Serum Estradiol Levels In Postmenopausal Women With Breast Cancer Receiving Adjuvant Aromatase Inhibitors and Vaginal Estrogen

• To compare the rise in estradiol in women on letrozole vs. anastrozole during treatment with low dose vaginal 10 µg 17- β estradiol to see if there are differences between aromatase inhibitors. [ Time Frame: 2 years ] [ Designated as safety issue: No ]
• To describe patterns of estradiol and FSH levels over the twenty-four week study period. [ Time Frame: 24 weeks ] [ Designated as safety issue: No ]
• To compare the patient's Female Sexual Function Index (FSFI) scores and menopause quality of life questionnaire at baseline, week 12 and week 24. [ Time Frame: Week 12 and week 24 ] [ Designated as safety issue: No ]

• To compare the rise in estradiol in women on letrozole vs. anastrozole during treatment with low dose vaginal 25 µg 17- β estradiol to see if there are differences between aromatase inhibitors. [ Time Frame: 2 years ] [ Designated as safety issue: No ]
• To describe patterns of estradiol and FSH levels over the twenty-four week study period. [ Time Frame: 24 weeks ] [ Designated as safety issue: No ]
• To compare the patient's Female Sexual Function Index (FSFI) scores at baseline, week 12 and week 24. [ Time Frame: Week 12 and week 24 ] [ Designated as safety issue: No ]

The purpose of this study is to see if Vagifem® 10mcg is safe for women who have had breast cancer. Vagifem is an estrogen product. It is a tiny tablet that is inserted into the vagina. It relieves vaginal dryness. Women who have had breast cancer are usually told not to take estrogen. This is because estrogen use can lead to a breast cancer recurrence or a new primary breast cancer. It is unclear if the estrogen in Vagifem is only absorbed in the vagina. It may be absorbed into the blood stream for a short time and may cause a brief rise in your estrogen level. However, there is no clear evidence that this would cause any bad effects in patients with breast cancer. How much, if any, of these topical estrogens are absorbed through the vagina is not known. We also do not know what the impact is of low dose estrogen absorption on breast cancer outcomes. Also, the absorption should decrease as the mucus membranes are restored after estrogen exposure.

• Atrophic Vaginitis
• Breast Cancer

Inclusion Criteria:

• History of breast cancer, stages I-III with pathology confirmed at MSKCC
• Women who have completed all of their primary treatment (surgery, radiation therapy, adjuvant chemotherapy) with the exception of endocrine therapy and currently have no clinical evidence of disease.
• Women who are currently on aromatase inhibitors for at least three months--either letrozole or anastrozole
• Women with symptomatic urogenital atrophy: vaginal dryness, irritation, pruritus, dyspareunia, urinary frequency and/or urinary incontinence

• Menopausal at study entry defined as:

  • Bilateral salpingo-oophorectomy independent of age
  • If natural menopause, age ≥ 50 with cessation of menses for at least 12 months
  • If menopause induced by chemotherapy, age ≥ 50 with no menstrual period at least 12 months after chemotherapy finished
• At least 18 years of age
• Able to participate in the informed consent process
• Gynecology examination within six months
• Able to read/speak English

Exclusion Criteria:

• Inability to give informed consent
• Vaginal bleeding of unknown etiology within 12 months of study entry
• History of prior vaginal 17-β estradiol or other topical estrogen use within the past six months