De-escalation Therapy in Stage I ER-Positive Breast Cancer: A Non-Inferiority Trial (DESCENT)

A Prospective, Randomized, Open-label, Non-inferiority, Phase III Study Evaluating the Efficacy and Safety of 2 to 3 Years of Adjuvant Endocrine De-escalation Therapy for ER-positive/HER2-negative Stage I Breast Cancer

This study is a prospective, randomized, open-label, non-inferiority Phase III clinical trial, planning to enroll 2,934 patients, with a 1:1 allocation to either the conventional endocrine therapy group or the de-escalation therapy group. The aim is to evaluate the safety and efficacy of 2-3 years of de-escalated endocrine therapy in patients with T1N0M0 potentially low-risk breast cancer, respectively.

Study Overview

• Status: Not yet recruiting
• Conditions: Breast Cancer Early Stage Breast Cancer (Stage 1-3)
• Intervention / Treatment: Drug: Endocrine Therapy of Physician's Choice

• Study Type: Interventional
• Enrollment (Estimated): 2934
• Phase: Phase 3

Contacts and Locations

Study Locations

• China
  • Shanghai, China, 200032
    • 270 Dongan Road, Fudan University Shanghai Cancer Center

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: Adult; Older Adult
• Accepts Healthy Volunteers: No

Description

Inclusion Criteria:

• Females aged 18 years or older;
• Postoperative pathological stage I early breast cancer: histologically confirmed invasive carcinoma with a maximum diameter ≤2 cm and node-negative (N0);
• Immunohistochemistry (IHC) shows ER-positive (ER ≥50%), HER2 IHC score of 0, 1+, or 2+ with no amplification confirmed by FISH, and Ki-67 ≤20%;

• Presence of at least one of the following potential low-risk factors:

  1）Tumor size ≤1 cm, 2）21-gene recurrence score <11, 3）Fudan digital pathological subtype classified as SNF1, 4）Age ≥65 years;

• ECOG performance status of 0 or 1;
• Patients with bilateral synchronous invasive lesions are eligible if both lesions are ER-positive, HER2-negative, and meet the tumor size criteria;

• Normal major organ function, meeting the following criteria:

  1. Hematological: HB ≥90 g/L (no transfusion within 14 days), ANC ≥1.5×10⁹/L, PLT ≥100×10⁹/L;
  2. Biochemical: TBIL ≤1.5×ULN, ALT and AST ≤3×ULN, serum Cr ≤1×ULN, and creatinine clearance >50 mL/min (Cockcroft-Gault formula);
• Participants voluntarily enroll, sign informed consent, demonstrate good compliance, and cooperate with follow-up.

Exclusion Criteria:

• Primary tumor size >2 cm in maximum diameter and/or axillary lymph node positivity;
• Prior neoadjuvant therapy, any systemic therapy, or local therapy (except surgery), including chemotherapy, targeted therapy, radiotherapy, or endocrine therapy;
• Prior adjuvant chemotherapy;
• Use of CDK4/6 inhibitors in the adjuvant setting;
• History of other malignancies (except cured basal cell carcinoma or cervical carcinoma in situ);
• Metastasis at any site;
• Pregnancy, lactation, or women of childbearing potential unable to use effective contraception;
• Concurrent participation in other clinical trials;
• Severe cardiac, pulmonary, hepatic, or renal dysfunction; LVEF <50% (by echocardiography); severe cardio-cerebrovascular diseases within 6 months (e.g., unstable angina, chronic heart failure, uncontrolled hypertension >150/90 mmHg, myocardial infarction, or stroke); poorly controlled diabetes; severe hypertension;
• Severe or uncontrolled infections;
• History of drug abuse or psychiatric disorders;
• Patients deemed unsuitable for the study by the investigator.

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Treatment
• Allocation: Randomized
• Interventional Model: Parallel Assignment
• Masking: None (Open Label)

Number of Arms

2

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Active Comparator: 5 years of standard endocrine therapy; The control group receives 5 years of standard endocrine therapy: Premenopausal patients: Tamoxifen (10 mg, orally, twice daily, for 5 years) or Toremifene (60 mg, orally, once daily, for 5 years); Postmenopausal patients: Letrozole (2.5 mg, orally, once daily, for 5 years) or Anastrozole (1 mg, orally, once daily, for 5 years) or Exemestane (25 mg, orally, once daily, for 5 years); A sequential regimen of 2-3 years of Tamoxifen or Toremifene followed by 3-2 years of Letrozole, Anastrozole, or Exemestane is acceptable. Ovarian function suppression is permitted for premenopausal patients. CDK4/6 inhibitors are not allowed during the treatment course	Drug: Endocrine Therapy of Physician's Choice; This study employs a 2-3 year de-escalated endocrine therapy regimen in the experimental group, which distinguishes it from other escalation therapy studies.
Experimental: 2-3 years of de-escalated endocrine therapy; The experimental group receives 2-3 years of endocrine therapy: Premenopausal patients: Tamoxifen (10 mg, orally, twice daily, for 2-3 years) or Toremifene (60 mg, orally, once daily, for 2-3 years); Postmenopausal patients: Letrozole (2.5 mg, orally, once daily, for 2-3 years) or Anastrozole (1 mg, orally, once daily, for 2-3 years) or Exemestane (25 mg, orally, once daily, for 2-3 years). Ovarian function suppression is permitted for premenopausal patients. CDK4/6 inhibitors are not allowed during the treatment course.	Drug: Endocrine Therapy of Physician's Choice; This study employs a 2-3 year de-escalated endocrine therapy regimen in the experimental group, which distinguishes it from other escalation therapy studies.

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
5-year disease-free survival in the per-protocol population	The proportion of patients in a clinical trial who remained free of disease recurrence, secondary primary cancers, and death from the disease for five years following treatment initiation, calculated specifically among those who completed the study intervention as predefined in the trial protocol(i.e., without major deviations such as incomplete treatment, use of prohibited therapies, or significant protocol violations).	5 year

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
5-year disease-free survival in the Full Analysis Set	The proportion of patients in a clinical trial who remained free of disease recurrence, secondary primary cancers, and death from the disease for five years after randomization or initiation of treatment, analyzed within the Full Analysis Set (FAS) population-which includes all subjects randomized (or initially assigned to a treatment group) following the intention-to-treat (ITT) principle, regardless of whether they fully received, discontinued, or deviated from the protocol.	5 year
5-year invasive breast cancer-free survival in the per-protocol population	The proportion of participants in a clinical trial who, after receiving the full intended course of treatment without major protocol deviations, remained free of invasive ipsilateral or contralateral breast cancer recurrence, distant metastatic invasive breast cancer, and death from any cause for a period of five years from the start of treatment or randomization.	5 year
Overall survival in the per-protocol population	The length of time from randomization or initiation of treatment until death from any cause, measured specifically among participants who completed the study intervention without major protocol deviations, such as insufficient treatment exposure, use of prohibited therapies, or significant violations of inclusion/exclusion criteria.	5 year
Quality of Life score in the per-protocol population	The quality of life of patients was assessed using the EORTC QLQ-C30 questionnaire before, during, and after treatment.	5 year
safety	the evaluation of the adverse effects and potential risks of an investigational medical product (e.g., drug, device, or intervention) on participants throughout the study.	5 year

Collaborators and Investigators

• Sponsor: Fudan University

Study record dates

Study Major Dates

• Study Start (Estimated): September 1, 2025
• Primary Completion (Estimated): September 1, 2033
• Study Completion (Estimated): September 1, 2033

Study Registration Dates

• First Submitted: August 26, 2025
• First Submitted That Met QC Criteria: September 3, 2025
• First Posted (Estimated): September 4, 2025

Study Record Updates

• Last Update Posted (Estimated): September 4, 2025
• Last Update Submitted That Met QC Criteria: September 3, 2025
• Last Verified: September 1, 2025

More Information

Terms related to this study

• Other Study ID Numbers: SCHBCC-N097

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: NO

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: No
• Studies a U.S. FDA-regulated device product: No