The Most Common Questions Patients Ask About Radiation Treatment for Prostate Cancer

Click here if you have already had your prostate already removed,
to go to a different set of questions and answers. 

What is radiation and how does it work?

Radiation therapy is a type of x-ray treatment.  Very high voltages are used to generate x-rays, and these beams are invisible and pass through the body.   Radiation therapy x-rays beams are much more powerful than the x-rays used in a normal chest x-ray, and they are focused on the cancerous area.  These rays damage cells in their path, especially the DNA inside cells.  Normal healthy cells can repair DNA damage, but cancer cells cannot repair the damage as well, so some of the cancer cells will die off after each radiation treatment.  That is also why radiation treatment takes many days to give — each day we give a small dose of radiation which your normal body tissues can tolerate and repair, but the cancer cells cannot repair as well and will gradually die off.

What happens to the cancer cells when they die?

Billions of normal cells die inside your own body every day, and new cells are regenerated to take their place.  The body has built-in ways to recycle dead cells into their basic amino acids, fatty acids, and other building blocks.  When a cancer cell dies it is recycled by the body just like any other dead cell.  A cancer cell is only dangerous if it is alive and capable of dividing to form other cancer cells.  When it’s dead it is not contagious, it has no way to turn other cells into cancer, it is not poisonous.  A dead cancer cell is just a bunch of nutrients for your body to reuse.

What does the prostate gland do and what happens to the prostate gland after radiation?

The prostate gland is a small organ in men that is located under the bladder and in front of the rectum. It surrounds the urine passage (urethra) like a doughnut.  The prostate is walnut to lime sized, about 1 – 2 ounces.  Its purpose is to create much of the fluid in the ejaculation, and that fluid mixes with the sperm that comes from the testicles.   The entire prostate gland is radiated when we treat the cancer.   Radiation therapy has the side effect of damaging the fluid producing glands in the prostate, so less ejaculation fluid is produced — it will be dry or nearly dry.  You may still usually have erections and the same sensation of orgasm.   The prostate gland will also end up having internal scar tissue and it will shrink in size to about half its original weight within a couple years after finishing radiation.

Do I need any scans?

Prostate cancer can sometimes spread into the tissues surrounding the prostate gland, or to the lymph nodes or the bones.  Based on factors like your PSA, how much cancer was found on the biopsy, and the Gleason score, we can get an idea of whether your cancer has a low versus high risk of behaving aggressively.  If your cancer has a higher risk of being aggressive then we will typically do a bone scan to inspect the bones, and a CT scan of the abdomen and pelvis to look at the lymph glands.   If your cancer is low risk (PSA less than 10, Gleason score of 6 or less) then usually no scans are done, because the chance of having metastatic cancer is very slim.  PET scans (Axumin and PSMA) are done if the cancer is suspected to be recurring.  MRI scans are often done to better see the tumors within the prostate gland and to help map out the radiation therapy.

Will I be cured?

The goal of the treatment is to cure the cancer, i.e. to make it go away and never come back during your lifetime.  If you have an early (not aggressive) prostate cancer then you will probably be cured.  Cure rates with modern radiation therapy are about 80 – 95% for early stage prostate cancer, and about 50 – 80% for more aggressive cases.  The results are similar for surgery.

Which treatment would you choose?

When you see a specialist for an opinion about your cancer he will typically recommend the treatment that he performs.  If you go to a BMW dealership, you know the salesman is not going to recommend that you check out a Lexus across the street.  So that is why you must take with a grain of salt if your doctor tells you what treatment he would choose for himself or for his father.  Physicians tend to be biased towards the treatment they perform.

How long until I start treatment?

When you meet with your radiation oncologist for the first time you will not start treatment that day.  Typically it takes about 3 weeks until you start.  There are a lot of steps to be done first.  You may need to get marker seeds inserted into the prostate gland, then undergo a simulation / mapping procedure which involves taking a scan of the pelvis, then computer planning, then there is a mock treatment to make sure everything lines up properly, and then you’re finally ready to start treatment.  In addition, if your prostate cancer is considered aggressive then you may need to go on hormone therapy for 2 – 4 months first before radiation even starts!  Don’t get anxious about the delay in starting radiation because prostate cancer is very slow growing, and a few weeks does not make a difference.  And if you are placed on hormone therapy then the tumor will be shrinking before the radiation even starts.

Is there a certain dose you use?  Is it individualized?

External Beam Radiation is prescribed as a daily dosage to the prostate gland given for a certain number of days.    We do individualize the dose.   We will vary the dose depending on how aggressive the cancer is, whether the prostate has already been removed, etc.  We don’t have any tests to tell us exactly how much dose your cancer needs, so we use the highest dose that will likely cure your stage of cancer and that can be safely given.

Do I come for treatment at a certain time?

After you get simulated / mapped out for radiation, the therapist will discuss with you what time of day your treatment will be at.  You will come at the same time every day, and this is your “treatment slot” or appointment time.  The appointments usually run on time.  The treatments are usually during regular business hours.  If you know that you can’t make it at your regular time one day just give the therapists advance notice and they can usually accommodate you and find another time that day.

Do you (the doctor) administer the radiation treatment yourself?

Radiation therapy is a team effort.  The doctor does not actually push the button to turn the radiation beam on each day, but he supervises and coordinates the team effort.  The therapy technicians will get you set up on the treatment machine each day and run your treatment program.  Your radiation oncologist doctor will prescribe the radiation treatment dosage, do some of the treatment design on the computer, approve the final computerized treatment plan, verify that your treatment lines up properly every day, and visit with you every week to make sure you are tolerating the treatment.  There are other team members like the dosimetrist and physicist who you won’t meet, and they help design the treatment program and make sure everything is running 100% accurately.

What is a typical external radiation treatment like?

Each day you will come in at your appointment time.  You may have been told to drink a certain number of ounces of fluid and have a full bladder.  The therapists will bring you into the radiation treatment room.  You will lie down on the treatment table, with your pants and underwear pulled down to you knees and a towel covering your exposed parts.  Your legs will be in an “immobilization device” so that you cannot wiggle around much.  The therapists will then adjust the treatment table so that the marks on your skin line up with laser lights in the room.  The therapists will then leave the room, and the machine will take a scan of your prostate area. Your bladder, rectum, prostate, and the marker seeds show up on this scan.  The table is then finely adjusted to make sure the marker seeds line up perfectly so that the prostate will be centered in the middle of the treatment beams.  Next, the treatment itself is run.  The treatment machine will slowly rotate around the treatment table, stopping at certain angles.  The radiation beam will be on for a few minutes in total.  When the beam is on, you may here clicking noises from shaping of the radiation beam and adjustment of its intensity.  You cannot feel or see the radiation beam.  Once the radiation has fished, the therapists will come in the room, lower the treatment table, and you are on your way!

Are there any restrictions while on treatment?

There are almost no restrictions.  You can drive yourself to and from treatment, and do your normal activities and your work.  You will not feel sick.  You can eat before treatment.  You are not radioactive or contagious.  You can have normal sexual relations, although there may be some blood or discomfort.  You can eat your usual diet, but this may be modified to a low-fiber (low-residue) diet if you develop bowel irregularity.  You can exercise and in fact should exercise regularly to help prevent fatigue.  Some activities may irritate the prostate while you are undergoing radiation such as bicycle or motorcycle riding, lawn tractors, and riding horses –be cautious with these activities as they may cause some blood in the urine and prostate discomfort.  Almost all medicines can be continued while on radiation, some exceptions would be certain chemotherapy and immune suppressant drugs.  Cold, allergy, and cough medicines can make it more difficult to urinate.  A daily multivitamin is fine but you should avoid mega-dosages of supplements unless you clear it first with your doctor.

What happens if I miss a treatment?

Sometimes you end up missing a day or two — maybe it’s a holiday, the weather is bad, you’re feeling sick, you had a long weekend planned, etc.  Sometimes the radiation machine is being serviced by engineers and there are no treatments that day.  In those cases you’ll still end up having the same total number of treatments, but you will finish 1 day later. Missing a few days here or there and extending your treatment by a few days will not affect the success of the treatment.  Missing a few weeks may lower the success.  If you have to miss a lot of treatments we may do some twice-daily treatments to help catch up.

How do you know you’re hitting the right spot?

Since the radiation beams cannot be seen or felt many people wonder how we know we are aiming those invisible beams properly.  It all starts with the mapping simulation CT scan.  In the mapping your body is positioned on the CT scanner the exact same way it will be positioned for each of your radiation treatments, and a coordinate system kind of like GPS is created.   Just like a guided missile can be aimed for a certain coordinate on earth (like the Kremlin at 55.7517° N, 37.6178° E), radiation can be targeted to certain coordinates in your body, relative to the the little skin marks that were placed on your skin during the simulation.  Secondly, the treatment machine will do its own CT scan immediate before each radiation session.  The therapist will look at the marker seeds, prostate gland, bladder and rectum on the daily CT scan, and do some fine-tuning to ensure the prostate will be in the center of the radiation.

How do you know the right amount of radiation is being released?

Each person has his own treatment plan, which is like a computer program that directs the treatment machine.  The treatment plan controls how many radiation beams enter the body, what shape they are, how strong they are, how long they’re turned on for, etc.  Before you have any treatments, the physicist will run your treatment plan on a plastic dummy that has radiation sensors built inside.  He verifies that the dummy receives the identical dose that was prescribed for you.  Secondly, the radiation machine has built-in monitors to ensure that the radiation beam is being generated at the correct strength.

Will the treatment make me sick?

No, it will not make you sick.  There is no nausea and no hair loss.  You will be able to do all of your usual activities and work.  Some men may get a little fatigued.

What side effects can I expect?

Radiation therapy will cause some short term inflammation in the prostate gland, urine passage (urethra), bladder, and rectum.   Urinary symptoms can include more frequent urination during the day and night, having to rush to the bathroom (urgency), a slower urine stream, some burning, and possibly a little leakage.  We often prescribe medications like Flomax to help.  Rectal side effects can include mild diarrhea or constipation, hemorrhoid irritation, mucous in the stools, and bowel urgency.  You may get a few small suntanned patches on your skin in the pelvic area. These short term side effects will begin a few weeks after you start radiation, and they usually go away within 1 – 2 months after completing radiation.  Some scarring may occur when the inflammation heals and this scarring can cause long term side effects such as weakening of the erections, and a small chance of urinary passage (urethral) scarring / narrowing, urinary leakage, or rectal bleeding.  Radiation can cause short term side effects from inflammation, and long term side effects from scarring.

Will the treatment help my urination symptoms from my enlarged prostate gland?

Your prostate gland will shrink for about one year after radiation therapy.  However, the urine passage through the prostate gland does not always widen when the prostate shrinks, and in fact it may become scarred or narrowed.  The result is that the urine flow can end up better or worse when radiation therapy is all done with.  If you have a lot of urinary symptoms already, these symptoms will get worse during treatment, sometimes requiring a temporary catheter, but eventually may end up being better than they are now.  It is unpredictable.

Do you monitor the cancer during treatment?

No.  The treatment machine takes daily CT scans to make sure that everything lines up properly, but the scans cannot show the cancer in the prostate.  In addition, we do not monitor the PSA during treatment because it temporarily goes up due to inflammation.  Your radiation oncologist does monitor your side effects and he also monitors to make sure that the treatment is lining up properly each day.  He visits with you once a week to make sure you are tolerating treatment OK.

When do I get my first test to see if the cancer is gone?

After treatment is completed the main way we monitor the cancer is with the PSA blood test.  We usually wait 3 months after treatment before checking the PSA, to give the prostate inflammation a chance to settle down.  By the 3 month mark the PSA is usually down to between 0.5 and 3.0.  The PSA is checked every 3 to 6 months after that.  By 12 months it is typically down to less than 1.0.  If you have been on hormone therapy then the PSA will be lower than this, often close to zero by 3 months after radiation.  There are no scans or biopsies done after treatment unless the PSA starts to climb.

How do you know the cancer has been cured?

There is no test you can do to prove the cancer is cured.  Even if we do another biopsy and it comes back all clear then that’s great news, but there still could be cancer cells “hiding” in the prostate.  All we can say is that there are no signs of the cancer, and that there is a certain percentage chance that it is cured.  After treatment the PSA blood test should drop down to a low value, and stay there.  The more months and years that have passed since treatment is completed and the PSA remains low, the higher the chance that it is in fact cured.  If at 3 – 5 years after treatment your PSA is less than 0.5 then you are probably cured.

What happens if the cancer comes back?

If the PSA level rises several times in a row at some future point in time [or climbs 2.0 points above the post-treatment minimum] this could be the first sign that the prostate cancer is coming back.  At that time scans may be done and possibly another prostate biopsy.  If it looks like the cancer has spread to the bones or lymph nodes then the treatment will be hormone therapy injections to slow it down.  If the cancer is recurring in the prostate gland but is nowhere else in the body, you may be able to have cyrotherapy (freezing), HIFU (ultrasound ablation), hormone therapy, watchful waiting, or possibly surgery.

Are there any other questions I should have asked?

Always make sure you know your available options, the side effects, and the goals of treatment.

Douglas Kelly, MD
Cancer Treatment Centers of America