(P087) Early Experience of Radium-223 Treatment for Metastatic Castration-Resistant Prostate Cancer: A Preliminary Report

Neil F. Mariados, MD, Marc N. Bienz, Christopher M. Pieczonka, MD, Deborah Zehel, BSc, Modar Alom, MD, David M. Albala, MD, Vladimir Mouraviev, MD, PhD, John Crawford, MD; Associated Medical Professionals of NY; University of Montreal

Introduction and Objectives: The many advantages associated with Ra-223’s cytotoxic mechanism of action and excretion make it a stronger and less myelotoxic and nephrotoxic option than its counterparts (Sm-153 and Sr-89). We report the short-term pain evolution, side effects, and hematologic profile of patients with metastatic castration-resistant prostate cancer (mCRPC) undergoing Ra-223 treatment.

Methods: Clinical data from 19 mCRPC patients treated with Ra-223 were collected from a large multidisciplinary group. In accordance with the recommended dosage by the Food and Drug Administration (FDA), Ra-223 injections consisted of one dose of 50 kBq/kg monthly for 6 months. Up to the third injection, the World Health Organization (WHO) ladder for cancer pain was assessed, and the pain patterns were evaluated and classified in groups: no or minimal pain relief, worsening of pain, and improvement of pain. Also, short-term incidence of side effects was reported together with the hematologic parameters at each injection. Data are expressed as a median (range).

Results: This cohort comprised 19 Caucasian men of median age 74 years (range: 53–85 y). All had bone metastasis. At baseline, 13.3% graded the pain at 1 according to the WHO pain score. At the first follow-up, 27 days (range: 19–35 d) after the first injection, 21.5% (2/19) noticed pain relief and 37.5% had a WHO score of 1. At 22 days after the second injection (range: 21–22 d), 44.4% (8/18) had reduced pain symptoms and 37.5% had a WHO score of 1. At the third follow-up, 35 days (range: 22–35 d) after the third injection, 50% (6/12) had pain relief and 50% had a WHO score of 1. Also, for 10.5% (n = 2) of our cohort, pain symptoms worsened, while 21% (n = 4) reached total pain remission by the third injection. Increased bowel movement frequency was observed in 10.5% of our cohort, diarrhea in 31.6%, constipation in 5.3%, nausea in 26.3%, vomiting in 5.3%, bone pain flair response in 26.3%, and lower limb edema in 10.5%.

Conclusions: Our short-term results demonstrated promising bone pain-relieving effects of Ra-223 in 50% of our patients, even after a maximum of only three injections. Encountered side effects were mild, including mostly gastrointestinal symptoms, but a 21.3% platelet reduction was observed by the third injection.