Baseline basophil and basophil-to-lymphocyte status is associated with clinical outcomes in metastatic hormone sensitive prostate cancer.

BACKGROUND: Biomarkers have the potential to provide clinical guidance, but there is limited data for biomarkers in metastatic hormone sensitive prostate cancer (mHSPC). METHODS: We performed a retrospective multicenter review from Winship Cancer Institute at Emory University and Georgia Cancer Center for Excellence at Grady Memorial Hospital (2014-2020) in the United States of America (USA). We collected demographics, disease characteristics, and laboratory data, including complete blood counts (CBC) at the start of upfront therapy. We evaluated overall survival (OS) and progression-free survival (PFS) associated with baseline lab values. RESULTS: 165 patients were included with a median follow-up time of 33.5 months (mo). 105 (63.6%) had Gleason scores of 8-10 and 108 (65.9%) were classified as high-volume disease. 92 patients received upfront docetaxel (55.8%) and 73 received upfront abiraterone (44.2%). Univariate analyses (UVA) and multivariable analyses (MVA) identified worse clinical outcomes (CO) associated with elevated basophils and basophil-to-lymphocyte ratio (BLR). Based on MVA, elevated basophils (defined as ≥0.1, optimal cut) were associated with a hazard ratio (HR) of 3.51 (95% CI 1.65-7.43, P 0.001) for OS and HR of 1.88 (95% CI 1.05-3.38, P 0.034) for PFS. Our MVA also found that BLR ≥0.0142 was associated with HR 2.11 (95% CI 1.09-4.10, P 0.028) for OS; however, PFS was not statistically significant. CONCLUSION: We conclude that elevated baseline basophils and BLR are associated with worse clinical outcomes in mHSPC. Although results require further validation, BLR is a potential prognostic biomarker.