The number of high-risk factors is related to outcome in stage II colonic cancer patients.

BACKGROUND: A subgroup of stage II colonic cancer patients are considered to be at high-risk for recurrent/metastatic disease based on 1) tumour obstruction/perforation 2) <10 lymph nodes 3) T4 lesions and 4) lymphangio-invasion. Their prognosis is regarded as comparable to stage III (T1-4N+M0) colonic cancer and it is therefore strongly advised to treat them with adjuvant chemotherapy. The purpose of this study was i) to determine the magnitude of prognostic significance of the conventional high-risk factors and ii) to determine whether the number of high-risk factors influences outcome. METHODS: We retrospectively analyzed 212 stage II colonic cancer patients undergoing surgery between January 2002 and December 2008. No adjuvant chemotherapy was given. Survival analyses were performed. RESULTS: 154/212 (73%) patients were considered to be high-risk patients based on conventional high-risk factors. 58 patients did not meet any high-risk factor, 125 patients met 1 high-risk factor and 29 patients met ≥2 high-risk factors. Median follow up was 40 months. Multivariate analysis identified four independent risk factors for recurrent/metastatic disease: age, obstruction, perforation and lymphangio-invasion. The three-year-DFS-rates for the low-risk group, the high-risk group with 1 high-risk factor and the high-risk group with ≥2 high-risk criteria are 90.4%, 87.6% and 75.9% respectively. Patients meeting ≥2 conventional high-risk criteria had a significantly worse three-year disease free survival (p < 0.002). CONCLUSIONS: Four independent high-risk factors were identified. The number of high-risk factors does influence outcome. More attention should be given to the definition and treatment of high-risk stage II colonic cancer patients.