Breast ultrasound in breast cancer surveillance; incremental cancers found at what cost?

PURPOSE: To determine the diagnostic parameters of breast ultrasound (US) in the setting of routine radiological surveillance after a diagnosis of breast cancer and evaluate costs of the inclusion of breast US as well as any survival benefit of US detected cases of recurrence in surveillance. METHODS: 622 patients underwent breast cancer surgery and follow up at Austin Health from July 2009 to December 2015. Retrospective data analysis was performed to determine; diagnostic parameters, financial costs of US and survival outcomes of US detected cases of recurrence. RESULTS: Patients underwent 1-9 years of breast cancer surveillance, with a median of 4.24 years. 390 (62.7%) patients underwent additional breast US surveillance to mammography. 232 (38.3%) fit criteria for use of additional breast US. 199 abnormal imaging episodes occurred, leading to 16 screen detected-cases of locoregional recurrence. US alone generated 107 abnormal images and found 9 cancers. US had a sensitivity of 44.1%, specificity of 95.2% and positive predictive value of 11.7% in comparison to mammography; 20.6%, 97.4% and 9.9% respectively. US had a biopsy rate of 4.0% and lead to an incremental cancer detection rate of 0.38%. The cost of incremental cancer found was $31,463.72 AUD. Survival outcomes based on method of detection of recurrence were insignificant (p value = 0.71). CONCLUSIONS: Breast US has a sensitivity of 44.1% and detected seven recurrences that were mammographically occult. Breast US has a similar PPV to mammography in surveillance. Breast US generated considerable biopsy rates and costs. Survival analysis was not able to detect any benefit of US detected cases of recurrence.