Precision vs. Power: Choosing The Right Radiation For Prostate Cancer

The best decision is one made together with your physician, based on a thorough discussion of the benefits, risks, logistics, and your values. With the right plan in place, radiation therapy can be a powerful and effective tool in your fight against prostate cancer.

Radiation Therapy For Prostate Cancer: Understanding The Different Types

There is no one-size-fits-all approach to treating prostate cancer with radiation. Several different forms of the therapy exist, and many are equally effective. With ongoing advances in medical technology, treatment options continue to evolve — providing faster, more targeted, and more convenient ways to treat prostate cancer.

Choosing the right radiation treatment involves considering a number of factors, including your cancer stage, risk classification, personal preferences, lifestyle, and other medical conditions. This decision should always be made in close collaboration with your physician, often with input from a radiation oncologist, urologist, and sometimes a medical oncologist. Below, we explore the main types of radiation therapy available for prostate cancer and what you can expect with each.

External Beam Radiation Therapy (EBRT)

External beam radiation therapy (EBRT) is the most common type of radiation treatment for prostate cancer. It involves directing high-energy X-rays from outside the body at the prostate gland. This is done using a machine called a linear accelerator. EBRT is non-invasive and can be used as a primary treatment or in combination with other therapies.

Treatment is typically administered five days a week over the course of 6 to 8 weeks, though shorter regimens (called hypofractionated schedules) are becoming more common and may last only 4 to 5 weeks.

EBRT is versatile and can be used for patients with:

• Low-, intermediate-, and high-risk localized prostate cancer
• In post-operative settings after prostatectomy (if PSA remains detectable or recurs)
• Advanced or metastatic prostate cancer in palliative settings
• If recurrence after prior radiation or surgery occurs (in certain cases)

Side effects may include:

• Urinary symptoms (increased frequency, urgency, or mild incontinence)
• Bowel symptoms (loose stools, rectal irritation, or occasional bleeding)
• Fatigue (typically builds up over the course of treatment)
• Erectile dysfunction (may develop over time, especially when combined with hormone therapy)

Most side effects improve within a few months of completing therapy, though some may persist or occur years later.

EBRT offers excellent long-term cancer control, particularly when tailored to the patient’s risk group. When combined with androgen deprivation therapy (ADT) in intermediate- and high-risk cases, outcomes are even more favorable. Technological improvements such as image-guided radiation therapy (IGRT) and intensity-modulated radiation therapy (IMRT) have made EBRT more precise and safer than ever.

Stereotactic Body Radiotherapy (SBRT)

SBRT is a highly focused form of external beam radiation therapy. It delivers very high doses of radiation in a small number of treatment sessions — typically five or fewer. This form of therapy is also referred to as “ultra-hypofractionated” therapy.

SBRT is best suited for patients with:

• Low- and favorable intermediate-risk prostate cancers
• Unfavorable intermediate-risk disease, depending on prostate anatomy and size

It is generally not used for high-risk or very large prostates without careful consideration.

While SBRT is well-tolerated by many, its high-dose nature means side effects can be slightly more intense in the short term.

Side effects may include:

• Urinary frequency and urgency in the first few weeks after treatment
• Temporary bowel changes or rectal irritation
• Erectile function issues, though function can be preserved in many cases, especially in younger patients

Data from clinical trials and long-term follow-up studies indicate that SBRT provides excellent cancer control comparable to standard EBRT, with the added benefit of convenience. For appropriately selected patients, SBRT is a safe, effective, and efficient alternative to prolonged treatment courses.

Brachytherapy

Brachytherapy involves placing radioactive material directly inside or near the prostate gland. This can be done either as a stand-alone treatment or in combination with EBRT for more aggressive disease.

There are two main types: low-dose brachytherapy (LDR) and high-dose brachytherapy (HDR).

LDR involves implanting tiny radioactive seeds (commonly iodine-125 or palladium-103) into the prostate during a single procedure. The seeds stay in place permanently but deliver radiation over several months.

This approach is most frequently used for patients with low- and favorable intermediate-risk prostate cancer. To use this approach, patients cannot have an excessively large prostate or any significant urinary obstruction.

Side effects may include:

• Urinary symptoms
• Seed migration (this is rare with modern techniques)
• Rectal symptoms (though these are less common than with EBRT)

LDR brachytherapy offers high cure rates and is a highly effective treatment option with a long track record.

HDR brachytherapy uses temporary placement of catheters into the prostate through which a high-intensity radioactive source (often iridium-192) is inserted for a few minutes, then removed. This may be done over one or several sessions.

HDR is typically used for patients with intermediate- to high-risk prostate cancers — and it’s typically combined with EBRT as a “boost.”

Side effects are similar with LDR, with urinary symptoms being the most common. Some patients may need a short-term catheter after the procedure

HDR brachytherapy delivers a highly concentrated dose of radiation and has shown excellent cancer control with manageable side effects. Because the radiation is temporary, there’s no radioactive material left in the body after treatment.

Proton Beam Therapy

Proton therapy uses charged particles (protons) rather than X-rays to kill cancer cells.

“Proton therapy has a physical property called the Bragg peak,” Dr. Dal Pra explains. “This allows the radiation beam to enter the body, and there is a sharp fall-off. And when we develop the radiation volumes, the radiation field, this is able to spare more normal tissues.”

Proton therapy is similar to EBRT in delivery, but uses different equipment. Treatments are typically given daily over 4 to 8 weeks, though hypofractionated schedules are being explored.

This approach may be used for:

• Patients with localized prostate cancer who meet certain anatomic and insurance criteria
• Those seeking to reduce radiation dose to surrounding tissues (e.g., rectum or bladder)
• Men with prior pelvic radiation may benefit from proton’s precision

Advantages of proton therapy include the potential for fewer side effects due to less radiation dose to adjacent organs, a reduction in long-term risks of secondary cancers in younger patients, and it can be technically advantageous in patients with challenging anatomy. Unfortunately, proton therapy is not always available — and can carry a heftier price tag for patients.

Side effects are generally similar to those seen with standard EBRT. Some studies suggest slightly lower rates of bowel toxicity, though this is still under investigation.

Questions To Ask Your Doctor

• Based on my risk group, which type of radiation do you recommend for me?
• Are my chances better with proton or photon therapy?
• Will my insurance cover the recommended treatment approach?
• What should I do to prepare for treatment?

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