Systemic Inflammatory Markers Can Predictive Response in Radiation Therapy to the Prostate

Abstract

The neutrophil/lymphocyte ratio (NLR) is an independent predictor of recurrence in several cancers and is a well-established prognostic factor for prostate cancer (PCa). In a meta-analysis, NLR was found to be associated with a lower rate of overall survival and recurrence-free survival. We aim to identify a subgroup of patients with PCa who have different recurrence rate based on NLR. From our institutional database, we identified 628 patients who had primary external beam radiotherapy or permanent seed brachytherapy from April 2005 to August 2019. All patients had to have a complete blood count within 3 months before the start of treatment. Patients without a recurrence were included if they had a follow-up of at least 24 months. Only patients with CAPRA low (score 0-2) and intermediate–risk (3-5) cancers were included. No patient received either androgen deprivation or brachytherapy as a boost. Biochemical recurrence (BCR) was defined according to the Phoenix definition (nadir +2). Log-rank test was used in univariate analysis (UVA) and Cox regression analysis in multivariate analysis (MVA) to predict for BCR. Median follow-up without recurrence was 60 months (IQR 44-48months), 30 patients had a recurrence. An NLR >3 was more frequent in diabetics (p = 0.042) and in statin users (p = 0.014). On UVA, an NLR >3 was associated with less BCR (p = 0.029) while CAPRA low- vs. intermediate risk was not (p = 0.055). Additionally, on MVA, an NLR >3 was associated with less BCR (HR 0.37, 95% CI 0.15-0.90, p = 0.029). CAPRA intermediate risk patients with an NLR <3 (n = 157) had the worst (p = 0.009) BCR rates when compared to all other patients (n = 471). We were able to identify a subgroup of patients with CAPRA intermediate-risk PCa and an NLR<3 who had worse BCR. This is in contrast to most other cancers who have a worse prognosis when the NLR is high. Contrary to other cancers, prostate radiotherapy in low- and intermediate-risk cancers seems to benefit from a higher neutrophil ratio in peripheral blood.