Assessment of hepatic function decline after stereotactic body radiation therapy for primary liver cancer

Abstract

Purpose

This study aims to determine how the albumin-bilirubin (ALBI) score compares with the Child-Pugh (CP) score for assessing liver function following stereotactic body radiation therapy (SBRT).

Methods and materials

In total, 60 patients, 40 with hepatocellular carcinoma (HCC) and 20 with cholangiocarcinoma (CCA), were treated with SBRT. Liver function panels were obtained before and at 1, 3, 6, and 12 months after SBRT. Laboratory values were censored after locoregional recurrence, further liver-directed therapies, or liver transplant.

Results

A significant decline in hepatic function occurred after SBRT for HCC patients only (P = .001 by ALBI score; P < .0001 by CP score). By converting radiation doses to biologically equivalent doses by using a standard linear quadratic model using α/β of 10, the strongest dosimetric predictor of liver function decline for HCC was the volume of normal liver irradiated by a dose of 40 Gy when assessing liver function by the ALBI score (P = .07), and the volume of normal liver irradiated by a dose of 20 Gy by using the CP score (P= .0009). For CCA patients, the volume of normal liver irradiated by a dose of 40 Gy remained the strongest dosimetric predictor when using the ALBI score (P = .002), but no dosimetric predictor was significant using the CP score. Hepatic function decline correlated with worse overall survival for HCC (by ALBI, P = .0005; by CP, P < .0001) and for CCA (by ALBI, P = NS; by CP, P = .008).

Conclusions

ALBI score was similarly able to predict hepatic function decline compared with CP score, and both systems correlated with survival.

Introduction

Over the past decade, stereotactic body radiation therapy (SBRT) has emerged as an option for the treatment of primary liver cancer (PLC), especially for those tumors whose location, size, or distance from major vessels preclude the use of other local modalities.[1], [2], [3], [4], [5], [6], [7], [8], [9], [10], [11], [12], [13], [14], [15], [16] The applicability of SBRT is not limited by these characteristics, and it may even be combined with other local therapies.[17], [18], [19]

Despite these advantages, the use of SBRT for treatment of PLC is still limited by the concern of liver tolerance to radiation. The association of PLC with underlying cirrhosis leads to compromised hepatic function at diagnosis,[20], [21], [22] which, added to the intrinsic liver radiosensitivity, likely increases the risk of radiation injury.[23], [24], [25], [26], [27], [28]

The Child-Pugh (CP) score is one of the most widely used scoring systems to grade liver function²⁹ and stratify patients for a number of different therapies and treatment algorithms, including SBRT.[30], [31], [32] CP class has been shown to correlate with survival and toxicity in patients treated with SBRT.[2], [3], [4] As a result, current guidelines and prospective trials limit the use of SBRT to patients with Child class A cirrhosis[33], [34], [35]; however, the CP scoring system has a number of limitations, the most notable being the inclusion of subjective clinical criteria that requires an evaluation of the presence of ascites and encephalopathy with no consensus on how to distinguish the severity of these measures. CP score shows also a relative lack of granularity for assessing liver function because most patients with hepatocellular carcinoma (HCC) are CP A at diagnosis.³⁶ With these limitations in mind, the albumin-bilirubin (ALBI) score was developed as a novel and simple tool for assessing liver function that uses only the criteria of serum albumin and total bilirubin, eliminating the need for subjective clinical variables.[36], [37]

The purpose of this study was to compare the ALBI and CP grading systems in predicting prognosis and toxicity in patients treated for PLC with SBRT and to determine factors associated with liver function decline following therapy.