Small and diminutive polyps detected at screening CT colonography: a decision analysis for referral to colonoscopy.
OBJECTIVE
The objective of this study was to assess the clinical and economic impact of colonoscopic referral for small and diminutive polyps detected at CT colonography (CTC) screening.


METHODS
A decision analysis model was constructed incorporating the expected polyp distribution, advanced adenoma prevalence, colorectal cancer (CRC) risk, CTC performance, and costs related to CRC screening and treatment. The model conservatively assumed that CRC risk was independent of advanced adenoma size. The number of diminutive (< or = 5 mm), small (6-9 mm), and large (> or = 10 mm) CTC-detected polyps needed to be removed to detect one advanced adenoma or prevent one CRC over a 10-year time horizon was calculated. The cost-effectiveness of polypectomy was also assessed.


RESULTS
The estimated 10-year CRC risk for unresected diminutive, small, and large polyps was 0.08%, 0.7%, and 15.7%, respectively. The number of diminutive, small, and large polyps needed to be removed to avoid leaving behind one advanced adenoma was 562, 71, and 2.5, respectively; similarly, 2,352, 297, and 10.7 polypectomies would be needed, respectively, to prevent one CRC over 10 years. The incremental cost-effectiveness ratio of removing all diminutive and small CTC-detected polyps was $464,407 and $59,015 per life-year gained, respectively. Polypectomy for large CTC-detected polyps yielded a cost-saving of $151 per person screened.


CONCLUSIONS
For diminutive polyps detected at CTC screening, the very low likelihood of advanced neoplasia and the high costs associated with polypectomy argue against colonoscopic referral, whereas removal of large CTC-detected polyps is highly effective. The yield of colonoscopic referral for small polyps is relatively low, suggesting that CTC surveillance may be a reasonable management option.
Pickhardt
Perry J
PJ
Department of Radiology, University of Wisconsin Medical School, E3/311 Clinical Science Center, 600 Highland Ave., Madison, WI 53792-3252, USA.
Hassan
Cesare
C
Laghi
Andrea
A
Zullo
Angelo
A
Kim
David H
DH
Iafrate
Franco
F
Morini
Sergio
S
D000236:Adenoma / Q000175:diagnosis / Q000453:epidemiology / Q000601:surgery; D000368:Aged; D003110:Colonic Neoplasms / Q000175:diagnosis / Q000453:epidemiology / Q000601:surgery; D003111:Colonic Polyps / Q000145:classification / Q000175:diagnosis* / Q000453:epidemiology / Q000601:surgery; D023881:Colonography, Computed Tomographic; D003113:Colonoscopy / Q000191:economics*; D015897:Comorbidity; D003362:Cost-Benefit Analysis; D003661:Decision Support Techniques; D003663:Decision Trees; D003937:Diagnosis, Differential; D017048:Health Care Costs; D006801:Humans; D008017:Life Expectancy; D008403:Mass Screening / Q000191:economics*; D008875:Middle Aged; D009010:Monte Carlo Method; D015995:Prevalence; D012017:Referral and Consultation / Q000191:economics*; D018570:Risk Assessment; D012680:Sensitivity and Specificity