Systematic review with meta‐analysis: the incidence of advanced neoplasia after polypectomy in patients with and without low‐risk adenomas

• Published in: Alimentary pharmacology & therapeutics Vol. 39; no. 9; pp. 905 - 912
• Main Authors: Hassan, C., Gimeno‐García, A., Kalager, M., Spada, C., Zullo, A., Costamagna, G., Senore, C., Rex, D. K., Quintero, E.
• Format: Journal Article
• Language: English
• Published: Oxford Blackwell 01-05-2014
• Subjects: Adenoma - diagnosis; Adenoma - pathology; Adenoma - surgery; Biological and medical sciences; Colonic Polyps - diagnosis; Colonic Polyps - pathology; Colonic Polyps - surgery; Colonoscopy; Colorectal Neoplasms - diagnosis; Colorectal Neoplasms - epidemiology; Colorectal Neoplasms - pathology; Humans; Incidence; Medical sciences; Multiple tumors. Solid tumors. Tumors in childhood (general aspects); Risk; Time Factors; Tumors; Human; Systematic review; Adenoma; Review; Malignant tumor; Epidemiology; Low risk; Incidence; Metaanalysis; Advanced stage; Benign neoplasm; Cancer; Polyp
• ISSN: 0269-2813; 1365-2036
• DOI: 10.1111/apt.12682

Summary
Background
Patients with one to two tubular adenomas <1 cm in size without high‐grade dysplasia (low‐risk group) are considered at low risk for colorectal cancer. However, it is uncertain whether they have the same risk of subsequent advanced neoplasia as those with no neoplasia at baseline colonoscopy.
Aim
To compare incidence of metachronous advanced neoplasia between patients in the low‐risk adenoma group and those without neoplasia at index colonoscopy.
Methods
Relevant publications were identified by MEDLINE/EMBASE and other databases for the period 1992–2013. Studies comparing the incidence of post‐polypectomy advanced neoplasia (adenomas ≥10 mm/high‐grade dysplasia/villous or cancer) between the low‐risk group and patients without colorectal neoplasia at the first colonoscopy were included. Detection rates for advanced neoplasia at endoscopic surveillance were extracted. Study quality was ascertained according to Newcastle–Ottawa Scale. Forest plot was produced based on random‐effect models. Inter‐study heterogeneity was assessed using the I2 statistic.
Results
Seven studies provided data on 11 387 patients. Mean surveillance periods ranged between 2 and 5 years. Altogether, 267 patients with post‐polypectomy advanced neoplasia were detected in the two groups. The incidence of advanced neoplasia was 1.6% (119/7308) in those without neoplasia and 3.6% (148/4079) in those with low‐risk adenoma, respectively, corresponding to a relative risk of 1.8 (95% CI: 1.3–2.6). Inter‐study heterogeneity was only moderate (I2: 37%). No publication bias was present.
Conclusions
Patients with low‐risk adenomas at baseline had a higher risk of metachronous advanced neoplasia than the group with no adenomas at baseline, though the absolute risk was low in both groups.