Abstract Details

Title Treatment-related adverse effects in patients with brain cancer: identification of distinctive features for pseudoprogression and treatment-induced necrosis.

Topic Neuro-oncology

Presentation(s) S30 - Brain Cancer: From Epidemiology to Quality of Life (3:52 PM-4:03 PM)

Poster/Presentation
Number 003

Objective To characterize the clinical, radiographic, and histopathological features of pseudoprogression (PP) and treatment-induced necrosis (TN) and improve non-invasive diagnostic differentiation from true disease progression.

Background PP and TN are insufficiently characterized, clinically challenging conditions in neuro-oncology. Since both entities radiographically mimic recurrent disease, patients frequently undergo potentially unnecessary surgical interventions to guide management.

Design/Methods Patients with malignant glioma and a diagnosis of either PP (appearance <5 months post-radiotherapy [RT] completion) or TN (appearance >5 months post-RT) were retrospectively identified and compared using clinical-radiographic and histopathological data. Each imaging event/lesion [ROI] diagnosed as PP or TN was evaluated by T1+C weighted MRI and correlated to the RT dose distribution curves.

Results Cumulatively, PP (n=27) and TN (n=37) groups comprised 137 individual radiographic ROIs (n=62 biopsy-proven, n=75 radiographic diagnosis). Most patients received concurrent+sequential chemotherapy. Gender and KPS did not differ significantly between groups. Patients with PP had mostly glioblastomas (81 vs 40%; p<0.002), fewer IDH1 mutations (p<0.006), a greater incidence of recurrence (p=0.03) and a shorter median overall survival (3.25 years vs. not reached (62% survival estimate at 24.5 years); p<0.0001). PP lesions occurred earlier (median onset post-RT: 1 vs. 11 months; p<0.00001), mostly during anti-neoplastic treatment (85 vs 32%; p<0.0005), and necessitated more steroid-based interventions (p<0.04). TN lesions often initially appeared periventricularly (n=22/37; 60%), were more numerous (median: 2 vs. 1 ROIs; p=0.01), and contained fewer malignant elements upon biopsy (p=0.008). While distance from the tumor resection cavity (RC) varied considerably for TN lesions (median: 21.5mm; range: 0–78mm), PP predominantly developed at the RC as a non-nodular, ring-like enhancing structure (p<0.0001).*

Conclusions

PP and TN appear to occur in clinically distinct patient populations and differ significantly in spatio-temporal radiographic pattern and histopathology. Increased familiarity with their unique features will improve patient management and may avoid unnecessary surgical procedures.

*Data will be presented at SNO 2018.

Authors/Disclosures
Sebastian Friedrich Winter (MGH Cancer Center) PRESENTER	Mr. Winter has nothing to disclose.
	No disclosure on file
Alona Muzikansky	No disclosure on file
	No disclosure on file
Helen Shih (MGH)	No disclosure on file
Maria Martinez-Lage, MD (Massachusetts General Hospital)	The institution of Dr. Martinez-Lage has received research support from NIH.
	No disclosure on file
	No disclosure on file
Jorg Dietrich, MD, PhD, FAAN	Dr. Dietrich has received personal compensation in the range of $500-$4,999 for serving as a Consultant for Amgen. Dr. Dietrich has received personal compensation in the range of $500-$4,999 for serving as a Consultant for Novartis. Dr. Dietrich has received personal compensation in the range of $500-$4,999 for serving as a Consultant for Ono Therapeutics. Dr. Dietrich has received personal compensation in the range of $500-$4,999 for serving on a Scientific Advisory or Data Safety Monitoring board for Johnson & Johnson. Dr. Dietrich has received publishing royalties from a publication relating to health care.

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