Is a biopsy necessary for colon polyps suitable for polypectomy when performing a colonoscopy?

Area of Science:

• Gastroenterology
• Oncology
• Pathology

Background:

• Colorectal cancer incidence is rising in Taiwan.
• Adenomatous polyps are precancerous and require removal.
• Advanced endoscopic techniques for polyp identification are not widely accessible.

Purpose of the Study:

• Analyze the conventional biopsy method for diagnosing early colon cancer.
• Evaluate the necessity of surgery after polypectomy for adenomatous polyps.

Main Methods:

• Retrospective analysis of 1027 adenomatous polyp specimens from 720 patients (2002-2007).
• Focus on 26 specimens with early cancer or high-grade dysplasia.
• Classification of protruding polyps: pedunculated (o-Ip), subpedunculated (o-Isp), and sessile (o-Is).

Main Results:

• Of 26 high-risk specimens, 14 were o-Ip, 10 o-Isp, 2 o-Is.
• Pathology revealed high-grade dysplasia (n=5), mucosal adenocarcinoma (n=18), submucosal adenocarcinoma (n=3).
• Randomized biopsy in 7 patients had an 86% false negative rate for malignancy.

Conclusions:

• Randomized biopsy of adenomatous polyps has a high false negative rate for detecting early colon cancer and high-grade dysplasia.
• Direct polypectomy is sufficient for protruding polyps, potentially obviating the need for further surgery.
• Adequate polypectomy can achieve complete removal of protruding early colon cancer.