Incident pain and analgesic consumption decrease after samarium infusion: a pilot study

Abstract

The aim of this pilot study was to observe the variations of pain intensity on movement and at rest and the variation of analgesic drug consumption in patients with prostate cancer and painful bone metastases treated with a single dose of 1.0 mCi/kg of samarium-153 (153-Sm) lexidronam. Case series. The Nuclear Medicine Unit and Pain Therapy and Palliative Care Unit, National Cancer Institute of Milan, Italy. Thirteen outpatients with hormone refractory prostate cancer and painful multiple bone metastases. Infusion of a single dose of 1.0 mCi/kg of 153-Sm lexidronam, pain therapy, and the assessment of pain intensity at rest and on movement. Variation of pain intensity on movement and at rest by means of a verbal scale and the reduction of analgesic drug consumption 4 weeks after infusion of 153-Sm lexidronam. From baseline, 61.5% of patients reported a decrease of at least two levels of pain intensity on movement and 53.8% of patients had an improvement of pain at rest. Of the patients, 15.4% were not in pain at rest or on movement at baseline and continued to be free of pain 4 weeks after the administration of samarium. All ten patients, but one, who were on analgesic drugs before samarium infusion, reduced the regular drug administration or rescue medication. Bone marrow toxicity was mild and readily reversible in three patients. In patients with bone metastases, pain on movement is a frequent and often difficult clinical problem to treat and the most frequent cause of breakthrough pain. In patients with painful multiple bone metastases due to prostate cancer, the infusion of a single dose of 1.0 mCi/kg of 153-Sm lexidronam may be considered an effective and safe treatment for pain either at rest or during movement.