Abstract PD7-05: Comparative costs of breast cancer screening with digital breast tomosynthesis versus digital mammography: A health system perspective
Authors: Liao GJ , Glick HA , Synnestvedt MB , Schnall MD , Conant EF 
Published: February 2018

Abstract
Background
Digital breast tomosynthesis (DBT) is being rapidly implemented in breast cancer screening and demonstrates improved specificity and sensitivity compared to screening with digital mammography (DM) alone. Prior work based on payer perspectives has demonstrated that DBT can be cost-effective. However, DBT is costlier than DM, and there are little data from a health system perspective about the comparative test performance and costs of DBT versus DM.
Methods
We evaluated breast cancer screening episodes in a single health system between January 1, 2012 and December 31, 2013. A screening episode was defined as a single screening mammogram and all downstream breast diagnosis related costs for the following 1 year. Episodes were excluded if the patient had a prior diagnosis of breast cancer or reached 90 years of age before the end of the follow-up period. Test performance with respect to four outcomes – true positive (TP), true negative (TN), false positive (FP), and false negative (FN) rates – was determined by comparing the BI-RADS score assigned at screening with data about subsequent cancer diagnosis from institutional and state cancer registries. Cost data were developed using CPT codes collected from organizational billing systems and converted to the Medicare Physician Fee Payment Schedule for our region with an imputed additional charge of $60.16 for DBT. Based on this approach, a DM screening exam cost $155.66 and a DBT screening exam cost $215.82. We evaluated overall costs across a screening episode, as well as by four windows: screening, follow-up, diagnosis, and cancer treatment. Data were described using percentages, and Chi-squared and Fisher's exact tests were used to evaluate differences in test performance outcomes and costs based on screening technology.
Results
There were a total of 46,483 cost episodes during the study period, of which 24,502 (52.7%) were screened by DM and 21,981 (47.3%) were screened by DBT. Overall, there were 224 TP (0.5%), 29 FN (0.1%), 4,530 FP (9.8%), and 41,700 TN (89.7%) episodes. Compared to DM episodes, DBT episodes had lower FP (8.6% vs. 10.8%, p&lt;0.001) and higher TN (90.9% vs. 88.7%, p&lt;0.001) rates. There were no statistically significant differences between DBT and DM episodes with respect to TP and FN rates.
Overall, average episode costs were higher for DBT compared to DM ($378.02 vs. $286.62, p&lt;0.001). This $91.40 difference was driven by higher average screening costs ($215.94 vs. $155.76, p&lt;0.001), which approximated the additional charge for DBT, as well as follow-up costs ($23.67 vs. $12.11, p&lt;0.001). There was no significant difference in costs between DBT and DM episodes within the diagnosis or cancer treatment windows.
Compared to DM episodes, DBT episodes had equivalent average episode costs per woman screened for FP ($67.75 vs. $65.71, p=0.49), FN ($4.63 vs. $5.60, p=0.69) and TP ($85.80 vs. $65.15, p=0.07) outcomes, but higher costs for TN ($219.84 vs. $150.16, p&lt;0.001) outcomes.
Conclusion
At a single health system, screening with DBT decreased FP rates and increased TN rates compared to screening with DM. DBT costs more overall, but not on a per-woman-screened basis for FP, FN, and TP outcomes.
Citation Format: Liao GJ, Glick HA, Synnestvedt MB, Schnall MD, Conant EF. Comparative costs of breast cancer screening with digital breast tomosynthesis versus digital mammography: A health system perspective [abstract]. In: Proceedings of the 2017 San Antonio Breast Cancer Symposium; 2017 Dec 5-9; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2018;78(4 Suppl):Abstract nr PD7-05.