Quantification of risk of recurrence associated with high risk factors in Stage II colon cancer: A retrospective study from a tertiary cancer institute in India

Background: Surgery is the primary modality of treatment for Stage II colon cancer, and the role of adjuvant chemotherapy is not well defined. Attempts have been made to find out various high-risk sub-groups within Stage II colon cancer, who might benefit from the adjuvant chemotherapy. Most of these studies do not quantify the risks associated with each of the high-risk factors and the survival benefits conferred by adjuvant chemotherapy based on them. Aim: This study aimed to analyze the prognostic and predictive significance of various high-risk factors among patients with Stage II colon cancer and to define the role of adjuvant chemotherapy among these if any with respect to various high-risk factors. Materials and Methods: An audit on postoperative Stage II colon carcinoma patients was performed retrospectively from the patient database of our hospital, registered over the period from January 2010 to August 2017. Results: A total of 41 pathological Stage II colon carcinoma patients were reviewed. Twelve (29.3%) patients without any high-risk features were spared of adjuvant chemotherapy. Twenty-nine (70.7%) patients had at least one high-risk feature and received adjuvant chemotherapy. Mean disease-free survival (DFS) after a minimum 20-month follow-up period was 26.8 months. On univariate analysis, there was a statistically significant difference in mean DFS according to the T stage (T3 vs. T4; P = 0.04), lympho-vascular invasion (LVI) status (absent vs. present; P < 0.01), perineural invasion status (absent vs. present; P = 0.03) and number of lymph nodes in the histopathology specimen (≥12 vs. <12; P < 0.01). On multivariate analysis, LVI positivity and inadequate lymph node dissection (<12 lymph nodes in the specimen) were independent high-risk factors for recurrence. Conclusion: The presence of LVI, inadequate lymph node dissection, or presence of multiple high-risk factors are associated with higher risks of recurrence even with adjuvant 5-flourouracil-based chemotherapy.