title: Pseudoprogression in glioblastoma patients: the impact of extent of resection.
abstract: Pseudoprogression (psPD) is a radiation-induced toxicity that has substantial neurological consequence in glioblastoma (GBM) patients. MGMT promoter methylation has been shown to be an important prognostic factor of psPD, but the significance of extent of resection (EOR) remains unclear. We performed a retrospective analysis on newly diagnosed GBM patients with assessable MGMT promoter status who underwent the Stupp protocol. EOR was grouped into gross total resection (GTR), subtotal resection (STR), partial resection (PR) and stereotactic biopsy. Contrast enhancing lesion enlargement was classified as psPD or non-psPD. Among a total of 101 patients, GTR, STR, PR and stereotactic biopsy was performed in 57 (56.4%), 34 (33.7%), 9 (8.9%) and 1 patient (1%), respectively. Follow-up imaging at the end of Stupp protocol classified 45 patients (44.6%) as psPD and 56 (55.4%) as non-psPD. psPD was observed in 24 (61.5%) of 39 patients with methylated MGMT promoter and 21 (33.9%) of 62 patients with unmethylated MGMT promoter (p < 0.01). psPD was documented in 17 (29.8%), 19 (55.9%), 8 (88.9%) and 1 (100%) patient with GTR, STR, PR and stereotactic biopsy (p < 0.01), respectively. On multivariate analysis MGMT promoter status (OR 3.36, 95% CI 1.36-8.34) and EOR (OR 4.12, 95% CI 1.71-9.91) were independent predictors of psPD. A Cox proportional hazards model showed that MGMT status (HR 2.51, p < 0.01) and EOR (HR 2.99, p < 0.01) significantly influenced survival. MGMT status and EOR have a significant impact on psPD. GTR can reduce the side effects of psPD and prolong survival.
authors.affiliation: Departments of Neurosurgery, Yonsei University College of Medicine, Seoul, Korea.|Brain Tumor Center, Yonsei University College of Medicine, Seoul, Korea.
authors.forename: Hun Ho
authors.initials: HH
authors.lastname: Park
authors.affiliation: Departments of Neurosurgery, Yonsei University College of Medicine, Seoul, Korea.|Brain Tumor Center, Yonsei University College of Medicine, Seoul, Korea.
authors.forename: Tae Hoon
authors.initials: TH
authors.lastname: Roh
authors.affiliation: Departments of Neurosurgery, Yonsei University College of Medicine, Seoul, Korea.|Brain Tumor Center, Yonsei University College of Medicine, Seoul, Korea.|Brain Research Institute, Yonsei University College of Medicine, Seoul, Korea.
authors.forename: Seok Gu
authors.initials: SG
authors.lastname: Kang
authors.affiliation: Departments of Neurosurgery, Yonsei University College of Medicine, Seoul, Korea.|Brain Tumor Center, Yonsei University College of Medicine, Seoul, Korea.|Brain Research Institute, Yonsei University College of Medicine, Seoul, Korea.
authors.forename: Eui Hyun
authors.initials: EH
authors.lastname: Kim
authors.affiliation: Departments of Neurosurgery, Yonsei University College of Medicine, Seoul, Korea.
authors.forename: Chang-Ki
authors.initials: CK
authors.lastname: Hong
authors.affiliation: Departments of Pathology, Yonsei University College of Medicine, Seoul, Korea.|Brain Tumor Center, Yonsei University College of Medicine, Seoul, Korea.|Brain Research Institute, Yonsei University College of Medicine, Seoul, Korea.
authors.forename: Se Hoon
authors.initials: SH
authors.lastname: Kim
authors.affiliation: Departments of Radiology, Yonsei University College of Medicine, Seoul, Korea.|Brain Tumor Center, Yonsei University College of Medicine, Seoul, Korea.
authors.forename: Sung Soo
authors.initials: SS
authors.lastname: Ahn
authors.affiliation: Departments of Radiology, Yonsei University College of Medicine, Seoul, Korea.|Brain Tumor Center, Yonsei University College of Medicine, Seoul, Korea.
authors.forename: Seung Koo
authors.initials: SK
authors.lastname: Lee
authors.affiliation: Departments of Medical Oncology, Yonsei University College of Medicine, Seoul, Korea.|Brain Tumor Center, Yonsei University College of Medicine, Seoul, Korea.
authors.forename: Hye Jin
authors.initials: HJ
authors.lastname: Choi
authors.affiliation: Departments of Radiation Oncology, Yonsei University College of Medicine, Seoul, Korea.|Brain Tumor Center, Yonsei University College of Medicine, Seoul, Korea.
authors.forename: Jaeho
authors.initials: J
authors.lastname: Cho
authors.affiliation: Departments of Neurosurgery, Yonsei University College of Medicine, Seoul, Korea.|Brain Tumor Center, Yonsei University College of Medicine, Seoul, Korea.|Brain Research Institute, Yonsei University College of Medicine, Seoul, Korea.
authors.forename: Sun Ho
authors.initials: SH
authors.lastname: Kim
authors.affiliation: Departments of Neurosurgery, Yonsei University College of Medicine, Seoul, Korea.|Brain Tumor Center, Yonsei University College of Medicine, Seoul, Korea.|Brain Research Institute, Yonsei University College of Medicine, Seoul, Korea.
authors.forename: Kyu-Sung
authors.initials: KS
authors.lastname: Lee
authors.affiliation: Departments of Radiation Oncology, Yonsei University College of Medicine, Seoul, Korea. cosuh317@yuhs.ac.|Brain Tumor Center, Yonsei University College of Medicine, Seoul, Korea. cosuh317@yuhs.ac.|Department of Radiation Oncology, Yonsei University Health System, Yonsei University College of Medicine, 50-1 Yonsei-ro, Seodaemun-gu, Seoul, 120-752, Korea. cosuh317@yuhs.ac.
authors.forename: Chang-Ok
authors.initials: CO
authors.lastname: Suh
authors.affiliation: Departments of Neurosurgery, Yonsei University College of Medicine, Seoul, Korea. changjh@yuhs.ac.|Brain Tumor Center, Yonsei University College of Medicine, Seoul, Korea. changjh@yuhs.ac.|Brain Research Institute, Yonsei University College of Medicine, Seoul, Korea. changjh@yuhs.ac.|Department of Neurosurgery, Yonsei University Health System, Yonsei University College of Medicine, 50-1 Yonsei-ro, Seodaemun-gu, Seoul, 120-752, Korean. changjh@yuhs.ac.
authors.forename: Jong Hee
authors.initials: JH
authors.lastname: Chang
mesh_terms: D000328:Adult; D000368:Aged; D001932:Brain Neoplasms / Q000473:pathology* / Q000601:surgery*; D018450:Disease Progression; D005260:Female; D005500:Follow-Up Studies; D005909:Glioblastoma / Q000473:pathology* / Q000601:surgery*; D006801:Humans; D008297:Male; D008875:Middle Aged; D060787:Neoplasm Grading; D019635:Neurosurgical Procedures / Q000009:adverse effects*; D011183:Postoperative Complications; D011379:Prognosis; D012189:Retrospective Studies; D015996:Survival Rate; D055815:Young Adult
keywords: Extent of resection; Glioblastoma; MGMT promoter status; Pseudoprogression