The baseline strategy of no screening cost $204,319,642, flexible sigmoidoscopy cost $273,875,213, CT colonography cost $317,473,877 with an experienced reader and $327,385,334 with an inexperienced reader, CT colonography plus computer-aided detection cost $332,519,965 with an experienced reader and $338,269,265 with an inexperienced reader, and optical colonoscopy cost $378,964,158.
The life-years saved were 8194 with flexible sigmoidoscopy; 10,331 with CT colonography with an experienced reader and 8247 with an inexperienced reader; 10,576 with CT colonography plus computer-aided detection with an experienced reader and 9,504 with an inexperienced reader; and 10,669 with optical colonoscopy.
An incremental analysis was conducted and the strategies were ranked by their cost compared with the next best alternative. The incremental cost effectiveness ratio (ICER) for flexible sigmoidoscopy compared with no screening was $8,489 per LY saved. For CT colonography with experienced readers compared with flexible sigmoidoscopy it was $20,399. For CT colonography plus computer-aided detection with experienced readers compared with CT colonography with experienced readers it was $61,354. For optical colonoscopy compared with CT colonography plus computer-aided detection with an experienced reader it was $498,668.
When the analysis was limited to the addition of computer-aided detection, the ICER for CT colonography plus computer-aided detection compared with CT colonography alone, with inexperienced readers, was $8,661 and with experienced readers it was $61,354 per LY saved.
In the Monte Carlo analysis, the ICER for CT colonography with computer-aided detection over CT colonography alone ranged from zero to $35,927 with inexperienced readers and from zero to $178,337 with experienced readers. An increase from $50 to $92, in the cost of adding computer-aided detection to a CT colonography, resulted in an ICER of more than $100,000 for CT colonography plus computer-aided detection over CT colonography alone, with experienced readers.