Prognostic Nutritional Index (PNI) and Controlling Nutritional Status (CONUT) score for predicting outcomes of breast cancer: A systematic review and meta-analysis.

Objective: To assess prognostic nutritional index (PNI) and controlling nutritional status (CONUT) score could predict overall survival (OS) and disease-free survival (DFS) in patients with breast cancer.

Methods: PubMed, Embase, ScienceDirect, CENTRAL, and Google Scholar were searched from 1 January 2000 to 10 October 2021 for studies assessing the association between PNI or CONUT and outcomes of breast cancer by following the PRISMA guidelines. Keywords used were "Prognostic nutritional index", "Controlling nutritional status", "CONUT", and "Breast cancer".

Results: Nine studies were included. On pooled analysis, we noted a statistically significant improved OS in patients with high PNI as compared to low PNI. Meta-analysis revealed no significant difference in DFS between patients with high PNI and low PNI. However, on the exclusion of one study, we noted that high PNI was associated with significantly improved DFS as compared to low PNI. On pooled analysis, we also noted that a high CONUT score was associated with significantly reduced OS in breast cancer patients.

Conclusion: Our results indicate that PNI is an important prognostic factor for patients with breast cancer. Pre-treatment low PNI is associated with worse OS and DFS. Scarce data also indicates that a high CONUT score is predictive of poor OS in breast cancer.