Two Versus One Week Breast Radiotherapy (RT) (PRATO)

Prospective Randomized Trial of Two Versus One Week Accelerated Radiotherapy (PRATO)

This study is comparing two different radiation therapy approaches for early breast cancer to see which one is better for patients. One group will receive radiation over one week (based on the FAST-FORWARD trial), and the other group will receive radiation over two weeks with an extra focused dose (called a "concomitant boost"). The study will look at how the treatments affect side effects, breast appearance, and cancer control in the breast. It also aims to find out if the two-week treatment does a better job at preventing cancer from coming back in the breast over the long term.

Study Overview

• Status: Recruiting
• Conditions: Breast Cancer
• Intervention / Treatment: Radiation: Radiation therapy - 1 week; Radiation: Radiation therapy - 2 weeks

Detailed Description

Radiotherapy: one week (Arm 1) 2600 cGy in 5 fractions whole breast radiotherapy over one week versus 2 weeks (Arm 2), 3200 cGy in 10 fractions with a concomitant tumor bed boost to 3600 cGy. In Arm 2, if no cavity is visible due to oncoplastic surgery, we will deliver 32 Gy to the whole breast only, without a boost.

Hypothesis: A regimen of whole breast radiotherapy to 2600 in five fractions, the current UK standard for early breast cancer (Arm 2), is not inferior to 3200cGy with a concomitant tumor bed boost to 3600 cGy in 10 fractions (Arm 1), in terms of acute toxicity and long-term fibrosis, breast cosmesis and local control at 2 and 5 years. It will also test the hypothesis of superior local control at 10 years in Arm 2 compared to Arm 1.

• Study Type: Interventional
• Enrollment (Estimated): 400
• Phase: Phase 3

Contacts and Locations

• Study Contact: Name: Fabiana Gregucci, MD; Phone Number: 6469623110; Email: fgr4002@med.cornell.edu
• Study Contact Backup: Name: Fereshteh Talebi, MD; Phone Number: 6467027830; Email: fet4007@med.cornell.edu

Study Locations

• United States
  • New York
    • New York, New York, United States, 11215
      • Recruiting
      • Brooklyn Methodist Hospital
      • Principal Investigator: Hani Ashamalla, MD
      • Contact: Izael Nino; Phone Number: (929) 470-9426; Email: izn4001@med.cornell.edu
    • New York, New York, United States, 11355
      • Recruiting
      • New York Presbyterian Hospital
      • Contact: Krystalle Lyons; Phone Number: 718-670-1541; Email: krl4003@med.cornell.edu
      • Principal Investigator: Steven DiBiase, MD
    • New York, New York, United States, 11355
      • Recruiting
      • New York-Presbyterian Weill Cornell Medical College
      • Contact: Maahi Patel, Bachelors of Science, BS; Phone Number: 9784025630; Email: map4044@med.cornell.edu
      • Contact: Fabiana Gregucci, MD
      • Principal Investigator: Silvia C. Formenti, MD

Participation Criteria

Eligibility Criteria

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

Description

Inclusion Criteria:

1. Women status post segmental mastectomy.
2. If unilateral, pT1-2 breast cancer excised with negative margins.
3. If bilateral, pT1-2 breast cancer excised with negative margins AND/OR pTis excised with negative margins.
4. Clinically N0 (cN0 as determined by ultrasound/SOUND criteria) or pN0-1 or Nx or sentinel node negative.
5. Ductal carcinoma in situ DCIS with negative margins (no DCIS on inked margins).
6. Women with previous contralateral treated breast cancer can be enrolled in the trial.

Exclusion Criteria:

1. Previous radiation therapy to the ipsilateral breast.
2. >90 days from last surgery, unless s/p adjuvant chemotherapy.
3. >60 days from last chemotherapy.
4. Male breast cancer.
5. Ongoing treatment for severe autoimmune disease.

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
Experimental: ARM 1-2600 cGy in 5 fractions whole breast radiotherapy; Patients randomized to ARM 1 will receive 2600 cGy in 5 fractions whole breast radiotherapy over one week	Radiation: Radiation therapy - 1 week; 2600 cGy whole breast radiotherapy in five fractions (Arm 1) over 1 week
Experimental: ARM 2- 3200 cGy in 10 fractions with a concomitant tumor bed boost to 3600 cGy; Patients randomized to ARM 2 will receive 3200 cGy in 10 fractions with a concomitant tumor bed boost to 3600 cGy.	Radiation: Radiation therapy - 2 weeks; 3200 cGy whole breast radiotherapy with a concomitant tumor bed boost to 3600 cGy in 10 fractions (Arm 2) over 2 weeks. In Arm 2, if no cavity is visible due to oncoplastic surgery, we will deliver 32 Gy to the whole breast only, without a boost.

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Rate of RT-related acute toxicity	The rate of RT-related acute toxicity is defined as cumulative acute toxicity events from the start of radiation treatment to 1 month follow up post RT. The toxicities will be graded by the research nurses assigned to the study according to Common Terminology Criteria for Adverse Events, version 5.0.	1 month

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
The long-term evaluations at 2 years of fibrosis based on LENT/SOMA	The number of subjects scoring Grades 1 through 4 using the LENT/SOMA (Late Effects Normal Tissues (LENT)-Subjective, Objective, Management, Analytic (SOMA)) system will be reported. The patients will grade the following items based on the following scale: Mild; Moderate; Severe; Life-threatening	24 months
The long-term evaluations at 2 years of breast cosmesis	Patient self-reported breast cosmesis will be assessed using the BCTOS questionnaire (Breast Cancer Treatment Outcome Scale).The number of subjects scoring Grades 1 through 4 will be reported. The patients will grade the following items based on the following scale: = No difference between treated and untreated breast/area; = Slight difference; = Moderate difference; = Large difference	24 months
The long-term evaluations at 2 years of local control	Number of subjects with Local control at 2 years will be extracted from the medical record, and can be derived from clinical reports from medical, surgical or radiation oncologists as well as from the primary care doctor who is following the patient.	24 months
The long-term evaluations at 5 years OF fibrosis based on LENT/SOMA	The number of subjects scoring Grades 1 through 4 using the LENT/SOMA (Late Effects Normal Tissues (LENT)-Subjective, Objective, Management, Analytic (SOMA)) system will be reported. The patients will grade the following items based on the following scale: Mild; Moderate; Severe; Life-threatening	60 months
The long-term evaluations at 5 years of breast cosmesis	Patient self-reported breast cosmesis will be assessed using the BCTOS questionnaire (Breast Cancer Treatment Outcome Scale). The number of subjects scoring Grades 1 through 4 will be reported. The patients will grade the following items based on the following scale: = No difference between treated and untreated breast/area; = Slight difference; = Moderate difference; = Large difference	60 months
The long-term evaluations at 5 years of local control.	Number of subjects with Local control at 5 years will be extracted from the medical record, and can be derived from clinical reports from medical, surgical or radiation oncologists as well as from the primary care doctor who is following the patient.	60 months
Superior local control at 10 years	Number of subjects with Local control at 10 years will be extracted from the medical record, and can be derived from clinical reports from medical, surgical or radiation oncologists as well as from the primary care doctor who is following the patient.	120 months

Collaborators and Investigators

• Sponsor: Weill Medical College of Cornell University
• Investigators: Principal Investigator: Silvia C. Formenti, MD, Weill Medical College of Cornell University

Study record dates

Study Major Dates

• Study Start (Actual): April 29, 2025
• Primary Completion (Estimated): December 31, 2030
• Study Completion (Estimated): December 31, 2040

Study Registration Dates

• First Submitted: April 28, 2025
• First Submitted That Met QC Criteria: April 28, 2025
• First Posted (Actual): May 7, 2025

Study Record Updates

• Last Update Posted (Actual): July 25, 2025
• Last Update Submitted That Met QC Criteria: July 24, 2025
• Last Verified: July 1, 2025

More Information

Terms related to this study

• Keywords: Prone Position; Adjuvant Setting; Accelerated Radiotherapy; Non-Inferiority; Concomitant Boost
• Other Study ID Numbers: 25-01028391

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: Yes
• product manufactured in and exported from the U.S.: No