title: Vascular invasion, but not lymphatic invasion, of the primary tumor is a strong prognostic factor in patients with colorectal cancer.
abstract: BACKGROUND
  We previously showed that the presence of vascular invasion, but not lymphatic invasion, was a strong prognostic factor for breast cancer. Lymphatic invasion may represent mainly the selective affinity of cancer cells for lymph nodes. The present study was undertaken to evaluate the presence of vascular invasion that may reflect systemic disease as a predictor of disease recurrence in colorectal cancer, separate from lymphatic invasion of the primary tumor.
  
  
  METHODS
  We retrospectively evaluated the cases of 177 consecutive patients with primary colorectal cancer who underwent colorectal resection. We examined the relationship between recurrence and the prognostic significance of clinicopathological factors, particularly lymphatic and vascular invasion.
  
  
  RESULTS
  The presence of vascular invasion (v) was significant, while that of lymphatic invasion (ly) was not significant in univariate analysis. The presence of vascular invasion was an independent prognostic factor in multivariate analysis. Among the 60 patients in the ly-/v- group, one (1.7%) had disease recurrence, and among the 33 patients in the ly+/v- group, one (3.0%) had disease recurrence. On the other hand, among the 71 patients in the ly+/v+ group, 16 patients (22.5%) suffered recurrence, and among the 13 patients in the ly-/v+ group, four (30.8%) suffered recurrence. It is interesting to note that despite the presence of lymphatic invasion, the group without vascular invasion (ly+/v-) had a few patients with distant metastases, a result which is similar to that of the ly-/v- group.
  
  
  CONCLUSIONS
  The presence of vascular invasion, but not lymphatic invasion, could be an indicator of high biological aggressiveness and may be a strong prognostic factor for colorectal cancer.
authors.affiliation: Department of General Surgical Science, Gunma University Graduate School of Medicine. Maebashi, Gunma, Japan taka.jifu@gmail.com.
authors.forename: Takaaki
authors.initials: T
authors.lastname: Fujii
authors.affiliation: Department of General Surgical Science, Gunma University Graduate School of Medicine. Maebashi, Gunma, Japan.
authors.forename: Toshinaga
authors.initials: T
authors.lastname: Sutoh
authors.affiliation: Department of General Surgical Science, Gunma University Graduate School of Medicine. Maebashi, Gunma, Japan.
authors.forename: Hiroki
authors.initials: H
authors.lastname: Morita
authors.affiliation: Department of General Surgical Science, Gunma University Graduate School of Medicine. Maebashi, Gunma, Japan.
authors.forename: Reina
authors.initials: R
authors.lastname: Yajima
authors.affiliation: Department of Surgical Oncology, Dokkyo Medical University, Mibu, Tochigi, Japan.
authors.forename: Satoru
authors.initials: S
authors.lastname: Yamaguchi
authors.affiliation: Department of General Surgical Science, Gunma University Graduate School of Medicine. Maebashi, Gunma, Japan.
authors.forename: Soichi
authors.initials: S
authors.lastname: Tsutsumi
authors.affiliation: Oncology Clinical Development, Gunma University Graduate School of Medicine. Maebashi, Gunma, Japan.
authors.forename: Takayuki
authors.initials: T
authors.lastname: Asao
authors.affiliation: Department of General Surgical Science, Gunma University Graduate School of Medicine. Maebashi, Gunma, Japan.
authors.forename: Hiroyuki
authors.initials: H
authors.lastname: Kuwano
mesh_terms: D000230:Adenocarcinoma / Q000098:blood supply / Q000401:mortality / Q000556:secondary*; D000368:Aged; D015179:Colorectal Neoplasms / Q000098:blood supply / Q000401:mortality / Q000473:pathology*; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008198:Lymph Nodes / Q000098:blood supply / Q000473:pathology*; D008207:Lymphatic Metastasis; D042601:Lymphatic Vessels / Q000473:pathology*; D008297:Male; D009361:Neoplasm Invasiveness; D009364:Neoplasm Recurrence, Local / Q000175:diagnosis* / Q000401:mortality; D009367:Neoplasm Staging; D009389:Neovascularization, Pathologic / Q000473:pathology*; D011379:Prognosis; D012189:Retrospective Studies; D015996:Survival Rate; D019043:Vascular Neoplasms / Q000098:blood supply / Q000401:mortality / Q000556:secondary*
keywords: Vascular invasion; colorectal cancer; lymphatic invasion; prognosis