American Statistical Association
New York City
Metropolitan Area Chapter

Memorial Sloan-Kettering Cancer Center
Biostatistics Seminar

Ann G. Zauber, Ph.D.
Associate Attending Biostatistician
Department of Epidemiology and Biostatistics
Memorial Sloan-Kettering Cancer Center


Authors: Ann G. Zauber, Amy B. Knudsen, Carolyn M. Rutter, Iris Lansdorp-Vogelaar, James E Savarino, Marjolein van Ballegooijen, Karen M. Kuntz

Background: The Center for Medicare and Medicaid Services (CMS) requested a National Coverage Determination (NCD) for computed tomography colonography (CTC) for colorectal cancer (CRC) screening in the average-risk Medicare-eligible population. Three CRC microsimulation models from the NCI Cancer Intervention and Surveillance Modeling Network (CISNET) independently performed a cost-effectiveness analysis of CTC compared to other recommended CRC screening tests, and in particular to optical colonoscopy (COL) to inform the NCD for the US average risk 65-year-old population from the CMS payer point of view.

Methods: The screening strategies considered were annual fecal occult blood testing (FOBT), flexible sigmoidoscopy (FS) every 5 years with and without annual FOBT, COL every 10 years, and CTC every 5 years with referral of patients with at least one lesion 6 mm or larger to COL (base case). CTC test parameters were based on the Department of Defense (DoD) and National CTC (NCTC) studies. Costs were based on CMS reimbursement.

Results: Base-Case Analysis: Life-years gained (LYG) per 1000 screened for the base-case CTC strategies were within 2-7 LYG for DoD and 9-13 LYG for NCTC of that for COL screening . However at a cost per test of $488 (current CMS reimbursement for a CT of the abdomen and pelvis, plus image processing), CTC is not cost-effective compared to the other strategies. If the CMS reimbursement per test were $108 to $205 (22-41% of COL cost), CTC would be cost-effective. If the cost per test were $179 to $237 (36-47% of COL cost), CTC would provide LYG at the same cost per year as the COL strategy.

Sensitivity Analysis: CTC strategies with referral of patients with at least one lesion 10 mm or larger to COL and/or with repeat screening every 10 years provided fewer LYG than CTC screening every 5 years with a 6mm COL referral threshold and were dominated at the base-case cost of $488 per scan. However, if screening adherence were 12 to 20% higher with CTC compared with other screening tests, CTC screening could be included among the efficient strategies at the base-case cost estimate.

Conclusions: Five-yearly CTC screening with a 6mm threshold for COL referral in the average risk population age 65 provides LYG almost comparable to COL, assuming equal adherence for both tests. However, to be an efficient screening strategy, CTC screening would need to be reimbursed at a lower rate than $488 per scan or attain a proportionally higher adherence than other CRC screening tests.

Date: Wednesday, May 6, 2009
Time: 4:00 - 5:00 P.M.
Location: Memorial Sloan-Kettering Cancer Center
Department of Epidemiology and Biostatistics
307 East 63rd Street
(between First and Second Avenues)
3rd Floor Conference Room
New York, New York
Note: To gain access to the building, please follow the directions by the telephone in the foyer.


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