Published online May 15, 2020. doi: 10.4251/wjgo.v12.i5.592
Peer-review started: December 30, 2019
First decision: February 21, 2020
Revised: March 23, 2020
Accepted: April 18, 2020
Article in press: April 18, 2020
Published online: May 15, 2020
Processing time: 135 Days and 13.3 Hours
Rectal cancer (RC) accounts about one third of all diagnosed colorectal cancers. Although TNM staging has proven as applicable in very early and late disease stages, accuracy in the intermediary stages of the RC remains controversial. Precise pathological examination is needed in order to determine which patients would benefit from adjuvant therapy. Few previous investigations have focused on correlation of presence of perineural invasion (PNI) or/as well as lymphovascular invasion (LVI) with the cancer-related outcome in RC patients, therefore more studies in this field are needed.
Considering the rising incidence of RC, we have investigated easily applicable and reliable factors that can potentially predict potential outcomes in patients with RC.
We evaluated the clinical significance of PNI as well as LVI in patients with stage I-III RC and further investigated whether these two histopathological features alone and combined affect survival of RC patients.
We have prospectively studied patients with early and intermediate RC. Using Kaplan-Meier method we have analyzed the median survival time, whereas Cox proportional hazards models were used to evaluate the influence of PNI and LVI as prognostic factors in RC patients.
Using Kaplan-Meier analysis for overall survival rate, we have found that both LVI and PNI were associated with lower overall survival rates as well as disease free survival rates (P < 0.01). Moreover when Cox multiple regression model was used, presence of LVI was associated with 3-fold higher risk of lethal outcome and 2-fold higher risk of disease recurrence (P < 0.05). Presence of PNI was associated with almost 4-fold higher risk of lethal outcome and 6-fold higher risk of disease recurrence (P < 0.05).
This study supports the hypothesis that PNI as well as LVI should be carefully and thoroughly examined in the histopathological analysis of RC patients even in early and intermediate disease stages, bearing in mind that such findings could have a great impact on the prognosis. Also patients with both LVI and PNI involvement even in early stages of the disease should not be overlooked, and must be monitored carefully with more frequent and detailed check-ups.
PNI and LVI should be included as obligatory analysis in histopathology reports of RC patients. Additional randomized prospective studies are necessary to confirm these results, and also to investigate other potential prognostic factors in RC patients.