GRACE-trial: a Randomized Active-controlled Trial for vulvovaGinal atRophy in breAst Cancer Patients on Endocrine Therapy.

In this prospective active-controlled randomized trial the investigators will assess for the first time ever the different local treatments of vulvovaginal atrophy in breast cancer patients on endocrine therapy. These patients are currently inadequately treated based on ignorance of possible treatment modalities and stigmatization of vulvovaginal atrophy.

Inclusion Criteria: * breast cancer patient * current endocrine therapy (AI or SERM) * postmenopausal status, defined by: * 12 months amenorrhoea or * 6 months amenorrhoe and FSH level of \>40 mIU/mL or \*\>6 weeks after bilateral oophorectomy or * induced postmenopause (ovarian function suppression using GnRH-analogue) * presence of one or more symptoms of vulvovaginal atrophy (dyspareunia, dryness, irritation) Exclusion Criteria: * a history of vulvar or vaginal surgery (Inclusion is possible after hysterectomy. For these subjects no microbiome sampling will be performed. Microbiome analysis is not performed for these subjects.) * current other vulvar or vaginal disease * recent use of antibiotics/antifungals/corticosteroids (less than 1 month) * current use of vaginal hormonal treatment or vaginal moisturizer: inclusion is possible after a washout period of 4 weeks