Radiation therapy (also known as radiotherapy) uses high doses of radiation to kill cancer cells and keep them from spreading. Two types of radiation are typically used:
- External: this is when the machine is outside of the body, aimed at the cancer cells
- Internal: this is when the radiation is placed inside the body, at or near the cancer cells
What is External Radiation Therapy?
A machine sends radiation to your body, targeted for a specific portion of your body. While the machine is large and will make noise, it doesn’t touch you.
Typical treatment runs once a day, five days a week, anywhere from two to 10 weeks, depending on the nature of the cancer and the treatment goals.
The interval of time between the first and last treatment is considered your “course of treatment.” Radiation therapy is usually outpatient, not requiring a hospital stay.
What to Expect
After a consultation with your doctor, you will be involved in a treatment planning session, also known as a simulation.
During this simulation, a radiation oncologist and radiation therapist will define your treatment area, where your body will receive the radiation. X-rays will be taken to determine the treatment area.
The radiation therapist will put marks on your skin in ink to designate the treatment area. These marks will remain throughout the course of your therapy.
If they are ink marks, they will fade in time; if tattoos, they will remain on your skin. You must be careful not to remove them and should let the therapist know if the marks fade.
A body mold may be taken, to help keep your body from moving during treatment, and to ensure that you are in the exact same position each day of treatment.
For radiation treatment to the head, a mask may be provided. This mask has air holes, and keeps your head in the same position for each treatment.
Also known as Gamma knife and Cyberknife, this form of radiation therapy focuses high-powered X-rays on a small area of the body.
It targets the cancer cells better than more conventional radiation therapy approaches.
Stereotactic radiosurgery is often used with patients who have tumors that are difficult to remove with conventional surgical approaches or in patients who might be too weak to undergo more traditional surgery.
This form of radiation therapy is used to treat:
- Brain metastases
- Pituitary tumors
- Uveal melanoma (cancer of the eye)
- Acoustic neuroma
- Spinal cord tumors
- Blood vessel malformations
- Movement disorders
- Some forms of epilepsy
- Parkinson’s disease
- Trigeminal neuralgia
Stereotactic radiosurgery is also being used (or considered for use) in:
- Liver cancer
- Lung cancer
- Prostate cancer
What is Internal Radiation Therapy?
Brachytherapy is a common form of internal radiation therapy in which radiation is contained in solid form, whether seeds, capsules or even ribbons.
These materials are then placed in the body at or near the cancer cells. This delivers a high dose of radiation to a smaller body area. Internal radiation can also be delivered in a liquid form, through a pill or an IV.
The liquid radiation travels through the body, targeting cancer cells.
Brachytherapy is often used with patients who have cancers of the:
- Gall Bladder
Liquid radiation is most often used in patients with:
- Thyroid cancer
- Non-Hodgkin lymphoma
Sometimes internal radiation is paired with other types of treatment.
Brachytherapy is typically applied with a catheter (thin tube), although it may be placed with a larger device called an applicator.
You will be sedated or anesthetized when the catheter is placed, preventing pain. Your doctor will place the catheter or applicator.
If you feel pain or discomfort, let your doctor or nurse know. They will give you medicine to help you manage the pain.
The radiation may be kept in place for a very short period of time or for a long period of time, depending on the condition, the type of brachytherapy, where the cancer is, your health and what other cancer treatments you have had.
What are the Types of Brachytherapy?
Low-dose rate (LDR) implants: Radiation is placed for one to seven days, during which time you will likely be hospitalized. Once the treatment is finished, the radiation sources are removed.
High-dose rate (HDR) implants: The radiation source is placed for 10 to 20 minutes at a time before it is taken out. Course of treatment may run twice a day for two to five days, or it may run once a week for two to five weeks, depending on the type of cancer. It may involve a hospital stay or you may be able to come and go to receive the treatment.
Permanent implants: In this course of treatment, the radiation source is placed and will always stay in your body. The radiation source gets weaker each day, although, when initially placed, you must be careful to not spend time with children or pregnant women. However, as time goes by, the radiation will lessen, ultimately going away, even though the implant will remain.
Depending on the course of treatment, particular precautions must be taken. Your doctor or nurse will inform you of whatever safety measures you must take.
If you receive high-dose radiation, you may have to stay at a private hospital room to protect others from the radiation coming from your body. Healthcare staff will provide the care you need but may keep a distance from you.
Visitors may have to follow the following precautions:
- Not being able to visit upon initial placement of radiation sources
- Checking with hospital staff before they see you
- Visiting you no more than 30 minutes each day, depending on the type of radiation and what area is being treated
- Staying at the door, versus entering the room
- No visits from children under 18 years or pregnant women
These precautions may also apply once you leave the hospital.
What Happens to Healthy Cells?
Radiation kills cancer cells, but can also harm healthy cells. Your doctor tries to protect healthy cells during the course of treatment through a variety of means:
- Using medicines: certain drugs can help protect parts of your body exposed to radiation
- Treatment time: spreading out the course of treatment over time allows normal cells to recover during therapy
- Precise targeting: doctors can use IMRT or 3-D conformal radiation therapy to more precisely aim doses of radiation at the cancer, reducing impact on nearby, healthy cells.
- Low doses: doctors determine the highest effective dose, while keeping dosages low enough to limit damage to healthy cells
Radiation therapy does not hurt, although side effects from it may cause discomfort or pain. Your doctor will help you manage any side effects of radiation therapy.
Life After Radiation Therapy
Once your course of treatment ends, you will need to regularly follow-up with your radiation oncologist or nurse. These checkups will help your doctor or nurse gauge:
- How effective the radiation therapy was
- What is the condition of your cancer
- Whether there are any additional side effects
Your doctor will also see how you are feeling, whether you need any additional medicines, and they may order additional lab tests or imaging tests.
You should be alert to any unusual symptoms after radiation therapy and should let your doctor or nurse practitioner know about them, including:
- New lumps, bumps, swellings, bruises, rashes or bleeding
- Changes in appetite
- Nausea, vomiting, diarrhea or constipation
- Unexplained weight loss
- Pain, fever, cough or hoarseness that does not go away
- Any other unusual symptoms that cause concern