Radiation for cancer treatment isn’t dramatic, like surgery. You don’t have to be admitted to a hospital. You don’t have to be put to sleep. Sometimes you don’t even have to change clothes.
But the drama is all going on inside you. In one type of treatment, cancer cells are stripped of their DNA, rendering them unable to reproduce. In another, super cold or superheated material destroys the tumor, bit by bit. One therapy sends a beam of protons into your body where they slow down when they reach the tumor, then change into the shape of your tumor right before they land.
The quantity of types of radiation therapies is remarkable. You and your team have many routes from which to choose the optimal treatment.
External beam radiation – The standard
Your medical team may recommend radiation therapy for your cancer.
- If cancer is confined to your prostate during the early stage, it may be the only treatment recommended for you.
- If your cancer is more serious, but still only in your prostate, your team may combine radiation with hormone therapy.
- If you have had surgery but there is a risk of recurrence, you might have radiation therapy.
- If your PSA has increased after surgery or there are signs of cancer in your pelvis, you might have radiation therapy.
- If cancer has spread beyond your prostate, you might have radiation therapy to targeted lesions to treat the cancer or lessen bone pain.
Radiation therapy is delivered by a linear accelerator that sends high-energy X-rays or photons to the prostate. The radiation kills cancer cells, but also affects healthy cells in the pathway of the beam.
Therapy sessions are numerous: usually 40-42 sessions spread out over 6 weeks. They are in an outpatient facility. Because your radiation team wants to target as much of the prostate and as little of the surrounding healthy tissue as possible, they spend a lot of time setting up the sessions. During a radiation session you lie on a padded bench and the radiation device moves around you. Because you need to lie as still as possible, you have a “dress rehearsal.” You are helped in finding your most comfortable position; the team uses pillows and supports that both make you comfortable and keep you still. The team marks your body to show where to position the beam. They may use computerized tomography (CT) scans to locate the exact area to treat.
The radiation itself lasts only a few minutes, and most of the time is devoted to positioning you. All in all, each session usually takes less than an hour.
Risks of radiation therapy
There are minimal side effects initially. The immediate side effects cause urinary frequency. Most of the side effects accumulate over time, and they become noticeable 3-5 years after radiation. The problem with radiation side effects is that when they happen, they are very challenging to treat. Here are a few long term side effects for which you could be at risk:
- Infertility: As with open or robotic assisted surgery, your fertility will most likely be eliminated. The semen your prostate and seminal vesicles produce is not of the same quality after irradiation as it was prior to it.
If you want to have children after the treatment, consider banking your sperm beforehand. In a sperm bank your sperm is frozen in liquid nitrogen. After thawing, up to 50% can be used for artificial insemination.
Or you could extract sperm cells directly from the testicles. In that case, one sperm cell is injected into one egg cell; if an embryo forms, it is implanted into the mother’s uterine wall for gestation and growth.
- Bowel dysfunction: You are more likely to have bowel dysfunction after external beam radiotherapy than after surgery or IMRT. This is because this procedure covers a wide swath of the rectum. Bowel dysfunction means diarrhea or frequency of stools, fecal incontinence, and rectal bleeding. But improvements in techniques have helped this risk decrease.
Bowel function remains the same or deteriorates after therapy is over. After two years 10-20% of men have diarrhea a few times a week. Rectal bleeding increased from 5% shortly after radiation to 25% after two years.
You sometimes can treat the rectal bleeding with laser therapy. Treatments for diarrhea are to take anti-diarrheal medicine and increase your fiber intake with whole grains, fruits, vegetables, or fiber supplements.
- Bladder dysfunction: In order for the radiation to get to the prostate it passes through the bladder. To minimize bladder injury you are encouraged to keep your bladder filled during radiation treatments. Towards the end of the radiation treatments your bladder will start to get angry, and you will have to pee every 15 minutes. This usually gets better within 1-2 months after stopping the radiation.
Late effects from the radiation in the bladder are called radiation cystitis. This presents as blood in the urine, which can cause pain and bleeding. This usually happens 5-7 years after radiation. Although most patients don’t develop radiation cystitis, it can be problematic if you do. Severe cases result in bleeding, hospital admissions, and occasionally bladder removal if the bleeding is too severe. Recently urologists have learned that high doses of oxygen (hyperbaric oxygen) can help reverse radiation cystitis.
Brachytherapy
Brachytherapy is a long-standing and successful therapy for LOW RISK prostate cancer. Years ago it was used for multiple different patients with bladder cancer. Now it is rarely used alone, although it may be used in combination with other treatments. LOW RISK prostate cancer is often treated with active surveillance now, so brachytherapy has fallen out of favor.
You might be a candidate for brachytherapy if any of the following descriptions apply to you:
- Your tumor has low risk of progressing and has not spread significantly beyond the prostate.
- You are nearing the end of your external beam radiation treatment and your tumor has a high risk of progressing, brachytherapy boost may decrease disease progression.
- Your tumor is larger with a greater chance of spreading, you may receive brachytherapy along with external beam radiation or hormone therapy.
If your cancer has spread to the lymph nodes or to other areas of your body, you are generally not a candidate for brachytherapy.
Brachytherapy works from the inside. Radioactive material placed in your prostate provides the radiation.
High dose rate brachytherapy is temporary; thin tubes are placed into your prostate through the perineum. Thin wires from a machine go through the tubes and deliver the radioactivity to the prostate. They are removed after the treatment. You may need several treatments.
Low dose rate brachytherapy is permanent. Radioactive rice-sized seeds are placed in your prostate. They emit radiology for several months; they stay in your body permanently. As a precaution, you may need to stay away from children and pregnant women for a short time after implantation. Your doctor may advise you to use a condom during sex.
MRI-assisted radiosurgery (MARS) is an addition to the brachytherapy process. It enables your provider to place the radiation sources much more precisely than earlier imaging techniques, such as CT or ultrasound.
Side effects of brachytherapy
Common side effects include
- Fatigue
- Pain and swelling in the perineum.
- Difficulty starting urination, urgency, pain, night urination, blood in the urine, not being able to empty your bladder
- Erectile dysfunction
- Bleeding from the rectum, blood in the stool, urgency, frequent bowel movements
- Bowel dysfunction following brachytherapy tends to be lower than with external beam radiotherapy and stays at under 10% of men after one year.
Rare complications
- Narrowing of the urethra
- Abnormal opening (fistula) in the wall of the rectum
- Bladder or rectal cancer caused by the radiation
Proton beam therapy
In proton therapy, unlike standard radiation therapies, the radiation conforms to the size and placement of your tumor. That means most tissue sitting beyond the tumor does not get irradiated, as it does in the “exit dose” of standard radiation therapy. The place where the most radiation energy is released is your tumor.
Protons from a synchrotron or cyclotron (a particle accelerator) enter the body, stop at the tumor, match its size and mass, and zap it. It sounds like magic, but it’s really physics, chemistry, and engineering.
The machines that deliver proton beam therapy are enormous, some as long as a football field and three stories high. The machinery is housed apart from the treatment rooms and serve multiple treatment rooms. You will not usually see it. Because of its complexity and cost, only certain facilities have one.
This therapy is appropriate only for certain types of cancer, including prostate cancer. Sessions for prostate cancer usually last 5 days. The same amount of radiation that is usually delivered over 40 sessions is compressed into 5 days. While initial studies seem like this is feasible, no long term studies on late side effects of proton therapy are available. This is still considered experimental for prostate cancer.
Intensity-modulated radiation therapy (IMRT)
Your tumor is targeted with multiple radiation beams, each of a different strength. IMRT delivers the highest possible dose of radiation to your tumor. The technology behind proton beam therapy is being incorporated into IMRT, but called IMPT (intensity modulated proton therapy).
Risk of bowel dysfunction stays low after two years at about 5% of men.
Focal Therapy
A large class of therapies is focal therapy, meaning that part of the prostate or even the entire prostate (minus the tumor) is left intact. Focal therapy has been successful in other forms of cancer such as breast, kidney, and lung cancer, wherein only the tumor is targeted. Some providers consider focal therapies for prostate cancer controversial, because prostate tumors are often located in more than one part of the prostate (multifocal disease). Advances in MRI technology, however, offer better, clearer, more complete views of the prostate than ultrasound. The theory is that better imaging (MRI) means better treatment of the cancer.
Interstitial Laser Therapy:
Focal therapy uses an MRI machine that delivers images in real time and simultaneously aims the laser at the tumor. It takes place inside an MRI machine. It is considered a mid-point treatment between active surveillance and radical prostatectomy. Interstitial laser therapy was developed at the NIH and is still considered experimental.
You might be a candidate if:
- If your cancer is at intermediate risk of progression, determined through biopsy and MRI imaging to be a single, suspicious area that is potentially lethal;
- If you put a high priority on retaining sexual function;
- If you are willing to commit to a strict regimen of follow-up visits,
Combining laser heat with ultrasound, the provider removes only the cancerous part of the prostate. The rest of the prostate is left intact. Doctors believe this extremely precise therapy preserves more healthy tissue than other procedures and helps you retain your quality of life better than other procedures.
HIFU
Transrectal high-intensity focused ultrasound, or HIFU Ultrasound ablation is a common type of focal therapy. The surgeon inserts an ultrasound probe into the rectum. The double-duty probe delivers the ultrasound and images the prostate. Each blast of ultrasound destroys tumor tissue about the size of a grain of rice. The procedure, delivered under general anesthesia, lasts about two hours.
If your tumor is at intermediate risk of growing and in only one area (the back or side) of the prostate or your prostate gland is small to moderate in size, you may be considered a good candidate.
On the other hand, if your prostate is large and the tumor is in the front of the gland, if you have calcification (cysts) in the prostate, if you have inflammatory bowel disease, prior rectal surgery, or the surgeon is unable to insert the probe into the rectum, you are probably not deemed a good candidate.
Side-effects of HIFU
- Urinary urgency, frequency, slow stream, difficult or painful urination: These can be managed with medication and usually resolve within a few weeks.
- New urinary incontinence and sexual dysfunction usually occur less frequently than with open prostatectomy, but that is dependent on the location of the tumor.
- Urinary retention, urinary infection, ejaculatory dysfunction, urethral contraction, rectal fistula (abnormal opening in the wall of the rectum; rare)
Most men can get back to regular activities in one to two days. Once the catheter comes out, you can up your activity level. The benefits – little or no erectile dysfunction. The cons – No long term studies showing that it improves 10 year survival. No head to head studies comparing it to radiation or radical prostatectomy. Small risk of fistula – injury to the rectum.
Cryoablation
In cryoablation, the tumor is frozen and thawed, usually twice before the probes are removed. Although techniques and advancements for lessening sexual side-effects with cryoablation are continually being developed, long-term sexual dysfunction is still a possible concern.
When the entire prostate is ablated with cryoablation, erectile dysfunction approaches 100%. There is usually little or no incontinence after this procedure. Patients may have temporary swelling of the prostate and need a catheter for 1-2 weeks immediately after the procedure. Long term studies show a much higher rate of recurrence than with surgery or radiation, but this remains a good treatment for patients who cannot undergo either surgery or radiation.
With partial cryoablation, there is much less risk of erectile dysfunction. However, again this is considered experimental since there are no good long term studies showing long term cancer control with partial therapy.
With cryoablation you are at many of the same risks after the treatment as with other treatments: erectile dysfunction, pain and swelling of the scrotum and penis, blood in the urine, and bleeding or infection.
TULSA
As you can imagine, a significant challenge is getting the heat localized precisely to the malignant tissue without overstepping any bounds into healthy tissue and destroying that, too. Another method is coming closer to achieving this goal: transurethral localized sonographic ablation or TULSA. An ultrasound treatment delivered through the urethra uses heat to kill cancer cells. The surgeon knows the temperature of the prostate and surrounding tissue, because software monitors it and constantly adjusts the ablation device’s power.
This procedure is for partial or whole gland ablation. It is not for precise ablation near critical structures.
It is still years away from proving how it compares to other procedures in the long term. But preliminary results suggest it is effective in preserving normal sexual and urinary function.
As with all procedures, you would be selected for TULSA based on many data points: your prostate’s anatomy, MRIs, PSA, biopsy, and treatment goals.
Minimally invasive therapy comes in a dizzying array of forms. Many were developed to accommodate the needs of patients with complicated histories, such as prior rectal surgery. Some are refinements of earlier techniques. Some are tried and true procedures that nevertheless, continue to be improved. Radiation therapy is another tool in your multidisciplinary team’s toolbox to find the best treatment for you.