August 1, 1996
Molecular diagnosis of genetic disease could lead to huge health care savings
TORONTO - Costs for screening children at risk of developing cancer of the retina would be reduced by as much as 70 percent if molecular screening methods were used, say researchers at The Hospital for Sick Children, The Toronto Hospital and the University of Toronto.
A cost analysis and comparision was done of molecular versus conventional screening for a prototype family consisting of seven at-risk relatives of a retinoblastoma patient. The research is published in the August issue of the American Journal of Human Genetics.
Collaborators in this research are Dr. Brenda Gallie, a Hospital for Sick Children ophthalmologist and Professor of Molecular and Medical Genetics at the University of Toronto; Dr. Allan Detsky, Director of the Division of General Internal Medicine and Clinical Epidemiology at The Toronto Hospital and Professor of Health Administration and Medicine at the University of Toronto; Hussein Noorani a former Hospital for Sick Children Ophthalmology research assistant; and Hamza N. Khan, an ophthalmology resident at the University of Toronto.
"The conventional method of screening this family would cost more than $31,000 while molecular screening would cost only $8,674," explains Gallie, the only ophthalmologist in Canada specializing exclusively in retinoblastoma research and treatment.
Cancer of the retina - known as retinoblastoma - affects approximately one in 20,000 infants. Retinoblastoma can be either hereditary or nonhereditary, but in either case results from a mutation in a tumor-suppressor gene called RB1. This mutation can be identified through molecular testing.
Conventional screening for retinoblastoma involves three clinic examinations and eight examinations under anaesthesia over the first three years of life for each relative of a child with retinoblastoma. This process is stressful, inconvenient, and includes invasive examinations. The molecular approach involves determining which family members have the RB1 gene mutation and subsequent vigilant monitoring of just those children.
In retinoblastoma, early detection is the key to improving long-term outcomes and makes it possible to use less extreme treatments, such as laser and freezing therapy. Delayed diagnosis can necessitate the use of radiation or chemotherapy and may result in the loss of one or both eyes.
While there is a potential that molecular testing could replace conventional testing for other genetic diseases, careful evaluation of costs of the two approaches is required.
"Preliminary data from a similar study for colon cancer does not show a the same magnitude of cost savings using the molecular method of screening," explains Dr Gallie. "However, given the potential cost savings and the positive impact on at-risk families, the screening methods for other genetic diseases should be evaluated.
This research is supported by grants from the Canadian Genetic Diseases Network, the National Cancer Institute of Canada, The Retinoblastoma Family Association and the Royal Arch Masons of Canada.
For more information, please contact:
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