Oestrogen deprivation therapy such as with tamoxifen or aromatase inhibitors can cause menopause-like symptoms, particularly genitourinary atrophy, with vaginal dryness, pain/discomfort or impaired sexual function. Over-the-counter vaginal moisturisers or lubricants can be used to ease symptoms. Topical vaginal preparations containing oestrogen can also be used, although with a risk of the breast cancer returning.^23,24

TKIs are associated with diarrhoea and neratinib may require intensive loperamide prophylaxis. Budesonide may also be used to help manage TKI-induced diarrhoea.¹⁹

Cardiotoxicity is associated with treatments such as trastuzumab, TKIs, anthracyclines such as doxorubicin and epirubicin, and radiotherapy. For this reason, trastuzumab is not normally given at the same time as an anthracycline.^19,25