An Increase in Splenic Volume After First-Line Immunotherapy is Associated with Worse PFS in Patients with Metastatic Renal Cell Carcinoma.

Reliable prognostic markers for immune checkpoint inhibitor (ICI) response in metastatic renal cell carcinoma (mRCC) remain limited. We examined the impact of splenic volume change after ICI initiation on progression-free survival (PFS) and overall survival (OS) in patients with mRCC.

We retrospectively reviewed the Emory Kidney Cancer database for patients with mRCC who underwent any first-line ICI treatment between 2015-2023 and had available abdominal imaging 30 days before and 60-120 days after ICI initiation. Using the formula 30 + (0.58 x width x length x thickness), baseline and follow-up splenic volume were calculated as a percentage difference and grouped into ≥ 10% increase and < 10% increase. Kaplan-Meier curves and multivariable Cox hazards regression models assessed differences in OS and PFS between groups.

A total of 109 patients met inclusion criteria. Median follow up time was 25.2 months (IQR 11.2-41.5), during which there were 47 mortality events. Patients with a splenic volume increase ≥ 10% at a median 2.8 months after ICI initiation had worse 2-year PFS (28.5% vs 50.4%, p = 0.022), but not OS (69.4% vs 77.8%, p = 0.853) compared to patients with a < 10% increase in splenic volume. On multivariable analysis, a splenic volume increase ≥ 10% was independently associated with worse PFS (2.33 [95% CI 1.37--4.17], p = 0.002).

In patients with mRCC, a splenic volume increase ≥ 10% at a median of 2.8 months following ICI initiation is independently associated with worse survival compared to an < 10% increase.

The oncologist. 2026 Jan 06 [Epub ahead of print]

Gregory Palmateer, Ahmet Yildirim, Taylor Goodstein, Dattatraya Patil, Samay Patel, Shreyas Joshi, Vikram Narayan, Jacqueline T Brown, Bassel Nazha, Shahid S Ahmed, Jordan Ciuro, Bradley C Carthon, Omer Kucuk, Haydn Kissick, Kenneth Ogan, Mehmet A Bilen, Viraj A Master

Department of Urology, Emory University School of Medicine, Atlanta, GA., Department of Hematology and Oncology, Emory University School of Medicine, Atlanta, GA.