title: Appraisal of 1 cm hepatectomy margins for intrahepatic micrometastases in patients with colorectal carcinoma liver metastasis.
abstract: BACKGROUND
  This study sought to clarify the distribution of intrahepatic micrometastases and elucidate an adequate hepatectomy margin for colorectal carcinoma liver metastases.
  
  
  METHODS
  Intrahepatic micrometastases in resected specimens from 90 patients who underwent hepatectomy for colorectal carcinoma liver metastases were examined retrospectively. Intrahepatic micrometastases were defined as microscopic lesions spatially separated from the gross tumor. Distances from these lesions to the hepatic tumor borders were measured histologically, and the density of intrahepatic micrometastases (number of lesions/mm(2)) calculated relative to the advancing tumor border in a zone <1 cm from the border (close) or >/=1 cm away (distant). Median follow-up time was 127 months.
  
  
  RESULTS
  A total of 294 intrahepatic micrometastases were detected in 52 (58%) patients; 95% of these occurred in the close zone. The density of intrahepatic micrometastases was significantly higher in the close zone (mean 74.8 x 10(-4 ) lesions/mm(2)) than in the distant zone (mean 7.4 x 10(-4 ) lesions/mm(2); P < 0.001). Hepatectomy margin status was positive by 0 cm in 10 patients or negative by <1 cm in 51, and by >/=1 cm in 29 patients. The median survival times were 18, 33, and 89 months in patients with hepatectomy margins 0 cm, <1 cm, and >/=1 cm, respectively. Hepatectomy margin status independently influenced survival (P < 0.001) and disease-free survival (P < 0.001).
  
  
  CONCLUSIONS
  The currently recommended >/=1 cm hepatectomy margin should remain the goal for resections of colorectal carcinoma liver metastases, based on the distribution of intrahepatic micrometastases and survival risk.
authors.affiliation: Division of Digestive and General Surgery, Niigata University Graduate School of Medical and Dental Sciences, 1-757 Asahimachi-dori, Chuo-ku, Niigata City, 951-8510, Japan. wakait@med.niigata-u.ac.jp
authors.forename: Toshifumi
authors.initials: T
authors.lastname: Wakai
authors.forename: Yoshio
authors.initials: Y
authors.lastname: Shirai
authors.forename: Jun
authors.initials: J
authors.lastname: Sakata
authors.forename: Vladimir A
authors.initials: VA
authors.lastname: Valera
authors.forename: Pavel V
authors.initials: PV
authors.lastname: Korita
authors.forename: Kouhei
authors.initials: K
authors.lastname: Akazawa
authors.forename: Yoichi
authors.initials: Y
authors.lastname: Ajioka
authors.forename: Katsuyoshi
authors.initials: K
authors.lastname: Hatakeyama
mesh_terms: D000230:Adenocarcinoma / Q000556:secondary / Q000601:surgery*; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D015179:Colorectal Neoplasms / Q000473:pathology* / Q000601:surgery; D005260:Female; D005500:Follow-Up Studies; D006498:Hepatectomy; D006801:Humans; D008113:Liver Neoplasms / Q000556:secondary / Q000601:surgery*; D008207:Lymphatic Metastasis; D008297:Male; D008875:Middle Aged; D009364:Neoplasm Recurrence, Local / Q000175:diagnosis*; D009367:Neoplasm Staging; D011379:Prognosis; D012189:Retrospective Studies; D015996:Survival Rate; D016896:Treatment Outcome