title: Ongoing and prolonged response in adult low-grade gliomas treated with radiotherapy.
abstract: The aim of the present study was to evaluate the impact of first-line radiotherapy on low-grade gliomas (LGGs) growth kinetics. The mean tumor diameter (MTD) of 39 LGGs was retrospectively measured on serial magnetic resonance images before (n = 16) and after radiotherapy onset (n = 39). After radiotherapy, a decrease of the MTD was observed in 37 patients. Median duration of the MTD decrease was 1.9 years (range 0-8.1 years). According to RANO criteria, the rates of partial and minor responses were 15 and 28 % at the first evaluation after radiotherapy and 36 and 34 % at the time of maximal MTD decrease. The presence of a 1p19q codeletion and the absence of p53 expression were associated with longer durations of MTD decrease (5.3 vs 1 years, p = 0.02 and 2.4 vs 1.8 years, p = 0.05, respectively) while no association was observed between IDH1-R132H expression and duration of MTD decrease. In most patients, MTD decrease after radiotherapy occurred in two phases: an initial phase of rapid MTD decrease followed by a second phase of slower MTD decrease. Patients with a high rate of MTD decrease during the initial phase (>7 mm/year) had both a shorter duration of response (1.9 vs 5.3 years, p = 0.003) and a shorter overall survival (5.5 vs 11.6 years, p = 0.0004). LGGs commonly display a prolonged and ongoing volume decrease after radiotherapy. However, patients who respond rapidly should be carefully monitored because they are at a higher risk of rapid progression.
authors: Lyon Neuroscience Research Center, INSERM U1028/CNRS UMR 5292, Université de Lyon - Université Claude Bernard Lyon 1, 69372, Lyon, France, francois.ducray@chu-lyon.fr.
authors: F
authors: F
authors: Ducray
authors: G
authors: G
authors: Kaloshi
authors: C
authors: C
authors: Houillier
authors: A
authors: A
authors: Idbaih
authors: B
authors: B
authors: Ribba
authors: D
authors: D
authors: Psimaras
authors: Y
authors: Y
authors: Marie
authors: B
authors: B
authors: Boisselier
authors: A
authors: A
authors: Alentorn
authors: L
authors: L
authors: Dainese
authors: S
authors: S
authors: Navarro
authors: K
authors: K
authors: Mokhtari
authors: M
authors: M
authors: Sanson
authors: K
authors: K
authors: Hoang-Xuan
authors: Jean-Yves
authors: JY
authors: Delattre
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D001932:Brain Neoplasms / Q000401:mortality / Q000473:pathology / Q000532:radiotherapy*; D018450:Disease Progression; D005260:Female; D005500:Follow-Up Studies; D005910:Glioma / Q000401:mortality / Q000473:pathology / Q000532:radiotherapy*; D006801:Humans; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D060787:Neoplasm Grading; D012189:Retrospective Studies; D015996:Survival Rate; D013997:Time Factors; D016896:Treatment Outcome; D055815:Young Adult
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