Background: The effect of preoperative nutritional status on the survival of patients with colorectal cancer is still unknown. The purpose of our study was to examine the impact of the prognostic nutritional index (PNI), prealbumin (PAB) and the albumin to globulin ratio (AGR) on survival outcomes in patients with colon and rectal cancer.
Methods: Between January 2012 and December 2013, 361 patients with colorectal cancer who underwent curative surgery in the survey and various clinical and haematological parameters were recorded. The optimal cut-off values of the PNI, PAB and AGR were determined by MedCalc software, and Cox regression analysis was performed to investigate the effect of the PNI, PAB and AGR on the overall survival (OS) of patients with colon and rectal cancer.
Results: In patients with colon and rectal cancer, a high PNI, PAB, and AGR correlate with higher survival times. Receiver operating characteristic (ROC) curve analysis showed that at most time points, the PNI has a higher area under the curve (AUC) in predicting colon and rectal cancer OS. Multivariate Cox regression analysis showed that of the PNI, PAB and AGR, only the PNI was an independent risk factor for OS in patients with colon and rectal cancer. Patients with a high PNI were predicted to have higher OS (hazard ratio [HR]: 0.479; 95% confidence interval [CI]: 0.233– 0.985; P = 0.045) in colon cancer and higher OS (HR: 0.225; 95% CI: 0.111– 0.454; P < 0.001) in rectal cancer compared with patients with a low PNI.
Conclusion: Preoperative PNI, PAB and AGR may be predictors of OS in patients with colon and rectal cancer after radical surgery, especially the PNI, which has a good ability to predict OS in both tumours.
Keywords: PNI, PAB, AGR, colon cancer, rectal cancer, overall survival
Colorectal cancer, including colon and rectal cancer, is the most common malignant tumour in the digestive system, accounting for approximately half of digestive system tumours.1 In 2019, an estimated 101,420 new colon cancer cases, 44,180 new rectal cancer cases and 51,020 deaths from colorectal cancer were diagnosed in the United States.2 Colorectal cancer is the third leading cause of morbidity and mortality in both men and women.3 With the improvement in living standards and changes in diet, the incidence of colorectal cancer continues to rise.4 The treatment of colorectal cancer includes surgery, chemotherapy, radiotherapy and other biological immunological treatments.5 Surgical treatment is the first choice for the treatment of colorectal cancer. Due to its high invasion and metastasis, the 5-year survival rate is only approximately 50%.6
Due to the physiological colorectal functions, patients with colorectal cancer are prone to malnutrition. Malnutrition is a common problem for patients with cancer, with up to 80% of patients with advanced cancer suffering from malnutrition.7 Although the basic mechanism of nutritional changes in cancer is not fully understood, the catabolic factors produced by cancer cells and the proinflammatory response of the host can induce energy consumption, resulting in weight loss and eventual malnutrition.8 It is of great significance to find an accurate and effective index before surgery to evaluate the nutritional status and surgical risk of patients and to determine the clinical outcome of patients after surgery.
At present, the prognostic nutritional index (PNI), prealbumin (PAB) and albumin to globulin ratio (AGR) are widely studied and have been used as new parameters for many kinds of malignant tumours, including gastric cancer and pancreatic cancer.9–11 However, there is still a lack of research on nutritional indicators for colon and rectal cancer. Our study analysed the relationship between the above three indicators and the prognosis of patients with colon and rectal cancer to explore which indicator has better predictive value.
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