Abstract

Objective: Renal failure is one of the most prominant adverse effect of the zoledronic acid (ZA) which is well known to decrease the skeletal-related events (SREs) in breast cancer patients developing bone metastasis. In this particular study, our object was to evaluate the incidence of this side effect and the risk factors leading to the development of renal failure.
Material and Method: A total of 97 patients who underwent ZA treatment for breast cancer with bone metastasis in our institute between March 2006 and December 2013 were evaluated. For the assesment of renal failure, serum creatinine levels were obtained before the treatment. Preliminary and the highest levels of creatinine levels during the treatment were used in calculation of creatinine clearance according to the Crockcroft-Gault formula. The age of the patients, the number ZA treatment periods, number of the infusions, the simultaneous anti-cancer treatments, non-steroidal anti-inflammatory drug use, diabetes mellitus and presence of hypertension were recorded.
Results: The mean age of the patients was 54±10 years and the treatment period of ZA was 37±18 months. In all of the patients participated in this study the preliminary creatinine levels were under 1.4 mg/dl. In 22 of our patients (23%) creatinine levels increased more than 0.5 mg/dL, besides creatinine clearance were found out to be decreased both of which were pointing out the renal toxicity. In two patients creatinine clearance was under 30 ml/min. and one of the patients has undergone renal dialysis. The only independent risk factor underlined was the advanced age (60 years ?) (p=0.017).
Conclusion: As a conclusion breast cancer patients with bone metastasis undergoing ZA treatment are prone to the development of renal failure. In order to avoid this particular risk of developing renal failure, serum creatinine levels should strictly be monitored before the treatment and meticulous attention to the hydration should be given during the treatment especially in patients with advanced age.

Key words: Metastatic breast cancer, renal failure, zoledronic acid