This is the third in a series of articles highlighting various radiation treatment modalities, how they work, and what patients can expect from each one.
Lung stereotactic body radiation therapy (SBRT) is a type of radiation treatment that uses carefully focused X-rays to target and destroy small tumors in the lung. Because the radiation is delivered precisely to the tumor, SBRT can provide an effective, noninvasive treatment option while limiting exposure to surrounding healthy tissue.
Adam Kole, M.D., Ph.D., associate professor, chief of the thoracic section, and director of Integration and Operations, explains how lung SBRT works, who may benefit from it, and what patients can expect during and after treatment.
What types of lung cancers or lung tumors are most commonly treated with SBRT?
Kole: The most common type of lung cancer is non-small cell lung cancer, or NSCLC, and this is the most common use for lung SBRT. However, we also treat less common types of lung cancer, such as small-cell lung cancer and carcinoid tumors.
If a different type of cancer from another part of the body spreads to the lung, we may also use lung SBRT as a treatment in that situation.
Who is a good candidate for lung SBRT, and why might it be recommended instead of surgery or conventional radiation therapy?
Kole: Tumors generally need to be small for SBRT to be considered. For patients with lung cancer, this typically means having stage I cancer.
Surgery is also an excellent treatment option, but some patients are unable to undergo surgery because of their overall health or because their lungs are not strong enough to have part of the lung removed. Other patients may prefer SBRT because it is a noninvasive treatment option. It doesn’t require anaesthesia, an operation, a stay in the hospital. It can be much less disruptive to a patients life.
Studies have shown that SBRT, which delivers a more powerful and focused dose of radiation than conventional radiation therapy, is more likely to successfully treat a small lung tumor. When patients have larger tumors or tumors that have spread to the lymph nodes, conventional radiation therapy may be needed—that is radiation delivered in smaller doses each day over a longer period of time-often weeks instead of days.
How do you account for tumor movement caused by breathing during lung SBRT?
Kole: Every patient undergoes a special type of CT scan that measures their breathing and how much the tumor moves as they breathe. We then customize the treatment for each patient based on that movement.
Some tumors do not move much with breathing, so treatment can proceed while the patient breathes normally. Other tumors move more significantly. In those cases, we may use a function on the treatment machine called gating. With gating, the machine turns on and off with each breath, allowing us to treat a much smaller portion of the normal lung.
At UAB, our team can also use small metallic seeds called fiducial markers. These markers are placed near a tumor, often in the same procedure as the biopsy, and help us visualize its location while radiation is being delivered, allowing us to be as precise as possible.
What does a typical lung SBRT treatment appointment look like from start to finish?
Kole: For the patient, treatment feels a lot like having a CT scan. You will lie on a table while a machine moves around you, carefully directing and focusing X-rays at the lung tumor.
Because the treatment uses X-rays, you will not feel the radiation while it is being delivered. Often times, the entire treatment from door to door is less than 30 minutes.
What are the main benefits and potential side effects of lung SBRT?
Kole: The main benefit is successfully treating the tumor so that it does not grow again. For a patient with stage I lung cancer, this can mean curing the cancer. For a patient whose cancer has spread to the lung from another part of the body, treating the tumor may prevent it from causing additional problems or symptoms. In some cases, it may also allow a patient to take a break from treatments such as chemotherapy. Other benefits include less time off work, less time away from family, and ability to maintain a normal schedule and lifestyle. There is no hospitalization, no incision, no recovery needed.
Potential side effects include fatigue, scarring in a small portion of the lung, cough, shortness of breath, rib pain, or heartburn with swallowing. Fortunately, most patients do not experience these symptoms, but the risk depends on the size and location of each patient’s tumor. Your doctor will review which side effects may be most likely in your individual case.
What kind of results have you seen with lung SBRT, and what follow-up care is needed after treatment?
Kole: SBRT generally has a high chance of curing stage I lung cancer, well over 90%. Patients are typically able to continue their normal activities before, during and after treatment.
After SBRT, patients commonly receive CT scans every few months to monitor the treated area of the lung.
What do you wish every patient knew before starting lung SBRT?
Kole: Patients with lung cancer at UAB should work with our entire lung cancer team to understand the full range of treatment options available to them, including surgery, radiation therapy, and chemotherapy. Working together allows the care team and patient to determine which approach is most appropriate for each individual.