Renal cell carcinoma (RCC) is the most common malignant tumor of the kidney, accounting for approximately 3% of all cancer cases worldwide. However, current prognostic tools for assessing the risk in localized RCC remain suboptimal. Commonly used tools, such as SSIGN or UISS, primarily rely on postoperative pathological features and lack imaging-based prognostic assessments. Given the spleen’s critical role as the body’s largest immune organ and its influence on tumor progression, this study aims to evaluate changes in spleen volume (SV) before and after surgery and analyze their association with RCC recurrence and survival outcomes.

This study includes 183 patients with localized RCC who underwent curative surgery at National Cheng Kung University Hospital between January 2013 and February 2020. Patients who underwent either radical or partial nephrectomy were included. Exclusion criteria comprised positive surgical margins, concurrent primary malignancies, bilateral renal tumors at diagnosis, age below 18 years, or the absence of preoperative CT or MRI imaging. Clinicopathologic data were collected, including age, gender, BMI, pathological TNM staging, Fuhrman grade, and comorbidities. The primary oncological outcome was progression-free survival (PFS), while overall survival (OS) served as a secondary endpoint. Statistical analyses were conducted using the Kaplan-Meier method, and a multivariate Cox proportional hazards model was employed to identify prognostic factors.

The cohort comprised 183 patients with a mean age of 57.7 years and a male predominance (male: female = 69%: 31%). The mean preoperative SV was 184.4 ± 96.4 mL, corresponding to 103.5 ± 49.9 mL/m² after body surface area (BSA) adjustment. Imaging follow-up at 24 months postoperatively was available for 103 patients, among whom 37 (36%) exhibited an increase in SV. Baseline SV/BSA showed no significant impact on PFS or OS. However, multivariate analysis identified an increase in SV/BSA after surgery as an independent risk factor for disease progression (HR: 1.16, p=0.02). Additional risk factors included pathological nodal (pN) stage, clear cell histological subtype, the presence of peri-nephric stranding, and posterior peri-nephric fat thickness ≥1 cm.

In patients with localized RCC, an increase in SV/BSA within two years after curative surgery may be associated with a higher risk of disease progression. This finding suggests that postoperative SV changes could serve as a potential prognostic indicator, providing clinicians with additional insights for risk stratification and patient management.