Table 1.
Screening test characteristics and costs used in the analyses*
| Test characteristics |
Test costs by perspective, $ | ||||||||
| Sensitivity† for adenomas by size and for CRC, % | Specificity, % | Source | |||||||
| Analysis/screening test | 1–5 mm | 6–9 mm | ≥10 mm | CRC | CMS‡ | Modified societal§ | Source | ||
| Base-case analysis | |||||||||
| Hemoccult II | 2 | 5 | 12 | 40 | 98 | (30) | 5 | 22 | (30) |
| Hemoccult SENSA | 7 | 12 | 24 | 70 | 93 | (30) | 5 | 22 | (30) |
| Immunochemical FOBT | 5 | 10 | 22 | 70 | 95 | (30) | 22 | 39 | (30) |
| Sigmoidoscopy without biopsy║ | 75 | 85 | 95 | 95 | 92¶ | Assumption | 161 | 270 | (30) |
| Sigmoidoscopy with biopsy║ | 75 | 85 | 95 | 95 | 100 | Assumption | 348 | 497 | (30) |
| Colonoscopy without polypectomy | 75 | 85 | 95 | 95 | 90¶ | (31) | 498# | 795# | (30) |
| Colonoscopy with polypectomy | 75 | 85 | 95 | 95 | 90¶ | (31) | 649# | 979# | (30) |
| CT colonography DoD | — | 84** | 92 | 92†† | 80‡‡ | (3) | 488 | 644 | Assumption |
| CT colonography NCTC | — | 57** | 84 | 84†† | 88‡‡ | (5) | 488 | 644 | Assumption |
| Sensitivity analysis | |||||||||
| CT colonography DoD | — | — | 92 | 92†† | 96‡‡ | (3) | 488 | 644 | Assumption |
| CT colonography NCTC | — | — | 84 | 84†† | 86‡‡ | (5) | 488 | 644 | Assumption |
— = Sensitivity is not provided because adenoma size is smaller than the referral threshold for a colonoscopy of 6 mm (base-case analysis) or 10 mm (sensitivity analysis); CMS = Centers for Medicare and Medicaid Services; CRC = colorectal cancer; CT = computed tomographic; DoD = Department of Defense study; FOBT = fecal occult blood test; NCTC = National CT Colonography Trial.
Sensitivity is provided per individual for FOBTs and per lesion for endoscopy and CT colonography.
Costs reflect 2007 CMS payment rates and do not include beneficiary copayments or patient time costs.
Costs reflect 2007 CMS payment rates, beneficiary copayments, and patient time costs.
Test characteristics for sigmoidoscopy apply only to lesions in the distal colon and rectum.
The lack of specificity with endoscopic tests reflects the detection of nonadenomatous lesions. With sigmoidoscopy, the presence of nonadenomatous lesions induces biopsy costs (in the case of sigmoidoscopy with biopsy) or results in referral for colonoscopy (in the case of sigmoidoscopy without biopsy). With colonoscopy, nonadenomatous lesions are removed and therefore induce polypectomy and biopsy costs.
The cost of colonoscopy includes the cost of sedation, assuming that it is not delivered by an anesthesiologist. Higher colonoscopy cost estimates were explored in a sensitivity analysis.
Sensitivity for CT colonography for adenomas 6–9 mm in size was calculated from published tables (3,5).
Sensitivity for colorectal cancer was assumed to be the same as for adenomas ≥10 mm because of the small number of colorectal cancers detected in the DoD and NCTC studies.
The lack of specificity with CT colonography reflects the detection of nonadenomatous polyps, artifacts, and adenomas smaller than the colonoscopy referral threshold (ie, adenomas <6 mm for the base-case analysis and adenomas <10 mm for the sensitivity analysis).