Initial clinical experience with ¹⁷⁷Lu-Zoledronate for the treatment of skeletal metastases in breast cancer

Metastatic bone cancer represents a significant and often debilitating complication in advanced diseases. It is estimated that approximately 70% of metastatic patients eventually develop bone metastases, with breast cancer being a common primary site. Radiopharmaceutical therapy has emerged as a valuable and cost-effective approach for alleviating bone pain in metastatic conditions, especially when combined with chemotherapy.

This study aims to evaluate the role of [⁶⁸Ga]Ga-NODAGA-Zoledronate PET/CT and assess the response to [¹⁷⁷Lu]Lu-DOTA-Zoledronate treatment in two breast cancer patients with multiple bone-only metastases affecting both the axial and appendicular skeleton.

Initial [¹⁸F]F-NaF and [⁶⁸Ga]Ga-Zoledronate PET/CT scans revealed numerous intense lytic-sclerotic lesions distributed throughout the axial skeleton. An activity of 3.7 GBq of [¹⁷⁷Lu]Lu-DOTA-Zoledronate was administered to the patients. Post-therapeutic imaging conducted 24 h after treatment confirmed the presence of multiple intense lesions throughout the axial skeleton, consistent with the initial PET/CT findings. Both patients experienced a gradual reduction in the use of pain relief medication, with one patient discontinuing it within one month and the other within two months post-treatment.

[¹⁷⁷Lu]Lu-Zoledronate shows promise for future bone pain palliation therapy due to its superior properties compared to other agents like ¹⁵³Sm and ¹⁸⁸Re. Additionally, [⁶⁸Ga]Ga-NODAGA-Zoledronate PET/CT can help assess eligibility for radionuclide therapy with [¹⁷⁷Lu]Lu-DOTA-Zoledronate, while [¹⁸F]FDG PET/CT is useful for monitoring treatment response.