[Indication for bone scans in early breast cancer staging]

OBJECTIVE

Evaluate the indication for bone scanning during staging of early breast cancer in the light of scientific evidence to assess the need to modify practices with scant effectiveness.

MATERIAL AND METHODS

The bone scans carried out in our Nuclear Medicine Department in 2007 on patients with primary breast cancer were reviewed retrospectively. Results were analyzed in relation to the clinical and histopathologic findings for each tumor. Bone scan results of tumors >2 cm y <or=5 cm (T2) were analyzed in two groups stratified by tumor size, <or=3 cm or >3 cm, and pre-treatment clinical stage.

RESULTS

Out of 245 bone scans of patients with breast cancer, 237 (97%) were negative for metastatic disease and 8 (3%) were positive. Lesions <2 cm (Tis and T1) were diagnosed in 131 patients (53.5%), none of which had bone metastasis at time of diagnosis. Lesions >2 cm and <or=5 cm (T2) were diagnosed in 84 patients (34%), of which 3.6% had bone metastasis. There were no differences in the rate of bone metastases in patients with stage T2 disease and lesions <or=3 cm vs. >3 cm. The bone scan findings did not modify staging in any of the 66 patients with T2 tumors stage IIA, but it did modify staging in 2 of 12 patients with stage IIB tumors. Twenty percent of 15 patients with T3 tumors and 13% of patients with T4 tumors had bone metastasis at time of diagnosis.

CONCLUSIONS

Ineffective practices should be modified and bone scanning should not be indicated in patients with early breast cancer Tis, T1 and T2 with tumor <or=2 cm, clinical stage IIA. Pre-treatment bone scanning is still indicated in T2 IIB, T3 and T4 disease.