title: Accuracy of CT staging of locally advanced gastric cancer after neoadjuvant chemotherapy: cohort evaluation within a randomized phase II study.
abstract: BACKGROUND
  Accuracy of the radiologic diagnosis of gastric cancer staging after neoadjuvant chemotherapy remains unclear.
  
  
  METHODS
  Patients enrolled in the COMPASS trial, a randomized phase II study comparing two and four courses of S-1 plus cisplatin and paclitaxel and cisplatin followed by gastrectomy, were examined. The radiologic stage was determined by using thin-slice computed tomography (CT) or multidetector low CT by following Habermann's method.
  
  
  RESULTS
  A total of 75 patients registered in the COMPASS study who underwent surgical resection were examined in this study. The radiologic T and pathologic T stages were not significantly correlated (p = 0.221). The radiologic accuracy and rates of underdiagnosis and overdiagnosis were 42.7, 10.7, and 46.7%, respectively. When patients were stratified according to the pathologic response of the primary tumor, the correlation was not significant in either the responders (n = 32, p = 0.410) or the nonresponders (n = 43, p = 0.742). The radiologic accuracy was 37.5% in the responders and 42.7% in the nonresponders. The radiologic N and pathologic N stages were significantly correlated (p = 0.000). The radiologic accuracy and rates of underdiagnosis and overdiagnosis were 44, 29.3, and 26.7%, respectively. When stratifying the patients with measurable lymph nodes according only to the radiologic response, the correlation was significant in the nonresponders (n = 23, p = 0.035) but not in the responders (n = 28, p = 0.634). The radiologic accuracy was 39.3% in the responders and 52.1% in the nonresponders.
  
  
  CONCLUSIONS
  Restaging using CT after neoadjuvant chemotherapy for gastric cancer is considered to be inaccurate and unreliable. In particular, the radiologic T-staging determined after neoadjuvant chemotherapy should not be considered in clinical decision-making.
authors.affiliation: Department of Gastrointestinal Surgery, Kanagawa Cancer Center, Yokohama, Japan, yoshikawat@kcch.jp.
authors.forename: Takaki
authors.initials: T
authors.lastname: Yoshikawa
authors.forename: Kazuaki
authors.initials: K
authors.lastname: Tanabe
authors.forename: Kazuhiro
authors.initials: K
authors.lastname: Nishikawa
authors.forename: Yuichi
authors.initials: Y
authors.lastname: Ito
authors.forename: Takanori
authors.initials: T
authors.lastname: Matsui
authors.forename: Yutaka
authors.initials: Y
authors.lastname: Kimura
authors.forename: Shinichi
authors.initials: S
authors.lastname: Hasegawa
authors.forename: Toru
authors.initials: T
authors.lastname: Aoyama
authors.forename: Tsutomu
authors.initials: T
authors.lastname: Hayashi
authors.forename: Satoshi
authors.initials: S
authors.lastname: Morita
authors.forename: Yumi
authors.initials: Y
authors.lastname: Miyashita
authors.forename: Akira
authors.initials: A
authors.lastname: Tsuburaya
authors.forename: Junichi
authors.initials: J
authors.lastname: Sakamoto
mesh_terms: D000230:Adenocarcinoma / Q000473:pathology* / Q000628:therapy; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000971:Antineoplastic Combined Chemotherapy Protocols / Q000627:therapeutic use*; D002945:Cisplatin / Q000008:administration & dosage; D015331:Cohort Studies; D003131:Combined Modality Therapy; D004338:Drug Combinations; D005260:Female; D005500:Follow-Up Studies; D005743:Gastrectomy; D006801:Humans; D008297:Male; D008875:Middle Aged; D020360:Neoadjuvant Therapy; D009367:Neoplasm Staging; D010094:Oxonic Acid / Q000008:administration & dosage; D017239:Paclitaxel / Q000008:administration & dosage; D011379:Prognosis; D011857:Radiographic Image Interpretation, Computer-Assisted; D013274:Stomach Neoplasms / Q000473:pathology* / Q000628:therapy; D015996:Survival Rate; D005641:Tegafur / Q000008:administration & dosage; D014057:Tomography, X-Ray Computed / Q000379:methods*
chemical_list: D004338:Drug Combinations; C079198:S 1 (combination); D005641:Tegafur; D010094:Oxonic Acid; D017239:Paclitaxel; D002945:Cisplatin