BACKGROUND: Extranodal tumor deposits are involved in TNM classification. However, it is uncertain whether a tumor deposit is a regular lymph node metastasis, and its prognostic significance in patients with stage II or III colorectal cancer remains to be established.
OBJECTIVE: This study aimed to determine the prognostic significance of tumor deposits for stage II and III colorectal cancer.
DESIGN: This study is a retrospective review of clinicopathological data.
SETTING: This study was conducted at a tertiary care hospital/referral center in Japan.
PATIENTS: We reviewed the clinical course of 171 stage II and 173 stage III consecutive patients between January 1999 and December 2006.
MAIN OUTCOME MEASURES: We examined the clinicopathological features of colorectal cancers with tumor deposits and calculated overall survival and recurrence-free survival of the patients according to the status of tumor deposits. The primary outcome was the impact of tumor deposits on patient survival.
RESULTS: Thirty-five (10.2%) patients with colorectal cancers had tumor deposits in the pericolic and/or mesocolic region. Survival rates among the patients with tumor deposits were significantly lower than those without (5-year overall survival: 58.4% vs 81.0%, p < 0.0001; 5-year recurrence-free survival: 47.1% vs 73.4%, p < 0.0001). Tumor deposit was an independent prognostic factor for patients with colorectal cancer in multivariate analysis (overall survival: HR, 2.30; 95% CI, 1.26–4.04; p = 0.04; recurrence-free survival: HR, 2.42; 95% CI, 1.04–4.90; p = 0.04). Tumor deposit was an independent prognostic factor in N0 and N1 colorectal cancer, whereas N2 cancer had poor survival outcome regardless of tumor deposit.
LIMITATIONS: Our study was a single-institution retrospective study, and the numbers of patients were relatively small to draw firm conclusions.
CONCLUSION: Tumor deposit may be an independent adverse prognostic factor for stage II and III N1 colorectal cancer.