Effectiveness of strontium-89 palliative therapy in patients with painful bone metastases

Bone metastases are observed in 30-70% of patients with cancer. Painful bone metastases require regular control and treatment. Systemic palliative radiotherapy using beta-emitting radionuclides is an alternative method to analgesics and external beam radiotherapy. The aim of the study was to establish the efficacy and risk of side effects of radionuclide therapy in patients with bone metastases.

Strontium-89 (Sr-89) therapy was performed in 49 patients, 14 women and 35 men, aged 42-82 (mean 62) years with bone metastases confirmed by MDP-Tc99m whole body scan. The primary tumour was prostate cancer in 28 patients, breast cancer in 14, bladder cancer in 2, lung cancer in 2, gastric cancer in 2, and renal cancer in 1 patient. Intravenous injection of 150 MBq of Sr-89 was given and patients were observed for at least 3 months. Blood count, intensity of pain, drugs intake, life activity, and duration of effect were assigned 0-3 points. The overall response index was very good when the points totalled 10-12, good - 7-9, satisfactory - 4-6, poor - 2-3 and no response 0-1 points. Haemotoxicity was evaluated according to the Common Toxicity Criteria of the World Health Organisation (WHO).

We found a very good response in 10 (20%) patients, good in 20 (41%), satisfactory in 8 (16%), poor in 2 (4%), and no response in 9 (19%) patients. Transient haemotoxicity of the Sr-89 therapy was observed in 39 (80%) patients. The mean decrease in platelets and leukocytes was 33-35%, but the haemoglobin concentration was reduced by only 15% in comparison to baseline values. The majority of patients did not require any treatment for haematologic side effects. Hospitalization was necessary in only 2 patients with grade 4 CTC WHO.

Palliative radionuclide treatment of painful bone metastases with Strontium-89 in various primary tumours is in most cases an effective therapy with limited haemotoxicity.