Prognostic value of lymphovascular invasion in stage II colorectal cancer patients with an inadequate examination of lymph nodes.

BACKGROUND

Lymphovascular invasion (LVI) is defined as the presence of cancer cells in lymphatics or blood vessels. This study aimed to evaluate the prognostic value of LVI in stage II colorectal cancer (CRC) patients with inadequate examination of lymph nodes (ELNs) and further combined LVI with the TNM staging system to determine the predictive efficacy for CRC prognosis. Adjuvant chemotherapy (ACT) was then evaluated for stage II CRC patients with LVI positivity (LVI+).

METHODS

In order to avoid the effects of different ACT regimens, among 409 stage II patients, we chose 121 patients who received FOLFOX regimen and the 144 patients who did not receive ACT as the object of study. LVI was examined by hematoxylin-eosin (HE) staining. Kaplan-Meier analysis followed by a log-rank test was used to analyze survival rates. Univariate and multivariate analyses were performed using a Cox proportional hazards model. Harrell's concordance index (C-index) was used to evaluate the accuracy of different systems in predicting prognosis.

RESULTS

The LVI+ status was significantly associated with pT stage, degree of differentiation, tumor stage, serum CEA and CA19-9 levels, perineural invasion (PNI), tumor budding (TB), and KRAS status. The 5-year overall survival (OS) rate of stage II patients with < 12 ELNs and LVI+ was less than stage IIIA. Multivariate analyses showed that LVI, pT-stage, serum CEA and CA19-9 levels, PNI, TB, and KRAS status were significant prognostic factors for stage II patients with < 12 ELNs. The 8th TNM staging system combined with LVI showed a higher C-index than the 8th TNM staging system alone (C-index, 0.895 vs. 0.833). Among patients with LVI+, the ACT group had a significantly higher 5-year OS and 5-year disease-free survival (DFS) than the surgery alone (SA) group (5-year OS, 66.7% vs. 40.9%, P = 0.004; 5-year DFS, 64.1% vs. 36.3%, P = 0.002).

CONCLUSIONS

LVI is an independent prognostic risk factor for stage II CRC patients. Combining LVI with the 8th TNM staging system improved the predictive accuracy for CRC prognosis. ACT in stage II CRC patients with LVI+ is beneficial for survival.