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NCT Number: NCT05861362

Feasibility and Metabolic Effects of a 5:2 Fasting Intervention in Women With Breast Cancer During Radiotherapy

The intervention consists of the adoption of a 5:2 intermittent fasting diet during radiotherapy of breast cancer patients. The aim of the study was to assess the feasibility of this intervention and its impact on body composition and selected metabolic blood parameters.

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Key information

Conditions

Breast Cancer Breast Diseases Breast Neoplasms Neoplasms Neoplasms by Site Skin Diseases Skin and Connective Tissue Diseases

Age range

18 year–75 year

Sex eligibility

Female

Study type

Interventional

Phase

Not applicable

Primary location

Department of Radiotherapy and Radiation Oncology, Schweinfurt, Bavaria, Germany

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About this study

The 5:2 intermittent fasting (FAST) intervention consisted of two nonconsecutive days of fasting per week that could be chosen freely according to the patient's weekly schedule. The minimum amount of time to count as a fasting day was 24 hours, but patients were advised to aim for a complete fasting day including the nights before and after that day. On a fasting day, only water and unsweetened tea or coffee was allowed. However, given that fat is the macronutrient interfering the least with the metabolic adaptions to fasting, while carbohydrates disturb the most [26], patients were allowed to consume small amounts of bone broth/meat broth, coconut oil, butter/ghee or heavy cream as an "emergency plan", i.e., in case that they felt they needed some energy-containing foods to complete an initiated fasting day.

The primary study outcome was the feasibility of the FAST intervention and its effects on longitudinal body composition changes from baseline until the final week of radiotherapy (body mass, fat mass, fat-free mass, muscle mass, extracellular and total body water). Secondary endpoints were absolute changes in metabolic parameters, hormones, and overall quality of life scores in the FAST group. As a surrogate marker for insulin resistance, the triglyceride-glucose index (TyG) was calculated according to TyG=ln⁡(fasting triglycerides [mg/dl]×fasting glucose [mg/dl]/ 2).

Who can participate

Healthy volunteers accepted: No

Only the study team can determine whether someone qualifies for participation.

Inclusion criteria

  • Non-metastasized breast cancer
  • Indication for curative radiotherapy

Exclusion criteria

  • metallic body parts that would interfere with electric bioimpedance (BIA) measurements
  • difficulties with understanding the aims of the study

Treatment and study plan

Curative radiotherapy

Radiation

Curative radiotherapy as indicated by the patient's disease and prescribed by the treating radiation oncologist

5:2 intermittent fasting

Behavioral

Two nonconsecutive days of fasting per week that could be chosen freely according to the patient's weekly schedule.

Primary outcomes

  1. Dropout rate in the FAST intervention group

    Time frame: Through study completion, an average of 5 weeks

    Used to measure feasibility. The intervention is rated as feasible if dropout rate is <30%

  2. Longitudinal changes in body mass

    Time frame: Through study completion, an average of 5 weeks

    Body mass (in kg) is measured by a bioimpedance device with an integrated scale (seca mBCA, seca Deutschland, Hamburg, Germany).

  3. Longitudinal changes in fat-free mass

    Time frame: Through study completion, an average of 5 weeks

    Fat-free mass (in kg) is estimated by a bioimpedance device with an integrated scale (seca mBCA, seca Deutschland, Hamburg, Germany).

  4. Longitudinal changes in skeletal muscle mass

    Time frame: Through study completion, an average of 5 weeks

    Skeletal muscle mass (in kg) is estimated by a bioimpedance device with an integrated scale (seca mBCA, seca Deutschland, Hamburg, Germany).

  5. Longitudinal changes in total body water

    Time frame: Through study completion, an average of 5 weeks

    Total body water content (in L) is estimated by a bioimpedance device with an integrated scale (seca mBCA, seca Deutschland, Hamburg, Germany).

  6. Longitudinal changes in extracellular water

    Time frame: Through study completion, an average of 5 weeks

    Extracellular water (in L) is estimated by a bioimpedance device with an integrated scale (seca mBCA, seca Deutschland, Hamburg, Germany).

Secondary outcomes

  1. Change between baseline and final (average 5 weeks) TyG index

    Time frame: Through study completion, an average of 5 weeks

    As a surrogate marker for insulin resistance, the triglyceride-glucose index (TyG) is calculated according to TyG=ln⁡(fasting triglycerides [mg/dl]×fasting glucose [mg/dl]/ 2)

Sponsors and collaborators

Lead sponsor

MVZ Leopoldina GmbH

Other

Registry information

Important dates

Study start
2022
Primary completion
2022
Study completion
2022
First posted
May 16, 2023
Registry last updated
May 16, 2023

OpenTrials presents study information sourced from ClinicalTrials.gov. The official registry record should be consulted for the latest information.

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This listing is for discovery and informational purposes only. It is not medical advice, does not guarantee that a study is recruiting, and does not determine eligibility. Contact the study team and a qualified healthcare professional when considering participation.

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