Brachytherapy for Prostate Cancer

Internal radiation used mainly in early-stage cancer

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Brachytherapy is a form of radiation therapy used to treat certain types of cancer. It places tiny pieces of radioactive material, called seeds or pellets, in either a tumor or the surgical cavity left after a tumor has been removed. The pellets are typically the size of a grain of rice.

In the case of prostate cancer, brachytherapy may be delivered by implanting seeds directly in the prostate or, less commonly, by inserting a high-dose radioactive needle into the tumor which is later removed.

How Brachytherapy Works

Brachytherapy works by preventing the cancer cells from actively replicating. Unlike normal cells, which have a set replication cycle and a limited lifespan, cancer cells divide erratically and are essentially "immortal" (meaning they can continue to multiply out of control until actively stopped).

While normal cells can be damaged by radiation, they have the ability to repair themselves and continue multiplying normally after treatment is stopped. Cancer cells are far less able to do so.

Brachytherapy Options in Prostate Cancer

With prostate cancer, the implantation of radioactive seeds can usually either kill the tumor or shrink it significantly. The procedure is most often used in men whose cancer is low-grade and slow-growing.

The seeds, implanted into the prostate, are designed to emit radiation for several weeks or months, depending on the size of the mass. If there is a risk that the cancer may spread (metastasize), external radiation may also be used.

Brachytherapy may not work as well in men with an enlarged prostate gland. In such case, doctors may start with a course of hormone therapy to shrink the prostate before attempting brachytherapy.

For men with a more advanced tumor, high-dose-rate (HDR) brachytherapy may provide a more focused attack on the tumor.

For this procedure, a soft catheter is placed into the prostate between the scrotum and anus. A needle containing high-dose radioactive seeds are then placed inside the catheter and kept there for five to 15 minutes. This is typically repeated three times over two days.

While less commonly used, HDR brachytherapy is able to deliver stronger radiation to the tumor while limiting damage to nearby, normal tissue.

Side Effects of Brachytherapy

Men undergoing long-term brachytherapy may be advised to stay away from pregnant women and small children for several weeks or months since the pellets will continuously emit radiation. The radiation is often strong enough, in fact, to be picked up by airport detection equipment in the early stages.

Men undergoing brachytherapy to treat prostate cancer may experience a number of side effects. Among them:

  • Urinary incontinence is a common problem and can sometimes be severe. Other men, meanwhile, will experience the opposite effect, urinating more frequently due to the persistent irritation to the urethra. Most of these problems tend to resolve once treatment is completed, although it can sometimes take months.
  • Rectal pain, burning, diarrhea, and bleeding can also occur. The condition, known as radiation proctitis, is rarely severe and tends to improve over time.
  • Erectile dysfunction may also occur but is more often seen in older men who have had previous problems achieving or sustaining an erection. Any erectile problem occurring in younger men or those with healthy sexual function tend to resolve quickly and completely once treatment is completed.

Source:

Chin, J.; Rumble, R.; Kollmeier, M. et al. "Brachytherapy for Patients With Prostate Cancer: American Society of Clinical Oncology/Cancer Care Ontario Joint Guideline Update." Journal of Clinical Oncology. 2017; 35(15):1737-1743.

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