PP62. DO THE RESPONSE ASSESSMENTS ON MRI SCAN PERFORMED AFTER TWO CYCLES OF BEVACIZUMAB (AVASTIN) CORRELATE WITH OVERALL SURVIVAL AND NEUROLOGICAL IMPROVEMENTS IN PATIENTS WITH GLIOBLASTOMA?
Authors: Dr Sanjay Dixit, Dr Diana Noma, Dr Mohan Hingorani, Mr Shailendra Achawal, Dr David Salvage
Journal: Neuro-Oncology (2017)

BACKGROUND: Many studies verified the association between the response assessment parameters measured on MRI scans and the survival, but such an association with neurological improvement has not been widely reported. MATERIALS AND METHODS: In this study, the author (DS), blinded to the outcomesmeasured the tumour in the two dimensions (perpendicular diameter) and in the one direction (length) for the objective assessment and ranked the degree of changes in the oedema and contrast enhancement for subjective assessment on the MRI performed after delivering 2 cycles of bevacizumab in thirty- four patients with progressive and recurrent glioblastoma. The percent changes of both, the diameter and the length, on the scans performed after cycle 2 are calculated comparing to those measured on the base- line MRI scans. Similarly, for the subjective assessment, changes in the degree of oedema on FLAIR sequences and in the degree of contrast enhancement on T1-contrast sequences (cycle 2) were marked as any degree of improvement (mild, moderate, or marked) or deterioration (unchanged or increased) compared to the those of base line images of similar sequences. The aims of this study were to assess if any of these response assessment parameters could correlate with the outcomes - neurological improvement and overall survival (OS). The neurological status of the patients were recorded prospectively every 2-week. The changes in the neurological status were calculated as the proportion of the number of weeks the patients had improved neurological status (% weeks) to the total number of weeks of bevacizumab exposure. OS is calculated from the date of first cycle to the date of last follow up or death. RESULTS: The mean number of chemotherapy exposure was 25 weeks, and the mean number of weeks the patients’ neurological status remained improved was 15 weeks. The mean proportion of number of weeks of improvement to that of exposure was 43%.The median survival of 34 patients was 9 months (IQR- 5.1 to 15.8 months). OBJECTIVE ASSESSMENT: More than 50% reduction in the perpendicular diameter is significantly associated with increased proportion of mean number of weeks of neurological improvement (34% vs 8%) and increased median survival (15 vs 7 months). More than one third (34%) reduction in the perpendicular diameter is not associated with the improved neurological duration but is significantly associated with the increased survival (11 vs 7 months). Percent reduction in the length is not associated with the improvement in the neurological status duration, but is significant related to the survival. (Spearman p=0.0388). SUBJECTIVE ASSESSMENT: Any degree of the reduction of the oedema on FLAIR sequences is associated with increased in proportionate number of weeks improvement in the neurological status (20.5 % weeks vs. 2.8% weeks) compared to that of unchanged or increased oedema. Similarly, decrease in oedema is associated with significantly longer median survival (9.8 months vs 6.3 months). Changes in the contrast enhancement are not associated with the improvement in the duration of increased neurological status; neither they are associated with overall survival.