Retrospective Study
Copyright ©The Author(s) 2017. Published by Baishideng Publishing Group Inc. All rights reserved.
World J Gastroenterol. May 7, 2017; 23(17): 3111-3121
Published online May 7, 2017. doi: 10.3748/wjg.v23.i17.3111
Rate of local tumor progression following radiofrequency ablation of pathologically early hepatocellular carcinoma
Yoshiteru Hao, Kazushi Numata, Tomohiro Ishii, Hiroyuki Fukuda, Shin Maeda, Masayuki Nakano, Katsuaki Tanaka
Yoshiteru Hao, Kazushi Numata, Tomohiro Ishii, Hiroyuki Fukuda, Katsuaki Tanaka, Gastroenterological Center, Yokohama City University Medical Center, Yokohama, Kanagawa 232-0024, Japan
Shin Maeda, Division of Gastroenterology, Yokohama City University Graduate School of Medicine, Yokohama, Kanagawa 236-0004, Japan
Masayuki Nakano, Pathological Department, Shonan Fujisawa Tokusyukai Hospital, Fujisawa, Kanagawa 251-0041, Japan
Author contributions: Hao Y designed and performed the research and wrote the article; Numata K designed the research and supervised the report; Ishii T, Fukuda H, Maeda S and Nakano M provided clinical advice; Tanaka K supervised the report.
Institutional review board statement: This study was reviewed and approved by the Ethics Committee of the Yokohama City University Medical Center.
Informed consent statement: All the patients included in this study provided written informed consent for the use of their clinical data.
Conflict-of-interest statement: We have no financial relationships to disclose.
Data sharing statement: No additional data are available.
Open-Access: This article is an open-access article which was selected by an in-house editor and fully peer-reviewed by external reviewers. It is distributed in accordance with the Creative Commons Attribution Non Commercial (CC BY-NC 4.0) license, which permits others to distribute, remix, adapt, build upon this work non-commercially, and license their derivative works on different terms, provided the original work is properly cited and the use is non-commercial. See: http://creativecommons.org/licenses/by-nc/4.0/
Correspondence to: Kazushi Numata, MD, Gastroenterological Center, Yokohama City University Medical Center, 4-57 Urafune-cho, Minami-ku, Yokohama, Kanagawa 232-0024, Japan. kz-numa@urahp.yokohama-cu.ac.jp
Telephone: +81-45-261-5656 Fax: +81-45-261-9492
Received: December 21, 2016
Peer-review started: December 23, 2016
First decision: January 10, 2017
Revised: February 8, 2017
Accepted: March 31, 2017
Article in press: March 31, 2017
Published online: May 7, 2017
Abstract
AIM

To evaluate whether pathologically early hepatocellular carcinoma (HCC) exhibited local tumor progression after radiofrequency ablation (RFA) less often than typical HCC.

METHODS

Fifty pathologically early HCCs [tumor diameter (mm): mean, 15.8; range, 10-23; follow-up days after RFA: median, 1213; range, 216-2137] and 187 typical HCCs [tumor diameter (mm): mean, 15.6; range, 6-30; follow-up days after RFA: median, 1116; range, 190-2328] were enrolled in this retrospective study. The presence of stromal invasion (namely, tumor cell invasion into the intratumoral portal tracts) was considered to be the most important pathologic finding for the diagnosis of early HCCs. Typical HCC was defined as the presence of a hyper-vascular lesion accompanied by delayed washout using contrast-enhanced computed tomography or contrast-enhanced magnetic resonance imaging. Follow-up examinations were performed at 3-mo intervals to monitor for signs of local tumor progression. The local tumor progression rates of pathologically early HCCs and typical HCCs were then determined using the Kaplan-Meier method.

RESULTS

During the follow-up period for the 50 pathologically early HCCs, 49 (98%) of the nodules did not exhibit local tumor progression. However, 1 nodule (2%) was associated with a local tumor progression found 636 d after RFA. For the 187 typical HCCs, 46 (24.6%) of the nodules exhibited local recurrence after RFA. The follow-up period until the local tumor progression of typical HCC was a median of 605 d, ranging from 181 to 1741 d. Among the cases with typical HCCs, local tumor progression had occurred in 7.0% (7/187), 16.0% (30/187), 21.9% (41/187) and 24.6% (46/187) of the cases at 1, 2, 3 and 4 years, respectively. Pathologically early HCC was statistically associated with a lower rate of local tumor progression, compared with typical HCC, when evaluated using a log-rank test (P = 0.002).

CONCLUSION

The rate of local tumor progression for pathologically early HCCs after RFA was significantly lower than that for typical HCCs.

Keywords: Early hepatocellular carcinoma, Local tumor progression, Radiofrequency ablation, Ablative margin, Contrast-enhanced ultrasonography

Core tip: This retrospective study evaluated whether pathologically early hepatocellular carcinoma (HCC) exhibited local tumor progression after radiofrequency ablation (RFA) less often than typical HCC. Among the 50 pathologically early HCCs, 49 (98%) of the nodules did not exhibit local tumor progression. However, 1 nodule (2%) was associated with a local tumor progression found 636 d after RFA. Among the 187 typical HCCs, 46 (24.6%) of the nodules exhibited local tumor progression after RFA. Pathologically early HCC was significantly associated with a lower rate of local tumor progression, compared with typical HCC, when evaluated using a log-rank test (P = 0.002).