Atypical Subtrochanteric Femur Fracture in Patient with Metastatic Breast Cancer Treated with Zoledronic Acid

e24144 Background: Zoledronic acid (ZA) and denosumab are both bone-modifying agents (BMAs) approved for use in patients with bone metastases with breast or prostate cancer as well as patients who are receiving aromatase inhibitors (breast cancer) or androgen deprivation therapy (prostate cancer). There are various frequencies of administration, doses, and duration of these agents depending on indication and extent of disease. Currently there is data to show that ZA can be given every 3 months in patients with metastatic breast and prostate cancer, however, there is no data that clearly indicates that denosumab every 3 months is non-inferior to every 28 days. This study aimed to analyze current prescribing patterns of ZA and denosumab in metastatic breast cancer and metastatic castration resistant prostate cancer patients at The University of Chicago Medicine (UCM). Methods: This was a retrospective study of 80 patients who received at least one dose of ZA or denosumab between July 1st 2018 to June 30th 2019 from UCM outpatient oncology clinic for the purpose of treating metastatic breast cancer or metastatic castration resistant prostate cancer in conjunction with standard antineoplastic therapy. All included patients must have bone metastases. Patients were divided into four groups by disease state (breast or prostate cancer) and BMA agent (ZA or denosumab). The primary outcome was BMA therapy adherence rate, which was defined by those who received greater than or equal to 80% of appropriately scheduled doses. Descriptive statistics were used for skeletal-related events (SREs) and BMA associated adverse effects. Results: Patients who received ZA achieved higher adherence rates (100% breast, 86% prostate) compared to patients that received denosumab (63% breast, 23% prostate). The most common reason for the lower adherence rate in denosumab groups was scheduling convenience. During the study period, there were 3, 0, 2 and 5 patients had SREs in the above four groups respectively. The predominant adverse event across all groups was hypocalcemia and two patients with prostate cancer on denosumab developed osteonecrosis of the jaw. The cost analysis showed using ZA as primary BMA agent might save up to 2.5 million dollars per year at UCM. Conclusions: The use ofZA was associated with higher adherence rates compared to denosumab. Implementing a pharmacy driven protocol for ZA use for patients with metastatic breast and prostate cancer may improve BMA regimen adherence rates and significantly reduce costs.

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Osteonecrosis of the jaw associated with intravenous bisphosphonate therapy—A single institution experience

Journal of Clinical Oncology ◽

10.1200/jco.2006.24.18_suppl.18553 ◽

2006 ◽

Vol 24 (18_suppl) ◽

pp. 18553-18553 ◽

Cited By ~ 2

Author(s):

E. M. Wallace ◽

K. I. Quintyne ◽

B. M. Cantwell ◽

P. M. Calvert ◽

G. D. Leonard

Keyword(s):

Breast Cancer ◽

Metastatic Breast Cancer ◽

Zoledronic Acid ◽

Metastatic Breast ◽

Median Number ◽

Osteonecrosis Of The Jaw ◽

Bisphosphonate Therapy ◽

Unknown Primary ◽

Dental Procedures ◽

Increased Risk

18553 Background: Osteonecrosis of the jaw (ONJ) is a debilitating disease that has been associated with cancer therapy. Recently a link between ONJ and chronic intravenous (IV) bisphosphonates has been suggested. We assessed the incidence of ONJ and its risk factors in patients treated with IV bishosphonates at our institution. Methods: All patients with a cancer diagnosis treated at our institution with at least four cycles of either IV Zoledronic Acid, Pamidronate, or a combination of both, from 2000–2005 were evaluated using outpatient records. Patients with ONJ were identified and their characteristics were compared to all patients receiving bisphosphonate therapy. Results: One hundred and twenty-one patients were evaluated, 36 Male and 85 Female. Median age- 62 (Range 34–85). Seventy-six had metastatic Breast cancer, 25 Prostate, 7 Lung, 3 Colorectal, 3 Renal, 2 unknown primary, 1 each of Penile, Bladder, Seminoma, Lymphoma and Melanoma. Forty patients received Pamidronate infusions alone, 51 Zoledronic Acid alone and 30 a combination of the two. The median number of Pamidronate infusions was 8 (Range 4–10), Zoledronic infusions 10.7 (Range 4–32), and a combination of pamidronate and zoledronic acid was 12 (Range 5–66). Three patients developed ONJ. All 3 patients were female, had a median age of 62 (range 52–74) and had metastatic breast cancer. The median number of bisphosphonate infusions prior to the development of ONJ was 35 (Range 18–47). All patients had chest wall radiotherapy and 1 had chemotherapy and steroids. No patients had dental procedures or prolonged antibacterial therapy. Conclusions: ONJ is a complication associated with IV Bisphosphonate therapy. Our study suggests that female sex, zoledronic acid, and prolonged administration of bisphosphonates, may confer an increased risk for the development of ONJ. Further prospective studies with adequate power are needed to clarify what patients are most at risk for developing ONJ and what measures are needed to prevent its occurrence. No significant financial relationships to disclose.

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