Active Monitoring With or Without Endocrine Therapy for Low-Risk Ductal Carcinoma In Situ
Authors: Hwang E. Shelley , Hyslop Terry , Lynch Thomas , Ryser Marc D. , Weiss Anna , Wolf Anna , Norris Kelsey , Witten Meredith , Grimm Lars , Schnitt Stuart , Badve Sunil , Factor Rachel , Frank Elizabeth , Collyar Deborah , Basila Desiree , Pinto Donna , Watson Mark A. , West Robert , Davies Louise , Donovan Jenny L. , Shimada Ayako , Li Yutong , Li Yan , Bennett Antonia V. , Rosenberg Shoshana , Marks Jeffrey , Winer Eric , Boisvert Marc , Giuliano Armando , Larson Kelsey E. , Yost Kathleen , McAuliffe Priscilla F. , Krie Amy , Tamirisa Nina , Carey Lisa A. , Thompson Alastair M. , Partridge Ann H. ,   COMET Study Investigators, Gudena Vinay , Chiba Akiko , Bensenhaver Jessica , Andreopoulou Eleni , Mittendorf Elizabeth , Matsen Cindy , Jackson Rubie , Sarma Deba , Dib Elie , Neuman Heather , Yen Tina , Agnese Doreen , Leong Rachelle , Cronin Patricia , Lizarraga Ingrid , Guenther Joseph , Gallagher Kristalyn , Batra Reema , Leitch Ann , Moore Timothy , Strickland Kimberly , Christoudias Moira , Howard-McNatt Marissa , Higham Anna , Gunturi Anasuya , Schallenkamp John , Log Karng , Seaward Samantha , Wright Heather , Rivere Amy , Feliberti Eric , Lai Lisa , Cintolo-Gonzalez Jessica , McGuire Kandace , Chung Ki , Thawani Anjali , Marcinkowski Emily , Marti Jennifer , Johnson Nathalie , Pruthi Sandhya , Phantana-Angkool April , Maxwell Jessica , Prabhakaran Sangeetha , Weckstein Douglas , Muzaffar Mahvish , Sinclair Sarah , McGreevy Christopher , Madden Steven , Peterson Laura , Sotirescu Dan , Hazard Hannah , Lad Thomas , McLaughlin Sarah , Feldman Sheldon , Weiss Matthias , Nurudeen Suliat , Ziauddin M. Firdos , Jaslowski Anthony , Abraham Ivy , Goldman Faith , DiBella Nicholas , Golshan Mehra , Dao Tuoc , Gross Howard , Tammaro Yolanda , Bowie Mindy , Yao Katharine , Kim Theodore , Aft Rebecca , Throckmorton Alyssa , Najera Jose Eugenio , Yee Lisa , Christman Jennifer , Sreenivasappa Shylendra , Le-Petross Huong , Factor Rachel , Ozanne Elissa , Punglia Rinaa , Gierisch Jennifer , Fayanju Lola , Kaplan Celia , Colletti Laura , Stewart Wendy , Smith Mary Lou , Elmore Joanne , Bowlby Lynn , Lehman Constance , Schnitt Stuart , Keurer Henry , Attai Deanna , Ganz Patricia , Earle Craig , Kerlikowske Karla , Etzioni Ruth , Hakim Rosemarie , Malin Jennifer , Palackdharry Carol , Webster David , Schilsky Richard L , Smith Robert , Calomeni Coralia , Wernberg Jessica , Levine Ellis , Unzeitig Gary , Manning Kenneth , Battelli Chiara , Dooley William , Hattiangadi Trupti , Mauer Ann , Mislowsky Angela , Bao Jean , Blaes Anne , Graves Theresa , Behrens Robert , Pulver Kerry , El Ayass Walid , Miller Seth 
Published: December 2024

Importance

Active monitoring for low-risk ductal carcinoma in situ (DCIS) of the breast has been proposed as an alternative to guideline-concordant care, but the safety of this approach is unknown.

Objective

To compare rates of invasive cancer in patients with low-risk DCIS receiving active monitoring vs guideline-concordant care.

Design, Setting, and Participants

Prospective, randomized noninferiority trial enrolling 995 women aged 40 years or older with a new diagnosis of hormone receptor–positive grade 1 or grade 2 DCIS without invasive cancer at 100 US Alliance Cancer Cooperative Group clinical trial sites from 2017 to 2023.

Interventions

Participants were randomized to receive active monitoring (follow-up every 6 months with breast imaging and physical examination; n = 484) or guideline-concordant care (surgery with or without radiation therapy; n = 473).

Main Outcomes and Measures

The primary outcome was 2-year cumulative risk of ipsilateral invasive cancer diagnosis, according to planned intention-to-treat and per-protocol analyses, with a noninferiority bound of 5%.

Results

The median age of the 957 participants analyzed was 63.6 (95% CI, 55.5-70.5) years in the guideline-concordant care group and 63.7 (95% CI, 60.0-71.6) years in the active monitoring group. Overall, 15.7% of participants were Black and 75.0% were White. In this prespecified primary analysis, median follow-up was 36.9 months; 346 patients had surgery for DCIS, 264 in the guideline-concordant care group and 82 in the active monitoring group. Forty-six women were diagnosed with invasive cancer, 19 in the active monitoring group and 27 in the guideline-concordant care group. The 2-year Kaplan-Meier cumulative rate of ipsilateral invasive cancer was 4.2% in the active monitoring group vs 5.9% in the guideline-concordant care group, a difference of −1.7% (upper limit of the 95% CI, 0.95%), indicating that active monitoring is not inferior to guideline-concordant care. Invasive tumor characteristics did not differ significantly between groups.

Conclusions and Relevance

Women with low-risk DCIS randomized to active monitoring did not have a higher rate of invasive cancer in the same breast at 2 years compared with those randomized to guideline-concordant care.

Trial Registration

ClinicalTrials.gov Identifier: NCT02926911