Abstract Details

Title Prognostic importance of the extent of resection in IDH-wild type grade II astrocytomas according to EGFR amplification and pTERT mutation.

Topic Neuro-oncology

Presentation(s) S16 - Neuro-oncology (4:00 PM-4:08 PM)

Poster/Presentation
Number 001

Background In IDH-wild type grade II astrocytomas, EGFR amplification and pTERT correlate with a poor prognosis. In a previous series of the Italian Association of Neuro-Oncology, we reported that IDH-wild type grade II astrocytomas benefit from gross total resection. However, the impact of surgery in the EGFR amplificated and pTERT-mutated subgroups has not been addressed so far.

Objective In a cohort of 120 IDH-wild type grade II astrocytomas, to assess the impact of the extent of resection (EOR) according to the EGFR and pTERT status.

Design/Methods

We re-analysed a national database of 120 patients with IDH-wild type grade II astrocytoma. EGFR amplification and pTERT mutation were analysed by FISH and gene sequencing, respectively. Kaplan-Meier curves were used for overall survival (OS).

Results

EGFR and pTERT statuses were available in 63 and 59 cases, respectively: EGFR amplification was found in 54 (86.0%) and pTERT mutation in 29 (49.2%). EGFR-amplificated patients had a shorter OS (23.5 vs 28.4 months, P=0.01). Similarly, pTERT-mutant patients had a shorter OS (31.9 vs 192.0 months, P = 0.006). Among patients without EGFR amplification, gross total resection (GTR) correlated to longer OS as compared to partial/subtotal (PR/SBT) resection (117.9 vs 20 months, P=0.04), whereas no significant difference was seen in the EGFR-amplificated group (11.8 vs 4.5 months, P=0.4). Similarly, among patients without pTERT mutation, GTR correlated to longer OS as compared to PR/SBT (not reached vs 53.7 months, P=0.05), while no significant difference was seen in the pTERT-mutant group (37.0 vs 22.0 months, P=0.6).

Conclusions

To our knowledge, this is the first study that investigated the impact of the EOR according to EGFR amplification and pTERT mutation in IDH-wild type grade II astrocytomas: interestingly, EGFR-amplificated and pTERT-mutant patients did not seem to benefit from the EOR, differently from those with no such alterations.

Authors/Disclosures
Francesco Bruno, MD (University and City Hospital of Health and Science) PRESENTER	No disclosure on file
	No disclosure on file
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	No disclosure on file
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	No disclosure on file
	No disclosure on file
	No disclosure on file
Riccardo Soffietti, MD (University of Turin)	Dr. Soffietti has nothing to disclose.
	No disclosure on file