Meta-analysis – perineural invasion as prognostic factor in rectal cancer

Abstract Objectives The aim of this analysis was to determine prognostic value of perineural invasion in rectal cancer. Methods Medline (PubMed, Ovid), Embase and Cochrane Library were searched for relevant reports published from January 1980 up to December 2017. All clinical trials which studied perineural invasion in rectal cancer, prospective observational studies, clinical registry data and retrospective case series which reported perineural invasion as an outcome were included. Case reports, abstracts, letters and comments were excluded. hazard ratio (HR) with 95% confidence interval (CI) was used to determine the prognostic value. Results Nineteen studies comprising 6438 patients with rectal cancer were analysed. The results indicate that perineural invasion is a negative prognostic factor as evident from the overall survival (HR = 1.30, 95% CI 1.13–1.50, p < 0.01) and disease-free survival (HR = 2.14, 95% CI 2.06–2.22, p < 0.01). Conclusion This study shows that presence of perineural invasion is associated with poor prognosis in rectal cancer.