Notably, among PSA responders, patients with elevated PLR still showed significantly shorter OS compared with those with low PLR, indicating that PLR adds prognostic information beyond biochemical response; this observation aligns with prior meta-analyses demonstrating the adverse prognostic role of PLR in prostate cancer, but, to the best of our knowledge, no previous study has directly combined PSA response with SIMs to refine prognostic stratification [26,27,38]; therefore, our results suggest that integration of PSA and PLR may enhance risk assessment in daily practice. Here, KLK3 is linked to prostate cancer.