Talking about tamoxifen

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’.