title: Prognostic and survival analysis of 837 Chinese colorectal cancer patients.
abstract: OBJECTIVE
  To develop a prognostic model to predict survival of patients with colorectal cancer (CRC).
  
  
  METHODS
  Survival data of 837 CRC patients undergoing surgery between 1996 and 2006 were collected and analyzed by univariate analysis and Cox proportional hazard regression model to reveal the prognostic factors for CRC. All data were recorded using a standard data form and analyzed using SPSS version 18.0 (SPSS, Chicago, IL, United States). Survival curves were calculated by the Kaplan-Meier method. The log rank test was used to assess differences in survival. Univariate hazard ratios and significant and independent predictors of disease-specific survival and were identified by Cox proportional hazard analysis. The stepwise procedure was set to a threshold of 0.05. Statistical significance was defined as P < 0.05.
  
  
  RESULTS
  The survival rate was 74% at 3 years and 68% at 5 years. The results of univariate analysis suggested age, preoperative obstruction, serum carcinoembryonic antigen level at diagnosis, status of resection, tumor size, histological grade, pathological type, lymphovascular invasion, invasion of adjacent organs, and tumor node metastasis (TNM) staging were positive prognostic factors (P < 0.05). Lymph node ratio (LNR) was also a strong prognostic factor in stage III CRC (P < 0.0001). We divided 341 stage III patients into three groups according to LNR values (LNR1, LNR ≤ 0.33, n = 211; LNR2, LNR 0.34-0.66, n = 76; and LNR3, LNR ≥ 0.67, n = 54). Univariate analysis showed a significant statistical difference in 3-year survival among these groups: LNR1, 73%; LNR2, 55%; and LNR3, 42% (P < 0.0001). The multivariate analysis results showed that histological grade, depth of bowel wall invasion, and number of metastatic lymph nodes were the most important prognostic factors for CRC if we did not consider the interaction of the TNM staging system (P < 0.05). When the TNM staging was taken into account, histological grade lost its statistical significance, while the specific TNM staging system showed a statistically significant difference (P < 0.0001).
  
  
  CONCLUSIONS
  The overall survival of CRC patients has improved between 1996 and 2006. LNR is a powerful factor for estimating the survival of stage III CRC patients.
authors.affiliation: Department of Medical Oncology, 2 Hospital of Zhejiang University College of Medicine, Hangzhou 310009, Zhejiang Province, China.
authors.forename: Ying
authors.initials: Y
authors.lastname: Yuan
authors.forename: Mo-Dan
authors.initials: MD
authors.lastname: Li
authors.forename: Han-Guang
authors.initials: HG
authors.lastname: Hu
authors.forename: Cai-Xia
authors.initials: CX
authors.lastname: Dong
authors.forename: Jia-Qi
authors.initials: JQ
authors.lastname: Chen
authors.forename: Xiao-Fen
authors.initials: XF
authors.lastname: Li
authors.forename: Jing-Jing
authors.initials: JJ
authors.lastname: Li
authors.forename: Hong
authors.initials: H
authors.lastname: Shen
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D044466:Asian People; D002681:China / Q000453:epidemiology; D015179:Colorectal Neoplasms / Q000175:diagnosis / Q000208:ethnology / Q000401:mortality / Q000473:pathology*; D005260:Female; D006801:Humans; D053208:Kaplan-Meier Estimate; D008207:Lymphatic Metastasis; D008297:Male; D008875:Middle Aged; D015999:Multivariate Analysis; D060787:Neoplasm Grading; D009361:Neoplasm Invasiveness; D009367:Neoplasm Staging; D011379:Prognosis; D016016:Proportional Hazards Models; D012307:Risk Factors; D015996:Survival Rate; D013997:Time Factors; D055815:Young Adult
keywords: Colorectal cancer; Cox proportional hazard regression; Lymph node ratio; Prognostic factors