An increase in splenic volume after first-line immunotherapy is associated with worse PFS in patients with metastatic renal cell carcinoma

TL;DR

A 10% increase in spleen size after starting immunotherapy for kidney cancer is linked to worse disease progression, suggesting it could help guide treatment decisions.

Contribution

Identifies splenic volume increase as a novel radiographic marker for predicting progression-free survival in mRCC patients undergoing immunotherapy.

Findings

Patients with ≥10% splenic volume increase had worse 2-year PFS (28.5% vs 50.4%) compared to those with <10% increase.

Splenic volume increase ≥10% was independently associated with worse PFS (HR 2.33, 95% CI 1.37-3.96).

No significant difference in overall survival was observed between the two groups.

Abstract

Reliable prognostic markers for immune checkpoint inhibitor (ICI) response in metastatic renal cell carcinoma (mRCC) remain limited.

To examine the impact of splenic volume change after ICI initiation on progression-free survival (PFS) and overall survival (OS) in patients with mRCC.

A retrospective cohort study reviewing data from 2015 to 2023.

The Emory Kidney Cancer database (single-center academic instution).

Patients with mRCC who underwent first-line ICI treatment and had available abdominal imaging 30 days before and 60-120 days after ICI initiation. A total of 109 patients met inclusion criteria.

Splenic volume change calculated as a percentage difference between baseline and follow-up imaging (median 2.8 months post-initiation) using a standardized formula, grouped into ≥10% increase and <10% increase.

Differences in OS and PFS assessed using Kaplan–Meier curves and multivariable Cox hazards regression models.

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 = .022) but not OS (69.4% vs 77.8%, P = .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 1.37-3.96], P = .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. Monitoring splenic volume changes may serve as a cost-effective radiographic prognostic marker to guide treatment sequencing.

Graphical Abstract

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