Adjuvant oral clodronate improves the overall survival of primary breast cancer patients with micrometastases to the bone marrow-a long-term follow-up

Background: Adding oral clodronate to postoperative adjuvant breast cancer therapy significantly improves disease-free survival (DFS) and overall survival (OS). Long-term follow-up data from the prospective, randomized, controlled study are reported. Patients and methods: Patients with primary breast cancer received clodronate 1600 mg/day for 2 years or no treatment along with standard adjuvant breast cancer treatment. Results: Analysis of 290 of 302 patients demonstrated that a significant improvement in OS was maintained in the clodronate group at a median follow-up of 103 +/- 12 months; 20.4% of patients in the clodronate group versus 40.7% of control group patients (P = 0.04) died during the 8.5 years following primary surgical therapy. Significant reductions in the incidence of bony and visceral metastases and improvement in duration of DFS at 36- and 55-month follow-up periods were no longer seen with clodronate. Conclusion: These long-term survival data extend the survival advantage reported in previous studies with oral clodronate in breast cancer.