Stereotactic Body Radiation Therapy and What to Expect During Treatment

If you or a loved one is currently undergoing or considering lung cancer treatment, it is understandable how difficult and overwhelming this can be. This article highlights some information about stereotactic body radiation therapy (SBRT). This type of external beam radiation therapy uses a machine to target the tumor or cancer site with a radiation beam from outside the body. This article will provide more insight into SBRT and help you make an informed decision about your treatment options.

The X-ray-producing machine used in SBRT is called a linear accelerator. One to five high-dose beams are delivered to the tumor during lung cancer treatment from different angles.

This specialized form of radiation therapy (RT) is commonly used in lung cancer treatment for its reliability and reproducibility. It involves four steps that are repeated during the simulation and every treatment session:

• Patient immobilization and accurate repositioning – devices like body frames, cushions, and plastic restraints are used to immobilize the patient comfortably. During a simulation, patients will be fixed in an immobilization position that is used in every subsequent treatment session. The same position is important for treatment accuracy. Patients will also receive tattoos at the side and the center of the chest to mark the direction of the radiation beam.
• Use of image guidance – The treatment areas are guided using CT scans. When the tumor is hard to differentiate from normal tissue, MRI or PET. The treatment area/field is fixed on the lung tumor, and minor adjustments are made every day of treatment.
• Tumor motion control – Sometimes, tumor location may move slightly in relation to the surrounding organs or structures, along with breathing motion. Several ways, including the use of a tumor tracking system, exist to compensate for tumor motion and assure reproducibility and accuracy.
• Treatment planning – Careful treatment planning is overseen by a team of radiation oncologists, radiologists, radiation therapists, and radiation nurses.

The American Society For Radiation Oncology has made a video on what to expect during SBRT for lung cancer.

When used in treating primary stage 1 non-small cell lung cancer (NSCLC), it is an alternative to surgery for non-surgical candidates (people who are too old or frail and those who refuse surgery).

When used in treating advanced-stage cancer, it is considered when there are multiple metastatic tumors in the lungs and other body parts (to minimize organ removal by surgery). This is because SBRT is highly precise and can deliver high-dose radiation to small tumors.

The radiation toxicity and side effects are greatly reduced, thanks to the extreme accuracy of SBRT.

SBRT has a shorter treatment time frame than standard RT (daily treatment over multiple weeks). It is completed in 3-5 days within 1-2 weeks, with 20-60 minutes per session.

The median cost of SBRT in the US is around $26,000-$27,000. Medicare covers the procedure for

• Early-stage primary tumors in medically inoperable patients
• Tumors metastatic to the lung in patients with good performance status

Many private insurers provide partial coverage for the cost of this technique. Although it is more costly than standard RT, it has significantly enhanced lung cancer treatment results. Reviewing your insurance policies to determine if you are eligible for coverage is advisable. The expense can be a significant concern and may increase your stress. Your healthcare providers should be able to offer you all the necessary advice and assistance concerning your treatment and financial planning. It can be a significant financial burden but do not lose hope and always speak to your healthcare providers if there are alternative routes to cover the cost.

Due to the high doses used in SBRT, there is also an increased risk of damage to normal tissue if care is not taken. To balance the benefits of SBRT with the potential risks to normal tissues, doctors will consider factors like

• Tumor size
• Proximity from major airway (trachea)
• Proximity from critical organs like the heart, major vessels, nerves, and the spinal cord

Based on clinical evidence, SBRT should only be recommended when the treatment field is at least 2 cm from the structures mentioned above.

Common short-term side effects of SBRT include fatigue, nausea or vomiting, and skin irritation around the radiation site. Very rarely, patients may experience radiation toxicity (damage to normal tissue) like:

• Brachial plexus injury – chronic arm or shoulder pain due to nerve damage
• Pulmonary fibrosis – scarring of the lung by radiation, decreasing lung function

The risk of these side effects can be minimized through careful treatment planning and dose optimization.

Additionally, advances in radiation therapy technology, such as image-guided radiation therapy (IGRT) and motion management techniques, can help improve treatment precision and reduce the likelihood of damage to surrounding healthy tissue.

The management of side effects and radiation toxicity from SBRT is tailored to the individual patient's needs and the specific circumstances of their treatment. Patients should have a detailed discussion with their radiation oncologist to understand the potential risks and benefits of SBRT and the strategies for managing any potential side effects.