Hepatocellular carcinoma (HCC) is one of the leading cancers in Taiwan, and is often associated with chronic hepatitis B or hepatitis C infection. Patient’s liver function is often compromised by liver cirrhosis or viral infection. Surgery is considered as the treatment of choice for early stage HCC, but is not feasible for those with poor liver function. Radiofrequency ablation (RFA) or percuataneous ethanol or injection (PEI) is an alternative to surgery for patients with a single localized mass or several small tumors. Liver transplantation can’t be routinely undertaken due to the limited sources for the donor. For those not suitable for above treatments, transcatheter arterial chemoembolization (TACE), target therapy or Y90 microsphere therapy is shown to prolong patients’ survival time.
Liver tissue is very sensitive to radiation damage; the radiosensitivity is even unpredictable for cirrhotic or chronic viral-infected liver, and this explains why in the past radiotherapy did not play a curative role in the HCC treatment. However, modern X-ray radiotherapy employs the techniques such as image-guided radiotherapy (IGRT), stereotatic body radiation therapy (SBRT) and target tracking or respiratory gating, and is able to give curative dose to some HCC patients.
Proton therapy is the “target therapy” for radiotherapy. High energy proton penetrates into tumor and kills tumor cells. The radiation dose is concentrated in the tumors and no dose to the normal liver after the desired depth at tumors. Since the dose to the normal liver is spared, proton therapy is able to deliver higher radiation dose to tumors than X-ray and achieves good local tumor control rate. Several proton centers in Japan have reported that the respective local control rate is 85-95% for tumor size less than 5 cm and 80% for 5-10cm. Proton therapy is therefore a new effective weapon for treating HCC, but is not indicated for tumors with diffuse infiltration in the liver or synchronous multiple tumors in different lobe of liver.
Article author: Dr. Ji-Hong Hong
- Professional doctor team:Dr. Ji-Hong Hong、Dr. Ngan-Ming Tsang、Dr. Bin-Shen Hung
- Articles maintained by Dr. Wei-Heng Kao