The intraocular cancer retinoblastoma accounts for about 4 percent of all pediatric cancers, according to Drs. Carol L. Shields and Jerry A. Shields in a 2004 article in the journal Cancer Control. One treatment for retinoblastoma is plaque radiotherapy, in which the eye surgeon places a radioactive plaque on the eye for up to four days. The use of plaque radiotherapy is limited by the size of the tumor but can be used as primary therapy or after the failure of chemotherapy or external radiation. Plaque radiotherapy can cause some side effects to the treated eye.
Radiation Retinopathy
Due to the placement of the plaque, the retina may be affected by the radiation, leading to radiation retinopathy. In radiation retinopathy, the blood vessels of the retina become damaged. The retina then develops inflammation with bleeding and retinal cell changes, according to the Digital Journal of Ophthalmology. Patients with radiation retinopathy may develop vision loss, depending on the amount of retina involved and the location of the damage. About 25 percent of children treated with plaque radiotherapy have radiation retinopathy five years after the treatment.
Radiation Damage of the Optic Nerve
The optic nerve can also suffer radiation damage after plaque radiotherapy for retinoblastoma, according to the Digital Journal of Ophthalmology. The optic nerve becomes swollen and does not receive enough blood from its blood vessels, according to Myron Yanoff and Jay S. Duker in the 2009 textbook Ophthalmology. The amount of damage from the radiation depends on the proximity of the plaque to the optic nerve. Around 26 percent of patients develop optic-nerve radiation damage within five years, according to the Cancer Control article.
Cataract Formation
After plaque radiotherapy, patients may develop a cataract, according to Retinoblastomainfo.com. This side effect also depends on the location of the plaque during therapy. If the plaque is located anteriorly and closer to the natural lens of the eye, the risk of cataract formation is increased, according to Paul T. Finger in a 2000 article in the British Journal of Ophthalmology. If the cataract interferes with vision, the child can undergo cataract extraction.
References
- Cancer Control: Diagnosis and Management of Retinoblastoma
- Retinal Physician: Advances in the Management of Retinoblastoma
- Digital Journal of Ophthalmology: Retinoblastoma
- EyeCancerMD.org: Retinoblastoma
- Digital Journal of Ophthalmology: 53 Year Old Female Complaining of "Seeing Blood" OU for 4 Weeks
