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

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. Resumo: Objetivo: Este estudo buscou determinar o valor prognóstico da invasão perineural no câncer retal. Métodos: Relatos relevantes publicados entre janeiro de 1980 e dezembro de 2017 foram buscados nas bases de dados Medline (PubMed, Ovid), Embase e Cochrane Library. Todos os ensaios clínicos que avaliaram a IPN no câncer de reto, estudos observacionais prospectivos, dados de registro clínico e séries de casos retrospectivos que relataram IPN como um desfecho foram incluídos. Relatos de casos, resumos, cartas e comentários foram excluídos. A razão de risco (hazard ratio [HR]) com intervalo de confiança (IC) de 95% foi usada para determinar o valor prognóstico. Resultados: Foram analisados 19 estudos compreendendo 6.438 pacientes com câncer retal. Os resultados indicam que a invasão perineural é um fator prognóstico negativo, conforme demonstrado pela sobrevida global (HR = 1,30; IC 95%: 1,13-1,50; p < 0,01) e sobrevida livre de doença (HR = 2,14; IC 95%: 2,06-2,22, p < 0,01). Conclusão: O estudo demonstrou que a presença de invasão perineural está associada a um prognóstico ruim no câncer retal. Keywords: Rectal cancer, Perineural invasion, Survival, Prognosis, Palavras-chave: Câncer retal, Invasão perineural, Sobrevida, Prognóstic