Talking about tamoxifen

Abstract

Thank you for Andrew Herxheimer's thoughtful editorial.1 As the source for his reference to the deepening of the voice associated with tamoxifen use, 2 I feel I should add a personal note to the discussion. First, I wish to modify his statement slightly, to read: ‘The sometimes irreversible deepening of the singing voice that has been reported to occur with long-term use of tamoxifen for breast cancer is an example of a side effect that prescribers, manufacturers, and drug regulators seem to have considered trivial and have not investigated’ [my emphasis]. My own experience, of serious voice problems 2–3 weeks after starting to take 40 mg a day of tamoxifen in 1987, led me to enquire further of other women, in particular members of the charity Breast Cancer Care (then the Breast Care and Mastectomy Association). I found that similar problems had been reported to the then Director, Jinty Blanckenhagen, who had also notified the manufacturer, ICI Pharmaceuticals. However, this side-effect had not made it to the data sheet. So I conducted a small pilot study among readers of the BCMA newsletter, Network. I invited singers to write in if they had noticed any voice changes. Of the 10 who wrote in, seven had noticed changes similar to my own: mainly croakiness and a lowering of pitch. 2 To me this confirmed that my experience was not unique and I imagined that the drug company would wish to know about it. So early in 1992 I wrote to them, with copies to various other bodies such as the Committee on Safety of Medicines, as well as some eminent breast cancer specialists. The result astonished me. I was living in West Sussex at that time, and a senior member of the ICI medical team flew from Macclesfield to Gatwick, accompanied by another member of staff who seemed to have a Public Relations role, to see me in my home. It felt as if the object of this expensive exercise was to persuade me to shut up. This I did not do, but this particular side effect has still not been listed in the British National Formulary. The problem may be partly dose-related, and now the standard dose is 20 mg, not 40 mg. But I believe that the effect is real and that singers should know about it before embarking on tamoxifen treatment, which is only likely to benefit those with ER+ tumours. It is particularly important to mention it in any trials of tamoxifen for ‘prevention’.