Precise Radiation for Prostate Cancer
Prostate cancer is the most common cancer affecting men, but treating it with traditional radiation therapy can be difficult. Older radiation delivery methods expose nearby healthy organs to damage.
However, cutting-edge therapies, such as Intensity Modulated Radiation Therapy (IMRT) and Image-Guided Radiation Therapy (IGRT) enable physicians to deliver higher doses of precisely focused radiation to cancerous tumors while sparing nearby healthy tissue. For example, one study compared IMRT to traditional radiation therapy and found that the higher dose rates delivered by IMRT significantly improved the rate of localized tumor control while reducing the incidence of rectal bleeding from 10% to 2% of patients.*
* Zelefsky MJ, Chan H, Hunt M, et al, Long-term outcome of high dose intensity modulated radiation therapy for patients with clinically localized prostate cancer, Journal of Urology, 2006 Oct;172(4 Pt 1):1415-9.
What Is Prostate Cancer?
The prostate is a walnut-sized male gland just below the bladder that surrounds the urethra (the tube that carries urine from the bladder). Its cells produce components of seminal fluid.
Male hormones cause the prostate to grow until adulthood. Sometimes, it continues growing benignly and can cause problems with urination. Cancer can develop if the size and shape of prostate gland cells begin to change. As men age their risk for prostate cancer increases. More than 65% of prostate cancers occur in men older than 65, according to the Prostate Cancer Foundation.
Who Gets Prostate Cancer?
An estimated one in six men will be diagnosed with prostate cancer during their lifetimes, but advances in treatment mean only one in 35 will die of the disease, according to the American Cancer Society. Treatment is most effective when prostate cancer is diagnosed early, before it spreads to other parts of the body.
The risk of prostate cancer increases dramatically as men age. It affects only one in 10,000 men younger than forty, but one in 14 men in their sixties. A number of factors can increase risk:
- African American men are 61% more likely than white men to develop prostate cancer.
- Men are twice as likely to develop prostate cancer if their father or a brother or son has had the disease.
- If more than two first-degree relatives have had prostate cancer, the risk increases fourfold.
- Men are at even higher risk if a relative was diagnosed with the disease before age 60.
How Do I Know If I Have Prostate Cancer?
Men with prostate cancer sometimes experience no symptoms, and tumors can grow so slowly that they never cause problems. However, without early detection, more aggressive forms of the disease can be difficult to treat effectively and can be fatal. In fact, about 27,000 men in the United States die from prostate cancer each year, according to the American Cancer Society (ACS).
For this reason, the ACS recommends that physicians offer their male patients digital rectal exams and prostate-specific antigen (PSA) tests beginning at age 50, or at age 40 or 45 if they fall into high-risk groups. Blood levels of PSA, an enzyme produced by prostate gland cells, generally rise in men with prostate cancer.
When prostate cancer does cause symptoms, these may include problems with urination and erectile function, painful or burning urination or ejaculation, blood in urine or semen, or frequent pain or stiffness in hips, lower back, or upper thighs.
As with other cancers, the only way to know for sure is with a biopsy—a procedure in which a sample of the tumor is sent to the lab to be examined under a microscope.
What Are My Treatment Options?
Physicians use the results of diagnostic tests to determine the site of the cancer and to stage it—or tell how far it has spread. This helps determine the outlook for recovery and the best course of treatment. While prostate cancer is very treatable, it can be life threatening. Therefore, any treatment decisions should be made through consultation with physician specialists such as urologists, radiation oncologists, and medical oncologists. Patients and their physicians can choose among several treatment options that may be used alone or in combination. All treatments can affect quality of life in different ways and to different degrees, and all carry the risk of impotency.
Since some prostate cancers may never produce symptoms or affect longevity, watchful waiting is an option for some men who prefer to avoid the potential side effects of cancer treatment. These patients undergo PSA tests and digital rectal exams every six months and prostate biopsies yearly to determine whether growing tumors warrant treatment.
Men with early stage, localized prostate cancer often undergo surgical removal of all or parts of their prostate glands. Surgeons use a variety of techniques to perform prostatectomies. Some methods are less invasive than others, and some may spare the nerves that control erections. If you are considering prostatectomy, discuss the risks and benefits of these different approaches with your physician.
Patients typically spend two to three days in the hospital. A urinary catheter is placed during surgery and removed two to three weeks later, and total recuperation can take up to twelve weeks.
As with any major surgery, prostatectomy carries risks associated with anesthesia and incisions including vascular complications, blood loss, infections and death. The most common side effects include impotence and incontinence.
Additional therapies kill prostate cancer cells by freezing or burning them, but these approaches are less frequently used since less is known about their long-term outcomes.
Cryosurgery Also called cryoablation, this treatment delivers cold gasses through probes to freeze prostate cells. These probes are inserted through incisions between the anus and scrotum. The procedure requires a brief hospital stay and use of a urinary catheter for a couple of weeks. Immediately after the procedure, patients may experience swelling, bruising, soreness, and some blood in the urine.
While cryosurgery is less invasive than prostatectomy, freezing temperatures can damage the nerves, bladder, and intestines. Impotence and incontinence are more common after cryosurgery than prostatectomy.
Neither of these treatments can cure prostate cancer, but they may impede tumor growth and lessen symptoms. They may be used to treat cancer that has spread, or metastasized, to other part of the body, or they may be used as palliative treatments to reduce pain. However, their unpleasant side effects can significantly affect quality of life.
Hormone Therapy (Androgen Deprivation) Hormones or androgens, such as testosterone, cause prostate cancer cells to grow. By lowering the levels of male hormones, this treatment may shrink tumors or slow their growth. Since hormone therapy can control but not cure prostate cancer, it often complements other therapies. It may involve surgical removal of the testicles, which produce testosterone, or more commonly the use of various drugs to lower hormone levels.
Most prostate cancer cells respond to androgen deprivation, but some continue to grow. Over time, hormone therapies become less effective. For this reason, drug therapies are often administered in on-again, off-again cycles. This approach may extend the treatment’s usefulness and offer patients respite from side effects. Medical studies are underway to determine the overall effectiveness of hormone therapies and the best ways to administer them.
Side effects of hormone therapy include reduced or eliminated sexual desire, impotence, weakened bones, anemia, hot flashes, breast growth and tenderness, fatigue, loss of muscle mass, reduced mental acuity, weight gain, lowered levels of “good” cholesterol, and depression. Some drugs may also cause diarrhea, nausea, and liver problems.
Chemotherapy Chemotherapy (also called “chemo”) employs oral or injected drugs to kill cancer cells. Historically, chemotherapy was not considered to be very effective against prostate cancer, but newer drugs show more promise. Still, like hormone therapy, chemotherapy may help control tumor growth and reduce symptoms but is not considered a cure.
Because chemo kills some normal cells in addition to malignant ones, it can cause side effects that vary depending on the type of drug used. These include, but are not limited to, fatigue, nausea, vomiting, loss of appetite, hair loss and mouth sores. It can also cause low white blood cell and platelet counts resulting in higher risk of infection and easy bruising/bleeding.
Radiation that kills cells or shrinks tumors may be used alone or in combination with other treatments for early stage, localized prostate cancer or for recurrent malignancy. Generally performed on an outpatient basis, radiation does not require urinary catheterization like surgical procedures, and it can be delivered in a variety of ways.
Brachytherapy With this approach, radiation is delivered inside the body directly to the prostate. Low-dose methods involve permanently implanting radioactive seeds. The seeds give off small amounts of radiation for several weeks, so patients may be advised to stay away from children and pregnant women and to wear condoms during sex. Side effects such as impotence and problems with the bladder and bowels may occur less frequently with brachytherapy than with some other treatments. This radiation delivery method carries small risks associated with seed migration within the body.
Newer high-dose brachytherapy involves brief insertion of radioactive materials through needles placed in the prostate. Patients usually receive three treatments over a couple of days.
Both brachytherapy methods may cause pain and reddish-brown urine for a few days.
Replacing traditional external-beam radiation therapy in a growing number of facilities is IMRT/IGRT, which delivers higher radiation doses to cancerous tumors while avoiding healthy tissue. With IMRT/IGRT, physicians can more effectively treat the disease while reducing the chance of side effects caused by damage to the bladder, bowels, and other organs. The precision of IMRT/IGRT enables physicians to treat some cancers for which radiation therapy previously was not an option.
Your Prostate Cancer Treatment Partner
At Century Cancer Centers Denver, we offer patients a variety of treatment options, from traditional to cutting-edge treatments such as IMRT and IGRT that may not be widely available in other centers. Regardless of the treatment path, we pride ourselves on providing each patient with the best outpatient experience in the most comfortable atmosphere. Treating Prostate cancer can be a complicated process, so our personal Cancer Navigators help guide each patient through their journey.
IMRT & IGRT: Fighting Prostate Cancer with Precision
Quick and painless, external-beam radiation therapy has long been used to destroy cancer cells. The latest methods—Intensity-Modulated Radiation Therapy (IMRT) and Image-Guided Radiation Therapy (IGRT)—provide the most advanced technology for fighting cancer. Used alone or in conjunction, these therapies allow higher doses of radiation to be delivered with greater precision without destroying surrounding, healthy tissue.
For patients, IMRT/IGRT means:
- more effective treatment focused on cancer cells.
- less radiation exposure to normal tissue.
- potentially fewer and milder side effects.
- the ability to treat some tumors that couldn’t previously be treated by radiation.
Since the prostate is located near the bladder, bowels, and anus, physicians traditionally limited the amount of external-beam radiation delivered close to these sensitive organs. Still, healthy tissue is often damaged when less precise methods are used. Unlike cancerous cells, normal cells can adapt and survive, but unnecessary radiation exposure can still lead to incontinence and bowel problems. While some of these side effects may manifest immediately, others develop over time. By increasing radiation exposure to malignant cells and decreasing it to healthy tissue, IMRT alone may reduce such complications.
Clinical studies conducted at Memorial Sloan Kettering Cancer Center indicate that higher dose rates delivered with IMRT significantly improve local tumor control while reducing some of the complications caused by damage to normal tissue.1,2 While IMRT may be used in conjunction with other treatments, it may also offer an noninvasive, outpatient alternative to surgery for some patients.
1 Zelefsky MJ, Chan H, Hunt M, et al, Long-term outcome of high dose intensity modulated radiation therapy for patients with clinically localized prostate cancer, Journal of Urology, 2006 Oct;172(4 Pt 1):1415-9.
2 Zelefsky MJ, Fuks Z, Hunt M, et al, High-dose intensity modulated radiation therapy for prostate cancer: Early toxicity and biochemical outcome in 772 patients, International Journal of Radiation Oncology • Biology • Physics, 2002 Aug 1; 53(5):1111-6.
How IMRT Works
IMRT is a specialized radiation therapy that uses powerful treatment planning software to calculate precise beam angles, shapes and exposure times tailored to each tumor. The radiation beam can be broken up into many smaller beams and the intensity of each small beam can be adjusted individually. This may allow a higher dose of radiation to be delivered to the tumor with less risk to nearby healthy tissue, potentially decreasing the duration of treatment and increasing the chance of a cure.
How IGRT Works
Tumors can move during a course of treatment. IGRT combines imaging and treatment capabilities on a single machine. This way, tumors can be tracked between, as well as during, treatments, allowing radiation to be focused more precisely. Images captured before each radiation session are compared to previous sessions so that clinicians know the exact location of the tumor each time. IGRT software also accounts for breathing and motion during treatment, ensuring the radiation stays focused on the tumor.
What to Expect During Treatment
The treatment process is similar for IMRT and IGRT.
First, we’ll schedule an appointment with a radiation oncologist. During this visit, we’ll perform a simulation of the treatment. You will be positioned on the treatment machine the same way you will be for actual treatment. The radiation oncologist will determine the need to use an immobilization device (such as a cast, mold or headrest) to keep you in the same position during treatment. Then, we’ll take a CT scan to precisely map your anatomy. Using information from the CT scan, the radiation therapist will mark the area(s) to be treated, either on your skin or on the immobilization device. Simulation sessions take 30 to 60 minutes and may be repeated at intervals throughout your course of treatment.
Next, your radiation oncologist and treatment team will design a treatment plan tailored to you. They will use information from the simulation session, anatomical maps obtained from the CT scan, previous medical tests and, in many cases, sophisticated treatment planning software.
For prostate cancer, radiation therapy is typically administered 5 days per week, for 8 to 9 weeks, but your treatment team will determine the best course of treatment for you. During each session, positioning takes from 5 to 15 minutes. Actual treatment time lasts about 10 minutes and is painless. The radiation is delivered using a machine called a “linear accelerator” which generates x-rays or photon radiation. The linear accelerator moves so that patients can lie comfortably without being re-positioned during treatment.
The treatment room is spacious, and you will not be completely enclosed by equipment. A radiation therapist will position you to ensure successful treatment then go to an adjoining control room. From there, he or she will monitor you closely during radiation treatment using video cameras. The therapist can hear you at all times, and the treatment can be immediately discontinued if you feel uncomfortable or ill. If IMRT/IGRT are employed, the therapist may move the machine or treatment table during treatment to best target the exact area of the tumor. Once each treatment is complete, you can return to your normal daily activities.
A follow up exam with your radiation oncologist will be scheduled about after your last treatment to discuss side effects. From there, physicians will determine the proper course of ongoing treatment.