Doctors in the United Kingdom have created a table to predict when a woman who has undergone radiation therapy as a part of cancer treatment regimen in her abdominal or pelvic area may become sterile, according to a new study published in the July 2005 issue of the International Journal of Radiation Oncology*Biology*Physics, the official journal of ASTRO, the American Society for Therapeutic Radiology and Oncology.
Radiation therapy to the abdominal and pelvic regions in children and adolescents may potentially expose the ovaries to radiation and cause premature ovarian failure. Though their window of opportunity to become pregnant may be smaller, receiving radiation therapy does not preclude them from natural conception and a successful pregnancy. The researchers developed a formula that takes into account the age of the patient at the time of treatment, the number of premature eggs present at the time of treatment and the dose of radiation received to determine a window of fertility and at what age the woman may experience ovarian failure.
With the help of modern three-dimensional radiation therapy planning, clinicians are able to determine how much radiation the ovaries are exposed to and using the method they developed, the doctors would be able to determine a window of roughly 7.6 years for when a woman could expect to become infertile. The exact window of opportunity will vary from patient to patient.
“Our research has made it possible for doctors to predict when a young woman who has been successfully treated for cancer will develop ovarian failure,” said Hamish Wallace, M.D., lead author of the study and Senior Lecturer at the University of Edinburgh and a children's cancer specialist at the Royal Hospital for Sick Children in Edinburgh, Scotland. “This will allow doctors to treat them with hormone replacement therapy and prevent osteoporosis and other disabling symptoms of the menopause. This knowledge will also guide patients and doctors to their future window of opportunity to have a baby. For those young women who are at risk of a very early menopause, it is now possible to counsel them of the options currently available to preserve their fertility before their treatment starts.”
“We acknowledge this is a predictive model based on pre-clinical work and does not take into account the current use of combined modality treatments in pediatric and adolescent cancer survivors,” said Frank Saran, M.D., co-author of the study and Consultant Clinical Oncologist and Honorary Senior Lecturer at Royal Marsden NHS Trust Foundation in Sutton, United Kingdom. “We hope this enables doctors to confidently counsel women on their reproductive potential following the successful treatment of their cancer.”
“This information can be used either to vary the treatment – so that less radiation is received by the ovary – or possibly commence freezing of ovarian tissue, which is a new technique that potentially enables fertility after serious damage to the ovaries,” said Tom W. Kelsey, B.Sc., M.Sc., Ph.D., co-author of the study and a computer scientist at University of St. Andrews in Scotland. “Our results are exciting and useful, and further data is needed to improve the accuracy of our methods.”