Lymphovascular invasion represents a superior prognostic and predictive pathological factor of the duration of adjuvant chemotherapy for stage III colon cancer patients

Purpose: Lymphovascular invasion (LVI) and perineural invasion (PNI) can indicate poor survival outcomes in colorectal cancer, but few studies have focused on stage III colon cancer. The current study aimed to confirm the prognostic value of LVI and PNI and identify patients who could benefit from a complete duration of adjuvant chemotherapy based on the two pathological factors. Methods: We enrolled 402 consecutive patients with stage III colon cancer who received colon tumor resection from November 2007 to June 2016 at Sun Yat-sen University Cancer Center. Survival analyses were performed by using Kaplan–Meier method with log-rank tests. Risk factors related to disease-free survival (DFS) and overall survival (OS) were identified through Cox proportional hazards analysis. Results: 141 (35.1%) patients presented with LVI, and 108 (26.9%) patients with PNI. The LVI-positive group was associated with poorer 3-year DFS (86.5% vs. 76.3%, P=0.001) and OS (96.0% vs. 89.1%, P=0.003) rates compared with the LVI-negative group. The PNI-positive group showed a worse survival outcome compared with the PNI-negative group in 3-year DFS rate (72.5% vs. 86.7%, P < 0.001). Moreover, LVI-positive group present better 3-year DFS and OS rate in patients completing 6–8 cycles of adjuvant chemotherapy than those less than 6 cycles (3-year DFS: 80.0% vs. 64.9%, P=0.019; 3-year OS: 93.2% vs. 76.3%, P = 0.002). Conclusions: LVI is a superior prognostic factor to PNI in stage III colon cancer patients undergoing curative treatment. Furthermore, LVI also represents an effective indicator for adjuvant chemotherapy duration.