Introduction and objectives: This study assessed the prognostic value of maximal evaluable lesion size (MLS) in predicting the efficacy and outcomes of nivolumab plus ipilimumab (NIVO+IPI) therapy for metastatic renal cell carcinoma (mRCC).
Methods: We retrospectively analyzed 99 mRCC patients treated with NIVO + IPI. Patients were divided into larger-MLS (≥ 35 mm) and smaller-MLS (< 35 mm) groups based on the median MLS. Objective response rate (ORR), progression-free survival (PFS), and overall survival (OS) were compared, and predictive factors for PFS and OS were identified.
Results: The median follow-up period was 29.5 months. In the larger-MLS group (50 patients), the number of patients who did not undergo cytoreductive nephrectomy, as well as the number of patients in whom the kidney, lymph node, and lung were identified as an organ of MLS origin, was significantly higher compared to the smaller-MLS group. ORR was 40% in the larger-MLS group and 32.7% in the smaller-MLS group (p = 0.4315). However, PFS and OS were significantly worse in the larger-MLS group (p = 0.0016 and p = 0.0002, respectively). Multivariate analysis identified Karnofsky performance status (KPS) < 80%, non-clear cell histology, and larger MLS as independent predictors of worse PFS and OS. A prognostic model integrating MLS, KPS, and histology stratified patients effectively, with ≥ 2 risk factors predicting significantly worse OS (p < 0.0001).
Conclusions: MLS is a key prognostic factor in mRCC patients treated with NIVO+IPI. A risk model incorporating MLS, KPS, and histology can aid in patient stratification and treatment decisions.
Keywords: maximal evaluable lesion size; metastatic renal cell carcinoma; nivolumab plus ipilimumab therapy; tumor volume.
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