Selective application of routine preoperative axillary ultrasonography reduces costs for invasive breast cancers

Preoperative axillary sonography with fine needle aspiration (FNA) in patients with invasive breast cancer identifies patients with nodal metastasis who can be spared further surgery. Indiscriminate use of the diagnostic modality can increase costs and yield inaccurate results. We evaluate the costs associated with the use of highly sensitive axillary ultrasonography in patients with stage ≥T2 tumors.

We constructed a decision analysis tree using TreeAge Pro 2009 software comparing direct hospital charges between patients with and without routine use of axillary ultrasound. Base case estimates were derived from our institutional data and compared with those derived from the literature. One- and two-way sensitivity analyses were performed to check the validity of our inferences.

We found that, for the base case estimate with 35% lymph node positivity in stage ≥T2 tumors and sensitivity of the axillary ultrasound set at 86% with a specificity of 40%, the strategy to perform preoperative axillary ultrasound yielded rollback costs of $15,215, compared with $15,940 for surgery plus sentinel lymph node biopsy (cost difference, $725 per patient favoring axillary ultrasound). On two-way sensitivity analysis, the cost benefit for axillary ultrasound was not seen in patients with a low risk for nodal metastasis.

The adoption of routine preoperative axillary sonography with FNA is a lower-cost strategy than conventional strategies in patients with stage ≥T2 invasive breast cancer.