classification of retinoblastoma
Last reviewed 01/2018
Retinoblastoma can be:
- familial or sporadic
- around 94% of newly diagnosed retinoblatomas are sporadic (without a family history of the disease)
- the remaining 6% are familial
- bilateral or unilateral
- the disease is unilateral in 70-75% of patients and bilateral in the remaining
- heritable or non heritable
- around 40-50% of cases are hereditary
- results from germline mutations which can be either a new-onset germline mutation (negative family history) or from a mutation transmitted as an autosomal trait (1,2)
- typically inherited in an autosomal dominant pattern (2)
- can manifest as either unilateral or bilateral disease (1)
- 50-60% are non hereditary (1)
- occurs secondary to somatic mutations (2)
- the tumour always manifests as unilateral disease (1)
All three classification schemes are interrelated (1).
- bilateral and familial retinoblastomas results from a germline mutation and are thus considered heritable tumours (3)
- unilateral sporadic disease is usually not considered as a heritable condition
- around 10-15% of unilateral sporadic cases have a germline mutation while the remaining are caused by somatic mutations (1,3)
- (1) McDaid C et al. Systematic review of effectiveness of different treatments for childhood retinoblastoma. Health Technol Assess. 2005;9(48):iii, ix-x, 1-145.
- (2) Melamud A, Palekar R, Singh A. Retinoblastoma. Am Fam Physician. 2006;73(6):1039-44.
- (3) Shields CL, Shields JA. Diagnosis and management of retinoblastoma. Cancer Control. 2004;11(5):317-27.