. . .continued
External beam radiation has been used since
the early 1900's as a way to save the eye(s) and vision. Retinoblastoma
is sensitive to radiation, and frequently the treatment is successful.
The radiation treatment is performed on an outpatient basis five
times per week over a 3 to 4 week stretch. Custom-made plaster-of
paris molds are made to prevent the head from moving during treatment
and sometimes sedatives (medicines which help relax the children)
are prescribed prior to treatment.
Tumors usually get smaller (regress)
and look scarred after external beam radiation treatment but they
rarely disappear completely. In fact, they may even become more
obvious to the parent as they shrink, because the pinkish-grey tumor
mass is replaced by white calcium. Immediately after treatment,
the skin may be sunburned or a small patch of hair may be lost in
the back of the head from the beam exit position. Following external
beam radiation, long-term effects can include cataracts, radiation
retinopathy (bleeding and exudates of the retina), impaired vision,
and temporal bone suppression (bones on the side of the head which
do not grow normally). Radiation can also increase a child's risk
of developing other tumors outside the eye for those children
who carry the abnormal gene in every cell of their bodies.
are disks of radioactive material that were developed in the 1930's
to radiate retinoblastoma. Today, the isotope iodine-125 is used
and the plaques are custom-built for each child. According to New
York State radiation safety rules, the child must be hospitalized
for this procedure, and undergoes two separate operations (one to
insert the plaque and one to remove it) over 3 to 7 days. No pregnant
visitors or health care professionals may visit or care for the
child, and children under twelve years old are not permitted to
visit. Patients take eye drops following plaque surgery for 3 to
4 weeks to prevent infection and inflammation. Following the plaque,
long-term effects including cataracts, radiation retinopathy, and
impaired vision may occur.
sometimes called photocoagulation or laser hyperthermia (which are
two different techniques), is a non-invasive treatment for retinoblastoma.
Lasers vey effectively destroy smaller retinoblastoma tumors. This
type of treatment is usually done by focusing light through the
pupil onto and surrounding the cancers in the eye. Recently a new
delivery system of the laser, called a diopexy probe, has enabled
treatment of the cancer by aiming the light through the wall of
the eye and not through the pupil. Laser treatment is done under
local or general anesthesia, usually does not have any post-operative
pain associated with it, and does not require any post-operative
medications. Laser can be used alone or in addition to external-beam
radiation, plaques, or cryotherapy.
continued . . .