Understanding the Role of Radiation Therapy in Liver Cancer: An Overview
Liver cancer, primarily hepatocellular carcinoma (HCC), is the most common type of primary
liver cancer, accounting for approximately 80% of cases. It is a life-threatening condition
often diagnosed at advanced stages. While surgical resection and liver transplantation are
preferred treatments for early-stage HCC, radiation therapy has emerged as an integral
component of multimodal management. Traditionally, the liver’s sensitivity to radiation
limited its application. However, modern advances in radiation oncology now offer precise,
safe, and effective solutions. This blog explores the role of radiation therapy in liver cancer
and highlights how recent technological developments are transforming patient outcomes.
How is radiation therapy used to treat liver cancer?
Radiation therapy uses high-energy rays (or particles) to destroy cancer cells by damaging
their DNA, preventing them from growing and dividing. While surgery and liver
transplantation remain the most definitive treatments, not all patients qualify for these
interventions. This is where radiation therapy steps in—as an option to control tumors,
shrink them before surgery, or relieve symptoms for patients with advanced-stage disease.
There are two primary forms of radiation therapy used for liver cancer:
- Stereotactic Body Radiation Therapy (SBRT): This method uses external beam radiotherapy machines to direct radiation to the liver
tumor. With SBRT, high doses of radiation can be precisely delivered over fewer sessions
(usually 1 to 5), minimizing harm to surrounding healthy tissue. SBRT can be delivered with a
linear accelerator, CyberKnife, or proton beam. It is typically indicated for patients with
inoperable HCC, including those who may not be eligible for other local therapies like
surgery, ablation, or trans arterial chemoembolization (TACE). SBRT can also serve as a
bridge to liver transplantation by helping to control tumor growth. - Trans arterial Radioembolization (TARE): TARE is a form of internal radiation therapy in which tiny radioactive beads are injected into
the liver’s blood vessels. This highly targeted approach delivers radiation directly to the
tumor while sparing healthy liver tissue.
When is Radiation Therapy Recommended?
- Patients with inoperable tumors: When surgery is not an option due to tumor size,
location, or underlying liver disease. - Bridging therapy: Radiation is used to shrink tumors while patients wait for liver
transplantation. - Advanced-stage liver cancer: In cases where the goal is to reduce symptoms such as
pain, bleeding, or jaundice. - Patients with vascular involvement: Radiation therapy can manage tumors that
involve major blood vessels like the portal vein and inferior vena cava, which are
difficult to treat surgically.
Advancements in Radiation Therapy for Liver Cancer
The field of radiation oncology has made remarkable strides in recent years. Technology-driven innovations allow oncologists to deliver radiation with greater accuracy, improving treatment outcomes and reducing side effects. Here are some key advancements:
1. Stereotactic Body Radiation Therapy (SBRT) with Linear Accelerators (LINACs):
Linac bases SBRT employs high-energy X-rays or photon beams to deliver high dose to the tumor. It is achieved by creating multiple beam angles that converge on the tumor, delivering a concentrated dose while sparing surrounding healthy tissues. Advanced techniques like Intensity-Modulated Radiation Therapy (IMRT) and Volumetric Modulated Arc Therapy (VMAT) and Motion management techniques like Deep inspiratory breath hold (DIBH) or 4D CT are often integrated to increase precision and reduce exposure to healthy tissue.
Advantages:
- Widely available and adaptable for different tumor sizes and shapes.
- Customizable dose delivery for complex liver anatomies.
- Built-in imaging systems improve accuracy and positioning.
- Motion management with DIBH and 4D CT scan
2. Proton Beam Therapy:
Proton therapy uses protons instead of X-rays, limiting radiation exposure to surrounding tissues. The unique property of protons, known as the ‘Bragg peak,’ allows it to deposit most of the energy directly at the tumor site. Additionally, proton beams have a ‘no-exit’ dose, which results in better sparing of normal liver tissue and reduces the risk of radiation-induced liver toxicity—a crucial factor for patients with underlying liver disease or cirrhosis.
Advantages:
- Reduced radiation exposure to healthy liver tissue, lowering the chance of liver dysfunction.
- Potentially better outcomes in patients with compromised liver function or tumors near sensitive organs.
- Lower cumulative radiation doses to non-cancerous tissues.
Dr. Shankar Vangipuram Senior Consultant-Radiation Oncology