Abstract
BACKGROUND: Despite the known clinical benefit of endocrine therapy (ET) after surgery for ductal carcinoma in situ (DCIS), ET uptake remains low. In April 2021, the authors initiated a surgeon-led DCIS program. This report evaluates the impact of the DCIS program on ET uptake.
METHODS: Patients undergoing surgery for DCIS were identified from prospectively maintained databases. Patients treated from January 2016 to March 2021 formed the historical cohort, and those treated from April 2021 to July 2024 formed the DCIS program cohort. Chi-square analyses were used to compare ET uptake and trends between the cohorts.
RESULTS: The study identified 1856 patients, with 1026 patients forming the historical cohort and 830 patients forming the DCIS program cohort. The median patient age was 59 years. Most of the patients (69.9 %) were postmenopausal, and 1573 (84.8 %) had estrogen receptor-positive (ER+) DCIS. Overall, ET uptake among the patients with ER+ DCIS did not differ between the cohorts (45.7 % and 45.1 %, respectively; p = 0.33). When analyzed by type of surgery, ET uptake among those undergoing breast-conserving surgery (BCS) also was similar (54.5 % and 52.1 %, respectively; p = 0.44). In postmenopausal women with ER+ DCIS undergoing BCS, use of aromatase inhibitors (AIs) decreased (67.3 % to 43.1 %) and use of tamoxifen increased (31.1 % to 56.9 %) in the DCIS program cohort (p < 0.001), with 91.9 % of eligible patients taking low-dose tamoxifen after its introduction in 2023.
CONCLUSIONS: Endocrine therapy uptake remained stable after initiation of a surgeon-led DCIS program. Prescribing patterns for postmenopausal women in the DCIS program favored tamoxifen over AI, driven largely by the introduction of low-dose tamoxifen.