Regression of a primary pulmonary adenocarcinoma after zoledronic acid monotherapy

Bisphosphonates are widely used for the treatment of metastatic skeletal tumors and hypercalcemia resulting from malignant tumors. Zoledronic acid (ZOL), a third-generation bisphosphonate agent, was recently demonstrated to show synergistic antitumor activity of ZOL when combined with chemotherapy in lung cancer patients. However, whether ZOL exerts direct antitumor activity on lung cancer remains unclear. Here, we report an atypical case encountered while treating a 57-year-old woman with pulmonary adenocarcinoma and multiple metastases of the liver, left adrenal gland, and bone. The nonskeletal lesions, consisting of the primary lesion and hepatic metastasis, regressed after treatment with ZOL alone. We believe this case demonstrates a possible antitumor effect of ZOL against lung cancer.