Assessing the role of prognostic nutritional index in predicting outcomes for rectal cancer surgery.

BACKGROUND & AIMS: The association of Prognostic Nutritional Index (PNI) with prognosis has been established for various cancer types, including rectal cancer. However, the precise relationship between PNI and body composition characteristics in patients with non-metastatic rectal cancer remain unclear. This study aimed to investigate the impact of PNI on overall survival and disease-free survival in non-metastatic rectal cancer patients undergoing total surgical resection. Additionally, it sought to assess the inflammatory status and body composition in patients across different PNI levels.

METHODS

Patients with non-metastatic rectal cancer who underwent total surgical resection, were consecutively enrolled. PNI was calculated using the formula: PNI = (10 × serum albumin [g/dl]) + (0.005 × lymphocytes/μL). Body composition was assessed using CT-derived measurements and laboratory tests performed at diagnosis were used to calculate inflammatory indices. Univariate and multivariate logistic regression analyses as well as Kaplan-Meier curves were used to determine prognostic values.

RESULTS

A total of 298 patients were included. Patients with low PNI demonstrated significantly reduced overall survival and disease-free survival compared to those with high PNI (Hazard ratio [HR] 1.85; Confidence interval [CI] 1.30-2 0.62; p = 0.001). Moreover, patients with low PNI exhibited heightened systemic inflammatory status and reduced skeletal muscle index, increased muscle radiodensity, as well as a decrease in subcutaneous adipose tissue area, subcutaneous fat index, and low attenuation of both subcutaneous and visceral adipose tissue.

CONCLUSION

The PNI, assessed prior to treatment initiation, serves as a prognostic biomarker for non-metastatic rectal cancer patients undergoing total surgical resection and is linked with both inflammation and alterations in body composition.