title: Validity of response assessment criteria in neoadjuvant chemotherapy for gastric cancer (JCOG0507-A).
abstract: BACKGROUND
  Neoadjuvant chemotherapy may improve outcomes in gastric cancer. Tumor responses can be evaluated with RECIST, Japanese Classification of Gastric Carcinoma (JCGC), and histological criteria. These approaches have not yet been compared.
  
  
  METHODS
  We analyzed two phase II trials of neoadjuvant chemotherapy using S-1 plus cisplatin. JCOG0210 included patients with linitis plastica and large ulcero-invasive tumors, whereas JCOG0405 comprised those with para-aortic or bulky lymph node metastases. Radiologic evaluations were conducted using RECIST in JCOG0405 and JCGC criteria in JCOG0210, because the latter included many patients without measurable lesions. A histological responder was defined as a patient in whom one third or more of the tumor was affected. The hazard ratios (HR) for death between responders and non-responders and response rate differences between short- and long-term survivors were estimated.
  
  
  RESULTS
  In JCOG0210 (n = 49), HR was 0.54 in JCGC responders (P = 0.059) and 0.40 in histological responders (P = 0.005). The difference in response rates between short- and long-term survivors using histological criteria (34 %, P = 0.023) was greater than that using JCGC criteria (24 %, P = 0.15). In JCOG0405 (n = 51), HR was 0.67 in RECIST responders (P = 0.35) and 0.39 in histological responders (P = 0.030). In short- and long-term survivors, respectively, RECIST response rates were 62  and 67 % (P = 0.77), whereas histological response rates were 33  and 63 % (P = 0.048).
  
  
  CONCLUSIONS
  Histological criteria showed higher response assessment validity than RECIST or JCGC criteria and yielded the best surrogate endpoint for overall survival.
authors.affiliation: Department of Gastroenterological Surgery, Osaka University Graduate School of Medicine, 2-2-E2 Yamadaoka, Suita, Osaka, Japan, ykurokawa@gesurg.med.osaka-u.ac.jp.
authors.forename: Yukinori
authors.initials: Y
authors.lastname: Kurokawa
authors.forename: Taro
authors.initials: T
authors.lastname: Shibata
authors.forename: Mitsuru
authors.initials: M
authors.lastname: Sasako
authors.forename: Takeshi
authors.initials: T
authors.lastname: Sano
authors.forename: Akira
authors.initials: A
authors.lastname: Tsuburaya
authors.forename: Yoshiaki
authors.initials: Y
authors.lastname: Iwasaki
authors.forename: Haruhiko
authors.initials: H
authors.lastname: Fukuda
mesh_terms: D000328:Adult; D000368:Aged; D000971:Antineoplastic Combined Chemotherapy Protocols / Q000627:therapeutic use*; D002945:Cisplatin / Q000008:administration & dosage; D004338:Drug Combinations; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D020360:Neoadjuvant Therapy / Q000379:methods; D009361:Neoplasm Invasiveness; D009362:Neoplasm Metastasis; D010094:Oxonic Acid / Q000008:administration & dosage; D016016:Proportional Hazards Models; D013274:Stomach Neoplasms / Q000145:classification / Q000188:drug therapy* / Q000473:pathology; D015996:Survival Rate; D005641:Tegafur / Q000008:administration & dosage; D013997:Time Factors; D016896:Treatment Outcome
chemical_list: D004338:Drug Combinations; C079198:S 1 (combination); D005641:Tegafur; D010094:Oxonic Acid; D002945:Cisplatin