Phase II single-arm study of preoperative letrozole for estrogen receptor–positive postmenopausal ductal carcinoma in situ: CALGB 40903 (Alliance)

E. Shelley Hwang, Terry Hyslop, Laura H. Hendrix, Stephanie Duong, Isabelle Bedrosian, Elissa Price, Abigail Caudle, Tina Hieken, Joseph Guenther, Clifford A. Hudis, Eric Winer, Alan P. Lyss, Diana Dickson-Witmer, Richard Hoefer, David W. Ollila, Timothy Hardman, Jeffrey Marks, Yunn Yi Chen, Gregor Krings, Laura EssermanNola Hylton

Research output: Contribution to journalArticlepeer-review

12 Scopus citations


PURPOSE Primary endocrine therapy for ductal carcinoma in situ (DCIS) as a potential alternative to surgery has been understudied. This trial explored the feasibility of a short-term course of letrozole and sought to determine whether treatment results in measurable radiographic and biologic changes in estrogen receptor (ER)–positive DCIS. PATIENTS AND METHODS A phase II single-arm multicenter cooperative-group trial was conducted in postmenopausal patients diagnosed with ER-positive DCIS without invasion. Patients were treated with letrozole 2.5 mg per day for 6 months before surgery. Breast magnetic resonance imaging (MRI) was obtained at baseline, 3 months, and 6 months. The primary end point was change in 6-month MRI enhancement volume compared with baseline. RESULTS Overall, 79 patients were enrolled and 70 completed 6 months of letrozole. Of these, 67 patients had MRI data available for each timepoint. Baseline MRI volumes ranged from 0.004 to 26.3 cm3. Median reductions from baseline MRI volume (1.4 cm3) were 0.6 cm3 (61.0%) at 3 months (P, .001) and 0.8 cm3 (71.7%) at 6 months (P, .001). Consistent reductions were seen in median baseline ER H-score (228; median reduction, 15.0; P = .005), progesterone receptor H-score (15; median reduction, 85.0; P, .001), and Ki67 score (12%; median reduction, 6.3%; P = .007). Of the 59 patients who underwent surgery per study protocol, persistent DCIS remained in 50 patients (85%), invasive cancer was detected in six patients (10%), and no residual DCIS or invasive cancer was seen in nine patients (15%). CONCLUSIONS In a cohort of postmenopausal women with ER-positive DCIS, preoperative letrozole resulted in significant imaging and biomarker changes. These findings support future trials of extended endocrine therapy as primary nonoperative treatment of some DCIS.

Original languageEnglish (US)
Pages (from-to)1284-1292
Number of pages9
JournalJournal of Clinical Oncology
Issue number12
StatePublished - Apr 20 2020

ASJC Scopus subject areas

  • Oncology
  • Cancer Research


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