In real-world practice, use of ovarian suppression therapy was not common among premenopausal patients with hormone receptor–positive, HER2-positive breast cancer, with tamoxifen being the preferred endocrine therapy.
Jasmine S. Sukumar, MD
In real-world practice, use of ovarian suppression therapy was not common among premenopausal patients with hormone receptor–positive, HER2-positive breast cancer, with tamoxifen being the preferred endocrine therapy, according to findings from a retrospective analysis presented during the 2022 San Antonio Breast Cancer Symposium.
Results from the multi-institutional analysis demonstrated that, in the overall cohort (N = 937), the most common endocrine therapy received by patients was tamoxifen (87%). Comparatively, an aromatase inhibitor plus ovarian suppression, tamoxifen plus ovarian suppression, or ovarian suppression monotherapy were used at a rates of 6.9%, 5.3%, and 0.4%, respectively.
The poster authors wrote, “Further investigation is warranted to characterize the utility of endocrine therapy including addition of ovarian oppression to prevent recurrence in premenopausal cancer subtype. This will better inform a personalized approach to tailor therapy.”
Results from the phase 3 SOFT (NCT00066690) and TEXT (NCT00066703) trials demonstrated that, regardless of HER2 status, women with hormone receptor–positive disease who received ovarian suppression in addition to tamoxifen or an aromatase inhibitor had improvements in disease-free survival, study authors noted. However, patients with hormone receptor–positive, HER2-positive breast cancer accounted for only 12% of the patient population and these trials occurred prior to the common use of trastuzumab (Herceptin) and chemotherapy which are now standard breast cancer treatments, they wrote.
In light of this knowledge gap, investigators initiated this first real-world study evaluating the frequency of use of ovarian suppression therapy in hormone receptor–positive, HER2-positive breast cancer. Data for the analysis was pulled from the American Society of Clinical Oncology (ASCO) CancerLinQ Discovery database from January 2010 to May 2020. Of the 360,540 patients who had invasive breast cancer, 937 met the inclusion criteria. Data were collected from 74 participating academic and community oncology sites from women under the age of 50 years who were treated with chemotherapy, the HER2-directed monoclonal antibody trastuzumab either with or without pertuzumab (Perjeta), and endocrine therapy.
The overall cohort had a median age of 41.7 years and the 4 endocrine therapy treatment groups that made up the cohort were as follows: aromatase inhibitor and ovarian suppression (n = 65), ovarian suppression only (n = 4), tamoxifen and ovarian suppression (n = 50), and tamoxifen only (n = 818). Patients had tumor grades of 1, 2, 3, and unknown at rates of 2.0%, 20.9%, 28.6%, and 48.5%, respectively.
Eighty-three percent of all patients had progesterone receptor–positive disease and 97.2% had estrogen receptor–positive disease. Disease stages of I, II, and III, were representative in 38.7%, 44.4%, and 16.9% of patients, respectively, and 78% had node-positive disease. The study defined adjuvant ovarian suppression as receipt of at least 6 months of goserelin or leuprolide or surgical bilateral oophorectomy.
It has not been determined if adjuvant endocrine therapy can reduce the rate of recurrence for patients with hormone receptor–positive, HER2-positive breast cancer, which affects approximately 10% of patients with breast cancers. It is also unknown if adding ovarian suppression to treatment provides clinical benefits for premenopausal women.
The poster authors wrote that underrepresentation in clinical trials is an issue in the treatment of hormone receptor–positive, HER2-positive breast cancer which has a risk for late relapses to occur. Approximately 50% of HER2-positive breast cancers are hormone receptor–positive and approximately 10% of breast cancers are hormone receptorpositive and HER2 positive.
Additional findings from a multivariable logistic regression model that was performed as part of the study showed that age was the only viable factor to predict the use of ovarian suppression treatment. Patients 35 years and older were less likely to receive ovarian suppression therapy vs those under the age of 35 (OR, 0.43; 95% CI, 0.27-0.68; P < .001). Other clinicopathologic variables such as nodal involvement (OR, 1.27; 95% CI, 0.76-2.14; P = .366), tumor grade (OR, 1.36; 95% CI, 0.79-2.33; P = .263), clinical stage (OR, 1.13; 95% CI, 0.67-1.90; P = .653), body mass index (OR, 0.72; 95% CI, 0.38-1.35; P = .308), and race (OR, 0.92; 95% CI, 0.45-1.90; P = .829) were not significant predictive factors in terms of the rate of use of ovarian suppression therapy.
Sukumar JS, Sardesai S, Ni A, et al. Real world treatment patterns of adjuvant endocrine therapy and ovarian suppression in premenopausal HR+/HER2+ breast cancer. Presented at 2022 San Antonio Breast Cancer Symposium; December 6-10, 2022; San Antonio, TX.