(002) An Update to The Safety of VE Therapy for Genitourinary Syndrome of Menopause in Women with a History of Breast Cancer – A Claims Database Analysis

Abstract

Abstract Introduction Systemic therapies for breast cancer (BC) may result in genitourinary syndrome of menopause (GSM) in up to 70% of postmenopausal breast cancer survivors. Though systemic estrogen therapy is usually avoided in these patients, vaginal estrogen (VE) therapy may be prescribed to treat GSM symptoms. However, we recently demonstrated, few eligible patients with GSM and a history of breast cancer are prescribed VE. Objective To assess the recurrence rates of breast cancer in women diagnosed with GSM with a history of breast cancer by VE therapy status using a large US claims database. Methods A US health research network was queried. Our cohort consisted of females diagnosed with BC within five years prior to the initial GSM diagnosis. Patients with active disease within three months prior to diagnosis of GSM were excluded. Recurrence was defined as mastectomy, radiation, chemotherapy, or secondary malignancy within three months to five years after initiating VE therapy for GSM. The study cohort included those with ≥3 VE prescriptions. The control cohort included women with BC without any VE prescriptions after GSM diagnosis. Propensity matching was performed. A sub-analysis evaluating the effect of concurrent aromatase inhibitor (AI) use with VE was also conducted with concurrent AI use defined as ≥3 AI prescriptions. Results We identified 42,113 females with a diagnosis of GSM following BC diagnosis with any ER status; 5.0% received VE. Of the initial cohort, 10,584 patients had ER+ BC; 3.9% of this group received VE. Risk of BC recurrence was comparable between those who received VE and those who did not in both the any-ER (RR 1.03, 95% CI [0.91-1.18]) and ER+ status (RR 0.94, 95% CI [0.77-1.15]) analyses. BC recurrence-free survival was comparable between those who received VE and those who did not in both the any-ER (HR 0.98, 95% CI [0.85 – 1.14]) and ER+ status (HR 0.88, 95% CI [0.69 – 1.12]) analysis. A sub-analysis comparing concurrent VE and AI prescriptions to those with VE-only was performed. Risk of BC recurrence was significantly higher among those who received AI+VE versus VE-only in both the any-ER (RR 5, 95% CI [3.05 – 8.19]) and ER+ status (RR 2.64, 95% CI [1.55 – 4.47]) analysis (Table 1). Significant differences in BC recurrence-free survival were observed between the AI+VE and VE-only groups in both the any-ER (HR 9.88, 95% CI [5.50 – 17.73]) and ER+ status (HR 4.82, 95% CI [2.36 – 9.84]) analysis. (Figure 1). No mortality event was observed at five- or ten-year follow-up in either analysis. Conclusions We found similar BC recurrence risk between BC survivors with and without prescriptions of VE. An increased risk of BC recurrence was seen with concurrent AI and VE use. These results suggest that VE therapy in select patients with GSM is safe. Disclosure No.