Published online Jun 7, 2017. doi: 10.3748/wjg.v23.i21.3797
Peer-review started: February 20, 2017
First decision: March 16, 2017
Revised: March 22, 2017
Accepted: May 4, 2017
Article in press: May 4, 2017
Published online: June 7, 2017
Spontaneous tumor regression is an extremely rare phenomenon in the oncology field. However, there are several case reports resulted in the regression of hepatocellular carcinoma (HCC) and the accumulation of clinical information and analyses of the mechanism can contribute to the development of a novel therapy. For this purpose, we have carefully reviewed 23 cases of spontaneously regressed HCC published in recent 5 years and our case. The information regarding the tumor size, tumor marker, treatments, etc., have been summarized. The mechanism of spontaneous regression has been discussed to date and presumed to be due to many factors, including hypoxia and immunological reactions. In this careful review of the 24 cases based on the clinical information, hypoxia, systemic inflammation, and both upon spontaneous regression were seen in 3, 8, and 4 cases, respectively among the 15 cases for which the information regarding the proposed mechanisms are available. Recent development of immunotherapeutic approaches in oncology shows promising results, therefore, accumulation of additional cases and analysis of mechanisms underlying the spontaneous regression of HCC are essential and could lead to the development of a new generation of immunotherapies including antibodies directed against immune reactions.
Core tip: Spontaneous tumor regression of hepatocellular carcinoma (HCC) have been reported in several reports although rare. The analyses of the mechanisms underlying this phenomenon is the potential target for the novel therapeutic methods for HCC. For this purpose, we have carefully reviewed 24 cases of spontaneously regressed HCC including cases published in recent 5-years and our case. The minute clinical information and clinical courses are reviewed and summarized. Based on the information, hypoxia and/or systemic inflammation are involved in all cases for which the information regarding the proposed mechanism is available. An accumulation of additional cases and the analysis of mechanism underlying the spontaneous regression of HCC could lead to the development of new therapeutic strategy for HCC.