Jill Tichy MD, Presenter: Nothing to Disclose

Mark Raymond Waddle BS, Abstract Co-Author: Nothing to Disclose

Allison Deal MS, Abstract Co-Author: Nothing to Disclose

Lisa A. Carey, Abstract Co-Author: Nothing to Disclose

Hyman Muss, Abstract Co-Author: Nothing to Disclose

Nisha Mehta MD, Abstract Co-Author: Grant, Siemens AG

Redundant use of imaging modalities for staging is not cost effective, and can result in unnecessary additional workup. This study aims to assess the added utility of routine bone scan (BS) above staging CT chest/abdomen/pelvis (CT) in detection of asymptomatic breast cancer bone metastasis (BM).

Eligible patients had stage I-III asymptomatic breast cancer diagnosed between 2010-2013 and underwent staging BS and CT <6 weeks apart. Radiographic discordance in BM detection was defined by indeterminate findings on either study with the other read as normal, provided that the area of abnormality was included on both. Discordant scans were blindly reviewed by a musculoskeletal radiologist to ensure true discordance. Fisher’s Exact and Wilcoxon sum rank tests evaluated the association of discordance and clinical characteristics.

Among 124 patients, the median age was 53, median tumor size 3.45 cm, and 82 had ≥ 1 positive lymph node. Varying receptor subsets were included. Median follow-up was 2.18 years. 102 (82.3%) were radiologically concordant for BM evaluation with 93 (75.0%) negative and 9 (7.3%) raising suspicion for metastatic disease. There were 22 (17.7%) radiologically discordant cases per initial reports, of which 9 were deemed truly discordant on review. 13 of the discordant patients underwent further workup with 1 biopsy confirmation. Of the 11 CT+/BS- patients, 9 are alive without disease, 1 died with BM, and 1 was lost to follow-up. Of the 11 BS+/CT- patients, 8 are alive without disease, 1 died with visceral-only metastases, 1 died with visceral+BM, and 1 was lost to follow up with confirmed BM. Skull-only metastases were suspected by BS in 2 cases; 1 died with visceral+BM. There was no association of any patient or tumor characteristic with measured discordance (p-values ≥ 0.07).

Of the cases demonstrating discordance between CT and BS, the vast majority had negative follow-up imaging for metastasis, and there was only 1 case out of 124 of isolated clinically significant BM identified by BS without associated abnormal CT findings. Therefore, bone scan routinely coupled with CT staging may be unnecessary in asymptomatic breast cancer.

Recommendations for asymptomatic breast cancer staging may merit reconsideration; BS may only be necessary in those with findings suspicious for osseous or visceral metastatic disease on CT staging.

Tichy, J, Waddle, M, Deal, A, Carey, L, Muss, H, Mehta, N, Is Computerized Tomography Sufficient without Bone Scan for Routine, Asymptomatic Breast Cancer Staging?.  Radiological Society of North America 2014 Scientific Assembly and Annual Meeting, - ,Chicago IL. http://archive.rsna.org/2014/14012164.html