Question

An 85-year-old man with previously normal bowel function began to complain of constipation, rectal bleeding, and pencil-like stool. The results of a physical examination were negative.

Studies	Results
Routine laboratory studies	Normal, except for the following:
Hemoglobin (Hgb), p. 251	10 g/dL (normal: 12–13 g/dL)
Hematocrit (Hct), p. 248	29% (normal: 36%–42%)
Examination of stool for occult blood, p. 800	Positive (normal: negative)
Carcinoembryonic antigen (CEA) test, p. 129	33 ng/mL (normal: <2 ng/mL)
Sigmoidoscopy, p. 531	No tumor seen
Barium enema (BE) study, p. 936	Stricture in left side of colon
Colonoscopy, p. 531	Tumor in left side of colon; no other synchronous lesion found
Colonoscopic biopsy, p. 1040	Adenocarcinoma
Computed tomography (CT) scan of abdomen and liver, p. 962	Large tumor of the left colon; no evidence of liver metastasis

Diagnostic Analysis

The elevated CEA level and the occult (hidden) blood in the stool indicated serious colorectal disease. Because the sigmoidoscopy was normal, the disease was suspected to be beyond the reach of the 25-cm sigmoidoscope. The barium enema study demonstrated a narrowing in the left side of the colon, which could have been caused by infection, infestation, or neoplasm. Adenocarcinoma of the colon was diagnosed by means of a colonoscopic biopsy. Another alternative to colonoscopy for this patient would be virtual colonoscopy. CT scan failed to show any evidence of metastasis. The patient had surgery to resect the left side of his colon. Postoperatively, his CEA level was 1.8 ng/mL. On examination 3 years later, no evidence of disease was found. Five years after surgery, his CEA had risen to 38 ng/mL. He was found to have liver metastasis from his primary tumor in the colon. He died 18 months after that diagnosis.

Critical Thinking Question

1. How would you respond if one of the patient’s children asked if he should be routinely screened for cancer by checking CEA levels?
2. What are the different levels of the bowel seen with the various forms of intestinal endoscopy?
3. What are the benefits of endoscopic colonoscopy compared to virtual colonoscopy?

Answer 1

1 . CEA( Carcinoembryonic antigen) is a protein which is seen in developing fetus and after birth this protein disappears. However, the presence of this protein indicates tumor . It is a tumor marker and the elevated levels of CEA in blood above 2ng/ml indicates the presence of tumour.

CEA test used to diagnose tumor as well as to check the effectiveness of the therapy.

I would respond to the patient's children by saying that - Yes , CEA test is performed inorder to check if the tumor has recurred as intestinal tumor is malignant which can spread to other organs and initial diagnosis helps in effective treatment.

2 . a. EGD - Esophagogastroduodenoscopy ----- Here, the upper part of the small intestine, duodenum is visualized.

b. Enteroscopy ---- Here , all the parts of small intestine is visualized.

c. Colonoscopy : Here all the parts - duodenum, jejunum and ileum is viewed.

3 . Benefits of endoscopic colonoscopy over virtual colonoscopy:

In endoscopic colonoscopy, biopsy from the tumor suspected part can be taken which is not possible with virtual colonoscopy.  

Thank you.