Hereditary breast and ovarian cancer genes could be detected during embryo screening, according to Belgian scientists.
Researchers from the university hospitals of Maastricht and Brussels say that preimplantation genetic diagnosis (PGD) for the breast cancer genes BRCA1/2 is now “feasible and established”.
Speaking at the European Society of Human Reproduction and Embryology (ESHRE) conference in Istanbul, Turkey, Professor Willem Verpoest from the Centre for Reproductive Medicine at Vrije Universiteit Brussel, explained why he was optimistic about the procedure.
The study looked at 145 PGD cycles for BRCA1/2 mutations performed in 70 couples at the two centres.
Almost 60 per cent of the mutation carriers were female, two-thirds of whom had the BRCA1 mutation. A total of 26.2 per cent of female carriers had undergone a prophylactic bilateral mastectomy.
Following IVF, 717 embryos were found suitable for genetic analysis. Of these, 43.1 per cent were found to be affected by the mutation and 40.7 per cent were unaffected and considered, therefore, to be suitable for transfer.
It meant that 62.1 per cent of the PGD cycles led to fresh embryo transfer, with 3.6 per cent transferred from one or two frozen-thawed unaffected embryos. This resulted in 42 pregnancies in 40 women. Pregnancy rates were 41.4 per cent per fresh embryo transfer and 23.1 per cent per frozen. The overall pregnancy rate was 29 per cent.
The series also included three cases of PGD on embryos previously cryopreserved for fertility preservation prior to chemotherapy, and these also led to two ongoing pregnancies.
While most PGD procedures are indicated to remove completely the risk of inherited sex-linked and single-gene diseases, such as cystic fibrosis, in the children of affected couples, PGD for the breast cancer mutations cannot remove the risk completely. Nor is breast cancer inevitable for a woman (or man) carrying a BRCA1/2 mutation.
Professor Verpoest said the results represented the biggest series of PGD for breast cancer in Europe so far and were robust, with a good unaffected pregnancy rate.
“We now believe that this technique offers an established option for those couples seeking to avoid the risk of inherited BRCA in their children,” he said.
“However, although there is no evidence of increased carcinogenesis in patients having ovarian stimulation for PGD in this population, the screening and monitoring measures – as well as multidisciplinary management – must still be in place.
“Our results suggest that PGD for BRCA1 and 2 mutations is feasible, with a good treatment outcome, but controversy will still remain over the ethical acceptability of PGD for a susceptible – yet preventable – condition.”
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