We conducted a retrospective study including 517 patients with invasive breast cancer classified pT1 less than 20mm. We estimated the relevance of bone scan in the screening of metastases at the time of primary presentation, as well as the costs incurred by such a screening. Postoperative systematic bone scan did not detect the two cases of synchronous bone metastases in this population. No bone metastasis was detected in groups with the highest metastatic risks (low profitability for all pT1 classified cancers). Bone scan's rate of false positive was high (17%). The global cost was estimated at 110,770 euros, that was 215 euros per patient (208 to 232 euros in the risk groups).