Defining a high-risk subgroup with colon cancer stages I and II for possible adjuvant therapy

Adjuvant therapy is not routinely recommended in UICC stages I and II colon cancer, but may be considered for high-risk patients. Our aim is to identify clinicopathologic characteristics in colon cancer stages I and II, which are associated with an increased risk of tumour recurrence and tumour-related death.

We analysed our prospectively documented clinical database of 775 patients with colon cancer stages I and II, which underwent curative resection between 1982 and 2006. No adjuvant chemotherapy was applied. The median follow-up time was 80 months.

For the entire study group, 5- and 10-year tumour-specific survival probabilities were 94.8+/-0.9% and 91.0+/-1.4%, respectively. Multivariate analysis identified three tumour characteristics as independent prognostic factors: lymphatic vessel invasion (p=0.034), poor tumour grading (G3/G4) (p=0.020) and extended tumour length (6 cm) (p=0.042). Five-year (10-year) tumour-specific survival for patients without any of the poor prognostic tumour characteristics (ppTCs) was 96.0% (94.7%). There was a significantly increased risk for tumour-related death with increasing numbers of ppTCs (p<0.001). While patients with only one ppTC had a 5-year (10-year) tumour-specific survival of 94.8% (88.9%), it decreased to 88.9% (78.4%) for patients with two ppTCs (hazard ratio (HR) 3.69, 95% confidence interval (CI) 1.67-8.13) and to 87.5% (72.9%) for patients with all three ppTCs (HR 6.56, 95% CI 1.50-26.62).

Patients with stage I or II colon cancer have a favourable prognosis after radical resection. The presence of two or three poor prognostic tumour characteristics identifies a small patient subgroup (12%) with an increased risk of tumour-related death that may be considered for adjuvant chemotherapy.