CT for breast-cancer metastasis can do what nuke bone imaging does—and for less

In staging advanced breast cancers for bony metastasis, CT of the thorax, abdomen and pelvis can effectively replace nuclear bone scans in facilities where both exams together are currently considered optimal. The CT-only approach stands to save money and, presumably, reduce patient stress.

That’s according to the authors of a supplement running in the September edition of the Royal College of Radiologists’ journal Clinical Radiology.

Dr. Sahithi Nishtala of Good Hope Hospital in the U.K., an affiliate of the University of Birmingham, and colleagues retrospectively reviewed cases at their institution over a 30-month window ending in June of 2015.

The review cohort comprised all asymptomatic patients with no history of malignancy who had both a CT and a bone scan with the radiotracer technetium-99m (Tc-99m) within two weeks of each other. The dual exam is the standard of care at Good Hope.

Of 113 patients who met the criteria, 22 were found to have metastatic bony involvement. Of these, 21—95 percent—were detected on CT.

In addition, the bone scans produced five false positives, and only one patient had bony metastasis that was seen on the bone scan but not on CT.

In their conclusions, the authors point out that Tc-99m bone scanning is more expensive than CT.

“There is huge potential cost saving by removing the bone scan from the routine workup of patients,” they write. “We propose an extended coverage during the staging CT from skull base to proximal femora with dedicated bone windows to replace the nuclear medicine examination.”

In this scenario, Tc99m bone scans would be reserved for dealing with problematic CT findings. The single-modality method, the authors add, would not only cut costs but also reduce radiation dose to the patient.