Can computed tomography replace nuclear medicine scans in the staging of breast cancer?

Introduction

Selected patients with breast cancer are staged using computed tomography (CT). CT demonstrates disease in the lungs, liver, lymph nodes and bones. Traditionally, isotope bone scanning (NM) is used to stage the skeleton. If bony pathology is imaged as well on CT as on NM, it may be possible to dispense with the bone scan.

Methods

Breast cancer patients who had CT and bone scanning within 1 month of each other were reviewed retrospectively to correlate the pathology.

Results

Out of 44 combined scans, 12 were normal on both investigations. Seventeen CT scans had normal bones but demonstrated extraskeletal pathology. On seven CT scans, the bony metastases were better visualised than on NM. Five bone scans showed abnormalities outside the CT scan field (humerii and femora) but only one of these was a solitary abnormality. Five hotspots on NM were confirmed as a degenerative change on CT.

Conclusion

CT is as sensitive as NM and is more specific, with the exception of those areas not included on the scan; however, these areas could be included on the CT scan. CT will show additional pathology. Bone scanning may not be needed when patients have had a CT scan.