Objective: The Prognostic Nutritional Index (PNI) is an indicator of the nutritional level and inflammatory status of a disease. Calculated from serum albumin and lymphocyte counts, it is applied to predict treatment outcomes, postoperative complications and prognostic survival in various diseases because of its simplicity, convenience and validity. However, the role of pretreatment PNI in the prognosis of breast cancer (BC) patients varies across studies. Therefore, we performed this meta-analysis to assess its value in prognostic prediction of BC patients. Methods: PubMed, Embase, Web Of Science, Cochrane Library, CINAHL Plus, China Knowledge Resources Integration Database (CNKI), Wanfang Database, China Biomedical Database (CBM), and VIP databases were searched for relevant studies up to identify the studies evaluating the association between PNI and survival such as overall survival (OS), disease–free survival (DFS) of BC. Quality assessment of the included studies was performed and Hazard ratios (HR) and 95% confidence intervals (CI) were extracted. Pooled analyses were performed using Stata15. Results: A total of 14 studies involving 3,382 patients met the inclusion criteria. High PNI was a favorable independent predictor of prolonged OS after clinical treatment in breast cancer patients compared to low PNI (HR = 0.42, 95% CIs 0.28 - 0.62, P < .001). And pooled results demonstrated no statistical difference in DFS between patients with low PNI and those with high PNI (HR = 1.02, 95% CIs: 0.51 - 2.04, p=0.965). In subgroup analysis, for OS, subgroups aged 50-60 and >60 years, PNI cutoff value calculated based on baseline information and follow-up >1 year showed no significant correlation between PNI and OS (p > 0.05); for DFS, there was a significant correlation between PNI and DFS in breast cancer patients in the subgroups of age 40-50 years, sample size, and follow-up time > 1 year (P < 0.05). Conclusion: PNI is a valuable prognostic index and improving the nutritional immune status may offer a therapeutic strategy for these patients. We suggest that individualized targeted treatment and long-term surveillance should be implemented for patients with different levels of PNI.
Keywords: prognostic nutritional index, breast cancer, meta-analysis