Brachytherapy

• Brachytherapy is a type of internal radiation therapy for cancer.
• It involves placing radioactive sources directly into or near a tumor.
• This method delivers a high dose of radiation to the cancer while sparing healthy tissue.
• There are different types, including temporary and permanent implants.
• The procedure is generally well-tolerated, with localized side effects.

What is Brachytherapy?

Brachytherapy is a specialized form of radiation therapy that involves placing radioactive sources inside the body, directly within or adjacent to the tumor. This technique allows for a very high dose of radiation to be delivered to the cancerous cells, while significantly reducing the radiation exposure to nearby healthy tissues and organs. It is often used to treat various cancers, including prostate, cervical, breast, skin, and head and neck cancers. According to the American Cancer Society, Brachytherapy can be a standalone treatment or used in conjunction with external beam radiation therapy, surgery, or chemotherapy, depending on the type and stage of cancer.

Types of Brachytherapy and How It Works

There are primarily two main types of brachytherapy for cancer: temporary and permanent. The choice between these depends on the specific cancer, its location, and the patient’s overall health.

• Temporary Brachytherapy: This involves placing radioactive sources into catheters or applicators that are inserted into the tumor site for a specific period, then removed.
  • High-Dose-Rate (HDR) Brachytherapy: In HDR brachytherapy, a highly radioactive source is delivered through catheters for several minutes at a time, often in multiple treatment sessions over days or weeks. This allows for precise control over the radiation dose and duration.
  • Low-Dose-Rate (LDR) Brachytherapy: LDR brachytherapy uses sources that remain in place for a longer continuous period, typically several days, delivering radiation at a lower dose rate. The patient usually stays in the hospital during this time.
• Permanent Brachytherapy (Seed Implants): This method involves implanting small, radioactive seeds (about the size of a grain of rice) directly into the tumor. These seeds remain in the body permanently, gradually releasing radiation over several weeks or months until their radioactivity decays. This approach is commonly used for prostate cancer.

The mechanism of how brachytherapy works involves the localized emission of radiation from the implanted sources. This radiation damages the DNA of cancer cells, preventing them from growing and dividing, ultimately leading to their death. Because the sources are placed directly within or very close to the tumor, the radiation dose falls off rapidly with distance, ensuring that healthy surrounding tissues receive minimal exposure. This targeted approach is a key advantage of brachytherapy, making it an effective treatment option for many patients.

Brachytherapy Procedure and Side Effects

The brachytherapy procedure and side effects vary depending on the type of brachytherapy and the cancer being treated. Before the procedure, imaging tests such as MRI, CT scans, or ultrasound are performed to precisely map the tumor and surrounding structures. During the procedure, the radioactive sources or applicators are inserted into the body. This insertion may require local, regional, or general anesthesia, depending on the site and complexity. For temporary brachytherapy, applicators or catheters are carefully positioned, and the radioactive source is then delivered remotely by a machine. For permanent brachytherapy, the radioactive seeds are implanted using thin needles.

Potential side effects of brachytherapy are typically localized to the treated area and are often temporary. They can include localized pain or discomfort at the site of implant or applicator insertion, swelling or bruising in the treated area, and general fatigue. When treating prostate or gynecological cancers, patients may experience urinary symptoms such as frequent urination, urgency, or discomfort. For pelvic cancers, bowel symptoms like diarrhea or rectal discomfort can occur. Skin irritation, such as redness or tenderness, may also be noted where applicators were placed. Most side effects are manageable with medication and tend to resolve within weeks or months after treatment. Patients are closely monitored by their healthcare team to manage any adverse reactions and ensure optimal recovery.