Radiotherapy explained: How it works, benefits, and treatment process

Radiotherapy plays a central role in modern cancer treatment, offering targeted and effective control of tumors while preserving as much healthy tissue as possible. As one of the most widely used cancer therapies worldwide, it is often integrated into personalized treatment plans alongside surgery or chemotherapy to achieve optimal outcomes.

Thanks to continuous advances in imaging, planning, and delivery techniques, radiotherapy has become increasingly precise and better tolerated by patients. Understanding how it works, who can benefit from it, and what to expect before, during, and after treatment can help patients and their families feel more prepared and confident throughout the therapeutic journey.

What is Radiotherapy?

Radiotherapy, also called radiation therapy, is a medical treatment that uses high-energy radiation such as X-rays, gamma rays, or charged particles to destroy or damage cancer cells. Its main goal is to stop these abnormal cells from growing, dividing, or spreading to other parts of the body.

Unlike chemotherapy, which works throughout the entire body, radiotherapy acts locally on the specific area where the tumor is located. By carefully targeting the radiation, doctors can eliminate cancer cells while preserving as much healthy tissue as possible.

This treatment can be used alone or in combination with other methods such as surgery, chemotherapy, or immunotherapy, depending on the type and stage of the cancer.

How does Radiotherapy work?

Radiotherapy works by using high-energy radiation to damage the DNA inside cells. When the DNA of a cell is damaged beyond repair, the cell can no longer divide and eventually dies. Cancer cells are more sensitive to radiation than most normal cells because they grow and divide more rapidly.

Radiotherapy goal

The goal of radiotherapy is to deliver a precise dose of radiation to the tumor while minimizing exposure to the surrounding healthy tissues. To achieve this, advanced imaging and computer-assisted planning are used to target the tumor from different angles.

After treatment, cancer cells continue to die gradually, and the tumor may shrink over several weeks or months. Meanwhile, normal cells that are affected by the radiation are usually able to repair themselves, which allows the treated area to heal over time.

What Radiotherapy treats?

Radiotherapy is used to treat many types of cancer and, in some cases, certain non-cancerous conditions. It can be applied at different stages of treatment, either to cure the disease, to prevent its return, or to relieve symptoms.

Cancers treated with Radiotherapy

Radiotherapy is effective for a wide range of cancers, including:

Breast cancer
Prostate cancer
Lung cancer
Head and neck cancers
Brain and spinal tumors
Cervical, uterine, and other gynecological cancers
Rectal and other gastrointestinal cancers
Skin cancers
Lymphomas

Therapeutic goals

Radiotherapy serves multiple therapeutic purposes in cancer care, depending on the type of tumor, its stage, and the overall treatment strategy chosen for the patient. It can be used alone or in combination with other treatments such as surgery, chemotherapy, or immunotherapy.

Curative treatment

The main goal of curative radiotherapy is to completely eliminate cancer cells and achieve full recovery. It is often indicated when surgery is not possible or when radiation can preserve the function of vital organs. In many cases, it is combined with chemotherapy to enhance its effectiveness, particularly in cancers of the head and neck, cervix, or lung.

Adjuvant treatment

Adjuvant radiotherapy is administered after surgery to destroy microscopic cancer cells that might remain in the surgical area. This approach helps reduce the risk of local recurrence and increase long-term survival rates. It is commonly used for breast cancer, rectal cancer, and certain brain tumors.

Neoadjuvant treatment

In some cases, radiotherapy is given before surgery to shrink the tumor and make it easier to remove while preserving healthy tissue. This neoadjuvant approach can improve surgical outcomes and limit the need for extensive operations. It is often used for rectal cancer, esophageal cancer, and some sarcomas.

Palliative treatment

When a cure is no longer possible, radiotherapy plays an essential role insymptom relief and quality of life improvement. Palliative radiotherapy can reduce pain, bleeding, or pressure caused by large or metastatic tumors. It is a key component of supportive cancer care, aiming to make patients more comfortable and maintain their dignity during advanced stages of the disease.

Non-cancerous conditions

In specific cases, radiotherapy may also be used to treat non-malignant diseases, such as certain benign brain tumors, keloids, or painful joint and bone conditions that do not respond to other therapies.

Types of Radiotherapy

Radiotherapy can be delivered in different ways depending on the tumor type, location, and treatment goals. Modern techniques allow doctors to precisely target cancer cells while preserving healthy tissue.

External Beam Radiotherapy (EBRT)

This is the most common form of radiotherapy. High-energy radiation beams are directed at the tumor from outside the body. Advanced EBRT techniques include:

Intensity-Modulated Radiotherapy (IMRT): varies the intensity of radiation within each beam to conform to the tumor shape.
Volumetric Modulated Arc Therapy (VMAT): delivers radiation while the machine rotates around the patient, allowing faster and more precise treatment.
Stereotactic Radiotherapy (SRS/SBRT): provides very high doses of radiation in a small number of sessions for small or hard-to-reach tumors.

Internal Radiotherapy (Brachytherapy)

In brachytherapy, a radioactive source is placed directly inside or next to the tumor. This allows a high dose to the cancer while minimizing exposure to surrounding healthy tissue. It is commonly used for cancers of the prostate, cervix, and certain head and neck tumors.

Systemic Radiotherapy

Also called radiopharmaceutical therapy, this approach uses radioactive substances that travel through the bloodstream to target cancer cells throughout the body. It is often used for cancers that have spread, such as certain types of thyroid or bone cancers.

Emerging and advanced techniques

Modern radiotherapy also includes techniques such as:

Image-Guided Radiotherapy (IGRT), which uses imaging during treatment to ensure accurate targeting.
Adaptive Radiotherapy, which allows adjustments during the treatment course based on tumor changes.
Proton Therapy, which delivers radiation with protons instead of X-rays for precise dose distribution, reducing exposure to healthy tissues.

What happens before Radiotherapy?

Before you start radiotherapy, several steps are taken to ensure your treatment is safe, accurate, and tailored to your needs. These steps involve consultations, imaging, and careful planning.

Consultation with your doctor

You will meet with a radiation oncologist at our oncology center who will evaluate your type of cancer, its location, and its stage. During this consultation, your doctor will:

Explain the goals of your treatment, whether it is intended to cure the cancer, shrink the tumor before surgery, destroy remaining cancer cells, or relieve symptoms.
Discuss the type of radiotherapy that is most suitable for you.
Review potential side effects and how they can be managed.
Consider any other treatments you may be receiving, such as surgery or chemotherapy.

Imaging and planning

To target your tumor accurately, you will undergo imaging scans, such as CT, MRI, or PET scans. These images help your medical team design a personalized treatment plan that specifies:

The exact location, shape, and size of the tumor.
The dose of radiation you will receive.
The optimal angles and techniques to deliver the radiation safely.

Simulation session

Before starting actual treatment, you may attend a simulation session. During this session, the team will:

Position you in the exact posture you will use during radiotherapy.
Create customized supports or masks if needed to keep you still.
Mark reference points on your body or your support equipment to guide precise radiation delivery.

By completing these steps, your care team ensures that your radiotherapy is planned specifically for you, maximizing effectiveness and minimizing risk to healthy tissues.

What happens during Radiotherapy?

During radiotherapy, you will undergo treatment sessions in a safe and controlled environment. Each session is carefully guided by your medical team to ensure accuracy and comfort.

Arrival and preparation

When you arrive for your session, a radiation therapist will guide you to the treatment room. You may be asked to:

Change into a hospital gown, if necessary.
Remove jewelry or any metal objects that could interfere with the radiation.
Lie down in the same position used during your simulation session, often on a specially designed table.

Positioning and verification

The team will make sure you are correctly positioned. They may use:

Custom supports or molds to help you stay still.
Marks or reference points on your skin or equipment to guide the radiation.
Imaging scans to confirm that the radiation will target the tumor precisely.

Radiation delivery

Once everything is ready, the radiation machine is turned on. During this process:

You will not feel the radiation, although you may hear the machine moving.
You need to stay still while the radiation is delivered. Sessions typically last a few minutes, though the total time in the room may be longer.
The medical team monitors you from a nearby control room and can communicate with you at all times.

Anesthesia or sedation

Most patients do not need anesthesia because the procedure is painless and brief. In rare cases, such as very young children, patients with severe anxiety, or when extreme precision is required, short-acting anesthesia or mild sedation may be used under strict medical supervision.

Session frequency

Radiotherapy is usually delivered in multiple sessions over several days or weeks, depending on your treatment plan. Each session is important for ensuring the overall effectiveness of your therapy.

What happens after Radiotherapy?

After completing your radiotherapy sessions, your medical team will guide you through follow-up care to help your body recover and ensure the treatment is effective.

Immediate aftercare

You can usually return home the same day and resume most of your normal activities.
You may feel tired, especially toward the end of your treatment course. Rest and pacing yourself are important.

Follow-up appointments

Your doctor will schedule regular follow-up visits to monitor your progress.
During these visits, your care team may perform imaging tests or other assessments to evaluate how well the treatment worked.
You will receive guidance on maintaining your health and supporting recovery.

Long-term monitoring

Even after treatment ends, you will continue to have scheduled check-ups over weeks or months.
Your doctor may recommend lifestyle adjustments or supportive care to help maintain overall health and prevent complications.

Following your post-treatment plan and attending all follow-up appointments helps ensure your recovery goes smoothly and that any necessary adjustments to your care can be made promptly.

Side effects of Radiotherapy and how to manage them

Radiotherapy can affect healthy cells near the tumor, causing side effects that vary depending on the area treated, the dose, and your overall health. Most side effects are temporary and can be managed effectively with guidance from your care team.

Fatigue

You may feel more tired than usual during your treatment course. This is common and expected as your body works to repair itself.

How to manage it:

Rest when needed but try to stay lightly active.
Break your day into manageable tasks.
Ask for help with household chores or errands if possible.

Skin changes

The skin in the treatment area may become red, dry, or sensitive, similar to a mild sunburn.

How to manage it:

Use gentle, unscented cleansers and moisturizers.
Avoid scratching, tight clothing, or harsh products.
Protect the area from sun exposure.

Hair loss

Hair may fall out only in the area receiving radiation. It usually grows back after treatment ends.

How to manage it:

Cover your head with a scarf, hat, or wig if desired.
Be gentle when brushing or washing hair.

Digestive changes

If your abdomen or pelvis is treated, you may experience nausea, diarrhea, or changes in appetite.

How to manage it:

Eat smaller, frequent meals and stay hydrated.
Follow any dietary recommendations from your doctor or dietitian.

Urinary or bladder changes

Radiation to the pelvic area may cause increased frequency, urgency, or mild discomfort when urinating.

How to manage it:

Drink enough fluids but avoid excessive caffeine or irritants.
Report any pain or persistent changes to your care team promptly.

Key advice

Keep track of how you feel and report new or worsening symptoms.
Your medical team can provide treatments or adjustments to make you more comfortable.
Most side effects gradually improve after treatment ends