How often are previously undetected radiographic abnormalities detected at the time of CT simulation for breast cancer patients?

OBJECTIVES

In most institutions, planning computed tomography (CT) scans are not interpreted by diagnostic radiologists. The purpose of this analysis was to determine the percentage of cases in which a previously undetected radiographic finding was found on review of CT simulation images by diagnostic radiology.

METHODS

At the Henry Ford West Bloomfield Center, CT simulations are prospectively interpreted by diagnostic radiologists and a formal report is generated. CT simulation scan reports of 332 consecutive breast cancer patients from 2000 to 2006 were reviewed. The percentage of these reports in which a previously undetected abnormality was noted on the planning CT was determined. Prior and subsequent diagnostic CT scans were also reviewed to determine the clinical relevance of these diagnostic abnormalities.

RESULTS

Of 332 patients with CT simulations for breast cancer treatment planning, 52 patients (16%) had a newly detected abnormality noted. Of these, 31 patients (or 60% of the abnormal findings) were deemed by diagnostic radiology to have potentially significant findings (e.g., "can not exclude metastatic disease"), and a follow-up CT or magnetic resonance imaging scan was recommended. Abnormalities in this category included previously undetected lung nodules, liver lesions, kidney/adrenal lesions, and sclerotic bony lesions. On follow-up, however, to date, these findings have demonstrated no clinical significance, although further follow-up is needed in many patients.

CONCLUSIONS

In this study, a significant proportion of breast cancer patients undergoing CT planning studies were diagnosed with potential abnormalities for which follow-up was recommended by diagnostic radiology. To date, these findings have not been clinically relevant, though further follow-up is needed in many of the patients. Thus, in cases of clinical uncertainty, a diagnostic radiologist should be consulted and follow-up imaging obtained if necessary.