The prognostic indicator in breast cancer treated with CDK4/6 inhibitors: the prognostic nutritional index.

Aims: The aim of this study was to evaluate the effect of prognostic nutritional index (PNI) on prognosis in patients with hormone receptor-positive, HER2-negative metastatic breast cancer who received CDK4/6 inhibitor + endocrine therapy. Methods: Patients receiving a CDK4/6 inhibitor were evaluated retrospectively. The PNI was calculated as: (10 × serum albumin [g/dl]) + (total lymphocyte count [×10 9 /l] × 5). Results: In a study of 106 patients, a statistically significant survival advantage was observed in the high-PNI group over the low-PNI group (mean overall survival: 28.03 ± 0.487 months vs 22.46 ± 1.14 months; p = 0.013). Conclusion: For the first time in the literature, this study demonstrated the prognostic role of PNI in patients with hormone receptor-positive, HER2-negative metastatic breast cancer treated with CDK4/6 inhibitors.