Bisphosphonates in the Management of Breast Cancer

[Effect of pamidronate infusion time on renal function in patients with multiple myeloma]

INTRODUCTION

Administration of biphosphonates in patients with renal failure requires a dosage adjustment.

OBJECTIVES

Analyse renal function evolution in multiple myeloma patients after reducing infusion time for 90 mg pamidronate by 2 h.

METHODS

In 2007, a retrospective study was carried out on all patients who presented multiple myeloma and bone metastasis treated with pamidronate administered every 4 h. Following a review of the literature, a protocol for administering pamidronate every 2 h was created in partnership with Haematology, and a specific dose reduction framework was established for patients with baseline renal failure. Additionally, a prospective follow-up study of those patients' renal function was completed to analyse its evolution after the change in infusion time.

RESULTS

A total of six patients received 90 mg pamidronate every 4 h. 33.32% of the patients (2/6) presented baseline renal insufficiency, and therefore needed to have the pamidronate dose adjusted according to the new protocol. Subsequently, all of them received the treatment every 2 h, and one patient (16.6%) experienced altered renal function after two treatment cycles.

DISCUSSION

Reducing administration time for pamidronate from four to 2 h did not lead to significant variations in patients' renal function. This therapeutic practice can improve patients' quality of life by shortening their hospital stay without aggravating their renal function.

The mechanism of metastasis

The establishment of clinically detectable skeletal metastasis is a multifactorial process. This process can be divided into three general areas of understanding. The first is that of the intrinsic characteristics and properties of the tumor cells, which allow and facilitate their migration from the site of primary neoplasia to the distant host skeleton. Second, there are anatomic considerations of the human body, which influence the distribution of metastatic seeding. Third, there are the considerations of the host organism's biology, including the immune system, the circulatory system, and the affected host skeleton, which hinder and, at times, potentiate the ability of neoplastic cells to establish skeletal lesions.