Colonic Polyps and Tumors
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Questions and Answers

What is the most common type of benign epithelial polyp in the colon?

  • Hyperplastic (correct)
  • Inflammatory
  • Hamartomatous
  • Adenomatous

    • What percentage of villous adenomas undergo malignant transformation?

  • 10%
  • 20%
  • 50%
  • 40% (correct)

    • What is the mode of inheritance of Familial Adenomatous Polyposis (FAP)?

  • Autosomal dominant (correct)
  • Autosomal recessive
  • Mitochondrial inheritance
  • X-linked recessive

    • What is the lifetime risk of developing colorectal cancer in FAP by age 50 years?

    <p>100%</p> Signup and view all the answers

    What is the name of the syndrome associated with FAP, which includes desmoid tumors and osteomas?

    <p>Gardner's syndrome</p> Signup and view all the answers

    What is the risk of colorectal cancer in patients with ulcerative colitis (UC) and Crohn's disease (CD) with pancolitis after 20 years?

    <p>8%</p> Signup and view all the answers

    What is the type of polyp associated with Peutz-Jeghers syndrome?

    <p>Hamartomatous</p> Signup and view all the answers

    What is a dietary factor that decreases the risk of colorectal cancer?

    <p>High vegetable fiber</p> Signup and view all the answers

    Approximately what percentage of colorectal cancer cases arise in patients with a known family history of CRC?

    <p>20%</p> Signup and view all the answers

    What is the typical location of tumors with poor prognosis and LOH pathway?

    <p>Left-sided tumors</p> Signup and view all the answers

    What is the primary treatment option for Curative treatment of Colorectal Cancer (CRC)?

    <p>Surgical Treatment</p> Signup and view all the answers

    What is the treatment for Caecal and ascending colon carcinoma?

    <p>Right Hemicolectomy (RHC)</p> Signup and view all the answers

    What is the most common symptom of colorectal cancer?

    <p>Change in bowel habits</p> Signup and view all the answers

    What is the treatment for Lower third cancer that is less than 2 cm above anal spincter?

    <p>Abdominoperineal Resection (APR)</p> Signup and view all the answers

    What is the significance of DRE in colorectal cancer?

    <p>Detects lower rectal mass or ulcer</p> Signup and view all the answers

    What is the definition of T1 in the TNM staging of CRC?

    <p>Tumor invades submucosa</p> Signup and view all the answers

    What is the treatment for Early cancer (CIS and malignant polyp with no deeper invasion)?

    <p>Local Excision or Polypectomy</p> Signup and view all the answers

    What is the investigation of choice for locating metastasis in Colorectal Cancer (CRC)?

    <p>PET Scan</p> Signup and view all the answers

    What is the 5-year survival rate for Stage I colorectal cancer?

    <p>90-100%</p> Signup and view all the answers

    What is the purpose of full colonoscopy in colorectal cancer?

    <p>To detect all of the above</p> Signup and view all the answers

    What is the target therapy used in Colorectal Cancer (CRC)?

    <p>All of the above</p> Signup and view all the answers

    What is the percentage of metachronous tumors detected by full colonoscopy?

    <p>10-40%</p> Signup and view all the answers

    What is the investigation used for obstructing tumours in Colorectal Cancer (CRC)?

    <p>Water-soluble contrast study</p> Signup and view all the answers

    What is the treatment for Locally advanced cancer or recurrent cancer?

    <p>Pelvic Exenteration</p> Signup and view all the answers

    Study Notes

    Colonic Tumors

    • There are five types of benign epithelial polyps:
      • Hyperplastic (regenerative) polyps
      • Adenomatous polyps
      • Hamartomatous polyps
      • Inflammatory polyps
      • Heterotopic polyps

    Familial Adenomatous Polyposis (FAP)

    • Autosomal dominant condition
    • Accounts for about 1% of all colorectal cancer (CRC) cases
    • Causes hundreds to thousands of adenomatous polyps
    • Lifetime risk approaches 100% by age 50 years
    • Associated with extraintestinal manifestations such as desmoid tumors, osteomas, and CNS tumors

    Colorectal Carcinoma (CRC)

    • Adenoma-carcinoma sequence
    • Risk factors:
      • Dietary factors (high animal fat, low fiber)
      • Aging
      • Sedentary lifestyle and obesity
      • Inflammatory bowel disease (IBD)
      • Cigarette smoking
      • Ureterosigmoidostomy
      • Acromegaly
      • Pelvic irradiation

    Genetics of CRC

    • Approximately 20% of CRC cases have a known family history
    • Oncogenes involved: K-ras, MYH
    • Tumor-suppressor genes involved: APC, DCC, p53, PTEN
    • Two major pathways: LOH pathway (left-sided tumors, poor prognosis) and Replication Error (RER) pathway (right-sided tumors, better prognosis)

    Clinical Presentation of CRC

    • Change in bowel habits
    • Rectal bleeding
    • Abdominal pain
    • Iron deficiency anemia
    • Unexplained weight loss
    • Perianal pain
    • Mucoid discharge
    • Tenesmus

    Examination of CRC

    • Digital rectal examination (DRE)
    • Abdominal examination (liver, ascites)
    • Rarely: Sister Joseph or Verchow's node

    TNM Staging of CRC

    • Tumor stage (T): Tis (carcinoma in situ), T1 (invades submucosa), T2 (invades muscularis propria), T3 (invades nonperitonealized or perirectal tissues), T4 (invades other organs or perforates)
    • Nodal stage (N): N0 (no lymph node metastasis), N1 (metastasis to 1-3 LNs), N2 (metastasis to >3 LNs), N3 (metastasis to any LN along a major named vascular trunk)
    • Distant metastasis (M): M0 (no distant metastasis), M1 (distant metastasis present)

    Modified Dukes' Classification

    • Stage I: Tumor limited to bowel wall (5-year survival rate 90-100%)
    • Stage II: Tumor extends beyond bowel wall (5-year survival rate 70%)
    • Stage III: Any T stage with lymph node metastasis (5-year survival rate 30%)
    • Stage IV: Distant metastases (5-year survival rate 10%)

    Investigations of CRC

    • Full colonoscopy
    • Endoscopic ultrasound (EUS)
    • Chest/abdominal/pelvic CT scan
    • MRI
    • Water-soluble contrast study (obstructing tumors)
    • PET scan
    • Preoperative CEA

    Treatment of CRC

    • Surgical treatment:
      • Open surgery
      • Laparoscopic surgery
      • Hand-assisted laparoscopic surgery
      • Totally laparoscopic surgery
    • Laparoscopic colectomy
    • Adjuvant therapy:
      • Systemic chemotherapy
      • Chemoradiation
      • Intraoperative radiation therapy (usually brachytherapy)
      • Target therapy (bevacizumab, erlotinib, cetuximab)

    Prevention and Screening of CRC

    • Early detection and removal of adenomatous polyps
    • Screening programs for high-risk individuals
    • Lifestyle modifications (diet, exercise, smoking cessation)

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    Description

    Learn about the different types of benign epithelial polyps, including hyperplastic, adenomatous, hamartomatous, inflammatory, and heterotopic polyps, as well as malignant transformation and polyp types.

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