Doctors in Scotland have come up with a way of predicting when a woman may become sterile after undergoing radiation therapy as part of cancer treatment, according to a study published in the International Journal of Radiation Oncology.
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 and the dosage of radiation received to determine a window of fertility and at what age the woman might enter premature menopause.
'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 Dr Hamish Wallace of the University of Edinburgh, the study's lead author and a children's cancer specialist at the Royal Hospital for Sick Children.
For example, a dose of 12 Gray - the typical dose used for total body irradiation when someone has leukaemia and needs a bone marrow transplant - at 15 years of age would mean most would reach menopause at the age of 19. A few would be left sterile immediately after treatment, and a few would be fertile until they were 23, said Dr Wallace.
Previously, doctors were only able to tell women and young girls undergoing radiotherapy that there was a risk, but they were unable to quantify it. The study's co-author, Dr Frank Saran, a radiation oncologist at the Royal Marsden NHS Trust in Sutton, hopes that the work will lead to cancer patients receiving better advice. 'We hope this enables doctors to confidently counsel women on their reproductive potential following the successful treatment of cancer,' he said.
'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,' said Dr Tom Kelsey, a computer scientist at the University of St Andrews and one of the study's co-authors.
The ability to predict when ovarian failure will occur will also help doctors to prevent osteoporosis and other disabling symptoms of the menopause.