Evaluation of safety and analgesic consumption in patients with advanced cancer treated with zoledronic acid

BACKGROUND: The aim of the study was evaluation of zoledronic acid with regard to safety, effect on analgesic consumption and impact on occurrence of skeletal related events in patients with bone lesions from solid tumors and multiple myeloma. METHODS: We conducted an observational, 12-month, phase IV and multi-center study. One hundred and twenty-five symptomatic (pain) bone-metastatic patients were included between 2007 and 2009: 92 prostate cancers, 28 multiple myelomas, 5 others. They were prescribed monthly infusions of zoledronic acid in accordance to each disease’s treatment guidelines. Analgesics consumption, pain and laboratory values were evaluated. RESULTS: Zoledronic acid was prescribed concurrent to initial therapy for myeloma and only in late stage of prostate cancer. With treatment, percentage of patients on analgesics decreased in myeloma group (from 57% to 24%) and increased in prostate cancer group (from 70% to 88%). In patients with any analgesics, the use of opiates’ prescription dropped from 72.9% to 64%, percentages of non-steroidal analgesics and other mild analgesics increased slightly. Pain score (Visual Analog Scale, VAS) decreased non significantly (by 22%) in prostate cancer but significantly in myeloma (by 97%). Hypocalcaemia grade 3 or 4 was observed in 4% of patients. Deviations in creatinine remained stable throughout. A total of 31 skeletal related events were reported for 10 patients (8%). CONCLUSIONS: Zoledronic acid was safe medication. Different response of pain was seen between prostate cancer and myeloma patients, which might be due to different stages of disease where it was prescribed according to present guidelines. Possibility of earlier start of treatment should be explored in prostate cancer.