Retinoblastoma

Retinoblastoma is the second most common primary intraocular malignancy in all age groups (melanoma is most common in adults) and is the most common intraocular malignancy of childhood. Its incidence is approximately 1 in every 14,000 births. Generally, there are 250 to 300 new cases in the United States annually.

The tumor occurs bilaterally in as many as 40% of cases. It is generally diagnosed between 14 and 18 months of age, and more than 90% of the tumors are diagnosed by the age of 3 years. Familial retinoblastoma accounts for 6% of patients, but 15% of unilateral cases are carriers for the retinoblastoma gene. The remaining 94% of cases are sporadic. Germinal mutations account for 25% of retinoblastoma cases and somatic mutations for 75%. Most bilateral cases are caused by germinal mutations. The disease is inherited through an autosomal recessive tumor suppressor gene; thus the phenotype appears similar to that of autosomal dominant inheritance with incomplete penetrance. It is difficult, if not impossible, to differentiate the genetic mutations clinically and to determine which tumors will be passed on to offspring. There are occasional rare cases of retinoblastoma related to chromosomal abnormalities (partial deletion of long arm of chromosome 13). It has also been associated with trisomy 21.

The diagnosis of retinoblastoma is made by the patient presenting with a white pupil (leukocoria) in 61% of cases, strabismus in 22% of cases, and sometimes with a retinal detachment, red painful eye, or spontaneous hyphema (Fig. 41-25). Generally, patients with small retinoblastomas have problems with vision or strabismus. More advanced lesions present with leukocoria and occasionally secondary glaucoma. The advanced lesions may metastasize to the orbit and produce proptosis through the orbital spread. In addition, patients with retinoblastoma may have systemic metastases to the CNS, skull bones, lymph nodes, and other organs.

The treatment of retinoblastoma is generally enucleation for patients with advanced retinoblastoma involving more than 50% of the eye. If the second eye is involved, treatment depends on the size of tumor and whether there is extraocular extension. External beam irradiation treatment may be performed on the second eye or bilaterally, when necessary. Photocoagulation and cryotherapy are equally effective for small retinoblastomas confined to the retinal periphery. Newer modalities are incorporating chemoreduction and radioactive plaque therapy for localized retinoblastoma and possible vision preservation. Systemic chemotherapy may be indicated after enucleation for advanced unilateral or bilateral cases.

KEY TREATMENT

Patients with retinoblastoma should receive long-term follow-up for evaluation of associated systemic cancers (Children's Oncology Group, 2006) (SOR: C).

Surgery for retinoblastoma requires specialist services and should be referred to supraregional centers when possible (National Collaborating Centre for Cancer, 2005) (SOR: C)

10 Ways To Fight Off Cancer

10 Ways To Fight Off Cancer

Learning About 10 Ways Fight Off Cancer Can Have Amazing Benefits For Your Life The Best Tips On How To Keep This Killer At Bay Discovering that you or a loved one has cancer can be utterly terrifying. All the same, once you comprehend the causes of cancer and learn how to reverse those causes, you or your loved one may have more than a fighting chance of beating out cancer.

Get My Free Ebook


Post a comment