Radiation & Brachytherapy for Prostate Cancer

Brachytherapy (seed implants) as a stand-alone treatment is generally only used to treat early-stage prostate cancer. In this treatment, the prostate specialist implants between 30 and 60 radioactive seeds into the prostate gland. The implanted seeds remain in place permanently but become inert (no longer radioactive) after a few months.

This therapy allows the radiation therapist to deliver a high dose of radiation to the prostate with limited radiation exposure to surrounding tissues. In some cases this seeding technique is used in combination with external-beam radiation in order to optimize the radiation dose for more advanced stage prostate cancer.

This is a traditional radiation technique that treats the entire prostate. For those at high risk of the cancer spreading, the radiation therapist also delivers radiation to the pelvic lymph nodes.

Conformal External-Beam Therapy

This type of therapy creates 3D representations of the prostate, most often from a CT scan. The machine then designs a high radiation dose that conforms to the specific shape of the prostate.

Conformal therapy allows radiation therapists to safely use doses above traditional levels without significant increases in serious side effects or affecting nearby healthy tissue.

Intensity-Modulated Radiotherapy (IMRT)

Intensity-modulated radiotherapy (IMRT) is a refinement of conformal external-beam therapy. It uses a highly flexible beam to target the radiation with extreme precision according to the unique anatomy of each patient.

Stereotactic radiosurgery is a form of external beam radiation that delivers highly focused radiation beams to target the prostate with the help of a precise image guidance system called CyberKnife. Equipped with one of the region's leading CyberKnife stereotactic radiosurgery centers, BIDMC offers this advanced prostate cancer treatment, which allows for accurate targeting of the tumor while helping protect surrounding healthy tissue.

The CyberKnife system uses a highly precise, fiducial-based tracking method to continuously adjust the radiation beam during treatment. This precision allows many patients to complete treatment in fewer sessions compared to traditional radiation therapy, with similar outcomes.

After CyberKnife treatment, very few men experience urinary incontinence. For sexual function, men under age 65 who had good erectile function before treatment have about an 80% chance of maintaining it afterward. Among those who experience erectile dysfunction, many respond well to medication such as Viagra.

Certain factors can affect how well these medications work, including:

• Being over age 65
• Having diabetes, vascular disease, or other health conditions
• Smoking
• Taking certain medications, such as beta blockers or antidepressants

In some caseswhere the cancer is more advanced or showing signs of becoming aggressive, the prostate care team may recommend temporary androgen deprivation therapy (ADT) in combination with external beam radiation. ADT is a form of hormone therapy that blocks the body's production of the male hormone testosterone. This causes prostate cancer to regress and become more sensitive to radiation therapy.

There are several forms of ADT that prostate specialists may use to completely block testosterone production.