Radiotherapy 101: A few facts

It is estimated more than 50% of cancer patients will receive radiotherapy at some point during their treatment. And currently ⅓ of the population will be affected by cancer over their lifetime. This means 16% or 1 out of every 6 people of the entire world’s population will have radiotherapy once in their life. So shouldn’t we all know a few facts about it? So lets start

Radiotherapy 101- What is radiotherapy, and how does it work? What is a tumor?

Tumors are made up of cells, these cells are cancerous. These cancerous cells are reproducing at abnormally high rates, and they have lost any purpose. Essentially all they do is multiply and invade healthy tissues.

Healthy cells are programmed to stop reproducing when they are not required to do so. Cancerous cells have lost this mechanism. So they continue to reproduce over and over. One important component needed for a cell to reproduce is the DNA molecule.

The DNA molecule is basically a set of instructions on how to build a cell. Radiotherapy targets the DNA molecule of the cancerous cell. Breaking the molecule kills the cell, but only when it tries to divide. The cell can continue to function with broken DNA until it tries to divide. Since cancerous cells are dividing at an abnormal rate, they also die faster when their DNA is damaged. DNA breaks can be repaired though. Healthy tissue divides slower, this lets them have more time to repair themselves before they divide.

Ever single cancerous cell needs to be killed to successfully stop the tumor. This requires a large amount of radiation, but when radiation is delivered it must travel through healthy tissue to the cancerous region. An entire dose of radiation can often not be delivered in one go as there would be too much damage to healthy tissue surrounding the cancerous cells. To give normal cells time to repair and heal, treatment are often given in small daily doses, or fractions of five per week, over many weeks.

Radiotherapy breaks DNA by exposing the cells to ionizing radiation. The ionizing radiation releases charged particles or free radicals that interact with the DNA molecule and cause breaks within it.

Radiotherapy 101- How is radiotherapy delivered? Is it in pill form? Do I need an injection?

No there are no pills or injections with radiotherapy, in fact you can’t really hear see or feel the radiation during treatment. Radiotherapy is considered a local therapy. This means the radiation is used in a way where it specifically targets local areas of the body. Chemotherapy on the other hand travels throughout the body and is not highly targets.

Radiotherapy is most commonly delivered using Linacs. Radiotherapy delivered like this is called external beam radiotherapy. There are other types of radiotherapy like brachytherapy, iodine therapy, and implant therapies, but we will focus on external beam therapy here. External beam radiotherapy is named this way because a beam of ionizing radiation is directed from outside the body to the target site.

External beam radiation therapy comes in a few different flavors. There is Megavoltage (MV) radiation therapy from linacs, Gamma therapy from Cobalt 60 machines, and there are proton beams and heavy ion beams. These last two are not that common as the machine need are very expensive.

Radiotherapy treatment are normally given once, or sometimes twice a day, depending on the treatment protocol your Radiation Oncologist has prescribed you. Treatments are given on 5 days of the week, with a break over the weekend for several weeks. The one thing to remember is a person receiving radiotherapy does not become radioactive or dangerous in any way, so no need to worry about that.

Are there any side effects? How long will they last?

Normal tissue on the path to the targeted cancer do absorb some dose, and thus can also get damaged. This causes side effects, but these side effects are limited to the area of the body being treated. For example, radiation to the abdomen can cause side effects like diarrhea. This is because the walls of the bowel are sensitive to radiation. However, radiation to the abdomen will not cause side effects like hair loss. Anyone who knows a little bit about anatomy know that the head is nowhere near the abdomen.

Side effects aren’t pleasant, but they are not limited to radiotherapy. Side effects are present in most medical treatments and procedures. Think surgery, every time that someone is anesthetized, or put under, there is a very slim chance that they won’t wake up. Yet we still perform thousands of surgeries a day.

Most side effects from radiotherapy are temporary and will gradually disappear after the treatment is complete. Your radiation oncologist can prescribe treatments to help deal with these side effects. While side effects are unpleasant, there are treatments to help deal with them, and most side effects are temporary, disappearing gradually after therapy is complete. The most common side effects associated with radiotherapy are;

• Skin reaction- The area of skin near the treatment side may react and become dry or irritated, similar to a sunburn, sometimes more severe though
• Hair loss- certainly you will lose hair around the treatment area, but you won’t lose hair on your scalp unless you are being treated in the head and neck region.
• Nutritional Problems- Radiation can affect the mouth and stomach and intestines, which may lead to less saliva production or difficulty swallowing, and diarrhea. Again these side effects are localized to the treatment area.
• Fatigue– One of the most common side effects is to feel tired or weak during radiotherapy. This normally only last a few weeks after your treatment finishes.
• Neutropenia- When you receive radiotherapy the body will lose many neutrophils it has. Neutrophils are types of white blood cells. This means the body is at an increased risk of infection. This should go back to normal after your treatment is finished.

These are all short term side effects and should be resolved within a few weeks to months after treatment. There is also a possibility of developing long term side effects 5 to 10 years after treatment. These are again normally associated with the treatment areas. Long term side effect include memory impairment and confusion if you have had brain radiotherapy, development of another cancer due to the damage to healthy tissue from radiation. You should talk to your doctor about the associated risks. But hey, in my opinion the increase risks are worth it because without good radiotherapy you wouldn’t be around after 5 to 10 years.

Is it doing anything? Is the Radiation working? How do I know?

How do you know if your radiotherapy is working. Well the answer varies and depends on the type of cancer you are being treated for. Often you will have diagnostic images taken, like CT scan, MRI scans, and PET Scans. This will allow your doctor to assess if the tumor has shrunk, stayed the same, or worse- grown.

Other cancers can be monitored using markers. Certain tumors can be measured through blood tests. Either measuring a substance produced by the tumor, in which case if it is going down you would associate this with the tumor decreasing in size. Other cancer can be monitored through patient’s symptoms. If the symptoms a patient had are decreasing, like pain, it may be a signal that the tumor is shrinking. After you have had all your radiotherapy treatments you will likely be monitored to ensure the tumor has responded fully to the treatment and is working.

Remember, we are not your doctor! If you have any serious concerns or medical needs go see your doctor! Always seek advice from your doctor, not the internet or google. If you want a second opinion talk to another doctor!

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Originally published at www.radicalradiationremedy.com on December 29, 2016.