The Incidence of Lymphovascular and Perineural Invasion and their Impact on Survival in Patients with Rectal Cancer.

Aim: Lymphovascular Invasion (LVI) and Perineural Invasion (PNI) represent undesirable but still realistic pathological features of rectal cancer, associated with poor prognosis and worse survival. The aim of this study is to assess the incidence of LVI and PNI in patients treated for rectal cancer and the impact of LVI and PNI on patient survival. Material and Methods: This retrospective single center observational study, conducted in the period of 2016-2019, includes patients with rectal cancer treated with/without long-course neoadjuvant chemoradiotherapy (nCRT). Data collection encompassed demographics, tumor characteristics, type of surgery (abdominal perineal rectal resection - APR and low anterior rectal resection - LAR), and LVI/PNI presence. Survival during follow-up was estimated and compared for patients with/without LVI and PNI involvement. Results: A total number of 234 patients (77 females and 157 males) with mean age of 61.3 enrolled in the study. Neoadjuvant CRT was conducted in 170 patients. APR procedure was performed in 67 of them and LAR in 167. LVI presence was noted in 55 (24.4%) and PNI in 77 (34.2%) patients. Mean survival during follow-up was 42.07 months. The use of nCRT influenced on survival (p < 0.033). Patients treated with LAR had better survival outcomes (p = 0.001). Presence of LVI and PNI was associated with a worse prognosis (p < 0.001). Conclusion: PNI was more frequent than the LVI in this study. Patients with nCRT conduction had better overall survival. LVI and PNI presence was associated with poor prognosis in terms of overall survival in patients with rectal cancer.