Verification of Range Accuracy and Correlation With Clinical Toxicity Using Offline PET/CT for Hypofractionated Proton Radiotherapy in Breast Cancer (OFFLINE-PET-PR)

This is a single-arm, single-center, prospective observational study. It uses offline PET/CT to verify and quantify the range accuracy of hypofractionated proton radiotherapy for postoperative breast cancer. The correlation between range error and clinical toxicities (radiation pneumonitis, rib fracture) will be analyzed. A PET signal-proton range correlation model will be established using Monte Carlo simulation to provide evidence for optimizing proton therapy planning.

Study Overview

• Status: Not yet recruiting
• Conditions: Breast Cancer
• Intervention / Treatment: Other: Offline PET/CT scanning

• Study Type: Observational
• Enrollment (Estimated): 30

Participation Criteria

Eligibility Criteria

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

• Sampling Method: Non-Probability Sample

Study Population

Female patients aged 18 years or older with pathologically confirmed breast cancer after curative surgery, who are scheduled to receive moderate or ultra-hypofractionated proton radiotherapy at Ruijin Hospital, Shanghai Jiao Tong University School of Medicine. Patients must have a KPS score ≥80, expected survival >5 years, and provide written informed consent.

Description

Inclusion Criteria:

1. Written informed consent obtained.
2. Female aged ≥18 years.
3. Pathologically confirmed breast cancer after curative surgery (breast-conserving or mastectomy) and indicated for postoperative adjuvant radiotherapy.
4. Scheduled to receive moderate or ultra-hypofractionated proton therapy.
5. KPS ≥80, expected survival >5 years.
6. Well-healed surgical incision without infection.
7. Fertile females must use contraception for ≥1 month before screening and throughout the study.

Exclusion Criteria:

1. Pregnant or lactating female.
2. Severe non-neoplastic medical comorbidities precluding radiotherapy.
3. Inability to cooperate or comply with offline PET/CT examination.

Study Plan

How is the study designed?

Number of groups / cohorts

1

Cohorts and Interventions

Group / Cohort

Intervention / Treatment

Breast Cancer Proton Therapy Cohort; This is a single prospective cohort of female patients with pathologically confirmed breast cancer after curative surgery, who are scheduled to receive moderate or ultra-hypofractionated proton radiotherapy. No additional therapeutic intervention is applied; only offline PET/CT scans are performed after proton treatment for range accuracy verification. Patients will be followed up for 24 months to assess radiation pneumonitis, rib fracture, and dosimetric parameters.

Other: Offline PET/CT scanning; Offline PET/CT scan performed after proton therapy to verify range accuracy; no therapeutic intervention

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Proton beam range accuracy verified by offline PET/CT	Quantify the range accuracy of hypofractionated proton radiotherapy for breast cancer using offline PET/CT imaging	During proton radiotherapy (at the time of offline PET/CT scanning)
Correlation between range error and radiation pneumonitis	Evaluate the correlation between proton range error measured by offline PET/CT and the incidence of radiation pneumonitis	Up to 24 months after completion of proton radiotherapy
Correlation between range error and rib fracture	Evaluate the correlation between proton range error measured by offline PET/CT and the incidence of rib fracture	Up to 24 months after completion of proton radiotherapy

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Correlation between range error and lung dosimetric parameters	Analyze the correlation between proton range error and lung V5, V10, V20	During proton radiotherapy
Correlation between range error and rib dosimetric parameters	Analyze the correlation between proton range error and rib Dmax, V30	During proton radiotherapy
Performance of PET signal-proton range prediction model	Establish and evaluate the PET signal-proton range quantitative model using Monte Carlo simulation	During proton radiotherapy

Collaborators and Investigators

• Sponsor: Ruijin Hospital

Study record dates

Study Major Dates

• Study Start (Estimated): April 16, 2026
• Primary Completion (Estimated): August 31, 2028
• Study Completion (Estimated): August 31, 2028

Study Registration Dates

• First Submitted: April 15, 2026
• First Submitted That Met QC Criteria: April 15, 2026
• First Posted (Actual): April 21, 2026

Study Record Updates

• Last Update Posted (Actual): April 21, 2026
• Last Update Submitted That Met QC Criteria: April 15, 2026
• Last Verified: April 1, 2026

More Information

Terms related to this study

• Additional Relevant MeSH Terms: Neoplasms by Site; Neoplasms; Skin Diseases; Breast Diseases; Skin and Connective Tissue Diseases; Breast Neoplasms
• Other Study ID Numbers: OFFLINE-PET-PR

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