Barium Enema in the detection of Colon Cancer Radiology Rotation Presentation Karen Joynt November 25, 2003

Case History Mr. J. is a 68 yo African-American male Presents for routine colon cancer screening, urged by his sister, whose husband recently passed away due to colon cancer Asymptomatic; no h/o GI bleed, no constipation, no diarrhea

Case History, continued PMHx: HTN, asthma in childhood, gout SocHx: lives with wife, retired engineer Allergies: NKDA Meds: Norvasc, aspirin Presents for routine screening, via barium enema

Barium Enema Bowel preparation the night before Three stages: filling with barium, gas insufflation, and radiography Smooth-muscle relaxant (20 mg of buscopan or 0.5–1 mg of glucagon) can be utilized to decrease cramping Requires considerable patient cooperation and mobility

Radiographic Findings: Normal

Radiographic Findings: Normal

Radiographic Findings: Polyp

Radiographic Findings: Polyp

Colon Polyps Most colorectal CA arises from adenomatous polyps; progression generally takes >10 years 2/3 of polyps are adenomas; prevalence of adenomas is 25% by age 50 and 50% by age 70 Hyperplastic polyps account for the remaining 1/3 and do not generally progress Current recommendations are that all adults over 50 should be screened for colon cancer Less than 40% of Americans for whom screening is indicated receive it

DCBE vs. the others DCBE detects half of adenomas larger than 1.0 cm and 39 percent of all polyps Abnormalities must be followed by colonoscopy False positives from retained stool, air, and other causes of mucosal irregularity Advantages: entire colon, relatively safe No studies evaluating effectiveness of DCBE in the prevention of CRC deaths (note: DCBE identifies lesions better than FOBT, which has been shown to lower CRC mortality)

DCBE vs. the others, continued Other screening options include FOBT yearly (cheap, but only 2% true-positive, doesn’t detect most polyps) Sigmoidoscopy every 5 years (more expensive, can see only half of the colon) Colonoscopy every 5-10 years (most expensive, most complications, but most sensitive and specific) No obvious winner in cost-effectiveness Final decision depends on patient preferences

References Grainger & Allison's Diagnostic Radiology: A Textbook of Medical Imaging, 4th Edition, 2001 UpToDate: uptodateonline.com, “Screening for colorectal cancer”