ACT-05 PREDICTIVE FACTORS RELATING TO OUTCOME AFTER RESECTION OF LOW-GRADE GLIOMAS WITHOUT CHEMOTHERAPY OR RADIOTHERAPY

• Published in: Neuro-oncology advances Vol. 1; no. Supplement_2; p. ii13
• Main Authors: Ikuta, Soko, Maruyama, Takashi, Saito, Taiichi, Nitta, Masayuki, Tsuzuki, Syunsuke, Fukui, Atsushi, Kawamata, Takakazu, Muragaki, Yoshihiro
• Format: Journal Article
• Language: English
• Published: US Oxford University Press 16.12.2019
• Subjects: Abstracts
• ISSN: 2632-2498; 2632-2498
• DOI: 10.1093/noajnl/vdz039.059

Abstract BACKGROUND There are several treatment options, including observation, after surgical removal of low-grade gliomas (LGG). If postoperative chemotherapy and/or radiotherapy are not provided, resection-alone approach will probably be alternative to a natural course of LGG under observation. The objective of this study was evaluation of prognostic factors associated with overall survival (OS) of patients with LGG treated with surgery alone. METHODS A consecutive series of 236 adult patients who underwent surgery for LGG without adjuvant therapy was analyzed retrospectively. In 193 cases (82%) histopathology of the tumor was re-classified based on evaluation of IDH1 mutational status and 1p/19q co-deletion according to criteria of WHO classification 2016. Cox proportional hazards model was used for statistical analysis. RESULTS Median extent of resection (EOR) was 95% (range, 1–100%) and in 210 cases (89%) EOR was >=90%. During postoperative follow-up tumor progression was noted in 106 patients, and 30 patients died of disease. Overall, 10-year OS rate was 82.0%. There was statistically significant difference (P <0.001) in OS among molecularly re-classified tumors, with 10-year OS rates of 90%, 79%, and 75% in cases of OD, DA IDH1-mutant, and DA IDH1-wild, respectively. In patients with EOR >=90% 10-year OS rate was 75%. Multivariate analysis revealed that only EOR >=90% (RR, 0.23; 95% CI, 0.09–0.66; P<0.007) and presence of 1p/19q co-deletion (RR, 0.41; 95% CI, 0.16–0.97; P = 0.042) are independently associated with OS. In patients with EOR >=90% such factors as type of disease manifestation, time interval between onset of symptoms and surgery, and molecular subtype of the tumor did not show significant associations with OS. CONCLUSION Survival outcome in patients with LGG who underwent surgical resection alone may be predicted by EOR and presence of 1p/19q co-deletion. In cases with EOR >=90% molecular subtype of the neoplasm does not impact OS.