Between June 2009 and August 2015, 234 patients with HCC treated with sorafenib (median age=72 years, range; 40–91 years, 182 males and 52 females) were admitted to the Division of Hepatobiliary and Pancreatic Disease, Department of Internal Medicine, Hyogo College of Medicine (Hyogo, Japan) and the Department of Gastroenterology and Hepatology, Osaka Red Cross Hospital (Osaka, Japan). Of these, two patients with insufficient clinical data were excluded from the analysis. Thus, 232 patients with HCC treated with sorafenib were analyzed in the present study. The majority of analyzed patients received previous therapies for HCC. Sorafenib therapy was recommended for patients with unresectable HCC and the following features, as determined by dynamic computed tomography (CT): i) The presence of distant metastases; ii) refractory response to previous transcatheter arterial therapies for HCC [transcatheter arterial chemoembolization (TACE) or transcatheter arterial infusion (TAI) chemotherapy]; iii) unsuitability for TACE or TAI due to anatomical reasons; iv) vascular invasion such as tumor thrombus in the portal vein (28–30). Patients with poor performance status [PS; Eastern Cooperative Oncology Group (ECOG) classification ≥3] were not recommended for sorafenib therapy (28,29).

Assessment of sarcopenia was performed using CT scans obtained prior to sorafenib therapy. The tissue Hounsfield unit (HU) limit for skeletal muscles on the CT image was −29 HU to +150 HU, as previously reported (27). The third lumbar vertebra (L3) was used as a standard landmark. Skeletal muscles at the L3 level included the erector spinae, transverse abdominis, psoas, quadratus lumborum, internal and external oblique abdominal muscle and the rectus abdominis muscle; these muscles were identified on the CT images. Cross-sectional areas (cm²) of the muscles were measured by manual tracing on the CT images, and their sum was calculated (27). A representative case is presented in Fig. 1. The cross-sectional areas were normalized for patient height [skeletal muscle index (SMI), cm²/m²]. Male patients with SMI ≤36.2 cm²/m² and female patients with SMI ≤29.6 cm²/m² were defined as having sarcopenia, based on the findings of a previous study (31).

The present study retrospectively compared baseline characteristics, overall survival (OS), progression-free survival (PFS), best treatment response of sorafenib and serious adverse events [SAEs; grade ≥3 as defined by the Common Terminology Criteria for Adverse Events (CTCAE); version 3 (32)] in the sarcopenia and the non-sarcopenia groups, and investigated factors associated with OS and PFS using univariate and multivariate analysis. The current study was performed in accordance with the Declaration of Helsinki and with approval from the Ethics Committees of each hospital (Hyogo College of Medicine and Osaka Red Cross Hospital). The requirement to obtain written informed consent for inclusion in the present study from patients was waived.

HCC was diagnosed according to the previously described methods (28,29). Briefly, dynamic CT of the liver was performed prior to initiating sorafenib therapy. For patients with atypical imaging findings, ultrasound-guided tumor biopsy was conducted for histological assessment. HCC was finally diagnosed based on radiological or histological findings in accordance with the guidelines of the European Association for the Study of the Liver (33).

For patients with no evident risk factors, the recommended initial dose of 800 mg/day of sorafenib (400 mg twice a day) was administered (7,8). The reduced initial dose was administered to a number of patients (n=166) based on clinical features, including body weight, age, ECOG-PS and liver function. During sorafenib treatment, each attending physician adjusted the daily dose of sorafenib according to the degree of adverse events. In patients who received an initial reduced dose of sorafenib and exhibited good tolerability, dose escalation from 400–600 mg/day or from 400–800 mg/day was permitted. In patients with adverse events of grade ≥3, sorafenib treatment was discontinued until the clinical symptoms resolved to grade 1 or 2. In principle, the treatment efficacy of sorafenib was assessed every 4–8 weeks following the initiation of therapy, according to the modified Response Evaluation Criteria in Solid Tumors (mRECIST) and/or the levels of tumor markers (28,29,34,35). Patients continued sorafenib until the development of the following conditions: Unacceptable sorafenib-associated toxicity, disease progression or the patient's wish to discontinue treatment. Following discontinuation of sorafenib therapy for any reason, physicians evaluated the clinical conditions (tumor status or the general status) of each patient and investigated the suitability of other therapies (TACE, TAI or systemic chemotherapy other than sorafenib) for achieving the best clinical outcome (28,29).

The best treatment efficacy achieved during sorafenib therapy was determined according to the mRECIST criteria and/or tumor marker levels as previously indicated (28,29,34). The treatment efficacy was classified into the following four categories: Complete response (CR); partial response (PR); stable disease (SD); progressive disease (PD). A patient with CR was characterized by the absence of enhancement in the arterial phase within all targeted nodules. A patient with PR was characterized by a ≥30% reduction in tumor size, which was determined by calculating the sum of the diameters of the targeted nodules. The size of the nodules was estimated via unidirectional measurement. A patient with PD was characterized by a ≥20% increase in the tumor size via calculating the sum of the maximal dimensions of the targeted nodules. A patient with SD was characterized by the absence of CR, PR or PD (29,34). The objective response rate (ORR) was defined as the percentage of patients with the best tumor response rates considering CR and PR. The disease control rate (DCR) was defined as the percentage of patients with the best tumor response rates considering CR, PR and SD.

Sorafenib associated adverse events, including rash, diarrhea, hand-foot skin reaction, hypertension, liver damage, fatigue, gastrointestinal hemorrhage and lung injury, were evaluated using CTCAE version 3.0 (32).

The categorical variables of the sarcopenia and non-sarcopenia groups were analyzed by Fisher's exact test, while the numerical variables were analyzed with the unpaired Student's t-test or with the Mann-Whitney U test as applicable. OS and PFS curves were generated using the Kaplan-Meier method and compared using the log-rank test. Factors with values of P<0.05 in univariate analysis were included in the multivariate analysis with the Cox proportional hazards model. In order to analyze the significance of predictors in multivariate analysis, numerous variables were divided by the median values for all cases (n=232) and treated as dichotomous covariates. OS was defined as the period from the initiation of sorafenib therapy until mortality (due to any cause) or the last follow-up visit. PFS was defined as the period from the initiation of sorafenib therapy until the date of the detection of progression-free disease or mortality (due to any cause) (28,29). Data are expressed as median values (range). P<0.05 was considered to indicate a statistically significant difference. All statistical analyses were performed using the JMP 11 software (SAS Institute, Inc., Cary, NC, USA).

The baseline characteristics of the patients (n=232) are presented in Table I. There were 181 male and 51 female patients with a median age of 72 years (range, 40–91). Sarcopenia was observed in 151 (65.1%) patients. There were 165 patients with Child-Pugh class A and 67 patients with Child-Pugh class B cirrhosis (36). In 66 (28.4%) patients, the standard dose of sorafenib (800 mg/day) was administered at the beginning of therapy. Previously, the most common therapies for were transcatheter arterial therapies, including TACE or TAI, followed by percutaneous ablative therapies and surgical resection.

Compared with those in the non-sarcopenia group, the proportion of sarcopenia in male patients as compared with that in female patients was significantly higher (P=0.0079; Fig. 2A) and the proportion of sarcopenia in patients with poorer ECOG-PS as compared with that in patients with PS-0 was significantly higher (P=0.0137; Fig. 2B), whereas the proportion of sarcopenia in patients with Child-Pugh class A cirrhosis as compared with Child-Pugh class B cirrhosis tended to be lower (P=0.0678; Fig. 2C) and patients treated with an initial sorafenib dose of 800 mg/day (P=0.096) in the sarcopenia group tended to be significantly lower compared with those in the non-sarcopenia group (Table II). Laboratory analysis revealed that the differences between the sarcopenia and non-sarcopenia groups were significant with regard to the levels of serum albumin (P=0.0022), aspartate aminotransferase (AST; P=0.0062) and des-γ-carboxy prothrombin (DCP; P=0.0007; Table II).

The median follow-up periods subsequent to sorafenib treatment were 170 days (range, 12–1,145) in the sarcopenia group and 419 days (range, 50–2,036) in the non-sarcopenia group. The median OS was 174 days in the sarcopenia group and 454 days in the non-sarcopenia group (P<0.0001; Fig. 3A). The median PFS was 77 days in the sarcopenia group and 106 days in the non-sarcopenia group (P=0.0131; Fig. 3B).

The median treatment duration was 66 days in the sarcopenia group, and 103 days in the non-sarcopenia group (P=0.001). The prevalence of sorafenib-associated SAEs of grade ≥3, as assessed by CTCAE version 3.0, was 41.1% (62/151) in the sarcopenia group and 33.3% (27/81) in the non-sarcopenia group (P=0.261).

In the analysis of the best tumor response in the sarcopenia group, CR was achieved in 1 patient, PR in 5, SD in 40 and PD in 61, while 44 were not evaluated (NE); the ORR and DCR were calculated to be 4.0% (6/151) and 30.5% (46/151), respectively. In the analysis of the best tumor response in the non-sarcopenia group, CR was achieved in 3 patients, PR in 8, SD in 27, PD in 30 and 13 were NE; the ORR and DCR were calculated to be 13.6% (11/81) and 46.9% (38/81), respectively. The best treatment efficacy significantly differed between the sarcopenia and non-sarcopenia groups (ORR, P=0.0146; DCR, P=0.0151; Table II).

In the sarcopenia group, 136 (90.1%) patients expired during the follow-up period: 111 due to HCC progression; 6 of liver failure; 19 of other causes. In the non-sarcopenia group, 63 (77.8%) patients perished during the follow-up period: 60 due to HCC progression; 1 of liver failure; 2 of other causes.

The univariate analysis identified that the following factors significantly contributed to OS for all cases (n=232): Sex (P=0.0079); initial dose of sorafenib (P=0.0394); sarcopenia (P<0.0001); ECOG-PS (P=0.0041); extrahepatic metastases (P=0.0024); portal vein invasion (P=0.0029); tumor burden ≥50% (P=0.0001); presence of ascites (P<0.0001); AST ≥50 IU/l (P=0.0081); alkaline phosphatase ≥401 IU/l (P=0.0301); serum albumin ≥3.4 g/dl (P=0.0010); α-fetoprotein ≥139.2 ng/ml (P=0.0286); DCP ≥748 mAU/ml (P=0.0037; Table III). The hazard ratios (HRs) and 95% confidence intervals (CIs) determined by multivariate analysis for the 13 variables (selected based on P<0.05 values in univariate analysis) are detailed in Table III. Using multivariate analysis, sarcopenia (P<0.0001), extrahepatic metastases (P<0.0001), tumor burden ≥50% (P=0.0004) and the presence of ascites (P=0.0002) were identified to be significant predictors of OS.

Univariate analysis identified sarcopenia (P=0.0131), ECOG-PS (P=0.0021), extrahepatic metastases (P=0.0019), portal vein invasion (P=0.0203), tumor burden ≥50% (P=0.0244), presence of ascites (P=0.0429) and DCP ≥748 mAU/ml (P=0.0266) to be significantly associated with PFS for all cases (n=232; Table IV). The HRs and 95% CIs determined by multivariate analysis for these seven factors (selected based on P<0.05 values in univariate analysis) are presented in Table IV. Multivariate analysis identified ECOG-PS (P=0.0452) and extrahepatic metastasis (P=0.0014) to be significant prognostic factors associated with PFS.