Molecular Subtype-Guided Postoperative Radiotherapy for Phyllodes Tumor of the Breast: A Randomized Controlled Trial

June 15, 2026 updated by: Sun Yat-Sen Memorial Hospital of Sun Yat-Sen University

Efficacy and Safety of Molecular Subtype-Guided Postoperative Radiotherapy for Phyllodes Tumor of the Breast: A Prospective, Open-Label, Randomized Controlled Trial

Phyllodes tumor (PT) of the breast is a rare fibroepithelial neoplasm, and the role of postoperative radiotherapy (PORT) remains controversial. Our team has previously established a molecular subtyping system for PT, classifying patients into four subtypes. Among them, the malignant novel 1/2 (MN1/MN2) subtypes exhibit extremely high risk of local recurrence, and retrospective data suggest that PORT may significantly improve local control in these subtypes. This study aims to evaluate the efficacy and safety of molecular subtype-guided postoperative radiotherapy (PORT) in patients with MN-subtype phyllodes tumor of the breast. This prospective, multicenter, open-label, randomized controlled trial plans to enroll 160 patients with molecularly confirmed MN1 or MN2 subtype who have undergone R0 resection. Patients will be randomized in a 1:1 ratio to either the PORT group or the observation-only group, with stratification by negative margin width (<1 cm vs. ≥1 cm) and molecular subtype (MN1 vs. MN2). The primary endpoint is 2-year local recurrence-free survival (LRFS). Secondary endpoints include distant metastasis-free survival (DMFS), disease-free survival (DFS), overall survival (OS), and the incidence of acute and late radiotherapy-related toxicities. By using an innovative molecular subtyping system to precisely select the target population, this study seeks to assess the benefit and safety of PORT in MN-subtype phyllodes tumors. The results are expected to provide the highest level of evidence for this specific subgroup, advance treatment strategies toward "molecular subtype-guided precision radiotherapy," improve patient outcomes, and inform future clinical guidelines.

Study Overview

Status

Not yet recruiting

Conditions

Intervention / Treatment

Study Type

Interventional

Enrollment (Estimated)

160

Phase

  • Not Applicable

Contacts and Locations

This section provides the contact details for those conducting the study, and information on where this study is being conducted.

Study Contact

Study Locations

  • China
    • Guangdong
      • Guangzhou, Guangdong, China, 510120
        • Sun Yat-sen Memorial Hospital, Sun Yat-sen University
        • Contact:
      • Shenzhen, Guangdong, China, 518000
        • Peking University Shenzhen Hospital
        • Contact:
          • Junwei Cui
          • Phone Number: +86 13828832157
    • Shandong
      • Jinan, Shandong, China, 250033
        • The Second Hospital of Shandong University
        • Contact:
      • Qingdao, Shandong, China, 266003
        • The Affiliated Hospital of Qingdao University
        • Contact:

Participation Criteria

Researchers look for people who fit a certain description, called eligibility criteria. Some examples of these criteria are a person's general health condition or prior treatments.

Eligibility Criteria

Ages Eligible for Study

  • Adult
  • Older Adult

Accepts Healthy Volunteers

No

Description

Inclusion Criteria:

  1. Female patients aged ≥18 years and ≤75 years.
  2. Histologically confirmed breast phyllodes tumor (PT) by the central laboratory, with molecular classification as MN1 or MN2 subtype via transcriptome sequencing or IHC;
  3. Primary or ipsilateral local recurrence following R0 resection (negative margins) before enrollment;
  4. Pathologically confirmed borderline or malignant PT;
  5. No evidence of distant metastasis (M0);
  6. ECOG performance status 0-1;
  7. Signed informed consent before treatment;
  8. Expected randomization and study entry within 8-12 weeks (no later than 16 weeks) after surgery.

Exclusion Criteria:

  1. Previous radiation to the same-side breast or chest;
  2. women, or those of childbearing potential refusing effective contraception; Pregnancy, lactation, or refusal of contraception by fertile subjects;
  3. Grade III-IV bone marrow suppression: WBC≤1.9*109/L，ANC≤0.9*109/L，PLT≤49*109/L，AST, ALT≥2*ULN;
  4. Significant diarrhea, severe active infection, uncontrolled systemic disease, interstitial lung disease, active connective tissue disease, or LVEF < 50%;
  5. Significant diarrhea, severe active infection, uncontrolled systemic disease, interstitial lung disease, active connective tissue disease, or LVEF < 50%;
  6. Prior or planned systemic anti-tumor therapy (chemotherapy, targeted therapy, immunotherapy, or investigational agents) during the study;
  7. Participation in other clinical trials that precludes study inclusion;
  8. Any other condition that, in the opinion of the investigator, renders the patient unsuitable for the trial.

Study Plan

This section provides details of the study plan, including how the study is designed and what the study is measuring.

How is the study designed?

Design Details

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

Arms and Interventions

Participant Group / Arm
Intervention / Treatment
No Intervention: Observation
Experimental: Postoperative Radiotherapy (PORT)
Patients receive postoperative radiotherapy starting within 8-12 weeks (max 16 weeks) after R0 resection. For breast-conserving surgery: whole-breast irradiation (50 Gy/25 fractions) plus sequential tumor bed boost (10-16 Gy/5-8 fractions). For mastectomy: chest wall irradiation (50 Gy/25 fractions). No routine regional nodal irradiation unless pathologically positive. Acute and late toxicities monitored per CTCAE v5.0.
Radiation: Postoperative Radiotherapy (PORT)
Radiotherapy delivered after R0 resection. For breast-conserving surgery: whole-breast irradiation (50 Gy in 25 fractions, 2 Gy/fraction, 5 fractions/week) followed by sequential tumor bed boost (10-16 Gy in 5-8 fractions, 2 Gy/fraction). For mastectomy: chest wall irradiation (50 Gy in 25 fractions). Techniques allowed: IMRT, VMAT, or TOMO. No routine regional nodal irradiation unless pathologically confirmed nodal involvement. Target volume and organ-at-risk constraints as per protocol (e.g., ipsilateral lung Dmean <15 Gy, heart Dmean <5 Gy for left-sided tumors). Acute and late toxicities assessed by CTCAE v5.0.

What is the study measuring?

Primary Outcome Measures

Outcome Measure
Measure Description
Time Frame
2-year Local Recurrence-Free Survival (LRFS)
Time Frame: From randomization up to 2 years post-randomization (primary analysis at 2 years)
Time from randomization to the first documented locoregional recurrence (ipsilateral breast/chest wall or regional lymph nodes) confirmed by imaging and/or pathology, or death from any cause, whichever occurs first. Patients alive without locoregional recurrence are censored at the date of last known follow-up.
From randomization up to 2 years post-randomization (primary analysis at 2 years)

Secondary Outcome Measures

Outcome Measure
Measure Description
Time Frame
Distant Metastasis-Free Survival (DMFS)
Time Frame: From randomization up to 5 years (primary analysis for secondary endpoints will be performed at 2 years, with extended follow-up up to 5 years)
From randomization up to 5 years (primary analysis for secondary endpoints will be performed at 2 years, with extended follow-up up to 5 years)
Disease-Free Survival (DFS)
Time Frame: From randomization up to 5 years (primary analysis of secondary endpoints at 2 years, with extended follow-up to 5 years)
From randomization up to 5 years (primary analysis of secondary endpoints at 2 years, with extended follow-up to 5 years)
Overall Survival (OS)
Time Frame: From randomization up to 5 years
From randomization up to 5 years
Incidence of Acute and Late Radiotherapy-Related Toxicities
Time Frame: From start of radiotherapy up to 5 years post-randomization (acute: within 90 days; late: from 90 days to 5 years)
Proportion of patients experiencing adverse events (AEs) assessed by Common Terminology Criteria for Adverse Events (CTCAE) version 5.0. Acute toxicity is defined as events occurring within 90 days after start of radiotherapy; late toxicity as events occurring >90 days after start of radiotherapy. Includes radiation dermatitis, radiation pneumonitis, cardiac toxicity, rib fracture, breast/chest wall fibrosis, and secondary malignancies.
From start of radiotherapy up to 5 years post-randomization (acute: within 90 days; late: from 90 days to 5 years)

Collaborators and Investigators

This is where you will find people and organizations involved with this study.

Sponsor

Sun Yat-Sen Memorial Hospital of Sun Yat-Sen University

Publications and helpful links

The person responsible for entering information about the study voluntarily provides these publications. These may be about anything related to the study.

General Publications

Study record dates

These dates track the progress of study record and summary results submissions to ClinicalTrials.gov. Study records and reported results are reviewed by the National Library of Medicine (NLM) to make sure they meet specific quality control standards before being posted on the public website.

Study Major Dates

Study Start (Estimated)

June 1, 2026

Primary Completion (Estimated)

December 31, 2030

Study Completion (Estimated)

December 31, 2030

Study Registration Dates

First Submitted

June 15, 2026

First Submitted That Met QC Criteria

June 15, 2026

First Posted (Actual)

June 18, 2026

Study Record Updates

Last Update Posted (Actual)

June 18, 2026

Last Update Submitted That Met QC Criteria

June 15, 2026

Last Verified

May 1, 2026

More Information

Terms related to this study

Additional Relevant MeSH Terms

Other Study ID Numbers

  • SYSKY-2026-390-02

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

This information was retrieved directly from the website clinicaltrials.gov without any changes. If you have any requests to change, remove or update your study details, please contact register@clinicaltrials.gov. As soon as a change is implemented on clinicaltrials.gov, this will be updated automatically on our website as well.

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