Analysis of clinical predictive factors of pathologic complete response after neoadjuvant chemoradiotherapy in rectal cancer

Abstract

To evaluate the clinical predictive factors associated with pathologic complete response (pCR) after neoadjuvant chemoradiotherapy in rectal cancer. A retrospective analysis was performed on clinical data of 87 patients with rectal cancer, who underwent neoadjuvant chemoradiotherapy followed by radical surgery from April 2007 to May 2015. All patients received pelvic intensity-modulated radiotherapy (50 Gy/25 fractions) with concurrent fluorouracil- based chemotherapy and then underwent radical surgery 4-8 weeks later. The clinical factors associated with pCR or non-pCR were analyzed by Logistic regression. Eighty-three patients had completed treatment, of which 15 patients (18.1%) achieved pCR after neoadjuvant chemoradiotherapy. Univariate analysis showed non-diabetes(P=0.033), pre-chemoradiotherapy plasma glucose(≤6.1 mmol/L)(P=0.033), pre-chemoradiotherapy CEA(≤5 μg/L)(P=0.026), pre- chemoradiotherapy plasma lymphocytes count(≤1.5×10(9)/L)(P=0.042), pre- chemoradiotherapy plasma platelet(≤240×10(12))(P=0.043), tumor pathological type(adenocarcinoma)(P=0.036)were significantly correlated with pCR after neoadjuvant chemoradiotherapy in rectal cancer. Logistic regression revealed that non-diabetes, pre-chemoradiotherapy plasma glucose, pre-chemoradiotherapy CEA(≤5 μg/L), pre-chemoradiotherapy plasma lymphocytes count(≤1.5×10(9)/L), tumor pathological type(adenocarcinoma) were independent predictive factors of pCR after neoadjuvant chemoradiotherapy in rectal cancer. Patients with non-diabetes, normal plasma glucose, normal CEA, lower plasma lymphocytes count and adenocarcinoma were associated with pCR after neoadjuvant chemoradiotherapy for rectal cancer.