Tamoxifen may preserve fertility through ovarian stimulation in breast cancer patients

Using tamoxifen as an ovarian stimulant may be a feasible means of fertility preservation for women who undergo chemotherapy for breast cancer, which often results in premature ovarian failure according to a report by US researchers, published in the January issue of Human Reproduction.

‘Sometimes the best ideas are the obvious ones; and tamoxifen seemed the obvious choice of drug to test,’ lead researcher Professor Kutluk Oktay from Cornell University in New York said. ‘Although to my knowledge, no one has tried it before in breast cancer patients.’

‘We hypothesised that tamoxifen stimulation would result in higher numbers of embryos compared with natural cycle IVF, while theoretically shielding breast cancer cells against oestrogen.’

Twelve breast cancer patients were treated by the researchers with 40mg to 60mg tamoxifen for a mean of 6.9 days beginning on days 2-3 of their menstrual cycle. The women underwent IVF with either fresh embryo transfer or cryopreservation. The results were retrospectively compared with those from a control group of five women who underwent natural cycle IVF.

Professor Oktay said there was a desire to find a safe way of preserving fertility among the 15% of breast cancer patients who are still of reproductive age when diagnosed with the disease.

‘These women can try natural cycle IVF without ovarian stimulation, but typically, no more than a single embryo can be achieved for immediate use or freezing,’ Professor Oktay said. ‘So we need to find a safe way of increasing the number of embryos.’

The trial showed that the women who received tamoxifen produced on average, 1.6 mature eggs compared with 0.7 in the non-tamoxifen group. All 12 women then went on to generate embryos to freeze for later attempts at pregnancy, compared with only three out of the five controls. Since then, one patient who had two embryos transferred has successfully given birth to twins. None of the women had a recurrence of their cancer after a mean follow-up of 15 months.

‘We exploited tamoxifen’s dual action as an ovarian stimulant and an anticancer agent. It would be especially fitting if a drug that has saved so many women’s lives should also turn out to be a means of preserving their fertility,’ Professor Oktay said.

Dr. Mark Johnson, a specialist in assisted conception at the Imperial College of Science, Technology and Medicine in London, said tamoxifen’s benefits as an IVF treatment was not suprising. Other physicians in the UK have used the drug to stimulate the ovaries in women with polycystic ovary syndrome, he said. But this is the first documented case of successful births.

However, the number of women who will benefit from this approach is quite small, he added. The number of patients with breast cancer who have fertility problems is not that large.

(Source: Reuters Health)