Table 1 shows the patients’ baseline characteristics. The mean age was 71.5 ± 8.9 years, and 53 of 70 patients (75.7%) were male. The mean body weight was 61.5 ± 12.2 kg. The causes of chronic liver disease were virus (n = 38), nonalcoholic fatty liver disease (n = 16), alcohol (n = 10), and others (n = 6). The number of patients with liver cirrhosis was 46 (65.7%). Lenvatinib was administered for vascular invasion (n = 24), metastatic disease (n = 22), and progression after locoregional treatment (n = 46). The types of treatment given were radiofrequency ablation (RFA) (n = 28), transcatheter arterial therapy (n = 50), and molecular targeted therapy (n = 6). There were 32 (45.7%) and 38 (54.3%) patients who were diagnosed as having Barcelona Clinic Liver Cancer (BCLC) stages B and C, respectively. There were 25, 35, and 10 patients who had daily initial doses of 12 mg, 8 mg, and 4 mg, respectively.
Clinical responses of patients who received lenvatinib
The numbers of complete response, partial response, stable disease, progressive disease (PD), and unevaluated response in maximal therapeutic response were 2 (2.9%), 24 (34.2%), 25 (35.7%), 15 (28.0%), and 4 (5.7%), respectively. The mean PFS and OS in all patients were 283 and 552 days (95% CI 215–351 and 450–655 days), respectively. Table 2 shows the treatment-related severe AEs in the study period. After discontinuation of lenvatinib therapy, administration of another molecularly targeted therapy, transcatheter treatment, and best supportive care were performed for 18 (25.7%), 8 (11.4%), and 29 (41.4%) patients, respectively.
Pretreatment NO levels
The mean NO level at baseline was 49.2 ± 39.8 nmol/mL. We analyzed the correlation between the NO levels and baseline characteristics [see Additional file 2]. BCLC stages B and C were 48.3 ± 40.5 and 50.0 ± 39.8, respectively. Up to 7 in and out were 46.6 ± 39.8 and 52.0 ± 40.6, respectively. The NO levels in patients with and without high blood pressure were 49.3 ± 41.2 and 49.1 ± 39.3, respectively. No significant differences were found among age, sex, body weight, etiology, tumor size, high blood pressure, BCLC stage, and presence of portal invasion.
Change levels and rate of NO after lenvatinib therapy
Lenvatinib reduced the NO levels in 39 (55.7%) patients. After lenvatinib administration, change levels in the NO from 49.2 ± 39.8 to 45.1 ± 32.5 nmol/ml were observed (P = 0.193) (Fig. 2A) and a change rate in the NO was observed from 0.27 to 4.16 (Fig. 2B).
Tumor response in the change levels and rate of NO after administration of lenvatinib
Non-PD and PD were –4.4 ± 28.5 and –3.2 ± 19.9 in the change levels of the NO. There was no difference between clinical response to lenvatinib therapy and change levels of the NO (P = 0.864) (Fig. 3A). Non-PD and PD were 1.3 ± 0.8 and 1.2 ± 0.7, in the change rate of the NO. There was no significant difference between clinical response to lenvatinib therapy in HCC and change rate of the NO (P = 0.632) (Fig. 3B).
SAE in the change levels and rate of NO after administration of lenvatinib
The change levels of the NO in the patients with the absence and presence of SAE were 1.12 ± 30.6 and –9.67 ± 19.6. The change levels of NO was higher in patients with AEs than in those without SAE (P = 0.085) (Fig. 3C). The change rate of the NO in the patients with the absence and presence of SAE were 1.4 ± 0.9 and 1.0 ± 0.52, respectively. The change rate of NO was significantly higher in patients with SAE than in those without SAE (P = 0.030) (Fig. 3D).
Correlation between high blood pressure (HBP) and change of NO after lenvatinib therapy
The change levels of NO in patients with and without high blood pressure (HBP) were –4.1 ± 18.1 and –3.9 ± 21.9, respectively. No significant correlation was found between the presence of HBP and change levels of NO (P = 0.561).
Furthermore, the change rate of NO in patients with and without high blood pressure (HBP) were 1.1 ± 1.0 and 1.2 ± 0.9, respectively. No significant correlation was found between the presence of HBP and change rate of NO (P = 0.813).
PFS and OS based on reduced NOS levels
Receiver-operating characteristic (ROC) curve analysis was performed to assess the occurrence of SAE in patients with HCC. The respective cut-off points for SAE after lenvatinib treatment were estimated using ROC curves for the change rate of the NO (see Additional file 3). Using a cut-off for the reduction of 0.8, predicting the occurrence of AEs had a sensitivity of 77.3% and a speciﬁcity of 42.3%. A reduction in NO rate of < 0.8 was defined as a clinically significant reduction of NO (CSRN).
The mean PFS in the CSRN and non-CSRN groups was 183 days and 339 days (95% CI 122–244 days and 245–434 days), respectively. Patients in the CSRN group experienced significantly worse PFS than those in the CSRN group (log-rank test for trend: PFS, P = 0.040) (Fig. 4A).
The mean OS in the CSRN and non-CSRN groups was 367 and 649 days (95% CI 251–483 days and 513–785 days), respectively. Patients in the CSRN group experienced significantly worse OS than those with non-CSRN (log-rank test for trend: OS, P = 0.005) (Fig. 4B).
Univariate and multivariate analysis of factors affecting PFS and OS
Table 3 shows the risk factors associated with PFS using a logistic regression model. In multivariate analysis, albumin and presence of CSRN were significantly associated with PFS (hazard ratio [HR] 2.225; 95% CI 1.10–4.62; P = 0.026 and HR 1.765; 95% CI 1.010–3.101; P = 0.046, respectively). Table 4 shows the risk factors associated with OS using a logistic regression model. In multivariate analysis, albumin and presence of CSRN were significantly associated with OS (HR 3.061; 95% CI 1.447–6.476; P = 0.003 and HR 2.100; 95% CI 1.178–3.743; P = 0.012, respectively).