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

Tweetable abstractThe prognostic nutritional index (PNI) as a useful, simple and new prognostic indicator in patients with HR-positive, HER2-negative metastatic breast cancer treated with CDK4/6 inhibitor + endocrine therapy. 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 x serum albumin [g/dl]) + (total lymphocyte count [x10(9)/l] x 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. Plain language summaryWhat is this article about? In cancer, in addition to known prognostic and predictive markers (e.g.,age, performance status, clinicopathological features and disease stage), nutritional status and immunity can predict treatment response and survival in many cancer types. In recent studies, simple indices have been created from various parameters available from blood samples. The prognostic nutritional index (PNI) is a simple immune-nutritional marker calculated using albumin, which reflects the nutritional status, and lymphocytes (immune cells). The predictive value of PNI in patients receiving conventional treatments (e.g., chemotherapy and radiotherapy) has been demonstrated in various cancers, including breast cancer, but there is no information about the prognostic and predictive value of PNI in patients treated with CDK4/6 inhibitor + endocrine therapy (ET), a targeted therapy recommended as first-line therapy in hormone receptor-positive, HER2-negative metastatic breast cancer (HR+, HER2(-) MBC). What were the results? We investigated the effect of the immune-nutritional status of patients using CDK4/6 inhibitors and ET on response to treatment and overall survival in HR+, HER2(-) MBC. Patients with high PNI values had longer survival and, although not statistically significant, higher treatment response rates. What do the results of the study mean? Although the number of patients in our study was small, this result showed that the immune-nutritional status should be evaluated appropriately and necessary support should be given in patients receiving CDK4/6 inhibitors. Due to the small number of patients in the study, we believe that the importance of PNI can be further emphasized with prospective and multicenter studies.