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[Table 3]. On univariate analysis, patients with tumor size Table 3: Univariate analysis of factors related to “one-off”
≤ 3 cm had a higher rate of achieving “one-off ” ablation radiofrequency ablation
than those with tumor size > 3 cm (92.0% vs. 85.3%, P Variables Achieved Failed P
= 0.003), while tumor close to the organs had a lower (n = 281) (%) (n = 181) (%)
rate of achieving “one-off ” ablation than those further Sex 221 (59.2) 152 (40.8) 0.156
Male
from organs (50.8% vs. 64.2%, P = 0.010). On multivariate Female 60 (67.4) 29 (32.6)
analysis using a logistic regression, tumor size ≤ 3 cm Age
[odds ratio (OR), 0.534; 95% confidence interval (CI): ≤ 60 180 (59.2) 125 (40.8) 0.268
> 60
0.346-0.825, P = 0.005] and tumor further from organs PLT (×10 /L) 101 (64.3) 56 (35.7) 0.119
143.0 ± 57.9
119.2 ± 54.6
9
(OR, 0.593; 95% CI: 0.387-0.909, P = 0.017) remained PT (s) 12.2 ± 0.98 12.4 ± 0.93 0.533
predictive for the success of “one-off ” RFA [Table 4]. Bilirubin (µmol/L) 17.8 ± 14.3 16.7 ± 6.1 0.713
Albumin (g/L) 41.2 ± 4.2 41.4 ± 4.0 0.857
DISCUSSION Prealbumin (mg/ 189.5 ± 54.9 183.8 ± 50.1 0.687
dL)
ALT (IU/L) 94.8 (9.40, 546.80) 70.2 (18.10, 154.80) 0.710
[14]
RFA, a newly developed local ablative technique, is AFP (ng/dL)
suggested by AASLD and the European Association for ≤ 400 225 (60.3) 148 (39.7) 0.652
the Study of the Liver (EASL) as the first-line treatment > 400 56 (62.9) 33 (37.1)
for HCC due to its safety, lower mortality and morbidity, Child-Pugh
classification
and shorter hospitalization. “One-off ” ablation, first Class A 267 (60.4) 175 (39.6) 0.390
[15]
proposed by Jiang et al., [9-11] defined as (1) the diameter Class B 14 (70.0) 6 (30.0)
of post-RFA zone demonstrated by contrast-enhanced Hepatitis
CT is more than the maximal length of the tumor, and background 140 (40.7) 0.253
HBV and/or HCV 204 (59.3)
(2) no tumor recurrence within 6 months after RFA. None 77 (65.3) 41 (34.7)
However, not all tumors can achieve “one-off ” ablation HBsAg
after a single-session RFA. So far, numerous investigators Present 197 (59.2) 136 (40.8) 0.239
Absent
45 (34.9)
84 (65.1)
have described prognostic factors for survival after RFA. HBeAg
However, no large study has illustrated the predictive Present 67 (57.2) 50 (42.7) 0.362
factors for the success of “one-off ” ablation after a single- Absent 214 (62.0) 131 (38.0)
session RFA. In the study, we focused on the analyses of Tumor size (cm) 184 (92.0) 142 (8.0) 0.003
≤ 3.0
the effectiveness of single-session RFA in single HCC, and > 3.0 97 (85.3) 39 (14.7)
investigated the risk factors influencing the success of Tumor location
“one-off ” ablation to provide clinicians a guideline for Parenchyma 181 (59.0) 126 (41.0) 0.248
Sub-capsular
their routine medical treatments. Close to organs 100 (64.5) 55 (35.5)
Yes 60 (50.8) 58 (49.2) 0.010
Our study showed that tumors measuring 3 cm in No 221 (64.2) 123 (37.8)
greatest dimension and which are further to organs were Close to blood
most suitable for a single-session, single application of vessels 25 (62.5) 15 (37.5) 0.820
Yes
percutaneous RFA [Table 3]. As reported, when RFA was No 256 (60.1) 166 (39.3)
performed on small HCC nodules (≤ 3 cm), complete PLT: platelet; PT: prothrombin time; ALT: alanine aminotransferase;
[16]
necrosis can be achieved in more than 90% patients. AFP: alpha fetal protein; HBV: hepatitis B virus; HCV: hepatitis C
As the tumor size increased, the therapeutic effect of virus; HBsAg: hepatitis B surface antigen; HBeAg: hepatitis B e
RFA decreased. For tumors 3.0-5.0 cm and tumors larger antigen
than 5.0 cm, complete tumor necrosis rates was 71% and Table 4: Multivariate analysis of factors related to “one-off”
45%, respectively. In this study, the mean tumor size is radiofrequency ablation
[17]
2.6 ± 1.1 cm. The primary effectiveness was 90.0% and Variables OR 95% CI P
the rate of “one-off ” ablation in our study was 60.8%. Tumor size (≤ 3 cm vs. > 3 cm) 0.534 0.346-0.825 0.005
Tumor close to organs (no vs. yes)
Patients with tumor size ≤ 3 cm had a higher rate to OR: odds ratio; CI: confidence interval 0.593 0.387-0.909 0.017
achieve “one-off ” ablation than those with tumor size
> 3 cm, similar to observations by Komorizono et al. that the cirrhotic tissue around small HCC behaved
[18]
Komorizono’s study showed that tumors measuring ≤ 2 like a thermal insulator, increasing the heat retention
cm in greatest dimension were indicated for an optimal within the tumor and preventing heating outside the
ablation. Tumor size may influence the success of “one- tumor. However, when the tumor is > 3 cm, heat may
[18]
[19]
off ” RFA due to three possible reasons: first, RFA induced be lost in the periphery. Meanwhile, Ahmed et al. used
tumor coagulative necrosis by putting high-frequency an established computer simulation model of RFA to
alternating electrodes within the tumor tissue. The characterize the combined effects of varying perfusion,
temperature inside the ablated tissue must be > 60 °C to electrical, and thermal conductivity on radiofrequency
achieve coagulation necrosis. Some authors suggested (RF) heating. They observed that electrical and thermal

50 Hepatoma Research | Volume 2 | Issue 2 | February 29, 2016