title: Assessment of objective responses in thymic epithelial tumors using ITMIG modified criteria.
abstract: Pleural metastases of thymic epithelial tumors (TETs) are relatively common, and this unique growth pattern makes the use of RECIST (response evaluation criteria in solid tumors) response criteria difficult. To standardize tumor measurement in TETs, the International Thymic Malignancy Interest Group (ITMIG) has proposed newly developed criteria. We compared evaluation of objective response between ITMIG modified criteria and RECIST 1.1 in patients with TET treated with systemic chemotherapy.
  
  
  
  We retrospectively evaluated the tumor response of 40 patients with unresectable TET who were enrolled in a phase II clinical trial using ITMIG modified criteria, and compared the findings with prospectively evaluated tumor response assessed by RECIST 1.1. Agreement analyses for the response at each time point, including overall response and declaring progression, were performed and the time to progression (TTP) was also assessed using the two different measurements.
  
  
  
  The overall response rate assessed by the two methods did not differ significantly, with kappa value of 0.897. Agreement analysis for declaring progression of disease (PD) at the date of RECIST 1.1-designated PD showed 95% concordance rate with ITMIG modified criteria (p=1.000, kappa index=0.875). The median TTP according to RECIST 1.1 and ITMIG modified criteria was 8.4 and 7.9 months (p=0.983), respectively. Validation with another cohort of 27 TET patients treated with neoadjuvant chemotherapy also showed a 96% concordance rate in overall response between the two different criteria.
  
  
  
  ITMIG modified criteria showed a high concordance rate with RECIST 1.1 criteria in response assessment of TETs. Given the rarity of TETs, further evaluation of ITMIG modified criteria in a larger number of patients will be required before their implementation in clinical trials.
authors.affiliation: Division of Hematology-Oncology, Department of Medicine, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, Republic of Korea; Division of Hematology-Oncology, Department of Medicine, Veterans Health Service Medical Center, Seoul, Republic of Korea.
authors.forename: Hae Su
authors.initials: HS
authors.lastname: Kim
authors.affiliation: Division of Hematology-Oncology, Department of Medicine, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, Republic of Korea.
authors.forename: Ji Yun
authors.initials: JY
authors.lastname: Lee
authors.affiliation: Division of Hematology-Oncology, Department of Medicine, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, Republic of Korea.
authors.forename: Sung Hee
authors.initials: SH
authors.lastname: Lim
authors.affiliation: Division of Hematology-Oncology, Department of Medicine, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, Republic of Korea.
authors.forename: Jong-Mu
authors.initials: JM
authors.lastname: Sun
authors.affiliation: Division of Hematology-Oncology, Department of Medicine, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, Republic of Korea.
authors.forename: Se Hoon
authors.initials: SH
authors.lastname: Lee
authors.affiliation: Division of Hematology-Oncology, Department of Medicine, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, Republic of Korea.
authors.forename: Jin Seok
authors.initials: JS
authors.lastname: Ahn
authors.affiliation: Division of Hematology-Oncology, Department of Medicine, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, Republic of Korea.
authors.forename: Keunchil
authors.initials: K
authors.lastname: Park
authors.affiliation: Division of Hematology-Oncology, Department of Medicine, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, Republic of Korea. Electronic address: silkahn@skku.edu.
authors.forename: Myung-Ju
authors.initials: MJ
authors.lastname: Ahn
mesh_terms: D000328:Adult; D000368:Aged; D017322:Clinical Trials, Phase II as Topic / Q000379:methods; D018450:Disease Progression; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D020360:Neoadjuvant Therapy; D009367:Neoplasm Staging; D009375:Neoplasms, Glandular and Epithelial / Q000175:diagnosis* / Q000188:drug therapy* / Q000473:pathology; D010997:Pleural Neoplasms / Q000000981:diagnostic imaging / Q000473:pathology / Q000556:secondary; D066066:Response Evaluation Criteria in Solid Tumors; D012189:Retrospective Studies; D013953:Thymus Neoplasms / Q000175:diagnosis* / Q000188:drug therapy* / Q000473:pathology; D014057:Tomography, X-Ray Computed; D016896:Treatment Outcome
keywords: ITMIG; RECIST; Response criteria; Thymic epithelial tumor; Validation