BACKGROUND & AIMS: Limited data exist regarding the actual risk of developing advanced adenomas and cancer after polypectomy or the factors that determine risk.
METHODS: We pooled individual data from 8 prospective studies comprising 9167 men and women aged 22 to 80 with previously resected colorectal adenomas to quantify their risk of developing subsequent advanced adenoma or cancer as well as identify factors associated with the development of advanced colorectal neoplasms during surveillance.
RESULTS: During a median follow-up period of 47.2 months, advanced colorectal neoplasia was diagnosed in 1082 (11.8%) of the patients, 58 of whom (0.6%) had invasive cancer. Risk of a metachronous advanced adenoma was higher among patients with 5 or more baseline adenomas (24.1%; standard error, 2.2) and those with an adenoma 20 mm in size or greater (19.3%; standard error, 1.5). Risk factor patterns were similar for advanced adenomas and invasive cancer. In multivariate analyses, older age (P < .0001 for trend) and male sex (odds ratio [OR], 1.40; 95% confidence interval [CI], 1.19-1.65) were associated significantly with an increased risk for metachronous advanced neoplasia, as were the number and size of prior adenomas (P < .0001 for trend), the presence of villous features (OR, 1.28; 95% CI, 1.07-1.52), and proximal location (OR, 1.68; 95% CI, 1.43-1.98). High-grade dysplasia was not associated independently with metachronous advanced neoplasia after adjustment for other adenoma characteristics.
CONCLUSIONS: Occurrence of advanced colorectal neoplasia is common after polypectomy. Factors that are associated most strongly with risk of advanced neoplasia are patient age and the number and size of prior adenomas.
BACKGROUND: Current guidelines stratify patients with a personal history of adenomas as low risk (ie, 1-2 small [<10 mm] adenomas at index colonoscopy) or high risk (> or =3 small adenomas or advanced adenoma at index colonoscopy) for recurrent advanced adenomas. Guidelines recommend longer intervals between surveillance colonoscopies for low-risk patients, but physicians frequently perform surveillance colonoscopy at shorter intervals for these patients. OBJECTIVE: Our purpose was to perform a meta-analysis about the incidence of advanced adenomas at 3-year surveillance colonoscopy among high- and low-risk patients. METHODS: Computer searches of MEDLINE, PREMEDLINE, and EMBASE were performed to identify appropriate studies. Study selection criteria were (1) study design--prospective or registry-based study, (2) study population--patients with a personal history of adenomas, and (3) intervention--completion of surveillance colonoscopy at an interval of > or =2 years. Data were extracted on (1) incidence of advanced adenomas at surveillance colonoscopy, (2) interval between colonoscopies, and (3) risk factors associated with recurrent adenomas. After the validity of study design was assessed and independent, duplicate data extraction was performed from selected trials, summary relative risks (RR) for the incidence of advanced adenomas at 3-year colonoscopy were calculated. RESULTS: Fifteen studies met study selection criteria, but only 5 studies stratified surveillance colonoscopy results according to findings at the index colonoscopy. Patients with > or =3 adenomas at index colonoscopy were more likely to have recurrent advanced adenomas than were patients with 1 to 2 adenomas: RR 2.52, 95% CI 1.07-5.97. Patients with adenomas with high-grade dysplasia at index colonoscopy were also at increased risk for recurrent advanced adenomas: RR 1.84, 95% CI 1.06-3.19. In the individual studies, increasing size of adenomas and increasing number of adenomas at index colonoscopy were the most commonly reported risk factors associated with recurrent advanced adenomas. No studies stratified surveillance colonoscopy results according to the definitions of low risk and high risk used in current guidelines. CONCLUSION: Few published studies stratify the incidence of advanced adenomas at surveillance colonoscopy according to index colonoscopy findings. In the future, large prospective studies or studies using pooled data from existing randomized controlled trial databases or polyp registries should be used to better define which patients are at low risk for advanced adenoma recurrence.
Limited data exist regarding the actual risk of developing advanced adenomas and cancer after polypectomy or the factors that determine risk.
METHODS:
We pooled individual data from 8 prospective studies comprising 9167 men and women aged 22 to 80 with previously resected colorectal adenomas to quantify their risk of developing subsequent advanced adenoma or cancer as well as identify factors associated with the development of advanced colorectal neoplasms during surveillance.
RESULTS:
During a median follow-up period of 47.2 months, advanced colorectal neoplasia was diagnosed in 1082 (11.8%) of the patients, 58 of whom (0.6%) had invasive cancer. Risk of a metachronous advanced adenoma was higher among patients with 5 or more baseline adenomas (24.1%; standard error, 2.2) and those with an adenoma 20 mm in size or greater (19.3%; standard error, 1.5). Risk factor patterns were similar for advanced adenomas and invasive cancer. In multivariate analyses, older age (P < .0001 for trend) and male sex (odds ratio [OR], 1.40; 95% confidence interval [CI], 1.19-1.65) were associated significantly with an increased risk for metachronous advanced neoplasia, as were the number and size of prior adenomas (P < .0001 for trend), the presence of villous features (OR, 1.28; 95% CI, 1.07-1.52), and proximal location (OR, 1.68; 95% CI, 1.43-1.98). High-grade dysplasia was not associated independently with metachronous advanced neoplasia after adjustment for other adenoma characteristics.
CONCLUSIONS:
Occurrence of advanced colorectal neoplasia is common after polypectomy. Factors that are associated most strongly with risk of advanced neoplasia are patient age and the number and size of prior adenomas.
