Influence of Orally Administered Probiotic Strains on Vaginal Microbiota in Women with Breast Cancer during Chemotherapy: A Randomized Placebo-Controlled Double-Blinded Pilot Study.

Background: Due to chemotherapy and estrogen deprivation therapy, genitourinary syndrome of menopause is a common condition in breast cancer patients. We aimed to determine the effect of an orally administered preparation on the vaginal microbiota in breast cancer patients.

Methods: Postmenopausal breast cancer patients receiving chemotherapy, with vaginal atrophy and an intermediate vaginal microbiota (Nugent score 4-6), were either randomized to the intervention group receiving probiotic capsules of 4 species or to the control group receiving placebo twice daily for 2 weeks. Consecutive vaginal swabs were taken at baseline, 1 day after administration of the last capsule (follow-up 1), and after 1 week (follow-up 2) in 22 patients (11 vs. 11).

Results: We observed a positive influence on the vaginal microbiota in 7/11 (63%) women in the intervention group, and 4/11 (36%) women in the control group. There was a shift in Nugent score towards normal microbiota levels in the intervention group (-1.3 at follow-up 1, -0.45 at follow-up 2) and a significant deterioration of the Nugent score in the control group (+0.4 at follow-up 1, +2.5 at follow-up 2).

Conclusion: The orally administered preparation has the potential to improve the vaginal microbiota in women undergoing chemotherapy for breast cancer.