Virtual CT offers cost-effective approach
to colorectal cancer screening
BY CHARLES BANKHEAD
A mathematical model that compared virtual CT
colonoscopy to other screening methods resulted
in comparable cost-effectiveness, though patient
compliance has a major influence.
Virtual computed tomography colonoscopy may offer a cost-effective alternative to other means of screening for colorectal cancer, a Stanford University study suggests.
Investigators developed a model representing the natural history of colorectal cancer (CRC) in a hypothetical cohort of 50-year-old patients. The researchers then calculated costs associated with screening, diagnosis, treatment and surveillance, using Medicare reimbursement rates. The model was verified using a published data base on CRC clinical outcomes, said Jill Fredrickson, Ph.D., a health services researcher at the university.
Cost, specificity, and sensitivity of virtual CT colonoscopy (VCTC) were compared with other screening methods, including fecal occult blood testing (FOBT), flexible sigmoidoscopy, and colonoscopy, each repeated at different time intervals. Patient compliance with each screening method was figured into the model.
The analysis suggested that VCTC screening every 3 years has the same cost effectiveness as annual FOBT, assuming 80% sensitivity, 85% specificity and 50% patient compliance. The model also assumed a $285 threshold cost for VCTC.
As compared to the expensive but diagnostically accurate colonoscopy, the threshold cost of VCTC decreased to $235 while maintaining the same marginal cost-effectiveness.
"An optimal screening interval can be chosen to match the expected range of patient compliance, which can maximize the cost-effectiveness of colorectal cancer screening with virtual CT colonoscopy," said Fredrickson. "Colorectal cancer screening strategies that incorporate VCTC compare favorably with other screening strategies at a reimbursable rate. Patient compliance is a key factor in cost-effectiveness."
