Radiation Therapy: How Does it Work? Purpose and Procedure

Radiation therapy is a popularly used cancer treatment that employs high-energy radiation to shrink tumors, eliminate cancer cells, and relieve symptoms. This treatment is called by other names like radiation therapy, radiotherapy, irradiation, and X-ray therapy. It plays a main role in cancer care, either as a standalone treatment or in combination with surgery, chemotherapy, or immunotherapy. This blog explores how this treatment works, its objectives, and the steps involved in administering it.

How Does It Work?

Radiation therapy uses high-energy waves or particles such as X-rays, gamma rays, electron beams, or protons to damage the DNA of cancer cells, preventing their growth, division, and spread. Unlike healthy cells, which can repair radiation-induced damage, cancer cells are more vulnerable and often die due to the treatment.

How Long Does It Take?

Radiation therapy courses usually span from 1 to 7 weeks, with treatments typically scheduled five days a week (Monday through Friday), allowing weekends for rest and recovery. Each session generally takes 10 to 30 minutes, most of which is used to position the patient accurately. The overall length and number of sessions vary based on the cancer’s type, location, and the intended treatment outcome.

Types

Radiation therapy primarily falls into two categories: external beam radiation therapy and internal radiation therapy. Both types aim to destroy the DNA within targeted cancer cells. Without DNA, these cells can no longer grow or divide, leading to their death and a reduction in tumour size.

External Beam Radiation Therapy (EBRT)

EBRT is a widely used method where high-energy radiation beams target cancerous tumours from outside the body. Radiation oncologists create a personalized treatment plan to focus on the tumour while minimizing exposure to surrounding healthy tissue.

EBRT includes several specialized techniques:

• 3D Conformal Radiation Therapy: This method uses CT scans and software to create a 3D image of the tumour. The machine directs radiation beams precisely at the tumour based on this model.
• Intensity-Modulated Radiation Therapy (IMRT): An advanced technique that adjusts the intensity of radiation beams. It applies higher doses to the tumour while reducing the exposure to nearby healthy tissues.
• Arc-Based Radiotherapy: This method delivers radiation in a rotating arc pattern. The varying beam intensity allows for faster and more efficient treatment than conventional approaches.
• Image-Guided Radiotherapy (IGRT): IGRT uses real-time imaging such as low-dose X-rays or mini CT scans to guide treatment. This ensures precise alignment and accurate radiation delivery.
• Particle Therapy: Instead of X-rays, this therapy uses protons to treat certain types of cancer more effectively, depending on the patient’s condition.
• Stereotactic Radiosurgery (SRS): Despite the name, no actual surgery is involved. This technique uses focused, high-dose radiation (like Gamma Knife) to treat brain tumours with extreme precision in a short time.
• Stereotactic Body Radiation Therapy: Similar to SRS, SBRT treats tumours outside the brain. It delivers highly focused radiation doses without the need for surgical procedures.
• Intraoperative Radiation Therapy (IORT): Doctors use IORT during surgery to directly target and destroy any remaining cancer cells that cannot be safely removed.

Internal Radiation Therapy

Internal radiation therapy places radioactive material inside the body, close to or within the tumour. Doctors commonly use this method to treat small tumours in areas like the breast, cervix, uterus, prostate, head, and neck.

There are two main forms of internal radiation:

• Brachytherapy: This involves implanting a small radioactive seed either inside or next to the tumour. These implants emit radiation over a limited area to destroy cancer cells. Depending on the treatment plan, implants may be temporary or permanent, with permanent ones eventually ceasing to emit radiation.
• Systemic Radiation Therapy: In this approach, patients receive a radioactive substance either orally or through an intravenous (IV) injection. The substance travels through the bloodstream to target and kill cancer cells throughout the body. A specialized form called radioimmunotherapy uses radioactive proteins that specifically bind to cancer cells and deliver radiation directly to them.

Purpose

Radiation therapy serves different purposes depending on the cancer stage and treatment goals:

• Curative Treatment: Used as a primary treatment for localized cancers, such as early-stage breast, prostate, or head and neck cancers, to eliminate tumors.
• Adjuvant Therapy: Applied after surgery or chemotherapy to destroy remaining cancer cells and prevent recurrence. For instance, breast cancer patients often receive radiation after a lumpectomy.
• Palliative Care: Helps alleviate symptoms in advanced cancer cases by shrinking tumors that cause pain, bleeding, or obstruction, improving a patient’s quality of life.
• Neoadjuvant Therapy: Administered before surgery to reduce tumor size, making it easier to remove and improving the chances of a successful procedure.

Process of the Therapy

The treatment process follows several essential steps to ensure safety, effectiveness, and patient-specific customization.

1. Consultation and Evaluation

A radiation oncologist assesses the patient’s medical history, conducts a physical exam, and discusses treatment options.

2. Treatment Planning (Simulation)

• Imaging Scans: CT, MRI, or PET scans help map the tumor’s exact location.
• Immobilization Devices: Custom molds or masks keep the patient still for precise targeting.
• Marking the Treatment Area: Small tattoos or skin marks guide the radiation beams.

3. Dosage Calculation

A team of radiation specialists determines the optimal radiation dose to destroy cancer cells while minimizing damage to healthy tissues.

4. Radiation Therapy Sessions

• EBRT: The patient lies on a treatment table while a linear accelerator delivers radiation. Each session lasts a few minutes and is typically given five days a week for several weeks.
• Brachytherapy: A radioactive source is placed inside the body near the tumor, either temporarily or permanently, depending on the treatment plan.

5. Monitoring and Follow-Up

Doctors regularly monitor the patient’s response and manage any side effects. Follow-up visits assess treatment effectiveness and determine further care if needed.

What is the Success Rate of Radiation Therapy?

The success of radiation therapy varies based on the cancer type, stage, patient’s overall health, and whether it is combined with other treatments or used alone.

• Early-stage cancers, such as prostate, breast, and cervical cancer, have a 70% to 90% success rate, especially when diagnosed early.
• Head and neck cancers respond well, with success rates ranging from 60% to 80%.
• Advanced-stage cancers may have lower success rates, but radiation therapy plays a major role in shrinking tumors, relieving symptoms, and enhancing quality of life.

Side Effects

Side effects will differ based on the treatment area but may include:

• Fatigue: A common response as the body heals.
• Skin Reactions: Redness, irritation, or peeling in the treated area.
• Nausea and Vomiting: More likely if the abdomen is treated.
• Hair Loss: Occurs in the treated area, such as scalp hair loss in head radiation.
• Long-Term Effects: Some patients may experience fibrosis or changes in organ function over time.

Doctors provide medications and supportive care to manage side effects and improve comfort.

How to Lower the Side Effects of Radiation Therapy?

Reducing the side effects of radiation therapy requires a mix of healthy habits and medical care.

• Maintain a Healthy Diet: Eat nutrient-rich foods, stay hydrated, and consume proteins, vitamins, and antioxidants to support healing and immunity.
• Protect Your Skin: Ensure the treated area is clean and moisturized with mild lotions, avoid sun exposure, and wear soft, loose clothing to prevent irritation.
• Manage Fatigue: Get enough rest, engage in light activities like walking, and practice relaxation techniques such as meditation or deep breathing.
• Stay Hydrated and Avoid Irritants: Drink plenty of water and limit caffeine, alcohol, and spicy foods to prevent dehydration and discomfort.
• Control Nausea and Digestive Issues: Eat small, frequent meals with bland foods and consult your doctor about anti-nausea medications if needed.
• Follow Medical Advice: Take prescribed medications, attend regular check-ups, and report any discomfort to your healthcare team for timely support.

Hope and Healing Through Radiation Therapy

Radiation therapy is a robust tool in cancer treatment, offering both curative and palliative benefits. By precisely targeting cancer cells, it helps shrink tumors, prevent recurrence, and enhance quality of life. Understanding the process enables patients to make informed decisions and prepare for treatment.

If you or a loved one is considering radiation therapy, consult an oncologist to discuss a personalized treatment plan. Advances in radiation technology continue to improve effectiveness, leading to better outcomes and enhanced patient well-being.

Frequently Asked Questions