Purpose: The aim of this retrospective study was to assess the possibilities of whole-body bone scintigraphy (WB BSc) in the monitoring of the effect of biphosphonate treatment in patients with breast cancer and bone metastases.
Patients and methods: 51 breast cancer patients with bone metastases, aged from 33 to 73 years, were included.WB BSc was performed on a Siemens DIACAM gamma camera, 2-4 h after i.v. injection of 740 MBq 99mTc-MDP, before the start of the biphosphonate treatment (baseline scintigraphy) with zoledronic acid(Zometa) and at least 6 months thereafter (control scintigraphy) in order to avoid the "flare" effect.
Results: At the baseline WB BSc 41 (80.4%) patients presented with multiple (over 3) bone metastatic lesions, 9 (17.6%) patients with single (up to 3) lesions and 1 (1.96%) patient with a solitary bone metastasis. All bone metastases had osteoblastic appearance. At the control scintigraphy 4 (8%) patients showed complete therapeutic response (CR; no bone lesions were visualized); 21 (41%) patients partial response (PR; decrease in the number and the intensity of the lesions); 16 (31%) patients stable bone lesions (SD; no change in the number or the intensity of the bone metastases); and 10(20%) patients showed disease progression (PD).
Conclusion: WB BSc is a reliable functional imaging modality for assessment of the biphosphonate therapeutic effect and an important method in the multimodal treatment planning of breast cancer patients.