Radiation Therapy

Radiation Therapy

With radiation therapy, we use high-energy beams or radioactive seeds to eliminate tumors. We’re innovators in this approach to treating prostate cancer, having developed and refined the use of sophisticated tools — including state-of-the-art linear accelerators, advanced imaging approaches, and high-speed computer-based systems — to deliver powerful doses of radiation directly to your tumor with incredible precision.

Keeping you as safe as possible is as important to us as treating your cancer. Advances in technology have made it possible to destroy prostate tumors while also avoiding injury to healthy tissue. Our radiation team works together to offer the highest level of safety during every step of your treatment.

The radiation therapy approach we recommend depends on the unique characteristics of your disease. We can offer radiation therapy, either alone or in combination with hormone therapy, to combat all stages of prostate cancer. In some cases, we use it as a primary treatment approach; in others, we use it after surgery if there are signs that your cancer has come back.

Pictured: Michael Zelefsky
Smoking May Interfere with Radiation Treatment for Prostate Cancer
Researchers call for intensified efforts to help men with prostate cancer quit smoking after a recent MSK study revealed that patients who smoke during radiation therapy face a higher risk of both having the disease return and dying from it.
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Which technique or set of techniques we use depends on the location and extent of your disease and the specific characteristics of your tumor. Our doctors will work with you and the other members of your treatment team to help you decide which approach, or combination of approaches, is best for you.

Whether you have an early-stage tumor or more advanced prostate cancer, our range of radiation therapy options include:

  • internal forms of radiation therapy (called brachytherapy), such as radioactive seed implantation and high-dose-rate (HDR) brachytherapy
  • external approaches, including image-guided radiation therapy (IGRT) and stereotactic radiosurgery

Radiation therapy is often as effective as surgery in men who have early-stage prostate cancer. It’s also often able to eliminate more aggressive localized disease and provide long-lasting remission as well as effectively treat painful bone metastases.

Because our radiation oncologists are continually working to advance the field, we also offer some patients access to clinical trials of new approaches to radiation therapy. By participating in a clinical trial, you may have access to radiation therapy techniques or combinations of therapies that are not yet widely available.

Types of Radiation Therapy

MSK radiation oncologists are recognized as world leaders in the field and pioneered the use of an internal form of radiation therapy called brachytherapy. There are two types of brachytherapy: low-dose-rate and high-dose-rate brachytherapy.

External-beam radiation therapy (EBRT) involves aiming radiation directly at your prostate from a device called a linear accelerator. We use this approach by itself to treat localized tumors, or we combine it with internal radiation therapy (brachytherapy) or other therapies to treat more aggressive disease.

At MSK, we use three primary types of EBRT to treat prostate cancer: image-guided radiation-therapy, stereotactic radiosurgery, and proton therapy.

With low-dose-rate (LDR) brachytherapy, we insert tiny titanium seeds containing radiation in or near the tumor while you’re under anesthesia. We use ultrasound imaging to guide the placement of the seeds. In 95 percent of cases, this technique is successful in eliminating the cancer.

At MSK, we perform LDR brachytherapy on an outpatient basis. It usually takes a little over an hour. Although the seeds are permanent, they cause little or no discomfort, and their radioactivity lessens after several weeks or a few months.

To ensure that the tumor receives high doses of radiation while the surrounding tissue is protected, we developed and use real-time image guidance when the radioactive seeds are implanted into your body.

During the procedure, while you’re under anesthesia, a mobile CT scanner (called an O-arm) provides up-to-the-second images of your prostate. A sophisticated computer software system fuses ultrasound images obtained before the procedure with these real-time CT scans. Using this data, the computer analyzes millions of possible seed locations and, in a matter of seconds, selects the ones that will deliver a precise dose of radiation to the tumor while avoiding injury to healthy tissue.

Before you leave the operating room, we take a final CT scan to ensure the seeds were placed at the ideal locations.

In high-dose-rate (HDR) brachytherapy, we deliver ultrahigh bursts of radiation in a short amount of time. After putting you under anesthesia, we insert a number of plastic catheters (tubes) into or near the tumor in your prostate. The catheters are attached to a machine that contains precise doses of radiation in the form of radioactive pellets. The pellets are released into the catheters for two to four 15-minute sessions, delivering radiation directly to the tumor.

The procedure sometimes requires an overnight hospital stay to complete. After the final treatment, the catheters are removed and you can return home.

As in LDR brachytherapy, our radiation oncology team uses computer technology during the procedure to ensure treatment with great precision. We often use real-time CT scans combined with imaging data gathered before the procedure to plan and guide your treatment, as well as to intensify the dose of radiation in regions of the prostate that require a more aggressive approach.

Typically we recommend HDR brachytherapy for men with more advanced disease and follow the treatment with a short course of image-guided radiation therapy.

With image-guided radiation therapy (IGRT), we use real-time imaging to mold radiation beams to the contours of your tumor. Because the normal movements of your body can cause the prostate to move slightly during or between treatments, we place several small markers in the prostate before beginning the radiation session. Having these markers placed is very similar to having a prostate biopsy. Called fiducial markers, they’re made of gold and allow a CT scanner that is part of the linear accelerator to locate the current location of the tumor and the prostate gland with sub-millimeter accuracy.

We also use a type of marker called a beacon transponder (the Calypso® system) to send signals to a specially designed tracking system. Similar to a GPS system, the beacon transponder allows your radiation therapists to precisely check the position of your tumor during each treatment. This helps us to make any necessary adjustments and ensures that the radiation poses the least risk to healthy tissues while maximizing the dose to the tumor.

When used alone, IGRT is given over a period of ten weeks (approximately 48 treatment sessions). When combined with radioactive seed implantation, we may give IGRT over a period of five weeks (28 sessions).

MSK’s radiation oncology team is also advancing the use of an extremely precise, ultrahigh-dose form of radiation therapy called stereotactic radiosurgery to eliminate prostate tumors. Stereotactic radiosurgery uses innovative imaging technologies combined with a sophisticated computer system (similar to the CyberKnife® system) to deliver very high doses of radiation to tumors with an accuracy of under a millimeter.

Treatment using stereotactic radiosurgery can be completed in five sessions or fewer, compared with daily sessions of up to ten weeks using IGRT. Stereotactic radiosurgery has been effective for many of our patients, providing similar or lesser side effects than more conventional external radiation techniques.

For some men with prostate cancer, we can use proton therapy, an advanced form of radiation therapy, to deliver high doses of radiation to tumors that may be resistant to conventional forms while minimizing exposure to the surrounding healthy tissues.

Proton therapy directs its cancer-fighting energy to precise locations within the body, allowing our doctors to deliver the necessary dose to the tumor — maximizing the chance of destroying it — while at the same time lowering the dose to normal tissue and thereby reducing the risk of treatment-related side effects.

Which Type of Radiation Therapy Is Right for You?

It can be confusing to know which radiation treatment approach is your best choice. We’re here to help. When recommending one approach or another, our team of radiation oncologists will factor in a number of considerations, including the aggressiveness of your tumor, how advanced your disease is, and your own preferences.

It can be helpful to know about different radiation treatment scenarios that occur based on the types of conditions we commonly see. Here are a few.

Localized prostate cancer refers to a tumor that is clearly confined within the prostate. Radiation therapy options for men with early-stage, localized prostate cancer include:

  • Low-dose-rate (LDR) brachytherapy
  • Image-guided radiation therapy (IGRT)
  • Stereotactic radiosurgery

For men with locally advanced prostate cancer, options may include:

  • LDR brachytherapy combined with IGRT
  • IGRT combined with hormone therapy
  • High-dose-rate (HDR) brachytherapy
  • HDR brachytherapy combined with IGRT

Together with your radiation oncologist, we can help you figure out which of these approaches is best for you.

Often, when a tumor is more advanced or aggressive, men receive hormone therapy before radiation therapy begins and continue it throughout the course of treatments; some receive hormone therapy after radiation therapy finishes as well. Hormone therapy reduces the level of testosterone throughout the body (testosterone stimulates the growth of prostate cancer cells).

Many men undergo radical prostatectomy (surgery to remove the prostate gland) as a primary treatment for prostate cancer. However, sometimes there will be indications several years after surgery that the cancer has returned. If you experience one or more of these signs that the cancer is back, such as a rising level of PSA or evidence on a scan, radiation therapy can eliminate or control it.

We may also recommend radiation therapy if the tumor has not been completely removed by surgery or if at the time of surgery the tumor was found to extend outside the prostate gland. Even if your PSA level is zero, radiation therapy can be important to eliminate cancer cells that escaped the prostate.

We commonly use IGRT following surgery. If a rising PSA level or a scan indicates that prostate cancer has recurred locally and has spread to nearby tissues, IGRT can be combined with hormone therapy, which reduces the level of testosterone throughout the body (testosterone stimulates the growth of prostate cancer cells).

Because radiation therapy is so focused, it’s not often used to treat cancer that has spread from the prostate to other parts of the body. However, we’ve developed and have extensive experience using stereotactic radiosurgery as a treatment for certain prostate cancers that have spread to the bones, where they can cause considerable pain.

Stereotactic radiosurgery, which can eliminate bone metastases with great precision, may dramatically improve your quality of life if you have advanced prostate cancer.

Radiation Safety

Ensuring your safety during radiation therapy is as important to us as treating your cancer. Our medical physicists work closely with your radiation oncologist to precisely plan radiation dosage before your treatment. Medical physicists are also present in the operating room during brachytherapy procedures to ensure that radiation is delivered correctly and in the optimal locations.

We’ve also set extensive safety protocols to manage our radiation therapy program. Redundancy is built into the review of the computer-based calculations that control the radiation dosage so that multiple experts check them independently. Medical physicists also examine the machinery frequently to maintain proper functioning.

Get answers to common questions about radiation safety.

Managing Side Effects

Advances in the precision of radiation therapy have lessened the risk of complications. Still, radiation can cause short- and long-term side effects, including incontinence (the involuntary loss of urine), erectile dysfunction, bowel problems, fatigue, and symptoms in other parts of the body (if you receive radiation therapy for disease that has spread outside the prostate).

Any side effects you experience depend on which part of the body receives radiation and, in the case of such techniques as image-guided radiation therapy and stereotactic radiosurgery, which normal structures are in the path of the radiation’s beam. In addition, radiation therapy is sometimes delivered in combination with hormonal therapy, which can cause impotence. Our experts will work closely with you and your medical team to manage any treatment-related difficulties you may experience, such as bladder, bowel, or erectile dysfunction.

During the course of radiation treatments, some men experience diarrhea or frequent and uncomfortable urination. Please tell your treatment team if you have any of these problems. We can recommend medications and other methods that can help alleviate these uncomfortable side effects.

Radiation therapy, whether external or internal, can cause erectile dysfunction in some men. Our team of doctors, nurse practitioners, and psychologists that specialize in sexual medicine can help you to manage these side effects. They are at the forefront of research and treatment for men who experience sexual side effects of prostate cancer treatment and will collaborate with your care team to minimize the impact of radiation therapy on your sexual health.

Everyone responds differently to radiation treatment. Some patients feel little effect; others may become fatigued as treatment progresses. Getting enough rest is important, and after treatment ends, almost all patients return to their previous energy levels. However, you should certainly report any unusual fatigue to your treatment team.