Clinical Significance of Perineural Invasion in Colorectal Cancer

Abstract

Purpose : Perineural invasion (PNI) is widely known to be correlated with poor survival in many type of malignancy but the connection between perineural invasion of colorectal cancer and the prognosis has not yet been clearly confirmed. Therefore, we examined perineural invasion in colorectal cancers and investigated its relationship to clinicopathological features such as tumor staging, lymph node metastasis, vascular invasion, lymphatic invasion and patient’s prognosis in this study Methods : The subjects were 148 colorectal cancer patients who underwent surgical resection in OOO. The pathologists who were not aware of the prognosis of the patients reexamined the existing biopsy results and reevaluated the perineural invasion. The presence of perineural invasion and the other clinicopathological factors were compared and the statistical significance of the correlation between these was examined. Results : Perineural invasion was confirmed in less than 10% of the patients in the initial biopsy results. However, it was confirmed in 20.9% of the patients reevaluating the biopsy. Perineural invasion in colorectal cancer was found to be unrelated to the T stage of the patients (p=0.114). On the other hand, perineural invasion appeared to be strongly related to lymph node metastasis of colorectal cancer (p more common in the patients with perineural invasion (p=0.001). Moreover, perineural invasion seemed to be related to the stage of cancer (p the level of differentiation nor to the distant metastasis since perineural invasion was expressed in 21% of the patients with distant metastasis and in 20% of the patients without distant metastasis. Conclusion : The correlation of perineural invasion in colorectal cancer to the clinicopathologic factors such as lymph node metastasis, lymphatic invasion, vascular invasion and the stage of disease were confirmed. And perineural invasion was significantly correlated with patient’s survival. This is thought to be that perineural invasion can be a prognostic factor of colorectal cancer and it should be utilized planning adjuvant therapy for colorectal cancer patients.