Diagnostic Work-Up of Small Bowel Adenocarcinoma

  • The differential diagnosis of a small bowel mass:
    • Is extensive
  • Focal small bowel wall thickening can be present in:
    • Bowel ischemia
    • Inflammation:
      • Inflammatory bowel disease
    • Infection
    • Radiation enteritis
    • In addition to small bowel neoplasms
  • Many of these conditions can be confirmed or excluded by:
    • The history and physical examination
    • Imaging characteristics
    • Further studies:
      • Endoscopy
  • True small bowel masses can:
    • Be either malignant or benign:
      • Malignant lesions include:
        • Adenocarcinoma (36.9% of the cases)
        • Carcinoid tumor (37.4% of the cases)
        • Gastrointestinal stromal tumor (8.4% of the cases)
        • Lymphoma (17.3% of the cases)
        • Metastatic disease
  • The most common benign small bowel masses include:
    • Adenomas
    • Leiomyomas
    • Lipomas
  • More rare benign small bowel masses include:
    • Fibromas
    • Desmoids
    • Hemangiomas
    • Hamartomas
    • Schwannomas
  • Patients who present with:
    • Obstruction, bleeding, or perforation from a small bowel mass:
      • Typically require exploration and resection:
        • Regardless of the etiology of the mass:
          • Unless they are medically unfit for surgery
  • Patients who are asymptomatic or present with mild symptoms from a small bowel mass:
    • Should be worked up further with:
      • Tumor markers
      • Endoscopic evaluation:
        • For biopsy and tattoo if the lesion is endoscopically accessible:
          • If the lesion is not endoscopically accessible:
            • Then surgical resection:
              • May be necessary for definitive diagnosis and treatment

Laboratory Test (Tumor Markers)

  • Carcinoembryonic antigen (CEA):
    • Is not sensitive or specific:
      • For small bowel adenocarcinoma:
        • But is elevated in 30% to 44% of those with:
          • Advanced local or metastatic disease
  • CA 19-9:
    • Is also elevated in 30 % to 40% of those with:
      • Advanced local or metastatic disease
  • These markers (CEA and CA 19-9) are best used:
    • To raise suspicion:
      • In patients being worked up for small bowel adenocarcinoma
    • For surveillance:
      • In those in whom it is elevated before treatment
    • Given the high false negative rate:
      • They should not be used to rule out adenocarcinoma

Imaging Work-Up

  • Imaging is critical to differentiate a malignant etiology of nonspecific gastrointestinal symptoms from other causes:
    • Nausea
    • Vomiting
    • Obstipation
    • Bleeding
  • Upper Gastrointestinal Series / Small Bowel Follow-through:
    • An upper gastrointestinal series with small bowel follow-through has a relatively low sensitivity in the detection of small bowel tumors (< 60%):
      • It is most commonly obtained in patients with a small bowel obstruction:
        • To help ascertain the presence and location of a complete small bowel obstruction and may reveal:
          • Intussusception
          • Mucosal defect
          • Tumor / mass:
            • Which should prompt further (cross-sectional) imaging
  • Computed Tomography Scan:
    • CT is useful to identify:
      • Small bowel masses
      • Nodal disease
      • Distant metastases
      • Alternative etiologies of abdominal symptoms
    • Its sensitivity in detection of primary small bowel adenocarcinomas is:
      • Approximately 80%
    • CT appearance of small bowel adenocarcinoma includes:
      • Demonstration of a discrete mass
      • Focal mural thickening
      • Small bowel obstruction
      • Intussusception without a clear associated mass
Small Bowel Adenocarcinoma – Small bowel cancer with dilated proximal loop of small bowel.
  • PET can be useful to:
    • Identify occult metastatic disease
    • Increase the suspicion of malignancy:
      • In nonspecific small bowel abnormalities on CT
  • Enterography:
    • Advanced cross-sectional imaging techniques, including:
      • CT and magnetic resonance enterography:
        • Can be more accurate than other imaging to confirm or exclude small bowel cancers:
          • However, they are not universally available and have not been well studied in this population
  • Endoscopy:
    • Endoscopic diagnosis of small bowel adenocarcinoma:
      • Is often definitive:
        • But is limited by the location of the tumor:
          • Which must reside in an endoscopically accessible location
      • Because adenocarcinomas are mucosal tumors:
        • They can often be visualized endoscopically:
          • Assuming they can be reached
      • Endoscopy also allows biopsy to be performed and can tattoo a lesion that may not be visible externally during bowel resection
      • Standard upper endoscopy is most useful if the suspected small bowel tumor is in the:
        • Duodenum or proximal jejunum.
  • Enteroscopy:
    • Enteroscopy refers to upper endoscopy beyond the range of standard endoscopy:
      • Into the proximal jejunum
    • Techniques employed to advance the endoscope include:
      • Push
      • Balloon
      • Intraoperative assistance
    • Advantages over standard endoscopy include:
      • Increased range:
        • 50 cm to 150 cm distal to the ligament of Treitz
          • Occasionally:
            • The entire small bowel can be visualized using:
              • Anterograde and retrograde (transanal) approaches
    • Disadvantages include:
      • Technical difficulty with a requisite learning curve
      • iIncreased rates of:
        • Pancreatitis
        • Perforation:
          • Over standard endoscopy
  • Wireless video capsule endoscopy:
    • Wireless video capsule endoscopy is typically used to:
      • Identify the source of occult gastrointestinal bleeding:
        • But is infrequently used to visualize small bowel masses
      • It has a high false negative rate (19%):
        • In identifying small bowel masses:
          • As well as a 2% false positive rate
    • Wireless capsule endoscopy:
      • Also has no biopsy capability
      • Can become lodged in nearly obstructing or obstructed segments of bowel

#Arrangoiz #Surgeon #CancerSurgeon #SurgicalOncologist #Teacher #SmallBowelCancer

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