Can pretreatment platelet-to-lymphocyte and neutrophil-to-lymphocyte ratios predict long-term oncologic outcomes after preoperative chemoradiation followed by surgery for locally advanced rectal cancer?

Objective: Systemic inflammation is associated with various malignancies, including colorectal cancer, as possible prognostic predictors. We aimed to evaluate the correlation of pretreatment the platelet-to-lymphocyte (PLR) and the neutrophil-to-lymphocyte (NLR) ratio with long-term oncologic outcomes and pathologic complete response (pCR) in locally ad vanced rectal cancer patients who received neoadjuvant concurrent chemoradiotherapy (CRT) followed by curative resection.

Methods: Between October 1996 and December 2015, 168 rectal cancer patients treated with preoperative CRT followed by surgery were enrolled. The set cut-off/mean PLR and NLR were 170 and 2.8. We analyzed the relationship between PLR, NLR, and the 5-year overall survival (OS), disease-free survival (DFS), and pCR rate.

Results: The 5-year OS rates were 75.9% and 59.8% in the highand low-PLR groups. The 5-year DFS rates were 62.9% and 50.8% in the high- and low-PLR groups, with no significant difference. In addition, the 5-year OS rates were 75.7% and 58.4%, and the 5-year DFS rates were 62.5% and 50.0% in the high- and low-NLR groups, respectively, both without any significant difference. Multivariate analysis showed only pretreatment PLR as an independent prognostic factor for OS (hazard ratio, 1.850; 95% confidence interval, 1.041-3.287; P=0.036), and both serologic markers were not independent prognostic factors for 5-year DFS.

Conclusions: Neither PLR nor NLR was associated with 5-year DFS nor pCR to neoadjuvant CRT. Only pretreatment PLR can be used in predicting OS in locally advanced rectal cancer patients who received neoadjuvant CRT followed by curative resection.