THE EFFECT OF REPEATED SR-89 CHLORIDE THERAPY ON BONE PAIN PALLIATIONIN PATIENTS WITH SKELETAL CANCER METASTASES

One hundred and eighteen patients with painful skeletal metastases of malignant diseases (predominantly prostate, breast and lung cancer) we re treated with 150 MBq of strontium-89 chloride (Metastron, Amersham, UK) intravenously. The results were evaluated according to a score co nsidering pain relief, mobility, analgesic intake and general feeling. In only five patients (4.2%) was no improvement observed; mild improv ement was noted in 48 (40.7%), and substantial or complete improvement in 56 (47.5%) and 9 (7.6%), respectively. The mean painless period af ter a single (SrCl)-Sr-89 dose was 3.3+/-2.28 months (in patients with prostate, lung, breast and other types of cancer it was 3.65+/-2.11, 3.29+/-1.27, 3.08+/-0.48 and 3.44+/-1.36 months, respectively). During a 3-year study, (SrCl)-Sr-89 treatment was successively repeated up t o 5 times in some patients (total number of Metastron applications was 256) who benefit ed from the first Metastron administration and did n ot show signs of myelosuppression. Even after repeated treatment, reli ef was consistent and the duration of the period without pain increase d (in particular in patients with breast cancer, in whom the period of relief was prolonged from 3.08+/-0.48 months after the first dose to 5.33+/-2.36 months after the fifth (SrCl)-Sr-89 administration). The i ncreased painless period was not observed after repeated treatment in the patient group comprising miscellaneous types of cancer, and the de gree of improvement was less apparent. During the course of successive (SrCl)-Sr-89 treatments, transient signs of myelosuppression indicate d by a decrease ill while cell and thrombocyte counts of at least 25% were observed 10 times after Metastron administration (twice in two pa tients), i.e. in 3.9% of all (SrCl)-Sr-89 administrations; these trans ient haematological changes of moderate grade were closely connected w ith Metastron administration. Palliative treatment of metastatic skele tal pain with (SrCl)-Sr-89 improves the quality of life in most patien ts suffering from prostate, lung and breast cancer and may be safely r epeated with the same benefit and without significant myelosuppression . The beneficial effect of (SrCl)-Sr-89 treatment seems to be less pro nounced in other types of cancer with painful skeletal metastases.