Prostate cancer occurs in the prostate, a gland in the male reproductive system. Read more about prostate cancer here.
What is radiotherapy?
This treatment uses high energy radiation in the form of X rays to cure the cancer. It aims at killing the cancerous cells and shrinking the tumours. Radiation therapy for prostate cancer has good five year survival rates.
When is radiotherapy given for prostate cancer?
Depending on the type and stage of the cancer and the treatment chosen, radiotherapy can be given as:
- As a part of main treatment: radiation therapy is given as the primary treatment to cure localised and low grade prostate cancer.
- Along with other treatments: Radiotherapy is also given along with hormone therapy for advanced stages of prostate cancer, in order to get better results and eliminate the cancer from the body. Read more about hormone therapy for prostate cancer here.
- Adjuvant therapy: When the cancer has not completely removed by other treatments like surgeries, radiation is given to kill the remaining cancer and reduce the risk of recurrent cancer.
- Palliative care: When the cancer is too advanced to be eliminated, radiation is used to relieve the patients from the symptoms of prostate cancer.
Types of Radiotherapy:
Radiation which is given to treat prostate cancer can be given internally or externally based on the type and stage of the cancer, when is the radiation given along with the tolerance levels and overall health of the patient. Following are the types of radiation therapies used in treating prostate cancer:
External beam radiation therapy (EBRT):
This treatment is given to treat early stages of prostate cancer or as a part of palliative care. The procedure is carried out with the patient being lied down on a flat table. A machine called the linear accelerator moves around the patient to give radiation from all sides and various angles to kill the cancer cells. The patient is left alone in a room and is monitored by the doctors from the CCTV fixed in the room. This procedure is painless and also causes less damage to the healthy tissues and other organs.
External beam radiotherapy is broadly categorized into the following types:
Three-dimensional conformal radiation therapy (3D-CRT):
The 3D-CRT procedure aims in killing the cancer cells without high damage to the healthy tissues. Here, specialized computers which precisely match the location of the cancer, shapes and aims the radiation in different angles and shapes.
Intensity modulated radiation therapy (IMRT):
This is one of the most commonly used type of radiation to treat prostate cancers. Similar to the 3D-CRT, the IMRT also uses special computers to shape and aim the radiation at the prostate. The advantage of this treatment is that the intensity can be adjusted during the procedure. Another type of IMRT is the volumetric modulated arc therapy (VMAT), which delivers the radiation very quickly in each round. This reduces the amount of time the radiation is given.
Image guided radiation therapy (IGRT):
To aim more precisely at the cancer, image guided radiation therapy (IGRT) is used, which has image scanners built to their computers. These scanners allow the doctors to take pictures of the prostate and change the intensity of the radiation on requirement.
Stereotactic body radiation therapy (SBRT):
Advances image guided techniques are used to deliver large doses of radiation to the prostate. This treatment is finished within a short period of time because of higher dosages. SBRT is more successful than IMRT in treating prostate cancer but can be used only in early stage lesions..
Proton beam radiation therapy:
In this treatment, proton beams are delivered instead of x-rays to treat the cancer. These release energy only after travelling certain distance, because of which they cause less damage to the nearby tissues even while delivering high doses of radiation.
However, proton beam radiation is very expensive and has not yet shown successful practical results in all cases.
This treatment is also known as implantation or interstitial radiation therapy. It involves the insertion of radioactive pellets or seed in a man’s prostate. Internal radiation therapy is recommended for low-grade early stages of prostate cancer. It is also combined with external radiation to treat advanced prostate cancer. For the brachytherapy procedure to carry forward, the patients are given spinal or general anesthesia and have to stay in the hospital for at least one night.
This procedure is also known as low dose rate brachytherapy. This is procedure is carried out by placing the radioactive seeds like iodine-125 or palladium-103 in the prostate. These seeds are contained in thin needles, which are inserted through the skin between the scrotum and the anus, and take inserted into the prostate. The seeds or pellets in the prostate and the needles are removed.
These seeds deliver low doses of radiation low doses of radiation for a few weeks. Temporary brachytherapy is used to deliver high doses of radiation in small areas. This treatment minimizes the damage of the healthy tissues. Depending on the size of the prostate, approximately 100 seeds are placed in the prostate. For metastasized prostate cancer, temporary brachytherapy is often given with EBRT.
This treatment is also known as high dose rate brachytherapy. It is very rarely recommended to treat prostate cancers. Temporary brachytherapy is carried out by inserting hollow needles in the prostate through the skin between the scrotum and the anus. These needles contain catheters, which are left in the prostate as a part of the treatment. Radioactive iridium-192 or cesium-137 are then placed in the catheters to for 5-10 minutes. This treatment is repeated for 3-4 times depending on the requirement. The catheters are removed at the end of the treatment. In some cases, HDR brachytherapy is combined with EBRT.
This is not mostly recommended because of the adverse side effects it has on the person.
Side effects of radiotherapy in prostate cancer:
Radiation therapy aims to kill the malignant cells and shrink the prostate tumours. In this procedure, the healthy cells are also damaged because of which the patients experience side effects. The following are the side effects of radiation therapy in the treatment of prostate cancer:
It is a feeling of extreme tiredness caused by radiation which does not go away even after taking rest
Radiation causes irritation of the rectum which leads to radiation proctitis, which causes the following:
- Blood in the stool
- Rectal leakage
Radiation irritates the bladders and leads to radiation cystitis, which caused the follow:
- Frequent urination
- Burning sensation while urinating
- Blood in urine
- Reduced control over urine
- Leakage of urine
- Urethral stricture
Erection problems do not occur immediately after radiation is given to the prostate, but slowly develops with time. Older men are more likely to develop erectile dysfunctions than younger men who are given radiation to treat prostate cancer. Read more about erectile dysfunction here.
Radiation can sometimes block the lymph nodes near the prostate area which leads to the accumulation of the fluid secreted by the lymph nodes in the legs and genital region.
On experiencing any of the side effects, a doctor has to be consulted immediately. Most of the side effects go away after the treatment is stopped. But, the patients have to deal with the long term side effects for years, or sometimes, for the rest of their life.
The dosage of radiation to the patients depends on many factors like stage and type of cancer, when is radiotherapy chosen, along with the tolerance and general medical condition of the patient. Generally, higher doses of radiation of radiation is more successful in killing the malignant cells. Treatment which uses higher doses is completed in less number of days than the treatment that uses lowered radiation.
Brachytherapy is given for for four to five days with three times of treatment in every two days.
The success rate of radiotherapy for intermediate risk prostate cancer is 95.5%, while that for high risk prostate cancer is 91.3%. The five year survival rate of radiotherapy for prostate cancer is 98.8%.