Study of histopathologic parameters to define the prognosis of stage II colon cancer

Purpose: Stage II colon cancer (CC) represents a challenging scenario for the choice of adjuvant chemotherapy; here, histologic factors need to be weighed up to establish the risk of recurrence. Tumor budding (TB) has recently been indicated as a confident predictor of clinical outcome in CC. Likewise, the presence of poorly differentiated clusters (PDCs) in a tumor has been pointed out as a leading criterion of a tumor grading system. Our aim was to evaluate in patients with stage II CC the relationship between these features and clinical outcome. Patients and methods: The study included 174 cases of stage II CC; histopathologic parameters such as TB, PDCs, microsatellite instability (MSI), and CDX2 expression were analyzed. Results: There were 107 (70.9%), 32 (21.2%), and 12 (7.9%) TB scored 1, 2, and 3 respectively; 113 (72.9%), 30 (19.4%), and 12 (7.7%) tumors showed grade 1, 2, and 3 PDCs respectively. A high-MSI was detected in 32 cases (18.4%) while CDX2 was negative in 20 (11.5%) tumor samples. In the whole study population, only the TB was found to be associated with disease-specific survival (P = 0.01). No parameter apart from age (P = 0.04) was a significant prognostic factor for overall survival (P < 0.05). Other commonly reported variables, including tumor size, degree of tumor differentiation, lymphovascular invasion, number of lymph nodes harvested ≥ 12, MSI, and PDCs, were not shown to have significant results. Conclusions: Although confirmatory studies are awaited, our work supports the role of the TB in defining risk groups of the stage II CC.