QLTI-07. IDENTIFYING RISK FACTORS FOR PROLONGED TRANSFUSION-DEPENDENT TEMOZOLOMIDE-INDUCED THROMBOCYTOPAENIA IN PATIENTS RECEIVING CONCURRENT CHEMO-RADIOTHERAPY FOR GLIOBLASTOMA (GBM)

Abstract BACKGROUND Temozolomide-induced thrombocytopaenia is a well-recognised clinical issue with significant inter-patient variation. However, knowledge of the extent problem and its potential risk factors remains limited. Our aim was to determine incidence patients requiring platelet transfusion ascertain associated using real-world data. METHODS Data from GBM receiving concurrent temozolomide-chemo-radiotherapy (CRT) 01/01/18-31/12/2019 retrospectively reviewed. Patients identified (Local policy: for count ≤ 30x109/L). Logistic regression chi-squared tests used compare variables in those not. RESULTS 111 received TMZ-CRT (60Gy/30#; 75mg/m2 temozolomide). 12/111 transfusion: 10 during concurrent-CRT 2 adjuvant-treatment. Numbers transfusions: 1-2: 7 patients; 3-4: ≥ 5 3 patients. Median time G3 100 11/12 patients: 38 days (range 6-72). 1 did not recover, patient died 84 following start thrombocytopaenia. Comparison transfused vs non-transfused cohort shows: transfused: 50% female; non-transfused: 36% female. Mean BSA: 1.73, SD0.21; non-transfused:1.96, SD0.22 (OR 0.01; 95% CI:0.0003 – 0.16). age: 57, SD15.8; 58, SD10.7 . baseline count: 329, SD185; 319, SD117. PTV: 400, SD115; 414, SD123. There were no statistically associations demographics, age, blood parameters or planning target volume. CONCLUSION This study demonstrates subset who experience severe prolonged Risk elucidated are female sex lower BSA. Large-scale prospective trials evaluating panel predictors including concomitant medications, MGMT variants temozolomide-metabolite concentrations would be valuable. Precise stratification this vulnerable subgroup may permit consideration temozolomide dose-capping future. Careful informed consent all caution intensifying treatment under vital presently.