The clinical use of staging bone scan in patients with breast carcinoma: reevaluation by the 2003 American Joint Committee on Cancer staging system

BACKGROUND: Using the new 2003 American Joint Committee on Cancer (AJCC) staging system, the authors evaluated the usefulness of the staging bone scan in patients with primary breast carcinoma. METHODS: The authors examined 1939 patients with primary breast carcinoma for staging bone scan who were treated at a single institution. Pathologic stage was assigned retrospectively according to the 1988 and the 2003 AJCC staging systems. RESULTS: Bone metastasis rates were 0.7% (4 of 586) for patients with Stage I disease, 0.7% (5 of 699) for patients with Stage IIA disease, 2.1% (10 of 479) for patients with Stage IIB disease, 4.5% (7 of 154) for patients with Stage IIIA disease, and 10.5% (2 of 19) for patients with Stage IIIB disease according to the 1988 AJCC staging system. The authors found a significant difference in the bone metastasis rate between patients with Stages IIA and IIB disease in the 1988 staging system (P = 0.039). Reevaluating the patients by the 2003 system resulted in significant upstaging, especially for patients with Stage II/III disease. According to the 2003 staging system, bone metastasis rates were 0.7% (4 of 586) for patients with Stage I disease, 0.6% (4 of 648) for patients with Stage IIA disease, 0.6% (2 of 310) for patients with Stage IIB disease, 4.0% (9 of 225) for patients with Stage IIIA disease, 16.7% (2 of 12) for patients with Stage IIIB disease, and 4.4% (7 of 158) for patients with Stage IIIC disease. It was noteworthy that there was a significant difference between Stages IIB and IIIA in the 2003 staging system (P = 0.010). CONCLUSIONS: Stage reclassification using the new AJCC staging system resulted in upstaging of high-risk patients, as well as a significant decrease in the bone metastasis rate in patients with Stage IIB breast carcinoma. Considering the cost-effectiveness of staging bone scan, the data suggested that it was of little value for patients with Stage I and II breast carcinoma, but was highly recommended for patients with worse than Stage III disease by the new 2003 staging system.