Radiation therapy for prostate cancer

概述

Radiation therapy uses high-energy rays or particles to kill cancer cells. Also called radiotherapy, radiation therapy may be used as the only treatment for prostate cancer. Or it may be used with other treatments, such as chemotherapy or surgery.

Radiation therapy for prostate cancer can be given inside or outside of the body.

External beam radiation therapy (EBRT) is a common type of radiation therapy used for prostate cancer. During EBRT, a large machine moves around the outside of your body and directs beams of radiation to a specific point on your body.

External beam radiation therapy most often uses X-rays. But there are other types of radiation therapy, including proton beam radiation.

Brachytherapy (brak-e-THER-uh-pee) is radiation treatment that you get inside of your body. This is sometimes called internal radiation therapy (IRT). During brachytherapy, a small radioactive device is placed in or near the prostate to deliver radiation directly to the treatment area.

You may have one or both kinds of radiation therapy. Your healthcare team will explain them and their possible risks and benefits. Together, you can decide whether radiation therapy is the best treatment for you.

目的

There are several ways your healthcare team might give you radiation therapy for prostate cancer:

• As the only treatment for early-stage and, sometimes, more-advanced prostate cancer. For some people, radiation therapy may be the only treatment.
• After surgery to reduce the risk of cancer returning. The radiation can help kill any cancer cells that might remain and lower the risk that the cancer could spread or come back. When used in this way, radiation therapy is known as adjuvant therapy.
• After surgery if the cancer wasn't completely removed or if the cancer returns in the prostate. This is called salvage radiation for prostate cancer (SRT).
• As one part of the overall treatment plan for more-serious or more-advanced cancers. These might include cancers that have grown outside the prostate into other parts of the body. For these cancers, radiation therapy may be used in addition to surgery or other treatments to help slow the cancer's growth. It also can help prevent or relieve symptoms, such as bone pain, caused by cancer that has spread beyond the prostate.

It's common to wonder which type of cancer treatment is best for you — and whether you should have radiation therapy alone or combined with other treatments. You may also wonder if external beam radiation therapy or brachytherapy is the right choice for radiation therapy.

The best treatment plan for you depends on the type, exact location and stage of your prostate cancer. Your care team works with you to determine the right treatment plan for your specific situation.

风险

Radiation therapy is a largely safe and effective way to treat prostate cancer. Some modern forms of radiotherapy aim precise beams of energy at cancer, which helps protect healthy tissue from high doses of radiation.

But radiation therapy may still damage healthy cells along with cancer cells. And side effects are possible. These side effects depend on several factors, including the type of radiation therapy you're having, the dose you receive and the amount of healthy tissue exposed to the radiation.

Most side effects of radiation therapy for prostate cancer are mild, temporary and improve over time once treatment has ended.

Side effects of radiation therapy for prostate cancer may include:

Urinary side effects. Radiation therapy can irritate surrounding organs, such as the base of the bladder or penis. This can lead to urinary symptoms such as frequent urination, trouble starting urination or blood in the urine. These symptoms typically begin within 2 to 3 weeks of starting radiation and go away within three months after finishing radiation.

Bowel side effects. Radiation therapy for prostate cancer may also cause irritation of the intestines. This may lead to diarrhea, frequent or urgent passing of stool, bloody stool, or a feeling that you can't empty your bowel completely.

Sexual side effects. Some people have trouble getting or keeping an erection after radiation therapy for prostate cancer. This condition is called erectile dysfunction. However long-term erectile function rates are similar in people with prostate cancer who don't have radiation therapy.

Fatigue. You may feel very tired while undergoing radiation therapy. This may continue for up to a few weeks or months after you finish treatment.

Skin reactions. If you're having external beam radiation therapy, the skin around the part of your body being treated may become red and sore, much like a sunburn.

Secondary cancers. People who have radiation therapy for prostate cancer have a minimal increased risk of certain other cancers, including bladder or gastrointestinal cancer.

Side effects may differ with proton beam radiation therapy

Because radiation therapy professionals can better control where proton beam therapy releases its highest concentration of energy, this therapy may affect less healthy tissue and have fewer side effects than do other forms of radiation therapy. Still, proton therapy releases some of its radiation in healthy tissue, and side effects are possible.

Risks and side effects specific to brachytherapy

While many of the risks and side effects of brachytherapy are similar to those of EBRT, there are also a couple of key differences.

If you have temporary brachytherapy, you may have some pain, tenderness or swelling in the area between your scrotum and rectum for about a week after treatment. You also may also notice that your urine is a darker, red-brown shade. There also is a small increased risk of urinary retention, which means that you may not be able to fully empty your bladder or you have trouble starting to urinate.

If you have permanent brachytherapy, the implanted devices give off small amounts of radiation for several weeks or months. Your healthcare team may recommend staying away from pregnant women and small children as a precaution during this time. If you travel by air, airport security systems may detect this radiation. You can ask your healthcare professional for a document explaining your treatment.

There's a small risk that some of the brachytherapy devices could move from their implant location. Wearing a condom during sex can help prevent you from passing these devices to your partner.

Your healthcare team may also ask you to strain your urine for a short time. If so, the team teaches you how to do this safely.

Side effects of hormone therapy during radiation treatment

Before or during radiation therapy for prostate cancer, your healthcare team may recommend hormone therapy to lower levels of testosterone or dihydrotestosterone. This is because these hormones, called androgens, help prostate cancer cells grow.

Lowering levels of androgens — or preventing them from getting into prostate cancer cells — may shrink prostate cancer or cause it to grow more slowly.

You may get hormone therapy before radiation therapy to shrink the cancer, or you may get it with radiation therapy if the cancer is at a higher risk of recurrence. You may get hormone therapy after radiation therapy if the cancer isn't fully removed or returns.

Hormone therapy given during radiation therapy may give you more side effects than radiation itself. Common side effects of hormone therapy include:

• Sexual side effects such as erectile dysfunction or lack of sexual desire.
• Hot flashes.
• Fatigue.
• Decreased sex drive.

Less common side effects may include weight gain, loss of muscle mass, increased cholesterol levels, depression, low red blood cell counts, also called anemia, and testicle and penis shrinkage.

These symptoms typically improve with time once you stop hormone therapy. Ask your healthcare team about the side effects you're most likely to experience during and after your treatment.

If you experience side effects of hormone therapy, your healthcare team can recommend treatments to prevent or treat these effects. These treatments may include medicines.

如何进行准备

The planning process for radiation therapy for prostate cancer depends on the type of treatment you get.

Preparing for external beam radiation therapy

Before you begin external radiation therapy for prostate cancer, your healthcare team guides you through a planning session. This is sometimes called a radiation simulation session.

The planning session helps your care team carefully plan your radiation. The plan ensures the radiation is delivered safely and accurately so that it reaches the exact spot in your body where it's needed.

Planning typically includes:

• Determining the best position for you during treatment. During a radiation planning session, your radiation therapy team helps you find a comfortable position for your treatment. Being comfortable is important because you need to lie completely still during your radiation treatment.

  During the planning session, you're positioned on the same kind of table that your care team uses during your treatment. Specially formed cushions help you stay in the right position. Your radiation therapy team makes small marks on the area of your body that receives the radiation. You may have these marks for a short time or for the rest of your life.

• Planning the path of the radiation with imaging scans. Your radiation therapy team may perform computerized tomography (CT) scans or magnetic resonance imaging (MRI) to determine the exact area of your body to be treated and how best to reach it with the radiation beams. Your team may also recommend a PSMA PET scan. This full-body scan allows your care team to see exactly where the cancer is.

After the planning session, your radiation therapy team decides what type of EBRT and what dose you'll receive based on your stage of cancer, your general health and the goals for your treatment.

A special consideration for proton beam therapy

Because of the higher cost of proton beam therapy, not all insurance policies cover this treatment. If your care team recommends proton beam therapy, talk with your health insurance provider to understand which costs are covered by insurance and which costs you'll be expected to pay.

Preparing for brachytherapy

Before you begin internal radiation therapy for prostate cancer, you meet with members of your care team to plan your treatment. You may also have imaging scans, such as computerized tomography (CT) scans or magnetic resonance imaging (MRI) to determine the exact area of your prostate to be treated.

Planning your treatment days

You'll likely be able to drive yourself to and from your radiation therapy appointments. However, if you find that you feel fatigued or ill during a treatment, it's best to arrange a ride for future treatments.

Wear clothing that's easy to remove since you'll likely need to change into a hospital gown.

Don't wear powders, deodorants or adhesive bandages in your pelvic area.

If you are receiving your radiation therapy over several weeks, you may need to take time off from work for treatment. Talk with your healthcare team about what to expect so you can plan for it.

可能出现的情况

During the procedure

The process of radiation therapy for prostate cancer differs depending on what type of radiation treatment you receive.

External beam radiation therapy

External beam radiation therapy (EBRT) for prostate cancer involves using a machine called a linear accelerator (LIN-ee-ur ak-SEL-ur-ay-tur) or a proton machine to aim beams of radiation at the body. During each session, this machine delivers the exact dose of radiation planned by your treatment team. The beams can be made of X-rays, protons or other types of energy.

EBRT is typically done on an outpatient basis five days a week for several weeks. Some medical centers offer shorter radiation therapy treatment schedules. For instance, you may get a higher dose of radiation over fewer days. This schedule is called hypofractionated radiation.

Your healthcare team may recommend a specific type of external beam radiation therapy, such as:

• Intensity-modulated radiation therapy (IMRT). This is the most common type of external beam radiation therapy for prostate cancer. With IMRT, the beams of radiation are carefully shaped to match the shape of the cancer. The intensity of each beam can be varied. The result is a precisely controlled radiation treatment.
• Stereotactic body radiotherapy (SBRT). This form of EBRT uses advanced 3D or 4D imaging and highly focused radiation beams to deliver precise, high doses of radiation. Because each dose is stronger than those of traditional radiation therapy, a full treatment cycle can usually be completed in 1 to 5 sessions. SBRT may also be referred to by the names of the machines used to give the treatment, such as Gamma Knife or X-knife radiation.
• Stereotactic body proton therapy (SBPT). SBPT combines SBRT techniques with proton therapy. A gel-like substance called a tissue spacer may be used during SBPT. This gel helps to create extra space between the prostate and rectum so the radiation can more safely target the prostate while reducing the radiation that reaches healthy tissue in the rectum. The tissue spacer naturally dissolves over time.
• Proton beam therapy. Proton beam therapy is a newer type of radiation therapy that uses high-powered energy to treat cancer. Instead of using X-ray beams, proton beam therapy uses energy from positively charged particles called protons. Because proton beams are so precise, this type of radiation may be able to deliver more radiation while doing less damage to healthy tissue.

Each treatment session usually lasts less than an hour. Most of that is preparation time. The radiation treatment itself only takes a few minutes.

During a treatment session:

• You lie on a table in the position you'd practiced during your radiation planning session.
• You might be positioned with special cushions or blocks that help keep you in the same position for each radiation therapy session.
• The linear accelerator machine may rotate around your body to deliver radiation beams from different directions. While this happens, you lie still and breathe normally.
• Your radiation therapy team stays nearby in a room with video and audio connections so they can see you and talk with you.

The process should be painless. Even though you'll be able to see the linear accelerator move, you won't be able to feel or see the radiation enter your body. If you're not comfortable at any point during the treatment, tell your radiation therapy team. They may be able to position you more comfortably.

Brachytherapy

Brachytherapy (brak-e-THER-uh-pee) involves placing radiation inside the body near the cancer to give the exact dose of radiation needed. The overall treatment time can be shorter with brachytherapy because a larger dose of radiation can be safely delivered at one time.

During brachytherapy, solid, radioactive devices about the size of a grain of rice are placed into the prostate gland. Ultrasound or another imaging test may be used to help guide the radioactive devices into place. These images help make sure that the treatment is in the right spot. The radioactive devices then deliver the exact dose of radiation needed.

Brachytherapy can be given in a brief treatment session, called temporary brachytherapy, or it can be placed in the body permanently, called permanent brachytherapy.

Temporary brachytherapy. This is sometimes called high-dose-rate (HDR) brachytherapy.

During temporary brachytherapy, higher doses of radioactive material are placed in the prostate for a short period of time — typically 5 to 20 minutes.

You may have one or two temporary brachytherapy treatments over a few days. After each treatment, the radioactive material is removed.

During temporary brachytherapy:

• You lie in a comfortable position on a table.
• Depending on the treatment, you may have anesthesia to make the procedure easier.
• Your radiation therapy team places the radiation delivery device — usually a simple tube or small needles — in your body between your scrotum and anus and into the prostate.
• The small radioactive sources are then placed in the prostate with the help of a machine.
• Your radiation therapy team goes to a nearby room with video and audio connections so that you can see and talk with each other. If you feel discomfort or have any concerns during your brachytherapy session, you can tell your care team.

Once the team removes the radioactive material from your body, you won't give off radiation or be radioactive. You can go on with your usual activities.

Permanent brachytherapy. This is sometimes called low-dose-rate (LDR) brachytherapy. During a permanent brachytherapy treatment, the radioactive material is left in your body. This is a common treatment for prostate cancer.

During permanent brachytherapy:

• You have anesthesia so you don't feel discomfort during the procedure.
• Your radiation therapy team places the small radioactive devices into the prostate gland through the area between the anus and scrotum.
• An imaging test, such as ultrasound or CT, might be used to make sure the radioactive material is in the right place.

You shouldn't feel any discomfort once these small radioactive devices are in place.

Your body gives off a low dose of radiation from the treatment area. This radiation gets weaker each day until it's gone. The risk to others is low, but you might need to avoid spending time with children and anyone who is pregnant in the days immediately following the procedure.

After the procedure

After radiation therapy is complete, you will have regular follow-up appointments with your healthcare team to assess how well the treatment worked. Your care team may recommend scans or blood tests to help show whether the treatment worked.

After treatment, you can go back to most of your regular daily activities, including work and driving. A few things to consider:

• Work. Many people continue to work when having radiation therapy for prostate cancer. If your treatment makes you tired, consider taking a few days off, changing your schedule or changing your workload, if possible. If you have urinary or bowel side effects, talk with your employer about taking more-frequent breaks.
• Driving. If you feel especially tired after treatment sessions or you're on medicines that make you drowsy, be safe and ask someone you trust for a ride home after treatment sessions.
• Sex. For most people, it's safe to be sexually active during and after treatment. If you are receiving permanent brachytherapy, your healthcare team may recommend wearing a condom.
• Exercise. Research shows that moderate exercise is safe after radiation therapy and may even help reduce cancer-related fatigue.

If you have permanent brachytherapy

The devices inserted in or near your prostate continue to give off radiation for a short amount of time. This radiation usually stays near the treatment area, so it's unlikely that other people will be affected. As a precaution, your healthcare team may recommend that you limit visitors for a few days, especially children and people who are pregnant.

结果

After radiation therapy is over, you have regular follow-up appointments with your healthcare team. You may have imaging tests or blood tests to determine how well the radiation worked.

Blood tests measure the level of prostate-specific antigen (PSA) in your blood. These tests may give your healthcare professional an idea of whether treatment succeeded.

Ask your healthcare professional when you can expect to know how well the treatment worked.

Success rate for radiation for prostate cancer

The success rate of radiation therapy for prostate cancer depends on several factors, including the stage and aggressiveness of the cancer, the person's health and age, and the overall treatment plan.

Radiation therapy for prostate cancer, especially when given with hormone therapy for higher risk cancers, is very effective. In most people, cancer shrinks or goes away.

Cure rates are very high, especially in people with low- and intermediate-risk prostate cancer. Cure rates for those with high-risk prostate cancer are also favorable but are directly related to the extent of the cancer.

In one large study, 10-year prostate cancer survival ranged from 90% for high-risk cancers to 98% for low-risk prostate cancers in people who had radiation therapy for prostate cancer.