Serum apolipoprotein B to apolipoprotein A-I ratio is an independent predictor of liver metastasis from locally advanced rectal cancer in patients receiving neoadjuvant chemoradiotherapy plus surgery

Background The ratio of serum apolipoprotein B (apoB) to apolipoprotein A-I (apoAI) had been reported as a prognostic factor in colorectal cancer. This retrospective study aimed to assess the implication of apoB-to-apoAI ratio in predicting liver metastasis from rectal cancer (RC). Methods The clinical data of 599 locally advanced RC patients treated with chemoradiotherapy followed by surgery were reviewed. Serum apoAI, apoB and apoB-to-apoAI ratio were analyzed for their correlation with the liver-metastasis-free, other-metastasis-free and overall survivals, together with the pretreatment and postsurgical pathoclinical features of the patients. Univariate and multivariate survival analyses were realized through the Kaplan-Meier approach and Cox model, respectively. Hazard ratios (HRs) and 95% confidence intervals (CIs) were calculated for independent predictors. Results Carbohydrate antigen 19 − 9 ≥ 26.3 U/ml, apoB-to-apoAI ratio ≥ 0.63, tumor regression grade 5 − 3, pT4 and pN + stage emerged as independent predictors of poorer liver-metastasis-free survival. The hazard ratios were 1.656 (95% CI, 1.094–2.506), 1.919 (95% CI, 1.174–3.145), 1.686 (95% CI, 1.053–2.703), 1.890 (95% CI, 1.110–3.226) and 2.012 (95% CI, 1.314–2.077), respectively. Except apoB-to-apoAI ratio, the other 4 factors were also independent predictors of poorer other-metastasis-free and overall survivals. And the independent predictors of poorer overall survival also included age ≥ 67 years old, distance to anal verge < 5 cm. Conclusions Serum apoB-to-apoAI ratio could be used as a biomarker for prediction of liver metastasis risk in locally advanced RC.