title: Does t3 subdivision correlate with nodal or distant metastasis in colorectal cancer?
abstract: OBJECTIVE
  We analyzed the clinical data of T3 colorectal cancer patients to assess whether T3 subdivision correlates with node (N) or metastasis (M) staging and stage-independent factors.
  
  
  METHODS
  Five hundred fifty-five patients who underwent surgery for primary colorectal cancer from January 2003 to December 2009 were analyzed for T3 subdivision. T3 subdivision was determined by the depth of invasion beyond the outer border of the proper muscle (T3a, <1 mm; T3b, 1 to 5 mm; T3c, >5 to 15 mm; T3d, >15 mm). We investigated the correlation between T3 subdivision and N, M staging and stage-independent prognostic factors including angiolymphatic invasion (ALI), venous invasion (VI) and perineural invasion (PNI).
  
  
  RESULTS
  The tumors of the 555 patients were subclassified as T3a in 86 patients (15.5%), T3b in 209 patients (37.7%), T3c in 210 patients (37.8%) and T3d in 50 patients (9.0%). The nodal metastasis rates were 39.5% for T3a, 56.5% for T3b, 75.7% for T3c and 74.0% for T3d. The distant metastasis rates were 7.0% for T3a 9.1% for T3b, 27.1% for T3c and 40.0% for T3d. Both N and M staging correlated with T3 subdivision (Spearman's rho = 0.288, 0.276, respectively; P < 0.001). Other stage-independent prognostic factors correlated well with T3 subdivision (Spearman's rho = 0.250, P < 0.001 for ALI; rho = 0.146, P < 0.001 for VI; rho = 0.271, P < 0.001 for PNI).
  
  
  CONCLUSIONS
  Subdivision of T3 colorectal cancer correlates with nodal and metastasis staging. Moreover, it correlates with other prognostic factors for colorectal cancer.
authors: Department of Surgery, Seoul National University College of Medicine, Seoul, Korea.
authors: Hong Yeol
authors: HY
authors: Yoo
authors: Rumi
authors: R
authors: Shin
authors: Heon-Kyun
authors: HK
authors: Ha
authors: Heung-Kwon
authors: HK
authors: Oh
authors: Seung-Yong
authors: SY
authors: Jeong
authors: Kyu Joo
authors: KJ
authors: Park
authors: Gyeong Hoon
authors: GH
authors: Kang
authors: Woo Ho
authors: WH
authors: Kim
authors: Jae-Gahb
authors: JG
authors: Park