The role of radiation therapy in cancer treatment

Treatments for cancer care have grown multi-fold across the globe, and regardless of the types of cancer and their severity, there is hope for recovering from the same. For a layperson, terms like surgery, chemotherapy, and radiation may sound familiar. But there are a lot of scientific and medical decisions that go into administering these treatments.

Radiation is a common, and perhaps the oldest treatment for cancers. Also known by various names, including radiation therapy, radiotherapy, irradiation, and x-ray therapy, the use of radiation in healthcare is over a 100-year-old technique. Yet, it has advanced incredibly in treating cancers and incorporates the various safety frontiers and measures for a better prognosis.

 What Is Radiation Therapy?

Radiation therapy is administered using high-energy waves or particles, including x-rays, gamma rays, protons, and electron beams to destroy the malignant cells. Radiation damages DNA of cells either directly or indirectly, through the formation of free radicals and reactive oxygen species.

Radiation therapy is prescribed for cancer patients depending on the type and stage of the cancer. More than half (about 60%) of people with cancer have radiation therapy. Sometimes, radiation may suffice for the entire treatment, but is often offered in combination with other therapies.

• The goals of radiation therapy include:

1)     Definitive Radiation Therapy- To cure patient using only radiation as treatment modality in early-stage cancer.

2)     Neo- Adjuvant RT- Shrinking or eliminating the cancer cells if the cancer is in an advanced stage before surgery.

3)     Adjuvant RT- To prevent the recurrence of cancer and stop them from spreading to other parts of the body after Surgery or Chemotherapy.

4)     Palliative RT- For symptomatic relief from conditions, including pain, inability to breathe easily, blockages in the bowel, etc., in the advanced stages of cancer.

• Is radiation therapy used with other types of cancer treatment?

Yes, radiation therapy is often used with other cancer treatments.

1. Radiation therapy and surgery.

Radiation may be given before, during, or after surgery. Doctors may use radiation to shrink the size of the cancer before surgery, or they may use radiation after surgery to kill any cancer cells that remain. Sometimes, radiation therapy is given during surgery, so that it goes straight to the cancer without passing through the skin. Radiation therapy given during surgery is called intraoperative radiation.

2. Radiation therapy and chemotherapy.

Radiation may be given before, during, or after chemotherapy. Before or during chemotherapy, radiation therapy can shrink the cancer so that chemotherapy works better. After chemotherapy, radiation therapy can be used to kill any cancer cells that remain.

• Does radiation therapy hurt?

No, radiation therapy does not hurt while it is being given.

• Common Side Effects OF RT-

Depending on the part of your body being treated, you may also have:

1. Diarrhea
2. Hair loss in treatment area
3. Mouth problems
4. Nausea and vomiting
5. Edema
6. Swallowing trouble
7. Urinary and bladder changes

• How Is Radiation Therapy Administered?

1. External Radiation

• What is external beam radiation therapy?

External beam radiation therapy comes from a machine that aims radiation at your cancer. The machine is large and may be noisy. It does not touch you, but it can move around you, sending radiation to your body from many directions. External beam radiation therapy is a local treatment, meaning that the radiation treats a specific part of your body. For example, if you have lung cancer, you will have radiation only to your chest, not to the rest of your body.

The patient does not need to follow any specific precautions after returning home after the treatment.

Different techniques utilized in of External radiations are as follows:

• Stereotactic Radio surgery (SRS) and Stereotactic Body Radiotherapy (SBRT)

Stereotactic Radio surgery (SRS) is a highly-advanced, non-invasive radiotherapy treatment that delivers very intense doses of radiation to cancer cells. When this treatment is administered to the other parts of the body besides the brain, it is referred to as Stereotactic Body Radiotherapy (SBRT) or Stereotactic Ablative Radiotherapy (SABR). SRS and SBRT are highly-effective in treating very tiny but well-defined tumours in inaccessible parts of the body, which are tough to remove surgically. With the help of advancements in technology, high doses of radiation are provided within a short duration to remove the tumour.

• Intensity Modulated Radiotherapy (IMRT) :

 High-precision RT that improves the ability to conform the treatment volume to concave tumour shapes

• Image-guided radiation therapy (IGRT)

Image-Guided RT (IGRT) Repeated imaging scans (CT, MRI or PET) are performed daily while pt is on treatment table.  Allows to identify changes in a tumour’s size and/or location and allows the position of the patient or dose to be adjusted during treatment as needed.  Can increase the accuracy of radiation treatment (reduction in the planned volume of tissue to be treated) decrease radiation to normal

2. Internal Radiation- Brachytherapy

A type of radiation therapy in which radioactive material sealed in needles, seeds, wires, or catheters is placed directly into or near a tumor. Internal radiotherapy delivers a high dose of radiation with some impact than external radiotherapy. This is because internal radiotherapy delivers radiation from inside the body, close to the cancer, so affects fewer healthy cells. However, internal radiotherapy is only suitable for smaller cancers.

Do not hesitate to talk to a doctor about what to expect during and after the treatment. Stay informed about the treatment options and always be in a positive mind for a faster recovery.

Dr. Rohit Kabre, Consultant – Radiation Oncologist, HCG Cancer Centre Vadodara.