title: [Analysis of metastatic patterns after curative colorectal cancer surgery based on primary tumor location].
abstract: OBJECTIVE
  To evaluate metastatic patterns of colorectal cancer following curative surgery based on primary tumor location in order to provide evidence for the decision of individualized adjuvant therapy and postoperative follow-up.
  
  
  METHODS
  Clinical and follow-up data of 904 patients who underwent curative colorectal cancer in The Affiliated Tumor Hospital of Zhengzhou University from October 2004 to October 2012 with complete follow-up data were analyzed retrospectively. A total 274 patients belonged to right-sided colon cancer group (cecum, ascending, hepatic flexure, and transverse colon), 243 belonged to left-sided colon cancer group(splenic flexure, descending, and sigmoid colon), and 387 belonged to rectal cancer group. The overall rate of distal metastasis and site-specific metastasis rates (liver, lung, and peritoneum) were compared among these 3 groups.
  
  
  RESULTS
  The cohort patients had a median follow-up of 37(4-122) months, and the median follow-up duration was similar in right-sided, left-sided, and rectal cancer groups with 39(5-119), 39(6-122) and 36(5-121) months(P=0.513). During the follow-up period, 44 patients (4.9%) had local recurrence alone, 137 (15.2%) distal metastasis alone, and 30(3.3%) local recurrence combined with distal metastasis. Compared to right-sided colon cancer group, rectal and left-sided cancer groups had significantly higher overall metastasis rates [23.5% (91/387), 17.3% (42/243) vs. 12.0% (33/274), P=0.000). With respect to specific regions, lung metastasis rate in rectal cancer group was 9.3%, which was significantly higher than that in left-sided(4.5%) and right-sided colon cancer group(2.6%)(P=0.001). Other sites of metastasis did not yield significant differences, including liver(P=0.130) and peritoneum(P=0.858).
  
  
  CONCLUSIONS
  Cancer location may be used as a reference of personalized adjuvant therapy and postoperative follow-up surveillance programs. Lower threshold for adjuvant therapy in rectal and left-sided colon cancers, and more aggressive surveillance for lung metastasis by chest X-ray or CT should be considered.
authors.forename: Jian
authors.initials: J
authors.lastname: Zhang
authors.affiliation: Departmeng of General Surgery, the Affiliated Tumor Hospital, Zhengzhou University, Zhengzhou 450008, China. 13673384555@163.com.
authors.forename: Guangsen
authors.initials: G
authors.lastname: Han
authors.forename: Zhiqiang
authors.initials: Z
authors.lastname: Jiang
authors.forename: Daohai
authors.initials: D
authors.lastname: Wang
mesh_terms: D000368:Aged; D044682:Colon, Ascending; D012809:Colon, Sigmoid; D044684:Colon, Transverse; D015179:Colorectal Neoplasms / Q000601:surgery*; D005260:Female; D006801:Humans; D008175:Lung Neoplasms; D008297:Male; D008875:Middle Aged; D009362:Neoplasm Metastasis; D009364:Neoplasm Recurrence, Local; D012189:Retrospective Studies