Breast cancer staging using technetium-99m sestamibi and indium-111 pentetreotide single-photon emission tomography

We evaluated the clinical usefulness of single-photon emission tomography (SPET) with technetium-99m sestamibi and indium-lll pentetreotide in breast cancer staging. Fifteen patients with clinical and/or mammographic findings suggesting Tl-2NO-1 breast cancer were studied. SPET images were acquired 20 min after Tc-99m-sestamibi injection and 4 and 24 h after In-111-pentetreotide injection. Patients underwent surgery the day after the later In-111-pentetreotide acquisition. Pathological examination showed 16 tumours in the 15 patients, with one bilateral carcinoma. The mean tumour diameter was 18.7 mm. Metastatic axillary involvement was found in 6/16 tumours, with a mean of five metastatic nodes per axilla. Both tracers correctly identified 15/16 primary tumours and five of the six cases of metastatic axillary node involvement. No difference between the tracers was observed in breast cancer staging. Tc-99m-sestamibi seems to be the better tracer in terms of physical characteristics, execution time and cost-effectiveness. Our data suggest the future possibility of using nuclear medicine imaging to avoid axillary dissection in patients with Tl breast cancer.