Measuring total liver function on sulfur colloid SPECT/CT for improved risk stratification and outcome prediction of hepatocellular carcinoma patients.

Background: Assessment of liver function is critical in hepatocellular carcinoma (HCC) patient management. We evaluated parameters of [(99m)Tc] sulfur colloid (SC) SPECT/CT liver uptake for association with clinical measures of liver function and outcome in HCC patients.

Methods: Thirty patients with HCC and variable Child-Turcotte-Pugh scores (CTP A5-C10) underwent [(99m)Tc]SC SPECT/CT scans for radiotherapy planning. Gross tumor volume (GTV), anatomic liver volume (ALV), and spleen were contoured on CT. SC SPECT image parameters include threshold-based functional liver volumes (FLV) relative to ALV, mean liver-to-spleen uptake ratio (L/Smean), and total liver function (TLF) ratio derived from the product of FLV and L/Smean. Optimal SC uptake thresholds were determined by ROC analysis for maximizing CTP classification accuracy. Image metrics were tested for rank correlation to composite scores and clinical liver function parameters. Image parameters of liver function were tested for association to overall survival with Cox proportional hazard regression.

Results: Optimized thresholds on SC SPECT were 58 % of maximum uptake for FLV, 38 % for L/Smean, and 58 % for TLF. TLF produced the highest CTP classification accuracy (AUC = 0.93) at threshold of 0.35 (sensitivity = 0.88, specificity = 0.86). Higher TLF was associated with lower CTP score: TLFA = 0.6 (0.4-0.8) versus TLFB = 0.2 (0.1-0.3), p < 10(-4). TLF was rank correlated to albumin and bilirubin (|R| > 0.63). Only TLF >0.30 was independently associated with overall survival when adjusting for CTP class (HR = 0.12, 95 % CI = 0.02-0.58, p = 0.008).

Conclusions: SC SPECT/CT liver uptake correlated with differential liver function. TLF was associated with improved overall survival and may aid in personalized oncologic management of HCC patients.