© 2017, GENASSIST, Inc.
By Keith S. Wexler, MBA, Maternal Fetal Medicine, Prenatal Diagnosis and Biotech/Life Sciences Consultant, GENASSIST, Inc.
Paul Wexler, M.D., F.A.C.O.G., Medical Director, GENASSIST, Inc.
Clinical Professor, Department of OB/GYN, University of Colorado Health Sciences Center
Clinical Professor, Division of Genetics/Dept. of Pediatrics, Univ. of Colorado/The Children’s Hospital
The term cancer evokes great fear and concern in patients and their loved ones. Although childhood cancer is rare and survival rates for many cancers continue to increase, the impact on families, classmates, schools and neighbors is considerable.
In decreasing frequency the most common childhood cancers are:
- Central Nervous System and/or Brain Cancer
- Lymphomas and other cancers involving the blood or lymphatic system
- Thyroid cancer Melanoma
- Cancers involving the genital system
- Sarcomas of muscle
- Malignant bone cancer
- Nervous system tumors (e.g. neuroblastoma)
- Renal system tumors
- Liver cancer
5 year survival rates may approach 80% for leukemias, up to 95% for lymphomas, 90-99% for thyroid cancer and melanoma and up to 90-95% for retinoblastoma and renal tumors.
We recently became aware of a young child with a new diagnosis of Retinoblastoma which brought to mind the successful surgical career of one physician who not only survived his childhood diagnosis of Retinoblastoma but went on to have a superior academic record pursuing a career in medicine and surgery despite experiencing the loss of one eye as a child.
- Retinoblastoma is a rare childhood cancer with an incidence in the United States of approximately
- 12 per 1,000,000 live births.
- Retinoblastoma makes up approximately 6% of childhood cancers between birth and 5 years of age.
- 10% of Retinoblastomas are diagnosed in the first year of life.
- Bilateral disease is usually diagnosed earlier (average age of diagnosis 12 months of age) than unilateral disease (average age 24 months of age).
- Over 90% of Retinoblastomas are diagnosed before 5 years of age but rarely the disease may not present until the late teens or early adulthood.
- Approximately 60% of Retinoblastomas are sporadic and are not usually associated with an increased risk for other cancers (i.e. sarcomas, brain tumors, lung, lymphoma, urogenital and other cancers). In these cases, the malignant retinal cells are usually found in one eye and are usually confined to a single eye.
- Approximately 40% of Retinoblastomas are due to mutations in the Retinoblastoma Tumor Suppressor Gene (RB1) on chromosome 13q14 which is present in all patient’s cells and confers an increased risk for bilateral eye disease and other cancers.
These cases are usually due to a germline mutation or mutations in the RB1 gene, are found in the blood in 10-15% of children with unilateral eye disease and can be identified in 90-95% of Retinoblastomas with bilateral eye disease.
The most common finding of the disease is a visible white reflex in the pupil(s) of the affected eye(s). These individuals are born with or inherit one mutation of the RB1 gene and either acquire a mutation in the RB1 locus of the other chromosome or have loss of heterozygosity (loss of a normal gene and possibly the surrounding chromosomal material on one chromosome 13 involving the q14 locus).
Treatment varies depending upon the extent of the disease and includes:
- Laser therapy
- Systemic or Intrarterial Chemotherapy
- External beam irradiation
- Instillation of radioactive discs (plaques)
- Reduction of tumor size with chemotherapy (chemoreduction)
- Enuncluation of the eye