Breast Cancer Exercise Intervention Study (BREXINT)

Breast Cancer Exercise Intervention Study (BREXINT)

This is a 24-week exercise programme consisting of aerobic exercise and muscle strength training, 3 sessions per week. The first 9 sessions are supervised by physiotherapists in person, followed by 63 sessions monitored remotely (video) or supervised by trainers at ActiveSG (Sport Singapore) gyms.

Study Overview

• Status: Recruiting
• Conditions: Locally Advanced Breast Cancer; Early-stage Breast Cancer
• Intervention / Treatment: Behavioral: Exercise Programme; Behavioral: Control

Detailed Description

This is a multi-centre, randomised controlled study of a 6-month (24-week) exercise programme versus observation in 2156 early stage and locally advanced breast cancer patients who have undergone curative breast surgery, and who have completed (neo)adjuvant chemotherapy (if given) or radiotherapy (if given). Patients are stratified by centre (NCC/SGH, NUH), menopausal status, ER/PR status, body fat/muscle ratio.

Cardiorespiratory fitness, muscle strength, level of routine daily physical activity, body fat/muscle ratio are monitored during the study period.

Blood is collected at baseline, 8 weeks, 16 weeks, 24 weeks, 52 weeks, then annually for 4 times.

Questionnaires are periodically conducted to assess quality of life (QoL). A food diary is kept.

• Study Type: Interventional
• Enrollment (Estimated): 2156
• Phase: Not Applicable

Contacts and Locations

• Study Contact: Name: Dr Elaine LIM, MD, PhD; Phone Number: +65 64368000; Email: elaine.lim.hsuen@singhealth.com.sg
• Study Contact Backup: Name: Catherine CELES; Email: catherine.celes@nccs.com.sg

Study Locations

• Singapore
  • Singapore, Singapore, 169608
    • Recruiting
    • Singapore General Hospital
    • Contact: Dr Veronique TAN, MD; Phone Number: +65 62223322; Email: veronique.tan.k.m@singhealth.com.sg
  • Singapore, Singapore, 119074
    • Recruiting
    • National University Hospital
    • Contact: Professor Soo Chin LEE, MD; Phone Number: +65 67737888; Email: ncis@nuhs.edu.sg
  • Singapore, Singapore, 168583
    • Recruiting
    • National Cancer Centre

Participation Criteria

Eligibility Criteria

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

Description

Inclusion Criteria:

• Patients with histologically or cytologically proven stage 1, 2, or 3 breast cancer
• Patients who have undergone curative breast surgery
• Patients who have received (neo)adjuvant chemotherapy (if given) and/or radiotherapy (if given)
• Females aged 21 years and older
• ≤ 8 weeks from breast surgery, or the last adjuvant chemotherapy or radiotherapy session, whichever is latest.

Exclusion Criteria:

• Cardiovascular, respiratory, musculoskeletal problems that preclude moderate physical activity.
• Major medical problems that are deemed by the investigator to be unsuitable for enrollment.

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: Exercise; The exercise intervention group will undergo an aerobic exercise and strength training programme, comprising 3 sessions per week, spanning 24 weeks (total: 3x24=72 sessions).	Behavioral: Exercise Programme; Aerobic exercise consists of 20-minute brisk walks or jogs (5-6 km/h) on the treadmill each session, reaching a heart rate corresponding to 50%-70% of the patient's VO2max (VO2max is determined before embarking on the exercise programme). Study participants are expected to aim for 50% VO2max at the start of the exercise programme, and gradually increasing to 70% VO2max in subsequent exercise sessions. Strength training comprises a series of circuit resistance exercises targeting the major muscle groups. Patients will perform 2-4 sets of these exercises each session, 8-10 repetitions per set. Both aerobic exercise and strength training are done in the same session. With warm-up and cool-down, each session is estimated to take up 1 hour.
Experimental: Control; The usual care group.	Behavioral: Control; Usual care group.

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Disease-Free Survival (DFS)	From the date of randomization to when an event, i.e. relapse, has occurred.	Up to 5 years.

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Overall Survival (OS)	From the date of randomization to when an event, i.e. death, has occurred.	Up to 5 years.

Other Outcome Measures

Outcome Measure	Measure Description	Time Frame
Body fat/muscle ratio.	Body fat mass (in grams) divided by body muscle mass (in grams).	Week 0, Week 8, Week 16 and Week 24.
Changes in absolute and relative VO2.	Changes in absolute (L/min) and relative VO2 (mL/kg/min) at 8, 16 and 24 weeks from baseline.	Week 8, Week 16 and Week 24.
Changes in heart rate at rest and during CPET.	Changes in heart rate (HR, beats/min) at rest and during CPET, at 8, 16 and 24 weeks from baseline.	Week 8, Week 16 and Week 24.
Changes in oxygen pulse (VO2/HR) during CPET.	Changes in oxygen pulse (VO2/HR) during CPET, at 8, 16, and 24 weeks from baseline.	Week 8, Week 16 and Week 24.
Changes in respiratory exchange ratio (RER) during CPET.	Changes in respiratory exchange ratio (RER, unitless) during CPET, at 8, 16, and 24 weeks from baseline	Week 8, Week 16 and Week 24.
Changes in weight lifted 10 repetition maximum.	Changes in weight lifted 10 repetition maximum (10-RM, Kg) for: a. Chest press; b. Latissimus pull-down; c. 2-arm curl; and d. Leg press.	Week 0, Week 8, Week 16 and Week 24.
Changes in absolute fat mass and relative fat mass from baseline.	Changes in absolute fat mass (kg) and relative fat mass (%) at 8, 16, and 24 weeks from baseline.	Week 8, Week 16 and Week 24.
Changes in absolute lean mass and relative lean mass from baseline.	Changes in absolute lean mass (kg) and relative lean mass (%) at 8, 16, and 24 weeks from baseline.	Week 8, Week 16 and Week 24.
Changes in absolute and relative bone mineral density (BMD) at 8, 16, and 24 weeks from baseline.	Changes in absolute and relative bone mineral density (BMD, in g/cm^2) at 8, 16, and 24 weeks from baseline.	Week 8, Week 16 and Week 24.

Collaborators and Investigators

• Sponsor: National Cancer Centre, Singapore
• Collaborators: Singapore General Hospital; Singapore Cancer Society; Genome Institute of Singapore; National University of Singapore
• Investigators: Principal Investigator: Dr Elaine LIM, MD, PhD, National Cancer Centre, Singapore

Study record dates

Study Major Dates

• Study Start (Actual): July 1, 2023
• Primary Completion (Estimated): May 31, 2028
• Study Completion (Estimated): May 31, 2033

Study Registration Dates

• First Submitted: June 13, 2023
• First Submitted That Met QC Criteria: July 19, 2023
• First Posted (Actual): July 24, 2023

Study Record Updates

• Last Update Posted (Estimated): September 5, 2025
• Last Update Submitted That Met QC Criteria: September 3, 2025
• Last Verified: September 1, 2025

More Information

Terms related to this study

• Keywords: Quality of Life; Cardiorespiratory Fitness; Muscular Strength; BREXINT
• Additional Relevant MeSH Terms: Neoplasms by Site; Neoplasms; Skin Diseases; Breast Diseases; Skin and Connective Tissue Diseases; Breast Neoplasms
• Other Study ID Numbers: BREXINT

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: YES
• IPD Plan Description: Once data is available, only de-identified IPD will be shared to collaborators.

Drug and device information, study documents

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