Radiation Therapy for Prostate Cancer

What is Radiation Therapy

 

Radiation Therapy is a form of treatment for cancer or abnormal growth by irradiating the target with radioactive material which can be gamma rays, electrons, alpha particles, and positrons. A radiation oncologist is the doctor that will prescribe the amount of radiation you will need to possibly eradicate all of the cancer and he will oversee the planning of your treatment with a team of physicist and the daily treatments. Your daily treatments are administered by Radiation Therapists. These are technologists that are trained in radiation therapy and licensed by the ARRT. You will see them everyday throughout your treatments and they are your first line of defense if any side effects or other issues arise. The therapists will create you treatment setup and simulate it, position you for treatments everyday, take X-rays on a weekly basis for positioning verification, keep a watchful eye on your progress and how you tolerate the treatments.

External Beam Radiation Therapy

The most common radiation treatment used to treat prostate cancer is called external beam radiation therapy or EBRT. External Beam radiation therapy uses man made radiation that is created by a machine called a LINAC or linear accelerator. The Linear Accelerator creates high powered X-rays that are focused on the tumor and used to kill the cancer cells. It is called external beam because the radiation is targeted at the tumor or area to be treated from the outside of the patient and enters the patient from the outside in the form of a beam. The beam enters the body through fields or ports at different points around the patient. The points that the radiation will enter is determined by a team of physicists and dosimetrists in the treatment planning process.

External Beam Radiation Therapy is a non-invasive procedure that is performed 5 days a week for over 8 to 10 weeks. It is painless and nothing is felt during the time that the radiation is on. The patient will usually be in the treatment room each day from 15 to 30 minutes depending on the clinic and their protocols.

BrachyTherapy

The second type of radiation therapy in use is called brachytherapy. This is where a radioactive material or source is placed in direct contact with the tissue that needs to be treated. The most common form of brachytherapy is the prostate seed implants but is also used most other sites of the body. Brachytherapy involves the placement of about 100 small "seeds" containing radioactive material (such as iodine-125 or palladium-103) with a needle through the skin of the perineum directly into the tumor. These seeds emit lower-energy X-rays which are only able to travel a short distance.

The prostate seed implant takes about 1 hour to complete under general anesethia and a couple of hours of recovery afterwards. The radiation oncologist will also instruct you after the procedure to keep at a safe distance from young children and pregnant woman for a certain amount of time after the procedure. The seeds will be active inside you until they reach their half lives and then there will be no more un safe radiation emitted.

If you are a candidate for the seed implants and you do choose to have this procedure done you will have around 5 weeks of External Beam Radiation Therapy and then the implants will be done. Usually if the patient is not receiving the seed implants they will continue the External Beam Radiation Therapy for another 4 to 5 weeks for a total of 8 to 10 weeks.

 

Side Effects

As with any treatment there will be side effects. The most common side effects associated with radiation treatments to the prostate are bowel problems such as diarrhea, bowel urgency, burning with bowel movements and flared up hemorrhoids and urinary problems. The most common side effects is overall tiredness as the radiation treatments start to build up. Usually after about 3 to 4 weeks of treatment the patients start to feel tired. This can be counteracted with rest.

Common Side Effects with Radiation Therapy to the Prostate:

• incontinence - is cause if the urinary sphincter is damaged by the radiation. Usually occurs in 1% to 3% of the patients. Medication can help relieve this.
• impotence - the inability to maintain an erection. The risk of developing impotence is less with radiation therapy that it is with surgery. The long term risk of impotence with radiation therapy is around 20% to 40% but can be helped with medication.
• infertility - chances are if you recieve radiation therapy you will becom infertile. Discuss with you doctor about possibly freezing your sperm if you still want to bear children.
• bowel problems - the most common bowel problem associated with radiation therapy is diarrhea. Other bowel problems such as bowel urgency, burning with bowel movements and flared up hemorrhoids and urinary problems may occur and most of the time these side effects are only temporary and can be controlled with medication that you doctor can prescribe
• Fatigue - this is probably the most common complaint of patients undegoing radiation treatments. The fatigue usually sets in around 4 weeks into treatment and stays with the patient until a month or two after treatments end. Proper diet and rest can help you with this.

Side effects from radiation therapy treatments were a big problem in the past. With newer technology and advancements in treatment some patients go through a full course of treatmetn with no side effects at all. Some may experiance a little tiredness and noting more. Everybody is different and everybody reacts differently to radiation.

With the advent of IMRT precise doses of radiation can be controlled and given to specific targets in the case of prostate cancer this would be the prostate and the seminal vesicles. IMRT combined with IGRT these precise doses can be target on the tumor and the tumor alone without effecting the bladder or the rectum which will cut down on incontinece and bowel problems tremendously.

Outcome

No matter which type of treatment it is the radiation will damage the DNA in the cancer cells and take away their ability to reproduce. Since cancer cells do not have the ability to repair themselves the damaged cells eventually die if they are not eliminated right away from the radiation. Normal healthy tissue is also effected by the radiation but since normal tissue can repair itself it will, this is also the reason why treatments are broken up over 4 - 10 weeks. This is called fractionation and it gives the normal cells a chance to repair themselves.

Radiation for prostate cancer can be given as External Beam Radiation Therapy which will be given over a period of about 8 weeks. This is the most common treatment for prostate cancer and has very good results. The benefits of this type of radiation treatment is it is non-invasive and with recent advances in radiation therapy such as IMRT (intensity modulated radiation therapy) and IGRT (image guided radiation therapy) side effects are minimal. For patients who are candidates for the prostate seed implants they might want to have this procedure done so they do not have to have 8 to 10 weeks of treatment everyday. Usually a trans rectal ultrasound is performed if you are considering having the seed implants to determine if you are a candidate.

The decision on whether to undergo External Radiation Therapy or Brachytherapy depends on the extent of the disease and other factors such as general overall health. This should all be discussed with your team of health care practitioners before a decision is made.