Predictive factors of early relapse in UICC stage I-III colorectal cancer patients after curative resection.

BACKGROUND AND OBJECTIVES: To predict the clinicopathologic factors for early relapse of UICC stage I-III colorectal cancer (CRC) patients undergoing curative resection and thus to identify a subgroup of patients who are at high risk for postoperative early relapse.
METHODS: Between January 2001 and June 2007, a total of 778 UICC stage I-III CRC patients who underwent a radical resection and regular follow-up were retrospectively analyzed. Of these 778 CRC patients, 521 colon cancer and 257 rectal cancer cases were analyzed, respectively, to determine the predictors of early relapse postoperatively. These 778 patients were followed-up intensively, and their outcomes were investigated retrospectively.
RESULTS: Out of 521 colon cancer patients, postoperative relapse after primary resection was found in 142 (27.3%) patients, and 77 (54.2%) of 142 recurrent colon cancer patients were classified as postoperative early relapse. Meanwhile, among 257 rectal cancer patients, postoperative relapse was found in 68 (26.5%) patients and 44 (64.7%) of 68 recurrent rectal cancer patients were identified as postoperative early relapse. Forty-nine (63.6%) of 77 early relapsed colon cancer patients were stage III, and likewise, 26 (59.1%) of 44 early relapsed rectal cancer patients were stage III. Univariately, postoperative early relapse of colon cancer patients was significantly correlated with the presence of vascular invasion (P < 0.001), perineural invasion (P < 0.001), high postoperative carcinoembryonic antigen (CEA) level (P = 0.001), and type of surgery (P = 0.016). Using a Cox proportional hazards analysis, the presence of vascular invasion (P = 0.033), perineural invasion (P = 0.005), and high postoperative CEA levels (P = 0.001) were demonstrated to be independent predictors of postoperative early relapse of colon cancer patients, while in rectal cancer patients, both vascular invasion (P = 0.039) and perineural invasion (P = 0.008) were statistically significant predictors of early relapse by univariate analysis. Using a Cox proportional hazards analysis, only perineural invasion (P = 0.043) was an independent factor. Early relapse cases had significant lower overall survival rates than non-early relapse cases either in colon cancer (P < 0.001) or in rectal cancer (P = 0.0091) patients.
CONCLUSIONS: This study suggests that vascular invasion, perineural invasion, and postoperative CEA level may be significant factors for postoperative early relapse of colon cancer; while only perineural invasion is considered to be a significant predictor in rectal cancer patients. Identification of these high-risk UICC stage I-III CRC patients of early relapse is important, and thus could help to define patients with this tumor entity for an enhanced follow-up and therapeutic program. Copyright 2009 Wiley-Liss, Inc.