Proton Therapy in Paediatric Cancer: What You Need to Know

A cancer diagnosis is difficult at any age and when it involves a child, the weight of that news can feel even greater. When a child needs radiation therapy treatment, parents may worry about how treatment could affect growth, learning, hormones and long-term health.

In Singapore, proton therapy may be considered for children with certain cancers because it can reduce radiation exposure to critical organs and healthy tissues near the tumour. While proton therapy is not suitable for every paediatric cancer, it can be especially beneficial when a tumour is close to developing organs or other sensitive areas of the body.

At the National Cancer Centre Singapore’s (NCCS) Goh Cheng Liang Proton Therapy Centre, the only proton therapy facility in public healthcare, a multidisciplinary care team evaluates each child’s diagnosis, age, tumour location and treatment needs to develop a personalised treatment plan.

Key Takeaways

• Proton therapy uses radiation to precisely target the cancer cells while minimising radiation exposure to nearby organs and healthy tissues, potentially reducing side effects.
• It can benefit children because their bodies and organs are still developing and can be more sensitive to radiation.
• Proton therapy may not be suitable for every child - the right option depends on the type of cancer, location and treatment goals.
• Treatment planning for proton therapy is highly detailed and may involve scans, customised immobilisation moulds or masks, and sometimes general anaesthesia for younger children who cannot remain still during treatment.
• A multidisciplinary care team reviews all treatment options including surgery, chemotherapy and radiation therapy to recommend the most appropriate approach based on the patient’s condition and post treatment care plan.

What is Proton Therapy?

Proton therapy is an advanced type of radiation treatment which uses positively charged subatomic particles called protons to precisely target and damage cancer cells and stop them from growing.

Protons can be planned to precisely target the tumour and stop at limited depth. This helps minimise radiation exposure to the nearby critical organs and healthy tissues and results in fewer side effects.

When is Proton Therapy Considered for Children?

Children have unique needs when it comes to cancer treatment. Their organs, bones, brain and hormonal systems are still developing and they have many years of life ahead after treatment.

Radiation therapy is a targeted treatment that plays a central role in managing certain cancers. Through careful planning, doctors work to minimise radiation exposure to healthy tissues and organs while maximising its effect on the tumour.

A multicentre study of children treated with proton therapy found that proton therapy can reduce the radiation dose received by healthy tissues surrounding the tumour compared with conventional radiation therapy. This is particularly important for children whose organs and tissues are still developing.

This may lower the risk of some long-term side effects, although the extent of the outcomes depend on the child’s overall health, cancer type, stage and location of the tumour.

How Does Proton Therapy Differ from Conventional Radiation Therapy?

Both approaches require careful planning. Patients are reviewed by a multidisciplinary care team to ensure that all possible treatment options have been considered and evaluated, and the most appropriate type of treatment is recommended based on their condition and post-treatment care plan.

Which Paediatric Cancers Can Be Treated with Proton Therapy?

In Singapore, proton therapy may be recommended for patients with certain conditions on the current MOH-approved list of indications, such as brain tumours, head and neck cancers, bone or soft tissue cancers.

Not every child with one of these conditions will require proton therapy as some tumours respond well to conventional radiation therapy, while others may be best managed through other or a combination of treatment approaches.

Proton therapy is also not typically recommended when cancer has spread widely and treatment is palliative in nature, such as to relieve symptoms like pain.

How does the Care Team Decide if Proton Therapy is Suitable?

Before a patient receives proton therapy, they are reviewed by a multidisciplinary care team who carefully weigh the risks and benefits of all treatment options before recommending the most appropriate treatment plan.

Some key considerations include:

• Type of cancer
• Size and location of the tumour
• Child’s age
• Whether the cancer has spread
• Whether surgery or chemotherapy is part of treatment
• Whether radiation therapy has been given before
• Likely benefits and side effects of each radiation therapy option
• Child’s overall health and ability to tolerate treatment

The goal is always to treat cancer effectively while protecting nearby organs and healthy tissues as much as possible to minimise the risk of side effects.

Parents are encouraged to have a discussion with the care team about whether proton therapy is suitable for their child. This should cover the expected benefits, possible risks, alternatives and what to expect before, during and after treatment.

What Happens Before Treatment Starts?

Planning scans

Proton therapy requires precise and careful planning. Before treatment starts, patients will undergo a CT scan and/or MRI scan to capture images that help the team map the tumour and nearby healthy organs and come up with a personalised treatment plan.

Positioning Equipment

Patients may need a customised immobilisation mask, cushion or support device to help them remain in the same position during every session.

An immobilisation mask is commonly used for treatment involving the head or neck. It is made to fit the child’s face and helps them stay completely still so that radiation can be delivered accurately to the tumour at every session.

General Anaesthesia for Young Children

Proton therapy is painless. However, children need to remain very still during treatment so that the radiation can target the tumour accurately.

Younger children, or those who have difficulty staying still, may need general anaesthesia for each treatment session. The team will explain what to expect and the preparations needed, including instructions on eating and drinking before general anaesthesia.

What to Expect During Proton Therapy Treatment?

Most children receive treatment over several weeks. The number of sessions depends on the cancer type and treatment plan.

A typical treatment may involve:

1. Checking in and preparing for the treatment
2. Changing into appropriate clothing, if needed
3. Positioning the child using the customised immobilisation mask, cushion or support device
4. Giving general anaesthesia, when required
5. Taking verification images to confirm the position
6. Delivering the proton therapy treatment
7. Monitoring recovery after general anaesthesia, if it was used

The radiation beam is delivered from outside the body. Your child will not feel the beam, and they will not become radioactive after treatment. They can safely be around family members and friends.

Parents are not able to be in the treatment room during the session, but the care team will monitor your child closely throughout to ensure their safety and comfort.

What Side Effects Can Occur?

While proton therapy can reduce radiation exposure to healthy tissues, less radiation does not mean there is no risk of side effects. As with any form of radiation treatment, patients may still experience side effects, depending on the area that is treated.

Side effects that patients may experience depend mainly on the area of the body being treated, the radiation dose and whether they are receiving other treatments at the same time. The care team will explain the potential side effects your child may experience and how they can be managed.

Some side effects may occur during or shortly after treatment. These can include:

• Tiredness
• Skin redness or sensitivity in the treatment area
• Hair loss
• Nausea or vomiting
• Headaches
• Sore throat or difficulty swallowing
• Changes in appetite
• Bowel or bladder irritation

Questions to Ask the Care Team

Before your appointment, consider writing down questions you have for the doctor. No question is too small when you are making decisions about your child’s care.

You may wish to ask:

• Why is proton therapy being considered for my child?
• What are the benefits of proton therapy for my child’s tumour location?
• What are the other treatment options?
• How many treatment sessions will my child need?
• Will my child need general anaesthesia?
• What side effects should we expect during treatment?
• Which long-term side effects will we monitor as my child grows?
• How will treatment affect school, sleep, eating and daily routines?
• What support is available for our family during and after treatment?

Supporting Your Child Through Treatment

Children may feel anxious about unfamiliar equipment, masks, scans or hospital visits. Parents can seek the care team’s advice on child-life support, counselling, play activities or other services that may help a child cope with treatment. The care team can also guide parents on how to explain proton therapy to their child in an age-appropriate way.

Keeping routines where possible can also make a difference. This may include bringing a familiar toy, playing their favourite songs, planning light activities after treatment or helping the child stay connected with school and friends when they feel well enough.

The NCCS Goh Cheng Liang Proton Therapy Centre offers virtual reality (VR) patient education modules that allow children to experience an animated walkthrough of the proton therapy process. Using a VR headset, they can explore an immersive simulation of what treatment involves, from the pre-treatment CT scan through to the actual proton therapy session. The Centre also has a dedicated playroom with toys and activities to help children relax before treatment.

Frequently Asked Questions

1. Does proton therapy hurt?
   The radiation beam does not hurt. Your child may feel discomfort from lying still or from side effects that develop later, such as skin irritation or tiredness, depending on the treatment area.
   
   
2. Will my child be radioactive after proton therapy?
   No. Proton therapy does not make your child radioactive. They can safely be near family members and other people after each session.
   
   
3. How long does proton therapy take?
   On average, each treatment session takes about 40 minutes including administering general anaesthesia when needed. The full course is often given over several weeks, although the exact schedule depends on the treatment plan.
   
   
4. Can proton therapy cure paediatric cancer?
   Proton therapy is used to treat or control certain cancers, usually part of a broader treatment plan. The chance of cure depends on the specific cancer type, stage and response to treatment.
   
   
5. Will my child still need follow-up care after proton therapy?
   Follow-up care is essential after childhood cancer treatment. The team will monitor recovery, cancer control, growth, development and any treatment-related effects over time.