Retinoblastoma is genetic, which
means that it is caused by mutations in a gene. These mutations prevent the
body from making certain proteins that when working control how cells
grow. When these proteins are not made
correctly, too many cells can build up in one place and form a tumor.
While all retinoblastoma is
genetic, only a proportion are hereditary.
About 70 to 75 percent of cases
are nonhereditary, meaning that the mutation develops in the child and is not
passed on to future generations. This is known as “sporadic retinoblastoma,”
and usually only one eye is affected. Children with nonhereditary
retinoblastoma tend to develop tumors later, and they do not have an increased
risk of other tumors.
About 25 to 30% cases or
retinoblastoma are hereditary. These children tend to develop tumors at a
younger age and are more likely to have tumors in both eyes. Children with
hereditary retinoblastoma are also at higher risk of developing other tumors,
including childhood tumors in the brain, or osteosarcoma (a tumor of the bone),
soft tissue sarcomas, or melanomas later in life.
To determine whether
the retinoblastoma is hereditary, all children with retinoblastoma seen at Dana-Farber/Boston Children’s are referred to the Pediatric Cancer Genetic Risk Program, a comprehensive program that provides genetic testing and counseling. If hereditary retinoblastoma is identified, further screening
recommendations and an invitation to enroll in screening studies may be offered. We also can provide testing of other family
members through this program.
The first step in treating your
child is to obtain an accurate and complete diagnosis. In addition to a
complete medical history and physical examination, your child’s doctor may
order one or more tests to determine the cause of his or her symptoms. Most
often, the tests are performed under general anesthesia, so your child won’t
feel a thing. Tests include:
- Complete eye (fundoscopic) examination – While
your child is under anesthesia, the doctor will dilate her pupils and look into
the inside of her eye, including the retina and optic nerve.
- Magnetic resonance imaging (MRI) of the orbits and brain
- Ultrasound of the eye
If advanced disease is
suspected, other work-up may be needed, including specialized imaging such as a
bone scan, and studies such as a lumbar puncture and evaluation of the bone
marrow. Retinoblastoma is usually diagnosed without a biopsy.
In addition to physical exam and
imaging procedures, our genetic counselors from the Pediatric Cancer Genetic
Risk Program will meet with you and discuss the possibility of taking a blood
sample and running tests to look for an abnormal retinoblastoma gene. This
allows us to have an informed discussion with you about whether the condition
in your child’s case is heritable (as described above in the "causes" section).
Stages of retinoblastoma
During the workup for retinoblastoma,
your child’s doctors will look to determine the size, number and location of
the tumor or tumors, and whether they have spread to the other parts of the
body. This is called staging, and is an important step in planning
treatment.
Your team will determine whether
the retinoblastoma is intraocular (inside the eye) or extraocular (the cancer
has also spread outside the eye).
Recurrent retinoblastoma refers
to cases where the tumor comes back after treatment.
After we complete all
necessary tests, our experts meet to review and discuss what they have learned
about your child's condition. Then we will meet with you and your family to
discuss the results and to outline the best treatment options for your child.
We understand how difficult a
diagnosis of retinoblastoma can be, both for your child and for your whole
family. That's why our specialists are focused on family-centered care: from
your first visit, you'll work with a team of professionals who are committed to
supporting all of your family's physical and psychosocial needs. We'll work
with you to create a care plan that's best for your child.
The good news is that since retinoblastoma
is usually found before it spreads outside of the sclera (the outer white part
of the eye), the condition is highly curable. Fortunately, there are several
types of treatment that can save sight in the affected eye. These are described
below:
Intra-arterial chemotherapy
Traditional forms of treatment for retinoblastoma carry the risk
of injuring the eye (for example, when radiation is used) or of causing
systemic symptoms, such as a weakened immune system (for example, when IV
chemotherapy is used). For these reasons, our retinoblastoma treatment team
will utilize intra-arterial
chemotherapy whenever
it is appropriate for a patient’s tumor.
Intra-arterial chemotherapy is a relatively
newer treatment for retinoblastoma in which the chemotherapy is injected
directly into the main blood vessel of the eye (the ophthalmic artery). This
treatment was designed to minimize the amount of contact the chemotherapy has
with the rest of your child’s body, so as to reduce side effects. Even though
the total dose of chemotherapy injected is lower than in traditional IV
treatment, the dose delivered directly to the eye is much higher, and so may
kill more cancer cells in fewer treatments. The eye is uniquely suited to intra-arterial
chemotherapy because the blood supply to the eye, in almost all cases, travels
through just one feeding artery.
During this procedure, your child is put to sleep by an
anesthesiologist. Then the surgeon inserts a thin catheter through a blood
vessel in your child’s groin, and feeds it up the arteries of the body to the
ophthalmic artery. At this point, the chemotherapy is injected through the catheter
directly to the eye. The average number of treatment sessions is three to four for
each affected eye, delivered about every four weeks.
Because young children have smaller and more fragile arteries than
adults, it is important that children who receive intra-arterial chemotherapy are
treated at a pediatric-specific cancer center. At Dana-Farber/Boston
Children’s, our interventional neuroradiologists have specialized expertise in
working with children, including babies and toddlers, and our complication
rates are the lowest published for comparable procedures performed at other
centers, including both adult and pediatric centers.

Chemoreduction
With chemoreduction, chemotherapy
is given through an IV. It passes through your child's blood stream, and if
successful, causes the tumors to shrink within a few weeks. Depending on which
drugs your doctor prescribes, your child may or may not be hospitalized during
treatment. Chemoreduction rarely, if ever, cures retinoblastoma when used alone,
so additionally treatments such as cryotherapy, thermotherapy,
photocoagulation, or radiation also would be needed (see descriptions below).
Surgery
Surgery is usually reserved for
children with advanced retinoblastoma that doesn't respond to other treatments.
In these cases, the eye may need to be removed during a procedure called
enucleation. While it is theoretically possible for the tumor to return even following
this procedure, such cases would be extremely rare.
Enucleation is a relatively
simple operation that is performed while your child is under general
anesthesia. Following the surgery, the eye is replaced with an orbital implant,
and after the eye has healed, an artificial eye – made to match your child's
healthy eye – can be worn. Some newer types of implants allow the artificial eye
to move, but implants are not yet able to provide vision. Children who have an
artificial eye can still participate in sports, as long as they use proper
protective eyewear.
Cryotherapy
Cryotherapy (sometimes called
cryosurgery), applies extreme cold directly to the tumor and is used to treat
small tumors or additional tumors that develop outside of the original tumor. Cryotherapy
is often used together with chemotherapy, or it may be used after radiation
therapy.
During cryotherapy, your child is
first put to sleep by an anesthesiologist. Then the surgeon uses ultrasound to
guide and place a small, extremely cold probe directly onto the tumor. The
surgeon takes extreme care to ensure that the surrounding healthy tissue
remains unharmed. Cryotherapy may be repeated on several occasions, if
necessary.
An advantage of cryotherapy is
that it may help prevent the need for enucleation or radiation therapy. The
major disadvantages are that cryotherapy may leave a scar which damages future vision
and that the procedure is not very effective in treating larger tumors.
Thermotherapy
Thermotherapy is a method of
delivering heat to the eye using ultrasound, microwaves, or infrared radiation.
Like cryotherapy, thermotherapy is only useful for very small tumors, and can
be combined with chemotherapy or radiation therapy. Thermotherapy leaves a
relatively small scar and tends to preserve more vision than cryotherapy.
Photocoagulation
Photocoagulation, also called
light coagulation, is another method for treating small tumors. This technique
uses focused light from a laser to destroy the tumor by destroying its blood
supply. Photocoagulation is sometimes used in combination with chemotherapy.
Radiation
Radiation therapy is a cancer
treatment that uses high-energy X-rays or other types of radiation to kill
cancer cells.
Side effects
All treatment types have side
effects associated with them. Your care team will discuss side effects and ways
to manage them before your child begins treatment.
Dana-Farber/Boston Children’s
also offers specialists who deliver complementary or alternative medicines.
These treatments, which may help control pain and the side effects of therapy,
include:
- acupuncture/acupressure
- therapeutic touch
- massage
- herbal supplements
- dietary recommendations
Talk to your child's team
about whether complementary or alternative medicine might be a good option for
your child.