title: Pseudoprogression and pseudoresponse in the management of high-grade glioma : optimal decision timing according to the response assessment of the neuro-oncology working group.
abstract: OBJECTIVE
  We evaluated pseudoprogression (PsPD) following radiation therapy combined with concurrent temozolomide (TMZ), and we assessed pseudoresponse following anti-angiogenic therapy for patients with recurrent disease using the Response Assessment of the Neuro-Oncology Working Group.
  
  
  METHODS
  Patients who were pathologically confirmed as having high-grade glioma received radiotherapy with concurrent TMZ followed by adjuvant TMZ. Bevacizumab (Avastin) with CPT-11 were used as a salvage option for cases of radiologic progression. Magnetic resonance imaging (MRI) was routinely performed 1 month after concurrent radiochemotherapy (CRT) and every 3 months thereafter. For cases treated with the bevacizumab-containing regimen for progressive disease, MRI was performed every 2 months.
  
  
  RESULTS
  Of 55 patients, 21 (38%) showed radiologic progression within 4 weeks after CRT. Of these patients, 16 (29%) showed progression at second post-CRT MRI (etPD) and five (9%) showed improvement (PsPD). Seven of thirty-four initially non-progressed patients showed progression at the second post-CRT MRI (ltPD). No difference in survival was observed between the etPD and ltPD groups (p=0.595). Five (50%) of ten patients showed a radiological response after salvage bevacizumab therapy. Four of those patients exhibited rapid progression immediately after discontinuation of the drug (drug holiday).
  
  
  CONCLUSIONS
  Twelve weeks following treatment could be the optimal timing to determine PsPD or true progression. MRI with gadolinium enhancement alone is not sufficient to characterize tumor response or growth. Clinical correlation with adequate follow-up duration and histopathologic validation may be helpful in discriminating PsPD from true progression.
authors.affiliation: Department of Radiation Oncology, Seoul National University Bundang Hospital, Seongnam, Korea.
authors.forename: Ji Hyun
authors.initials: JH
authors.lastname: Chang
authors.affiliation: Department of Neurosurgery, Seoul National University Bundang Hospital, Seongnam, Korea.
authors.forename: Chae-Yong
authors.initials: CY
authors.lastname: Kim
authors.affiliation: Department of Radiology, Seoul National University Bundang Hospital, Seongnam, Korea.
authors.forename: Byung Se
authors.initials: BS
authors.lastname: Choi
authors.affiliation: Department of Internal Medicine, Seoul National University Bundang Hospital, Seongnam, Korea.
authors.forename: Yu Jung
authors.initials: YJ
authors.lastname: Kim
authors.affiliation: Department of Radiation Oncology, Seoul National University Bundang Hospital, Seongnam, Korea.
authors.forename: Jae Sung
authors.initials: JS
authors.lastname: Kim
authors.affiliation: Department of Radiation Oncology, Seoul National University Bundang Hospital, Seongnam, Korea.
authors.forename: In Ah
authors.initials: IA
authors.lastname: Kim
keywords: Concurrent radiochemotherapy; High-grade glioma; Pseudoprogression; Pseudoresponse