INFLUENCE OF DETERMINATION OF PROGRESSION ON PATTERNS OF FLAIR FAILURE ANALYSIS IN PATIENTS WITH GRADE III ANAPLASTIC ASTROCYTOMA (AA) AND ASSOCIATION OF PATTERN OF FAILURE (POF) WITH SURVIVAL
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| Year of publication | 2014 |
| Type | Conference abstract |
| MU Faculty or unit | |
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| Description | Purpose/Objectives: RANO criteria have recently been proposed as response guidelines for contrast-enhancing high grade gliomas, but the utility of these guidelines has not been established in AA. In this report we evaluated the utility of RANO criteria in determining progression and POF in AA and evaluated the association of POF with overall survival (OS). Materials/Methods: We performed a retrospective review of MR images for 21 consecutive patients with AA and radiologically-proven recurrence after irradiation at the Mayo Clinic (Rochester, MN). Three different criteria for identification of progression were used for each patient: 1) standard RANO-based criteria (RANO-C; most often met by development of new contrast enhancement or enlargement of contrast-enhancing lesion), 2) RANO criteria for progression based on significant FLAIR increase (RANO-F) and 3) clinical progression based on oncologist interpretation of imaging and clinical status usually resulting in change in treatment (Clinical). Time to progression was assessed among the three criteria using Friedman’s test, and pairwise criteria using a sign test. After subtraction of tumor volume occurring on the best-response MR study, final structure was dosimetrically analyzed and different POF were characterized by the % volume encompassed within the 95% dose as follows: central (V95%95%), in-field (80%V95%<95%), marginal (20%V95%<80%), or distant (V95%<20%). Results: Time to progression based on RANO criteria preceeded the clinical diagnosis of progression by a median of 3.13 months (9.2 vs 12.6 mo p<0.0001, Sign test). New or progressive contrast enhancement (RANO-C) was almost entirely central or in-field (95% and 5%, respectively). POF of FLAIR component differed based on timepoint used to determine progression. FLAIR POF was significantly more often marginal or distant when progression was defined clinically compared to either RANO-C or RANO-F criteria (p=.03 and .007 respectively). POF for FLAIR abnormality at the time of RANO-C was 33% central, 24% in-field and 43% marginal; at RANO-F was 47%, 16% and 37% respectively, and at the time of Clinical recurrence were more often peripheral with 19% central, 24% in-field, 52% marginal and 1 patient (5%) distant. No association with POF and OS was seen when evaluated at the time of RANO defined progression. Central POF at Clinical determination of progression was associated with poorer OS (9.8 vs 29.7 months, p=0.0012). Conclusion: POF analysis in AA is dependent on method of progression determination. Time to progression based on RANO criteria generally preceeded clinician impression. POF at the time of RANO determination of progression was not associated with survival. Central recurrence as evaluated at the time of clinical progression is strongly associated with poorer OS. |