Elevated platelet count as predictor of recurrence in rectal cancer patients undergoing preoperative chemoradiotherapy followed by surgery

Abstract

The impact of systemic inflammatory response (SIR) on prognostic and predictive outcome in rectal cancer after neoadjuvant chemoradiotherapy (CRT) has not been fully investigated. This retrospective study enrolled 89 patients with locally advanced rectal cancer who underwent neoadjuvant CRT and for whom platelet (PLT) counts and SIR status [neutrophil/lymphocyte ratio (NLR) and platelet/lymphocyte ratio (PLR)] were available. Both clinical values of PLT and SIR status in rectal cancer patients were investigated. Elevated PLT, NLR, PLR, and pathologic TNM stage III [ypN(+)] were associated with significantly poor overall survival (OS). Elevated PLT, NLR, and ypN(+) were shown to independently predict OS. Elevated PLT and ypN(+) significantly predicted poor disease-free survival (DFS). Elevated PLT was identified as the only independent predictor of DFS. PLT counts are a promising pre-CRT biomarker for predicting recurrence and poor prognosis in rectal cancer.

Keywords: Chemoradiotherapy; Neutrophil/lymphocyte ratio; Platelet; Platelet/lymphocyte ratio; Prognosis; Rectal cancer.

Figures

Fig. 1

Correlations between PLT counts and SIR status. (A) PLT counts and NLR values were significantly correlated [ρ (95% CI) = 0.314 (0.113–0.490); P = 0.0027]. (B) PLT counts and PLR values were significantly correlated [ρ (95% CI) = 0.581 (0.424–0.704); P < 0.0001]. (C) NLR and PLR values were significantly correlated [ρ (95% CI) = 0.670 (0.536–0.771); P < 0.0001].

Fig. 2

Kaplan–Meier curves for OS, classified by PLT counts or SIR status prior to CRT or pathologic TNM stage of resected specimens in rectal cancer patients. (A) OS rates were significantly lower in rectal cancer patients with elevated PLT counts than in those with lower levels (P = 0.0001; log-rank test). (B) OS rates were significantly lower in rectal cancer patients with elevated NLR than in those with lower NLR (P = 0.0023; log-rank test). (C) OS rates were lower in rectal cancer patients with elevated PLR than in those with lower levels, but the difference was not significant (P = 0.0478; log-rank test). (D) OS rates were significantly lower in rectal cancer patients with pathologic TNM stage III [ypN(+)] than in those with TNM stage I–II [ypN(−)] (P = 0.0204; log-rank test).

Fig. 3

Kaplan–Meier curves for DFS classified by PLT counts or SIR status prior to CRT or pathologic TNM stage of resected specimens in rectal cancer patients. (A) DFS rates were significantly lower in rectal cancer patients with elevated PLT counts than in those with lower levels (P = 0.0145; log-rank test). (B) DFS rates tended to be lower in rectal cancer patients with elevated NLR than in those with lower NLR, but the difference was not significant (P = 0.233; log-rank test). (C) DFS rates were lower in rectal cancer patients with elevated PLR than in those with lower levels (P = 0.3973; log-rank test). (D) DFS rates were significantly lower in rectal cancer patients with pathologic TNM stage III [ypN(+)] than in those with TNM stage I–II [ypN(−)] (P = 0.0365; log-rank test).

Fig. 4

Kaplan–Meier curves for OS and DFS in ypN(−) and ypN(+) rectal cancer patients classified according to pre-CRT PLT counts. (A) OS rates were significantly lower in ypN(+) rectal cancer patients with elevated PLT counts than in those with lower levels (P = 0.0008; log-rank test). (B) DFS rates were not significantly different in ypN(+) rectal cancer patients with elevated PLT counts than from those with lower levels (P = 0.7846; log-rank test). (C) OS rates were significantly lower in ypN(−) rectal cancer patients with elevated PLT counts than in those with lower levels (P = 0.016; log-rank test). (D) DFS rates were significantly lower in ypN(−) rectal cancer patients with elevated PLT counts than in those with lower levels (P = 0.0023; log-rank test).