Preparing for radiotherapy session

Overview

Radiotherapy (also called radiation therapy) uses high-energy rays to destroy cancer cells. Preparing for a radiotherapy session means getting ready for targeted treatment that helps shrink or eliminate tumors while protecting healthy tissue nearby.

Radiotherapy is a standard part of treatment for many types of cancer. Millions of people worldwide receive it each year.

Radiotherapy is used for people with cancer — it may be given alone or alongside surgery, chemotherapy, or other treatments.

Symptoms

Common symptoms

• Feeling tired (fatigue) during the treatment course.
• Skin changes in the treated area, like redness, dryness, or peeling.
• Soreness or irritation in the treated area (for example, mouth soreness if treating head or neck).

Symptoms in children

• Children may feel more tired than usual.
• They might have changes in appetite or growth in the treated area.
• Skin reactions can be more sensitive in young skin.

Symptoms in older adults

• Older adults may experience more fatigue and need extra rest.
• Pre-existing health conditions can make side effects feel stronger.
• Skin may be thinner and more prone to irritation.

Causes

Main causes

• Radiotherapy is used to treat cancer. It works by damaging the DNA inside cancer cells, stopping them from growing and dividing.

Risk factors

• Having a cancer diagnosis that is sensitive to radiation, such as breast, prostate, lung, or head and neck cancers.

When to see a doctor

See a doctor urgently if:

• If you have any of the emergency or urgent symptoms listed above.
• If you develop a high fever or signs of infection in the treated area.

Book a routine appointment if:

• Before starting radiotherapy, you will have a planning session with your radiation oncology team.
• You will meet with your doctor weekly during treatment to review how you are doing.
• Call your care team if you have questions about side effects or how to manage them.

Diagnosis

Before radiotherapy begins, you will have a planning session called simulation. During simulation, the team uses scans (CT or MRI) to map the exact area to treat, creates a custom mould or mask if needed, and marks your skin with tiny tattoos or pen marks to guide the daily sessions.

Tests that may be done

• CT scan (computed tomography) to create a 3D image of the treatment area.
• Sometimes an MRI (magnetic resonance imaging) or PET scan (positron emission tomography) for more detail.

What to expect at your appointment

Simulation is painless and takes about an hour. You lie still on a table while the scanner takes images. The team may make small marks on your skin with a pen or permanent tattoo dots. These marks help them position you correctly every time.

Treatment

Radiotherapy is given in daily sessions (called fractions) over several weeks. Each session is like getting an X-ray but takes longer. You lie on a treatment table, the machine moves around you, and you cannot feel anything. The radiation dose is carefully controlled to target the cancer while sparing healthy tissue.

Self-care at home

• Wear loose, soft clothing to avoid rubbing the treated area.
• Gently wash the treated skin with lukewarm water and mild soap — pat dry, do not rub.
• Use only products recommended by your radiotherapy team (no perfumed creams or lotions).
• Get plenty of rest — your body needs energy to heal.
• Drink fluids and eat a balanced diet; ask your team if you need help with appetite.

Medical treatments

Sometimes radiotherapy is combined with other cancer treatments such as hormone therapy or targeted therapy. Your doctor will decide the best plan for your specific situation. Do not use any over-the-counter creams or medicines on the treated area without checking with your radiotherapy team first.

When is surgery considered?

Radiotherapy may be given before surgery to shrink a tumor, making it easier to remove. Or it may be given after surgery to kill any remaining cancer cells. Your team will explain if and how surgery fits into your treatment plan.

Living with this condition

During your course of radiotherapy, you can usually continue normal daily activities, but you might need to rest more. Plan your schedule around treatment times. Some people work or go to school; others need time off. Listen to your body and take breaks when needed.

Lifestyle tips

• Protect the treated skin from sun exposure — cover it or use high-SPF sunscreen (after checking with your team).
• Avoid swimming in chlorinated pools or hot tubs during treatment.
• Stop smoking if you smoke — smoking can worsen side effects and reduce treatment effectiveness.

Diet and exercise

Eat small, frequent meals if you feel full or nauseated. Focus on soft, easy-to-swallow foods if your mouth or throat is sore. Gentle exercise like walking can help with fatigue, but do not overdo it. Stay hydrated — sip water throughout the day.

Mental health and emotional wellbeing

Feeling anxious, sad, or frustrated during treatment is common. You are dealing with a serious condition and a lengthy treatment. It is okay to ask for emotional support. Talk to your healthcare team, a counsellor, or a trusted friend.

Prevention

You cannot prevent a cancer diagnosis, but you can reduce your risk of some cancers with a healthy lifestyle and regular screenings. Once you need radiotherapy, following your preparation instructions can help reduce side effects.

Vaccines

Some cancers can be prevented by vaccines (e.g., HPV vaccine, hepatitis B vaccine). Talk to your doctor about vaccines that might lower your cancer risk.

Screening programmes

Regular cancer screening (like mammograms, PSA tests, or colonoscopy) can detect cancer early, when treatment is more likely to succeed.

Complications

If left untreated

• If side effects from radiotherapy are not managed, they can worsen and lead to infection, severe skin damage, dehydration from mouth sores, or significant fatigue.
• In rare cases, untreated complications can delay or interrupt treatment, which may affect how well the cancer responds.

Long-term outlook

Most side effects from radiotherapy are temporary and improve after treatment ends. Your healthcare team will help you manage them so you can complete your full course of treatment. Radiotherapy is very effective for many cancers, and modern techniques aim to minimize long-term effects. Stay hopeful — you have a dedicated team working with you.

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