Systemic Inflammatory Index: A Novel Biomarker for Predicting the Progression in Active Surveillance in Patients with Prostate Cancer.

Objective: To investigate active surveillance (AS) for patients with prostate cancer to show the systemic inflammatory index (SII) progression and to evaluate whether SII will be an AS criterion in PCa patients.

Study Design: Descriptive study. Place and Duration of the Study: Department of Urology, University of Health Sciences, Prof. Dr. Cemil Tascioglu City Hospital, from February 2015 to December 2021.

Methodology: For active surveillance follow-up criteria, patients with prostate cancer who underwent AS with PSA <10 ng/ml, GS ≤6, clinical stage t1c-t2b, ≤2 core positive, and for each positive core had ≤50% tumour cells, were inducted and SII was determined.

Results: As a result of the univariate analysis, high SII values, number of cores involved, and length of the tumour in one core significantly affected progression (in order of p = 0.009, B = 1.830, Exp(B) = 6.233, CI [1.58-24.497]; p = 0.018, B = 0.682, Exp(B) = 1.978, CI [1.123-3.482]; p=0.006, B = 1.835, Exp(B) = 6.263 CI [1.692-23.181]). High SII values (>443.42) had better explanations for progression than the number of core involvement but were similar to the length of the tumour in one core. As a result of the multivariate analysis, high SII values (>443.42) and the tumour 's length in one core had similar effects on progression (in order of p = 0.011, B = 1.978, Exp(B) = 7.227, CI [1.570-33.269]; p = 0.009, B = 1.958, Exp(B) = 7.084, CI [1.642-30.555]).

Conclusion: Th use of SII early in the course of treatment can help to identify which prostate cancer patients can be selected for active treatment instead of active surveillance, and to assess the probability of progression.

Key Words: Prostate cancer, Active surveillance, Systemic inflammatory index, Biomarker.