With image-guided, intensity-modulated radiation therapy (IG-IMRT), 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, 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, IG-IMRT is given over a period of nine weeks (approximately 48 treatment sessions). When combined with radioactive seed implantation, we may give IG-IMRT over a period of five weeks (25 sessions). IG-IMRT is offered more commonly in men who have significant urinary problems before treatment begins.

Many of the people we care for have a type of radiation therapy called MSK Precise^TM. It is also called hypofractionated radiation therapy. The dose of radiation that is given with each treatment is larger than in standard radiation therapy, but there are fewer treatments over a shorter period of time. It is especially useful for cancer that has not spread beyond the prostate.

MSK Precise uses MRI combined with a sophisticated computer system to deliver high doses of radiation to prostate tumors. MRIs are used to help map out the treatments. They provide clarity so that doctors can see a tumor and target the therapy more accurately. With this approach, the treatment can sculpt the radiation to within a millimeter around the tumor. The technique minimizes the amount of healthy tissue that’s affected by the radiation. Only five treatment sessions are needed. Each one is about three to four minutes long. The entire course can be completed in a little over a week. By comparison, standard radiation requires close to 45-50 sessions over nine to ten weeks.

Because of its superior precision, MSK Precise has less side effects than more conventional radiation techniques, with extremely low rates of incontinence (urinary leakage) and rectal problems. The sexual side effects are low and similar to what is experienced with conventional external radiation techniques. A special feature of using MSK Precise to treat prostate cancer is the unique gel that is applied between the prostate and rectum. This creates a buffer to prevent the radiation from affecting healthy tissue. Using the gel further reduces the risk of side effects. MSK has the most experience of any hospital in the world using this type of protection.

MSK Precise is more commonly used in men with relatively good urinary function. For men with more-aggressive disease, we may recommend internal radiotherapy using brachytherapy seed implants in combination with MSK Precise.

Some men with prostate cancer may elect to receive proton therapy. Proton therapy is a form of external-beam radiation therapy. Proton therapy may be another way to deliver a high radiation dose to the prostate while lowering the radiation dose to normal surrounding tissue. It is unclear if there is any advantage to proton therapy compared with IG-IMRT. We are now studying how these approaches compare in terms of side effects and outcomes.

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:

For men with locally advanced prostate cancer — which means the cancer has spread outside the prostate to nearby tissues — options may include:

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 their treatment. 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 prostate-specific antigen (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 may have escaped the prostate.

We commonly use IG-IMRT following surgery. If a rising PSA level or a scan indicates that prostate cancer has recurred locally and has spread to nearby tissues, IG-IMRT 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. It can eliminate bone metastases with great precision and may dramatically improve your quality of life if you have advanced prostate cancer.

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 who specialize in sexual medicine can help you manage these side effects. We are studying treatments for men who experience the 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. After treatment ends, almost all patients return to their previous energy levels. However, you should certainly report any unusual fatigue to your treatment team.