Brachytherapy for Mesothelioma

What Is Brachytherapy?

Unlike traditional radiation therapy, brachytherapy uses no external radiation. Because of this defining property, it may also be referred to as internal radiation therapy, whereas the conventional type may be called external beam radiation therapy.

Internal radiation isn’t standard for lung cancer or mesothelioma, but researchers continue to test the treatment in clinical trials. Results from early studies show the potential for brachytherapy to extend life span and reduce the severity of symptoms. A March 2021 study reported thoracic cancer patients who receive brachytherapy benefit from fewer and less severe side effects after pulmonary surgery.

So far, it has been more effective in treating lung cancer. Researchers saw the best results for both types of cancer when they implemented a treatment called permanent brachytherapy. With this therapy, radioactive material is placed permanently into the tumor site and this material slowly loses its radioactivity over a few months.

How Is Brachytherapy Performed?

Brachytherapy uses a radioactive material called an implant. The material may come in the form of a wire or a “seed” about the size of a grain of rice.

It may be placed during surgery with an intraoperative radiation therapy technique or it may be inserted into cancer tissue with a hollow tube. With IORT, the patient receives local or general anesthesia and the doctor typically uses an imaging scan such as a CT or ultrasound.

Once the implant is in place, it commonly only attacks tissue within a radius of 1cm. This can be more effective but requires precision.

IORT brachytherapy is always administered in conjunction with surgery, and some lung cancer patients receive standard brachytherapy after surgery to kill any remaining cancer cells. It may also be used alongside conventional radiation therapy to target tumor growth in multiple ways. It may be used as a potentially curative treatment to eradicate cancer or as a palliative treatment to reduce symptoms such as coughing and difficulty breathing, depending on the individual patient’s situation.

Types of Brachytherapy

There are 2 primary types of brachytherapy: Low-dose rate and high-dose rate. People with lung cancer or mesothelioma usually receive a form of low-dose-rate treatment called permanent brachytherapy. This type continuously attacks the tumor with radiation for several months.

Depending on the type of therapy patients receive, they may undergo treatment for up to several weeks. This is shorter than the time needed to complete an external beam radiation therapy regimen, which can take up to 10 weeks.

Low-Dose Rate

Low-dose rate brachytherapy involves low doses of radiation for long periods. Radioactive material may be left in place for up to a week for this treatment.

The radiation can harm people nearby, so patients remain in the hospital while receiving LDR brachytherapy. Patients typically stay in private hospital rooms and can’t have guests for extended periods. LDR brachytherapy shouldn’t be painful or uncomfortable.

Permanent

This type of LDR involves permanently leaving seed implants in the body. This is the most common type used to treat mesothelioma and lung cancer because it has the most improved patient survival rates in clinical trials.

Typically, the implant is inserted during surgery as a form of IORT. Radioactive seeds are woven into a flexible mesh and stitched into place during a surgical procedure such as pneumonectomy or pleurectomy/decortication. This type of brachytherapy, designed to kill cancer cells that can’t be removed with surgery alone, actively emits radiation for about 3 months. Seeds may be mildly radioactive for another year. The inactive seeds then remain in the body permanently.

High-Dose Rate

High-dose-rate brachytherapy involves high doses of radiation for a maximum of 20 minutes. The patient receives HDR treatment once or twice daily for several days or weeks. After the physician inserts the seed via a tube, they typically leave the room while the radioactive material is in place. It doesn’t require a hospital stay and, like LDR brachytherapy, isn’t painful or uncomfortable.

Side Effects of Brachytherapy

The most common side effect is tenderness at the site of insertion, which subsides after a few months. Patients may also experience temporary swelling at the treatment site. Due to the sharp radiation dose fall-off with brachytherapy, it may be associated with fewer side effects than external beam radiation therapy in some cases.

Regardless of cancer type, brachytherapy can also cause skin irritation, such as redness, dryness, sensitivity or darkening under the breast or arm. In more severe cases, the skin may peel or develop moist ulcers. Doctors can prescribe prescription ointments that help relieve many of these side effects.

Most side effects usually go away after treatment ends, but you may feel very tired for 4 to 6 weeks after your last treatment. If symptoms worsen or don’t resolve with medications, your oncologist may refer you to a specialist to diagnose or further treat the problem.

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