Prognostic impact of peritonealisation in rectal cancer treated with preoperative chemoradiotherapy: extraperitoneal versus intraperitoneal rectal cancer

Abstract

Background and purpose: The oncologic outcomes of extraperitoneal (EP) rectal cancer are known to differ from those of intraperitoneal (IP) rectal cancer; however, these differences have not been studied in rectal patients treated by preoperative chemoradiotherapy (CRT). The aim of this study is to evaluate the prognostic impact of peritonealisation in rectal patients treated by preoperative CRT.

Materials and methods: This study analyzed the data of 362 patients who received preoperative CRT and underwent curative surgery for locally advanced rectal cancer at 3-9 cm above the anal verge. Patients were categorised into EP and IP groups based on whether peritonealisation was present, according to pathology reports. The oncologic outcomes between the two groups were compared.

Results: Peritonealisation was absent in 330 patients and present in 32 patients. In univariate analysis, disease-free survival was significantly worse in the EP group than in the IP group (73.0% versus 93.5%, p=0.035). Multivariate analysis revealed the following independent risk factors for recurrence: the absence of peritonealisation (p=0.023), ypT stage (p=0.015) and ypN stage (p<.0001).

Conclusions: Peritonealisation of rectal cancer may be a prognostic factor of disease-free survival in patients with rectal cancer treated by preoperative CRT and surgery.