From the Guidelines
A positive fecal occult blood test (FOBT) requires prompt follow-up with a colonoscopy to identify the source of bleeding, as recommended by the American Cancer Society and the US Multi-Society Task Force on Colorectal Cancer 1. This approach is based on the highest quality evidence available, which emphasizes the importance of colonoscopy in diagnosing the cause of bleeding in patients with a positive FOBT. The colonoscopy allows for direct visualization of the colon and rectum to detect polyps, cancer, or other causes of bleeding. While waiting for the colonoscopy, it is advisable to avoid taking aspirin, NSAIDs, and blood thinners if medically feasible, as these can increase bleeding 1. No specific medication is recommended before determining the cause of the bleeding. Maintaining adequate hydration and reporting any worsening symptoms like visible blood in stool, abdominal pain, or dizziness to the doctor immediately is crucial. The colonoscopy preparation typically involves dietary restrictions (clear liquids only) for 24 hours before the procedure and taking a bowel preparation solution (such as polyethylene glycol) to clean the colon. A positive occult blood test indicates microscopic amounts of blood in the stool, which can result from various conditions ranging from benign causes like hemorrhoids to more serious conditions like colorectal cancer, hence the importance of thorough investigation rather than empiric treatment 1.
Some key points to consider in the management of a positive FOBT include:
- The importance of prompt follow-up with colonoscopy to minimize the risk of missing a significant lesion
- The need to avoid medications that can increase bleeding risk before the colonoscopy
- The importance of adequate hydration and monitoring for worsening symptoms
- The role of colonoscopy in diagnosing the cause of bleeding and guiding further management. Given the potential for a positive FOBT to indicate a serious underlying condition like colorectal cancer, colonoscopy is the recommended next step in management, as supported by the guidelines from the American Cancer Society and the US Multi-Society Task Force on Colorectal Cancer 1.
From the Research
Treatment for a Positive Fecal Occult Blood Test (FOBT)
The treatment for a positive FOBT typically involves further diagnostic testing to determine the source of the bleeding. According to 2, the initial work-up for occult bleeding usually involves colonoscopy or esophagogastroduodenoscopy, or both.
- Key diagnostic tests include:
- Colonoscopy: considered the "gold standard" technique for evaluating the colon 3
- Esophagogastroduodenoscopy (EGD): used to examine the upper gastrointestinal tract 4
- Capsule endoscopy: a newer technique for noninvasive small bowel imaging 2, 4
- Small bowel endoscopy: difficult to perform but has a higher diagnostic yield 2
Treatment Options
Once the source of the bleeding is identified, treatment options may include:
- Endoscopic ablation of the bleeding site with thermal energy, if the site is accessible 2
- Angiographic embolization: used to treat lesions that cannot be reached endoscopically 2
- Medical treatment: usually with combined hormone therapy, but has limited utility 2
- Surgical treatment: often fails or is not feasible due to multiple bleeding sites 2
Follow-up Care
After a positive FOBT, follow-up care is crucial to ensure that the bleeding source is treated and to prevent future complications. According to 5, when a fecal occult blood test is positive, colonoscopy is recommended as the definitive method of diagnosis and often of treatment.
- Key follow-up care steps include:
- Colonoscopy: to examine the entire colon and rule out cancer or advanced neoplasia 5, 3
- Sigmoidoscopy with air-contrast barium enema: an alternative for direct visualization of the distal bowel and indirect investigation of the proximal colon 5
- Repeat testing: may be necessary to detect missed lesions or to monitor for recurrent bleeding 4