The effectiveness of Strontium-89 in metastatic bone pain palliative treatment

Full text: 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 alternative method for analgesics and external beam radiotherapy. The aim of the study was to establish efficacy and risk of side effects of radionuclide therapy in patients with bone metastases. Sr-89 therapy was given in 33 patients, 13 women and 20 men aged 42 to 79 years (mean 61) with bone metastases confirmed by MDP-Tc99m total body scan. In 18 patients primary tumour was prostate cancer, in 12-breast cancer, in 2-bladder cancer in 1 renal cancer. Intravenous injection of 150 MBq of Sr-89 was given and patients were observed for at least 3 months. Blood counts, intensity of pain, drugs intake, life activity and time of effect was evaluated from 0 to 3 points. Overall Response Index (RI) was very good if total points amounted 10-12, good - 7-9, satisfying - 4-6, poor - 2-3 and no response 0-1 points. Haematotoxicity was evaluated according to Common Toxicity Criteria by WHO. Very good response was noticed in 6 patients (18%), good in 15 (46%), satisfying in 6 (18%), poor in 2 (6%) and no response in 4 (12%) patients. Transient haematotoxicity post Sr-89 therapy was observed in 18 patients (55%), in 11 patients it was grade I CTC, in 3 grade II CTC, in 3 grade III CTC and in one man grade IV which had been treated. Survival after therapy was between 21 to 138 weeks (mean 58 weeks). In 16 (48%) patients after more than 3 months second dose was injected and in 2 patients (6%) third dose of Sr-89. Systemic radiopalliation with Sr-89 in literature is considered as highly effective treatment but in daily practice is still controversial because of potential haemotoxicity. On the other hand for patients with metastatic spread in bones the only alternative treatment is hemibody irradiation (HBI). Janjan concluded that HBI gives approximately very good and good response in 70% of cases and similar to Sr-89 risk of complications. Problem of visceral complications not seen in Sr-89 therapy seems to be weak side of HBI. Bolger et all. showed that Sr-89 and HBI results are comparable in efficacy and haematotoxicity. Dearnaley et al. stressed poor tolerance of HBI in confrontation with Sr-89. In our results transient haematotoxicity was observed in half of patients but only in one case patient required treatment. Response Index (RI) which was used in our study to estimate results is based on methods of evaluation used by other authors. Number of very good and good responses of Sr-89 therapy is comparable to results seen in literature. Robinson et al. analysed efficacy of Sr-89 therapy published in MEDLINE database. This data showed that in 80% of patients had decrease in pain and in 10% no pain was observed. Mean duration of response was 3-6 months and mild haematotoxicity was transient and observed no longer than 8 weeks. Data acquired in our study showed very good and good response in 64% of patients which is comparable to results of other authors. In conclusion, palliative radionuclide treatment of painful bone metastases with Strontium-89 is in most cases effective therapy with limited haematotoxicity. (author)