Multitarget stool DNA tests not as cost-effective as FIT for early CRC detection

Costs for early detection of advanced neoplasia and colorectal cancer (CRC) are higher with multitarget and next-generation stool DNA tests than with fecal immunochemical tests (FITs), a study found.

The brief research report comparing screening costs among the three testing modalities found that costs per additional early-detected CRC case would still be significantly higher than FIT-based screening even if newer tests' costs were lowered to less than 20% of their current costs.

German researchers analyzed results of two previous studies comparing the diagnostic performance of Exact Sciences' Cologuard (a multitarget DNA test) and Cologuard Plus (a next-generation test) and a commercial FIT, the costs per test reimbursed by Medicare, and uptake rates of colonoscopy after a positive result. Results were published May 13 by Annals of Internal Medicine.

Assuming 60% uptake of follow-up colonoscopy, screening costs per detected advanced neoplasia case or early-detected CRC were seven- to ninefold higher with the DNA and next-generation tests than with FIT-based screening. Costs per additional early-detected CRC case were more than $700,000 with either of the DNA tests, and approximately 40 and 30 times higher, respectively, than costs for the FIT-detected CRC cases.

The researchers also conducted an analysis assuming lower (30%) and higher (90%) follow-up colonoscopy uptake and hypothetical lower costs per DNA test. With the lower uptake rate of screening, incremental costs for early detection of one additional CRC case compared with FIT-based screening would increase to more than $1.4 million for the DNA test and more than $1.5 million for the next-generation test. With the higher uptake rate, the detection rates per CRC case would be lower, but the incremental costs for early detection of one additional CRC case would still be above $500,000 for both.

The researchers noted that although the DNA tests have higher sensitivity compared to FIT, the same sensitivity and specificity could be achieved at no incremental cost by lowering the FIT positivity threshold. FIT cutoffs vary widely in different countries, and the current practice in the United States hinders use of quantitative information from FITs. Flexibility in defining the positivity threshold should be reconsidered, the authors wrote.

Even if the costs per DNA test were lowered to $100, less than 20% of the current costs, the cost per additional case of CRC or advanced neoplasia detected by either compared with FIT would still be much higher, the study authors observed. “Although our study is not and does not claim to be a comprehensive cost-effectiveness analysis, our results indicate that there would be much to gain if the current trends of decreasing FIT use rates and increasing [multitarget stool DNA test] use rates in the United States could be reversed,” they wrote.