Lymph-vascular invasion affects the selection of time interval between surgery and postoperative chemotherapy in colon cancer.

[OBJECTIVES] The ideal timing for administering adjuvant chemotherapy following surgery for colon cancer remains a subject of debate, particularly regarding whether varying intervals should be recommended based on the presence of lymph-vascular invasion (LVI) in postoperative pathology. This study aims to evaluate the impact of the time-interval (TI) between surgery and chemotherapy on the tumor outcomes in patients with or without LVI.

[METHODS] A retrospective study was carried out on 505 colon cancer patients who received surgery and adjuvant chemotherapy from January 2013 to December 2022. Patients were categorized into two groups based on a 3.2-week interval. Overall survival (OS) and disease-free survival (DFS) were assessed between patients with intervals below and above 3.2 weeks in both the entire group and subgroups. Recurrence patterns were examined, and multivariate analyses were conducted to identify clinical factors correlated with DFS, local recurrence free survival (LRFS), and distant metastasis free survival (DMFS) in patients with LVI.

[RESULTS] Among patients with no LVI, there were no significant disparities in 5-year OS and DFS rates between the short TI and long TI groups. Conversely, in patients with LVI, the short TI group exhibited significantly superior OS and DFS rates compared to the long TI group, with the latter demonstrating a heightened incidence of distant metastases. Multivariate analysis revealed that the time interval independently predicted DFS and DMFS in patients with LVI.

[CONCLUSION] In colon cancer patients, the LVI status influences the selection of the timing of postoperative adjuvant chemotherapy.