Researchers at a breast cancer prevention clinic in Manchester, UK, have observed an increased uptake of preventative double mastectomies since May 2013, when Angelina Jolie announced that she had undergone the procedure.

In a Letter to the Editor, published in the open access journal Breast Cancer Research, researchers from the Genesis Prevention Centre Family History clinic report that the number of preventative double mastectomies performed after consultation at the clinic more than doubled from January 2014 to June 2015, with 83 procedures performed during this period, compared to 29 between January 2011 and June 2012.

Although the researchers did not collect information on women's motivation for undergoing surgery, they speculate that the increase is attributable to the heightened awareness of the procedure since Angelina Jolie publicly announced her decision. Angelina Jolie underwent a preventative double mastectomy after losing her mother to breast cancer and subsequently discovering that she carried a mutation in the BRCA1 gene, which increases the risk of developing breast cancer and ovarian cancer.

At the Genesis Prevention Centre Family History clinic, the number of preventative double mastectomies performed on women with BRCA1/2 mutations rose from 17 in the 18 month period covering January 2011 to June 2012, to 31 in the 18 months from January 2014 onward. The number of procedures performed in high-risk women without BRCA1/2 mutations rose from 12 to 52 over the same period.

Having previously identified an upsurge in referrals to breast cancer clinics immediately after Jolie's announcement, the authors point out that it takes between 9 and 12 months from initial enquiries to surgery taking place, which is why they hypothesize that they only started to observe increasing numbers of procedures in early 2014. Considering the level of risk identified in the women that underwent a preventative double mastectomy, all the procedures were deemed appropriate. The authors also note that they observed a sustained increase in the number of new referrals to their clinic through 2014, with referrals rising from 201 between January to June 2012, to 388 for the equivalent period in 2014 with a total of 754 referrals in 2014. The authors write that women attending the clinic still mention the effects of Angelina Jolie on their attendance, but these anecdotal reports cannot be formally linked with the uptake in surgery because of their circumstantial nature.

According to Gareth Evans, professor of clinical genetics at Genesis Breast Cancer Prevention, lead author of the letter, "At the Genesis Prevention Centre Family History clinic, we've seen a clear increase in the number of women undergoing preventative double mastectomies, starting around nine months after Angelina Jolie's announcement about her own surgery."

"While we haven't analysed women's motivations for undergoing this type of surgery, the correlation suggests that if the increased uptake of double mastectomies can be attributed to 'the Angelina effect', the effect has been prolonged and has resulted in both increased referrals to our clinic, and increased rates of preventative surgery. It would be interesting to see results from other centres in the UK and worldwide to determine whether this effect has been noticed elsewhere."