Liver volumetry improves evaluation of treatment response to hepatic artery infusion chemotherapy in uveal melanoma patients with liver metastases

In uveal melanoma patients, short-term evaluation of treatment response to hepatic artery infusion chemotherapy (HAIC) using the Response Evaluation Criteria in Solid Tumors (RECIST) 1.1 criteria is challenging due to the diffuse metastatic spread. As liver enlargement can frequently be observed, this study aims to compare RECIST 1.1 and liver volumetry (LV) for the evaluation of HAIC treatment response. Treatment response was evaluated in 143 patients (mean age 65.1 ± 10.9 years, 54% female) treated by HAIC by RECIST 1.1 and LV on CT imaging performed before and after HAIC. In LV, different increases in liver volume were evaluated to set an effective threshold to distinguish between stable disease (SD) and progressive disease (PD). Overall survival (OS) was calculated as the time from first HAIC to patient death using Kaplan-Meier test and multivariate analysis was performed for RECIST 1.1 and LV. In the overall population, median OS (mOS) was 13.5 months (95% CI 11.2-15.8 months). In LV, a threshold of 10% increase in liver volume was suited to identify patients with significantly reduced OS (SD: 103/143 patients, mOS 15.9 months; PD: 40/143 patients, 6.6 months; p < 0.001). Compared to RECIST 1.1, LV was the only significant prognostic factor that was able to identify a decreased OS. In uveal melanoma patients with liver metastases, LV with a threshold for liver volume increase of 10% was suitable to evaluate treatment response and would be able to be used as a valuable add-on or even alternative to RECIST 1.1.