Strontium - 89 (89Sr) safe and satisfying in 'SUPERSCANS'

Full text: Strontium 89 administration guidelines suggest that a 'superscan' or a platelet count <100 are relative contraindications to therapy. A prospective study of 98 patients referred for palliative therapy over a two year period was undertaken to assess the safety of 89Sr therapy in advanced bony disease. Baseline haematology and clinical review were performed and the bone scan was graded for extent of disease. In extensive disease, bone marrow reserves were scintigraphically assessed. Review was performed to a minimum of 4-6 weeks post treatment coinciding with the published time of count nadir. Review of clinical response was in the form of a pain diary. Results: 84 patients were considered suitable for therapy. Bone scan showed limited disease in 26 patients, extensive disease in 50 and a 'superscan' in 8. In the patients with 'superscan', no grade 3-4 NCI platelet toxicity occurred. One patient had grade 2 toxicity, four patients had grade 1 toxicity and the remaining three patients maintained normal counts. The largest percentage fall in platelet counts for 'superscan' patients was 41 per cent. All patients with superscan' responded to treatment with reduced pain. Maximum platelet toxicity in patients with extensive disease was grade 3 (n = 2). The maximum percentage fall in platelet counts was 61 per cent. Maximum platelet toxicity for limited disease was in grade 1 (n = 3). For patients with limited disease, the maximum percentage fall in platelet counts was 62 per cent. Two patients with a baseline platelet count of <100 (80-98 respectively), had NCI toxicities of grade 2 and 3 respectively with a percentage in counts of 33 per cent and 59 per cent respectively. None of 84 treated patients had significant neutropaenia. One patient had grade 4 red cell toxicity (Hb = 5) which occurred in the first week following treatment, was not associated with white cell or platelet toxicity and felt to be secondary to DIC rather than a result of strontium -89. The post-therapy percentage fall in platelet counts was not clearly related to extent of bone disease