A good preoperative immune prognostic index is precits a better prognosis for locally advanced rectal cancer patients with ypTNM stage II who underwent radical resection after neoadjuvant chemoradiotherapy.

Background: No studies have investigated the role of IPI in assessing the prognosis of locally advanced rectal cancer (LARC) patients undergoing nCRT.

Objective: We attempted to combine neutrophil-to-lymphocyte ratio (NLR) and serum lactate dehydrogenase (sLDH) to generate a new rectal immune prognostic index (RIPI) to explore whether RIPI is associated with LARC prognosis. We aimed to identify whether there is a population that might benefit from RIPI in LARC.

Methods: LARC patients who underwent radical surgery after Neoadjuvant chemoradiotherapy (nCRT) were enrolled between February 2012 and May 2017. Based on the best cut-off points of NLR and sLDH, we developed RIPI. The patients were grouped as follows: (1) good, RIPI = 0, good, 0 factors; (2) poor, RIPI = 1, 1 or 2 factors.

Results: This study enrolled 642 patients. In yp TNM stage II patients, 5-year disease-free survival (DFS) differed significantly between the RIPI = 1 and RIPI = 0 groups (p = 0.03). Five-year DFS did not differ significantly between IPI = 0 and IPI = 1 groups in ypCR, stage I, stage II, and stage III. In multivariate analysis, the significant factor predicting DFS was pre-nCRT RIPI score (p = 0.035).

Conclusion: The pre-nCRT RIPI was closely related to the prognosis of LARC patients undergoing nCRT. Particularly, RIPI is significant in evaluating the prognosis of ypTNM stage II LARC patients who underwent radical resection after nCRT.