Radiation Therapy for Cancer: How Does It Work?

Radiation therapy, also known as radiotherapy, is a cancer treatment that uses radiation, (commonly high-energy X-rays) to destroy cancer cells and shrink tumours. Radiation therapy can be used by itself or along with other treatments such as surgery and/or chemotherapy to treat various types of cancer.

What is Radiation Therapy?

Radiation therapy is used to treat various types of cancers by using high-energy particles or waves such as X-rays, protons, gamma rays or electron beams. It induces tiny breaks in the DNA of the cancer cells, inhibiting their growth and multiplication, ultimately causing them to die.

Unlike chemotherapy and other cancer treatments, radiation therapy is a localised approach, which targets the affected area precisely, while minimising the damage to the healthy surrounding cells.

Who Needs Radiation Therapy?

Radiation therapy is a common and often standalone treatment for cancer. It can also be combined with chemotherapy and/or surgery, depending on a variety of factors including the type and stage of cancer, and the patient's overall health.

How Does Radiation Therapy Work Against Cancer?

Radiation therapy uses high doses of radiation that kills the cancer cells or prevents them from multiplying division by damaging their DNA. It may take several days or weeks of radiation therapy for DNA damage to occur, leading to the death of the cancer cells. Post-therapy, the cancer cells may continue to die for weeks or even months.

Types of Radiation Therapy

There are two types of radiation therapy

• Internal radiation therapy
• External beam radiation therapy (EBRT)

Both therapies are used to target and destroy cancer cells, as well as shrink tumors.

The kind of radiation therapy used depends on:

• Type of cancer
• Location of the tumour
• Size of the tumour
• The tumor's proximity to healthy cells
• Other types of ongoing cancer treatments
• Age of the patient
• Patient’s medical history and general health condition

External Beam Radiation Therapy

EBRT is the most common form of radiation therapy where high-energy radiation beams, such as X-rays, protons, or electrons are directed towards the tumour. EBRT is a localised treatment, where only a specific part of the body is targeted.

Internal Radiation Therapy

Internal radiation therapy is used to treat smaller tumours in the neck, cervix, breast, head, prostate or uterus. There are 2 types of internal radiation therapy:

• Brachytherapy: This method uses a solid radiation source, i.e., capsules, seeds or ribbons, which is placed inside the body in or near the tumour. This is a localised treatment that targets a small area and destroys cancer cells in only a specific part of the body.
• Systemic therapy: In this method, liquid radioactive material is swallowed or injected through a vein The material travels through the bloodstream, targets the cancer cells, attaches to them and destroys them by releasing radiation.

Medical Professionals Who Provide Radiation Therapy Treatments

Radiation therapy is a specialised treatment that requires highly trained medical professionals to administer and care for cancer patients. The team may include:

• Radiation Oncologist supervises and manages cancer treatment using radiation therapy.
• Dosimetrist helps to create the best cancer treatment plan based on individual requirements along with the radiation oncologist.
• A Radiation Physicist oversees the proper operation of the radiation equipment and ensures the exact administration of the specified radiation doses.
• Radiation Therapist/Therapy Technologist operates the radiation equipment and maintains proper positioning throughout the treatment while ensuring patient safety and comfort.
• Radiation Therapy Nurse offers support and help to patients, assisting them in navigating the treatment and managing side effects.

Role of Radiation Therapy in Cancer Treatment

Radiation therapy is essential for treating cancer, controlling tumours and preventing recurrence. It also provides palliative care, alleviating symptoms and enhancing the patient's quality of life.

The palliative function of radiation therapy includes:

• External Beam Radiation: Shrinks tumours and alleviates pain, discomfort and symptoms.
• Systemic Radiation Treatment: Uses radiopharmaceuticals to treat and manage bone pain caused by cancer metastasis.

Types of Cancers Treated with Radiation Therapy

Specialised radiation therapy techniques, including the following, can be used to treat various types of cancers:

• EBRT: This versatile therapy can help to treat various types of cancers.
• Radioactive iodine (I-131): A systemic radiation therapy, radioactive iodine is used to treat specific types of thyroid cancer.
• Brachytherapy: This therapy is commonly used to treat breast, head and neck, eye, prostrate and cervix cancers.
• Targeted radionuclide therapy: Also called molecular radiotherapy, this is used to treat advanced gastroenteropancreatic neuroendocrine tumour (GEP-NET) and prostate cancer.

Combining Radiation Therapy With Other Cancer Treatments

Radiation therapy is commonly combined with other cancer treatments like chemotherapy, surgery and immunotherapy. The timing and purpose of radiation therapy vary based on the cancer type and treatment goals.

When used in combination with surgery, radiation therapy can be administered in the following ways:

• Pre-operative: To reduce the size of the cancer, facilitating its removal by surgery and also reducing the risk of recurrence.
• Intraoperative: by directly targeting cancer cells to protect the surrounding healthy tissues.
• Postoperative: To destroy any remaining cancer cells.

Radiation Dose Limits

There are limits to the amount of radiation a specific body part can receive. Re-treatment may not be possible if the radiation threshold is reached, but other areas can be treated as long as there is a sufficient distance separates them.

How Much Does Radiation Therapy Cost?

Radiation therapy for cancer can be costly due to equipment and specialised professionals. Costs vary based on factors like cancer type, therapy type, sessions and healthcare costs.

Check with insurance providers for coverage. Organisations and hospitals like Indian Cancer Society, Cancer Assist, Tata Memorial Hospital and AIIMS provide financial assistance and free treatments.

Special Diet Needs While on Radiation Therapy

Radiation therapy may cause side effects such as mouth sores, nausea and esophagitis, which may hinder eating. However, it is essential to consume a healthy protein-rich diet with adequate calories to enable the body to heal and maintain proper weight. It is advisable to consult the doctor, dietician or nurse for dietary assistance.

Working During Radiation Therapy

Patients undergoing radiation therapy may have varying abilities to work depending on their energy levels and individual circumstances. Fatigue and weakness are common side effects, and recovery can take weeks to months after treatment completion. It is advisable to consult the healthcare team for guidance and discuss medical leave options with the employer if necessary.

Pre-Radiation Therapy Preparations

• Internal radiation therapy
  • Physical examination and imaging
  • Get instructions from the radiation oncologist depending on the radiation delivery method

• EBRT

Simulation or planning appointment to:

• Customise treatment and plan the radiation dosage and delivery method
• MRI or CT scan to determine the location of the tumour to customise the X-rays for precise targeting
• Plan position on the table to determine proper alignment and mark the body to pinpoint areas to target radiation.

What to Expect During Radiation Therapy

• Internal radiation therapy
  • Conducted in the hospital or an outpatient treatment room.
  • Anaesthesia is administered to minimise any pain or discomfort during the treatment.
  • A radiation implant is inserted by the radiation oncologist and radioactive fluid is administered via an IV.

• EBRT
  • The patient is positioned on the table.
  • The radiation machine moves around the patient, delivering precise radiation to the tumour without any physical contact.
  • The radiation therapist operates the machine from a separate room and communicates with the patient via an intercom system.

Post-Radiation Therapy Procedure

• Internal radiation therapy
  • Discharge on the same day after a brief recovery period.
  • May require a hospital stay to eliminate radiation that may be secreted via bodily fluids
  • Must take precautions to prevent others from radiation exposure

• EBRT
  • No disruption in daily activities and the patient can return to normal routine immediately.
  • No risk of radiation exposure to others.

Side Effects of Radiation Therapy

Not only does radiation therapy destroy or retard the growth of cancer cells, but it can also damage the surrounding cells, causing side effects. The side effects depend on the area being treated.

Some of the common side effects of radiation therapy include:

• Fatigue
• Hair loss
• Dry, itchy scalp
• Nausea
• Vomiting
• Diarrhoea
• Blurry vision
• Headache
• Concentration or memory loss problems
• Skin irritation
• Mouth ulcers
• Reduced appetite
• Pain when swallowing
• Burning or pain when passing urine
• Frequent need to urinate
• Burning sensation in the chest or throat
• Abdominal cramps or bloating
• Urgency to pass stool

Advantages of Radiation Therapy

Radiation therapy has been used as a reliable and effective way to treat cancer. It helps to destroy cancer cells, enhances the effectiveness of other cancer treatments and improves the patient’s quality of life by reducing unpleasant cancer-related symptoms.

Risks or Complications of Radiation Therapy

While radiation therapy treats cancer effectively, it can increase the risk of the patient developing some other type of cancer in the future. It is recommended to consult with the oncologist and determine the pros and cons of the treatment.

Frequently Asked Questions

1. Does Radiation Therapy Cause Cancer?

Radiation therapy increases the risk of second cancers such as leukaemia and solid tumours, which can develop even 10 years or after the treatment.

2. Does Radiation Therapy Affect Pregnancy or Fertility?

Yes, radiation therapy can cause fertility issues in girls and women and boys and men too. It can also increase the risk of pregnancy-related complications and neonatal outcomes.

3. When Can I Get Back to My Regular Routine?

The effects of radiation therapy can vary from person to person. While some individuals may be able to resume their routine immediately, others may experience sickness and require rest. It's important to note that side effects of radiation therapy can occur even weeks after treatment.

4. When Should I See My Radiation Care Provider?

If you are encountering side effects from radiation therapy that are impacting your quality of life, it is important to consult your radiation care provider. They can assist by adjusting the treatment schedule, modifying the dosage or suggesting alternative treatments to alleviate the side effects.