Retinoblastoma is a cancer of the retina. Development of this tumor is initiated by mutations[1] that inactivate both copies of the RB1 gene, which codes for the retinoblastoma protein.[2]
Treatment
Until recently the only treatment was to remove the affected eyeball before the cancer spread. Chemotherapy is the treatment of choice for most unilateral cases. However, with locally advanced disease, external beam radiation may be needed, and if both eyes are involved, enucleation may be the only option. Affected children in developing countries present with advanced features and usually die of metastatic spread. In its initial stages, retinoblastoma is very similar to Coats' disease, a non-cancerous retina disease. Coats' disease should be ruled out before enucleation is done. A mis-diagnosis of retinoblastoma accounts for the greatest number of Coats' disease eyes being enucleated.
Many children with bilateral retinoblastoma can be treated with a preservation attempt. Tumor chemoreduction with carboplatin and other drugs may reduce the tumor volume making them amenable to local therapies [3]
Local therapies include-
- Laser therapy (Uses infrared laser light to precisely destroy the blood vessels surrounding a tumor.)
- Cryotherapy (use of a cold gas which is injected into the affected part of the retina to shrink the tumor.)
- Thermotherapy (A relatively new technique used mainly in new testing. It uses the principle that if heat is applied to the affected area, a tumor will sustain more damage than healthy cells because healthy cells can cool themselves better using healthy surrounding blood vessels. If this technique is not immediately successful it may increase the efficacy of other treatments such as chemotherapy and focused radiation plaques.)
- Radiotherapy (Generally used as a last resort, radiotherapy was previously the treatment of choice before the above mentioned treatments were developed. Radiotherapy destroys cancerous growths using gamma radiation or x-ray radiation but it carries with it many drawbacks, including:-
- Possibility of secondary cancerous growths which present themselves months or years later.
- Destruction of healthy cells in the area surrounding the treated tumor.
- Bone deformation due to the destruction of the growth plates mainly in the area of the temple.)
It is important that children with retinoblastoma are treated in specialist centers. It is considered to be one of the most common inherited cancer syndromes.
Brachytherapy with beta-emitting eye applicators have also been a successful major treatment. BEBIG (GmbH-Berlin-Germany) produces various kinds of ruthenium ophthalmic applicators for treating retinoblastoma.
Causes
In October 2007, researchers identified the specific cell that causes retinoblastoma.[4] [5]
See also
Additional images
References
- ^ Knudson A (1971). "Mutation and cancer: statistical study of retinoblastoma". Proc Natl Acad Sci U S A 68 (4): 820–3. doi:10.1073/pnas.68.4.820. PMID 5279523.
- ^ Friend S, Bernards R, Rogelj S, Weinberg R, Rapaport J, Albert D, Dryja T (1986). "A human DNA segment with properties of the gene that predisposes to retinoblastoma and osteosarcoma". Nature 323 (6089): 643–6. doi:10.1038/323643a0. PMID 2877398.
- ^ Dunkel IJ, Lee TC, Shi W, Beaverson KL, Novetsky D, Lyden D, Finlay JL, McCormick B, Abramson DH. (2007). "A phase II trial of carboplatin for intraocular retinoblastoma". Pediatr Blood Cancer. 49: 643. doi:10.1002/pbc.21163. PMID 17301956.
- ^ "Specific Cell That Causes Eye Cancer Identified, Disproving Long-held Theory". Science Daily (2007-11-08). Retrieved on 2008-09-27.
- ^ Ajioka, Itsuki; Rodrigo A.P. Martins, Ildar T. Bayazitov, Stacy Donovan, Dianna A. Johnson, Sharon Frase, Samantha Cicero, Kelli Boyd, Stanislav S. Zakharenko, and Michael A. Dyer (October 19, 2007). "Differentiated Horizontal Interneurons Clonally Expand to Form Metastatic Retinoblastoma in Mice". Cell 131 (2): 378 - 390. doi:10.1016/j.cell.2007.09.036. PMID 17956737. PMC:PMC2203617. Retrieved on 2008-09-27.
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