
  •            •Low Grade
  • – If high dysplasia is present or dysplasia occurs in a macroscopic lesion (DALM), total colectomy is advised
  •     CD
  • – Crohn’s Disease or ileocolitis patients have 4- 20 times increased risk of CRC in comparison to general population
  • Distribution of CRC:
  •  
  •   – Ascending Colon: 25%
  •   – Transverse Colon: 15%
  •   – Descending Colon: 5%
  •   – Sigmoid Colon: 25%
  •   – Rectum: 20%
  •   – Rectosigmoid: 10%
  •                      
  •                             Categories of risk for developing CRC:

 

  •                      Gross Appearance of CRC
  • – Polypoid : Large, bulky   Ca cecum, ascending Colon
  • – Annular Constricting (Napkin ring): Distal Colon, Rectum
  • – Flat Cancer: Spreads intramurally in the setting of IBD
  • – Ulceration, Necrosis: Features

 

  •             Colonoscopic View of a Colon Carcinoma
  •                             
  •                       Histologic Appearance:
  •       – Following histologic appearance have poor prognosis:
  •                       •Poorly differentiated cancer
  •                      • Colloid and Signet ring cell carcinoma

 

  •                      RECTAL CARCINOMA:
    Definition: Cancer that is located within 12 cm of the anal verge
    Treatment Options of Rectal Carcinoma:
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