P13CHANGING DOSE BANDINGS TO IMPROVE COMPLIANCE WITH TEMOZOLOMIDE CONCOMITANT WITH RADIOTHERAPY FOR HIGH GRADE GLIOMA; AN ANALYSIS OF SAFETY

INTRODUCTION: The current standard of care for the treatment of grade IV glioma is radiotherapy with concomitant temozolomide chemotherapy which conveys a 2.5 month improvement in overall survival and a 2.5 fold improvement in 2 year survival when compared to radiotherapy alone. The dose of concomitant Temozolomide, 75 mg/m2, often results in a complicated regimen of capsules of differing doses and has led to a clinical incident were the patient mixed up their different strength capsules resulting in an overdose. We changed the dose banding, rounding to the nearest 20 mg rather than 10 mg which was our previous practice, thereby eliminating the use of the 5 mg capsule. Using the previous dose banding the maximum potential dose received would be 78.6 mg/m2 however this increases to a potential 80.8 mg/m2 with the new dose banding. This is still below the maximum tolerated dose of 85 mg/m2 reported in the phase I trial. We audited the non-completion rate pre and post change and performed a root-cause analysis of any omitted doses to ensure tolerance of the new dose banding. METHOD: Retrospective case note analysis of all patients who underwent concomitant chemoradiotherapy for glioma 2 years before the dosage change and this was compared to those treated up to 20 months post change. RESULTS: Reasons for non completion were categorised as due to toxicity, clinical deterioration, logistics or co-morbidities. Pre dose change 102 patients were reviewed with 6.8% stopping their treatment due to toxicity. Post dose change 74 patients were reviewed with 2.7% stopping their treatment due to toxicity CONCLUSION: This comparison suggests that the newer dose banding is equally well tolerated when compared to the older dose.