Prognostic value of pretreatment bone scans in breast carcinoma

One hundred consecutive patients who had ^99mTc pyrophosphate bone scans prior to treatment for cancer of the breast between 1972 and 1976 were studied retrospectively to determine the contribution of the scans to staging, treatment, and prognosis. Patients were staged by the AJC-UICC 1973 TNM system using all information exclusive of that from bone scans. Bone scans were initially categorized as normal (60) and abnormal (40). The bone scans were reviewed without knowledge of the initial report; the consistency between the original and review interpretations was 78%. No correlation was found between abnormal bone scans and clinical status of the axillary nodes, but bone scans were significantly more often abnormal in locally advanced tumor (T3 and T4) and in the presence of distant metastasis (M1) (by studies other than bone scan) than in their absence. The patients were followed during an average period of 22 months. In clinical stages I and II, abnormal bone scans did predict a higher occurrence of distant metastasis (6 of 17, 35%) than normal ones (11 of 48, 24%) and predicted more frequent skeletal metastases: 5 of 27 (19%) vs 6 of 65 (9%). A poor 4-year actuarial survival was found in abnormal bone scans (48%) compared with normal ones (58%) among the patients with clinically undisseminated breast carcinoma (stage I-III). Reader variations and subjective aspects of interpretation clearly can influence the evaluation of bone scans as a clinical tool.