Late effects of treatments for retinoblastoma

Recovering from retinoblastoma and adjusting to life after treatment is different for each child, depending on the type and dose of treatment, the child’s age at the time of treatment and many other factors. The end of cancer treatment may bring mixed emotions. Even though treatment has ended, there may be other issues to deal with, such as coping with long-term side effects.

Your child’s healthcare team will watch for late side effects and can help to prepare you for what to expect. They can also suggest ways to help your child.

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

Other eye problems include difficulty judging the distance between objects and difficulty seeing to the side (peripheral vision). Eye problems can also lead to changes in balance.

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 to see on the side affected by retinoblastoma. 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 the use of:

• sunglasses with UV protection when in the sun
• protective eyewear during sports or when using power tools or harsh chemicals

Find out more about eye problems.

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

A temporary plastic shell with a hole in the middle (called a conformer), is often placed over the orbital implant. The conformer has an oval shape with an eye painted on it. The conformer is used while the eye area heals before an artificial (prosthetic) eye is fitted. Some children will not have a conformer.

The conformer may look shocking to children when they first see themselves after surgery. It is important to keep in mind that the eye will not look like this after the artificial eye is in place. Before the child leaves the hospital or once they are home, a parent or caregiver will be taught how to:

• care for the child’s eye socket
• remove, clean and replace the conformer (if it was used)
• clean the child’s eyelids
• properly put in eye drops (if the doctor prescribes them)

Children who have an orbital implant and artificial eye 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.

Once the child’s permanent artificial eye is in place, it will be difficult for others 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 artificial eye can be removed so it can be cleaned. Parents or caregivers will be taught how to clean and care for the prosthesis.

Surgery or radiation therapy to treat retinoblastoma may change the way a child looks. 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 can also affect a child’s appearance. Having an entire eye removed can be very distressing. An orbital implant and artificial eye can lessen the overall effect on appearance. A permanent artificial eye looks similar to the other eye, but it may not move as much. Other people may not notice the difference between the 2 eyes. But the child may feel that they look different, even if others don’t notice.

A change in appearance can affect a child’s self-esteem and body image. It can also affect how they think others see them. It takes time to adjust to a change in appearance and to learn how to cope with these changes. Children may find that it helps if they share feelings with people close to them.

Kidney problems may be a concern for children who have a stem cell transplant or who are given cisplatin as part of chemotherapy. Regular follow-up visits will let the doctor check kidney function. Blood and urine tests are done to check if the kidneys are working properly or if the child needs further testing or treatment. Sometimes electrolyte supplements (with magnesium, calcium, potassium or phosphate) are given. This may or may not be on a temporary basis.

Find out more about kidney problems.

Certain chemotherapy drugs, such as doxorubicin (Adriamycin), may cause heart problems, including weakening of the heart muscles.

The healthcare team will carefully monitor children who have chemotherapy, to look for any signs of heart damage. They will do regular physical exams and tests, such as echocardiograms (an ultrasound of the heart), electrocardiograms (ECG) and monitoring blood pressure. These exams and tests help doctors find heart problems early and determine if treatment is needed.

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, which 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 low levels of sex and growth hormones.

Younger children are more likely to develop side effects from radiation, so doctors try to avoid giving radiation to children under 3.

Find out more about bone and muscle problems.

Radiation therapy to the head and certain chemotherapy drugs, such as cisplatin and carboplatin (Paraplatin, Paraplatin AQ), may cause hearing loss when they are given to very young children. This may lead to other problems, such as issues with language and social development. Hearing tests are usually done at the end of treatment and then every year to monitor your child’s hearing. Your child may need a hearing aid or speech therapy.

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

Radiation therapy to areas around the pituitary gland and hypothalamus can reduce the amount of hormones that the pituitary gland releases. Your child will see a doctor who specializes in hormones (an endrocrinologist) to check for any hormone problems.

Lower levels of growth hormone (GH) can slow your child’s growth and affect their bones and height. This can result in short height and bones that don’t reach full maturity. GH replacement therapy is often given after treatment is completed to help children grow and develop normally.

Lower levels of thyroid-stimulating hormone (TSH) can lead to thyroid problems such as hypothyroidism (reduced thyroid hormones), which can cause tiredness, dry skin, weight gain, constipation, slowed bone growth and thinning hair. Thyroid-stimulating hormone replacement therapy may be given to help the thyroid function normally.

Lower levels of follicle-stimulating hormone (FSH) and luteinizing hormone (LH) can lead to changes in testosterone levels in males and changes in estrogen levels in females. This could cause male or female reproductive system problems such as early puberty or failure to fully develop through puberty, impotence in males and irregular menstrual periods in females. Hormone replacement therapy may be given to maintain normal testosterone levels in males and estrogen levels in females.

Find out more about bone and muscle problems, thyroid problems, female reproductive system problems and male reproductive system problems.

Radiation therapy to the brain and some chemotherapy drugs used to treat retinoblastoma can cause problems in the reproductive system.

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

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 chemotherapy, the greater the risk of damage.

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

People who have a family history of retinoblastoma may wish to have a genetic risk assessment and genetic testing. Inheriting a retinoblastoma 1 (RB1) gene mutation increases the risk of developing cancer, but it does not mean that cancer will definitely occur. Genes are not the only factor that affects cancer risk, and a damaged gene by itself is often not enough to cause cancer.

Genetic counselling is often 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.

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Children who have a parent with hereditary retinoblastoma have a 50% risk of 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.

Retinoblastoma survivors have a higher risk of developing a second cancer later in life, especially if they received radiation therapy or have the inherited form of retinoblastoma. The risk is even higher if chemotherapy is given with radiation therapy or radiation therapy is given at a younger age. But the benefit of treating a child’s cancer outweighs their 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 sarcomas – cancers that develop in muscle, tendons, ligaments and fatty tissue
• melanoma – a type of skin cancer
• brain tumours
• lung cancer
• lymphoma
• breast cancer
• bladder cancer
• treatment-related leukemia

Second cancers do not usually occur for 10 to 20 years after treatment. It is important for healthcare professionals who see the child regularly through their life to know about any previous cancer treatments so that screening can be done earlier.

As children get older, they should be aware of the risk of developing a second cancer. They should be advised not to smoke because smoking may increase a retinoblastoma survivor’s risk of developing a second cancer.

Find out more about second cancers.

Children with hereditary retinoblastoma have a risk of developing trilateral retinoblastoma. Trilateral retinoblastoma is when pineoblastoma develops along with retinoblastoma in both eyes (called bilateral retinoblastoma). Pineoblastoma is a type of childhood brain tumour that occurs in the pineal gland. The pineal gland is a gland in the brain that controls the sleep cycle and plays a role in sexual maturation.

Trilateral retinoblastoma usually occurs 20 months or more after retinoblastoma is diagnosed. Doctors often recommend that the child have MRI scans as often as every 6 months during the first 5 years after a retinoblastoma diagnosis.

Find out more about watching for late effects of childhood cancer. To make the decisions that are right for your child, ask the healthcare team questions about supportive care after treatment.