Late effects of treatments for retinoblastoma

Cancer treatment may cause side effects in the years after the treatment has ended. These side effects of treatment are called late effects. The benefits of treating retinoblastoma far outweigh the risk of late effects.

The risk of late effects depends on many factors, including:

• the types of treatments used
• the amount of treatment
• the type of retinoblastoma (heritable or non-heritable)
• your childʼs age at the time of treatment

Your child will have long-term follow-up care after treatment so that the healthcare team can find late effects early and start treating them right away. Your child’s healthcare team will tell you what they are watching for and why.

The following are possible late effects after treatments for retinoblastoma.

Retinoblastoma or its treatment can cause eye problems. Some children with retinoblastoma may lose sight in 1 or both eyes and others may have minor vision changes. Changes in vision can affect reading, writing, the ability to do school work, mobility (how a child gets around) and balance.

Other eye problems include:

• difficulty judging the distance between objects and difficulty seeing to the side (peripheral vision)
• dry eyes
• seeing dots or lines (called floaters) or flashes of light
• objects appearing darker or not as bright as before
• delayed movement of the upper eyelid when the eye is looking down (called lid lag)
• cataracts
• watery eyes
• swollen cornea

Losing some or all vision can be distressing and have a big impact on a child’s life. It takes time to adjust to vision changes. Children who have difficulty with peripheral vision may need to turn their heads more than once both ways when crossing the street and to always hold onto handrails or banisters when walking up and down stairs. Children who couldn’t see out of an eye because of cancer before it was removed often adjust more easily because there is no sudden change to their vision.

It’s important to protect your child’s eyes from further damage. Some ways to do this include:

• wearing sunglasses with UV protection when in the sun
• wearing protective eyewear during sports or when using power tools or harsh chemicals
• getting regular eye exams
• visiting the doctor right away for any eye infection or injury

Find out more about eye and vision problems.

Parents and caregivers of a child who has had an eye removed (enucleation) may be concerned about caring for an ocular prosthesis (an artificial eye).

A temporary generic ocular prosthesis is placed over the orbital implant while the eye area heals after surgery. The temporary, generic ocular prosthesis is used before a custom ocular prosthesis is fitted.

It may take you and your child some time to get used to the appearance of the temporary, generic ocular prosthesis after surgery because it won’t match the other eye. Itʼs important to keep in mind that the eye will not look like this after the custom ocular prosthesis is in place. Before your child leaves the hospital or once they are home, a parent or caregiver will be taught how to:

• care for your child’s eye socket
• remove, clean and replace the temporary ocular prosthesis
• clean your child’s eyelids
• properly put in eye drops (if the doctor prescribes them)

Once your child’s permanent ocular prosthesis is in place, itʼs usually difficult for people to tell the difference between it and the normal eye. It will look similar to the working eye, but it may not move as much.

An ocular prosthesis can be removed so it can be cleaned. Parents or caregivers will be taught how to clean and care for the prosthesis.

Children who have an orbital implant (a sphere that is placed in the eye socket to help maintain its shape after the eyeball is removed) and ocular prosthesis are usually advised to wear glasses with shatterproof lenses to protect the remaining working eye, especially when they play sports. Children who wouldn’t normally wear glasses can wear ones with non-prescription lenses. Children should also wear helmets with face guards, visors or face shields, depending on the type of sports they play.

Children with an ocular prosthesis should have an eye exam every 6 to 12 months to make sure that it fits correctly and for the healthcare team to answer any questions you may have.

Surgery or radiation therapy to treat retinoblastoma may change the way a child looks (their appearance). The amount and type of change that may occur will depend on the type of treatment or eye surgery that is done. A change in appearance can affect how children feel about themselves.

Radiation or surgery can cause changes in the bone around the eye. Some children may have scarring. Surgeons try to make incisions on the face along the lines of natural creases to make scars less visible. Scars usually fade and many become less noticeable over time.

An enucleation or exenteration will change a child’s appearance. An orbital implant and ocular prosthesis can lessen the overall effect on appearance. A permanent ocular prosthesis looks similar to the other eye, but it may not move as much. Other people usually wonʼt notice the difference between the 2 eyes. But your child may feel that they look different, even if others don’t notice.

Having an eye removed can be very distressing and affect a child’s self-esteem and body image. A change in your child’s appearance can also affect how they think others see them. It takes time to adjust and to learn how to cope with these changes. Children may find that it helps if they share their feelings with people close to them. Helping your child cope and talking about these complicated emotions is important. Ask your child’s healthcare team for support if you and your child need it.

Children who have had retinoblastoma have a higher risk of developing a second cancer later in life, especially if they had radiation therapy or have heritable retinoblastoma. This risk is higher if chemotherapy was given with radiation therapy or radiation therapy was given at a younger age.

The benefit of treating retinoblastoma outweighs your childʼs risk of developing a second cancer.

The most common second cancers that occur in retinoblastoma survivors include:

• osteosarcoma – a type of bone cancer
• soft tissue sarcoma
• melanoma
• brain tumours
• lung cancer
• Hodgkin lymphoma
• non-Hodgkin lymphoma
• breast cancer
• bladder cancer
• acute myeloid leukemia (AML)

Second cancers don’t usually develop for 10 to 20 years after treatment. Itʼs important for healthcare professionals who see your child regularly through their life to know about any previous cancer treatments so that cancer screening can be done earlier.

As your child gets older, they should be aware of the risk of developing a second cancer. It’s important they do things to reduce their risk of developing a second cancer, such as being safe in the sun and living smoke-free.

Find out more about second cancers.

Children with heritable retinoblastoma have a risk of developing trilateral retinoblastoma.

Trilateral retinoblastoma is when pineoblastoma develops along with heritable retinoblastoma in 1 or both eyes.

Pineoblastoma is a type of childhood brain tumour in the pineal gland. The pineal gland is located in the centre of the brain, behind the brain stem, and makes melatonin (a hormone that controls the sleep cycle).

Trilateral retinoblastoma usually occurs in children between 20 and 36 months old. Doctors often recommend that children with heritable retinoblastoma have MRI scans as often as every 6 months in the first 5 years after a retinoblastoma diagnosis.

Genetic counselling (including genetic risk assessment and genetic testing) is most helpful when the child is first diagnosed with retinoblastoma and once the child reaches adolescence. An adolescent with a history of retinoblastoma may want to learn more about how their condition could affect their wishes to have children and whether their children would be at risk of developing retinoblastoma.

A parent with heritable retinoblastoma has a 50% risk of passing on the retinoblastoma 1 (RB1) gene mutation. A child who inherits this RB1 mutation from their parent has a 100% risk they will develop retinoblastoma. Mutations in the RB1 gene are inherited in an autosomal dominant pattern. This means if you inherit the RB1 gene mutation from only one parent, you can still get retinoblastoma.

Find out more about genetic testing, including genetic risk assessment and genetic counselling.

Kidney problems may be a concern for children who have high-dose chemotherapy or cisplatin as part of their chemotherapy plan. Regular follow-up visits will let the doctor check kidney function. Specific blood and urine tests are done to check if the kidneys are working properly or if your child needs further testing or treatment. Sometimes electrolyte supplements (with magnesium, calcium, potassium or phosphate) are given.

Find out more about kidney problems.

Chemotherapy drugs such as doxorubicin may cause heart problems, including weakening of the heart muscles.

The healthcare team will carefully monitor children receiving chemotherapy for any signs of heart damage. They will continue to monitor blood pressure and do regular physical exams and tests, such as echocardiograms (an ultrasound of the heart) or electrocardiograms (ECG). These exams and tests help doctors find and treat heart problems early.

Find out more about heart problems.

Children treated with radiation therapy to the brain are at risk for growth hormone (GH) deficiency. If the body doesn’t have enough GH, it can develop musculoskeletal problems. These problems mean the bones and muscles don’t grow as they should. They can lead to underdeveloped muscles, curvature of the spine, shorter limbs and shorter height. Some children may need artificial (synthetic) GH replacements if their growth is affected.

Children treated with radiation therapy to the brain are also at risk for osteoporosis due to radiation therapy lowering the levels of sex and growth hormones.

Younger children are more vulnerable to the effects of radiation. So, doctors will try to avoid giving radiation to children younger than 3 years of age.

Find out more about bone and muscle problems.

Radiation therapy to the head and certain chemotherapy drugs, such as cisplatin and carboplatin, may cause hearing loss. In young children, this may lead to other concerns, such as delayed language development and impaired social development.

Hearing tests are usually done at the end of treatment and then once a year to monitor your child’s hearing. If necessary, your child may need a hearing aid or speech therapy.

Find out more about hearing problems and speech-language problems.

Radiation therapy to the brain can cause lowered amounts of certain hormones. Lowered amounts of follicle-stimulating hormone (FSH) and luteinizing hormone (LH) can lead to changes in testosterone or estrogen levels. This could cause reproductive system problems such as early puberty or failure to fully develop through puberty, impotence or irregular menstrual periods.

Certain chemotherapy drugs can affect the ovaries or testicles and cause reproductive problems for children as they get older. These problems include puberty starting earlier or later than average and infertility. The higher the total dose of certain chemotherapy drugs, the greater the risk of damage.

Find out more about male reproductive system problems, female reproductive system problems and fertility problems.

To make the decisions that are right for your child, find out more about late effects of childhood cancer and talk to the healthcare team about long-term survivorship.