543eP - Can baseline immune inflammation predict outcomes? The role of the pan-immune inflammation value in HR-positive, HER2-negative metastatic breast cancer treated with CDK4/6 inhibitors

Cebeci S., Birsin Z., Jeral S., Abbasov H., Aliyev V., Cerme E., ...Daha Fazla

ESMO BREAST CANCER 2026, Berlin, Almanya, 6 - 08 Mayıs 2026, ss.1, (Özet Bildiri)

Yayın Türü: Bildiri / Özet Bildiri
Basıldığı Şehir: Berlin
Basıldığı Ülke: Almanya
Sayfa Sayıları: ss.1
İstanbul Üniversitesi-Cerrahpaşa Adresli: Evet

Özet

Background

Hormone receptor (HR)–positive, HER2-negative metastatic breast cancer represents the majority of breast cancer cases and is routinely treated with CDK4/6 inhibitors in combination with endocrine therapy; however, clinical outcomes remain heterogeneous. Although this subtype is not considered highly immunogenic, CDK4/6 inhibitors may enhance antitumor immune responses. This study investigated whether baseline immune status, assessed using the Pan-Immune Inflammation Value (PIV), is associated with treatment outcomes in patients receiving CDK4/6 inhibitors.

Methods

Patients treated at Istanbul University–Cerrahpaşa Faculty of Medicine Hospital between January 2018 and December 2024 were retrospectively analyzed. PIV was calculated from baseline complete blood counts prior to CDK4/6 inhibitor initiation. As ROC analysis did not identify a significant cut-off, the median PIV value was used to stratify patients into low- and high-PIV groups. Progression-free and overall survival were analyzed using Kaplan–Meier methods, and prognostic factors were assessed with Cox regression analysis.

Results

Baseline clinical characteristics were similar between patients with low and high PIV levels; however, PIV levels were found to be statistically significantly higher in patients with brain metastases. Median PFS was 21 months in the low-PIV group and 24 months in the high-PIV group (p= 0.46). Median OS was 38 months in the low-PIV group and 37 months in the high-PIV group (p=0.55). In the analysis of prognostic factors, ECOG performance status, presence of more than two metastatic sites, and liver metastasis were identified as independent risk factors for both OS and PFS. Table: 543eP

	PIV (Low) (n=73) n (%)	PIV (High) (n=73) n (%)	p
Age	< 65	54 (51)	48 (49)	0.28
Age	≥ 65	19 (43)	25 (57)	0.28
CDK 4/6i	Ribo	58 (51)	56 (49)	0.69
CDK 4/6i	Palbo	15 (47)	17 (53)	0.69
Metastasis	Brain	-	72 (52)	67 (48)	0.05
	Brain	+	1 (14)	6 (86)	0.05
	Liver	-	54 (48)	59 (52)	0.32
	Liver	+	19 (58)	14 (42)	0.32
	Lung	-	53 (49)	54 (51)	0.85
	Lung	+	20 (51)	19 (49)	0.85
	Bone	-	25 (54)	21 (46)	0.48
	Bone	+	48 (48)	52 (52)	0.48
Progression	-	30 (45)	37 (55)	0.25
Progression	+	43 (54)	36 (46)	0.25
Survival	Alive	47 (49)	48 (51)	0.77
Survival	Ex	26 (52)	24 (48)	0.77
	Median (min-max)	Median (min-max)
Neutophil	3.1 (1.5-5.5)	5.1 (1.8-10.5)	0.02
Lymphocyte	1.8 (0.1-5.4)	1.5 (0.1-5)	0.7
Monocyte	0.4 (0.1-0.7)	0.6 (0.2-3.3)	0.002
Platelet	231 (55-443)	305 (145-733)	0.3
PFS (Month)	21 (13.2-28.7)	24 (16.1-31.4)	0.5
OS (Month)	38 (28-47.5)	37 (20.8-53.2)	0.55

Conclusions

Despite its prognostic role in other cancers, baseline PIV was not prognostically informative in our cohort, possibly reflecting limited immune modulation by CDK4/6 inhibitors in this patient population.