Protons or photons for hepatocellular carcinoma? Let's move forward together.

摘要

Hepatocellular carcinoma (HCC) is the third leading cause of global cancer mortality, with a 5-year survival rate of 5% and an increasing incidence in North America. Cure is possible in patients who are treated with liver transplantation, resection, or ablative therapies (e.g., radiofrequency ablation for tumors <3 cm). Unfortunately, in most patients, these local therapies are not options, and hepatic progression is inevitable. One may expect that radiation therapy would have an established role in HCC; yet radiation therapy is not a universally accepted treatment, and many radiation oncologists have never treated a patient with HCC. It is time to establish the role of radiation therapy in HCC. Progress has been slow in HCC for many reasons. Underlying liver disease and impaired liver function are almost universally present. Any insult to the liver (including treatment) can trigger liver failure and hasten death. The whole liver tolerance to radiation therapy is low and is reduced further in patients with HCC compared with those with liver metastases (1). As the liver volume irradiated increases, the risk of radiation induced liver disease rises. Reactivation of hepatitis B and a general decline in liver function are also possible, and both are poorly correlated with radiation dose and volume irradiated. Furthermore, the tolerance of other normal tissues around the liver (e.g., the stomach, duodenum, bowels, and kidneys) needs to be respected. In addition to potential toxicities, organ motion in the upper abdomen makes delivery of conformal HCC radiation therapy particularly challenging.