The Role of Serotonin in Hot Flashes After Breast Cancer

March 24, 2015 updated by: Indiana University School of Medicine
The purpose of this proposal is to improve our understanding of the role of tryptophan and serotonin in hot flashes. The main hypothesis is that alterations in tryptophan and serotonin levels are involved in the induction of hot flashes in women with breast cancer and genetic variations in the serotonin receptors and transporters also play a role.

Study Overview

Detailed Description

Among women with breast cancer, hot flashes are a frequent, severe and bothersome symptom. For this group, hot flashes are negatively related to mood, affect, and daily activities and can compromise compliance with life-saving medications (e.g., tamoxifen). Over 60% of breast cancer survivors report hot flashes, with 59% stating they are extremely severe and 44% reporting them to be extremely bothersome. Unfortunately, limitations in our understanding of hot flash physiology limit clinicians' abilities to fully treat this symptom. Although the current non-hormonal treatment of choice for hot flashes after breast cancer targets the central serotonin system (e.g., paroxetine, venlafaxine), the role of serotonin in hot flashes has not been directly tested. Because the effectiveness of these agents has been based largely on improvement in subjective reporting of hot flashes, it is not clear whether benefits are due to physiological effects on hot flashes or due to improvements in mood or other related symptoms. In addition, these and other currently available treatments are not acceptable, appropriate, or effective for all women with breast cancer. Understanding the physiological mechanisms involved in hot flashes after breast cancer will enable us to develop more targeted behavioral and/or pharmacological therapies to be used in lieu of, or in addition to, currently available therapies so that we can eradicate hot flashes and improve the quality of life for women with breast cancer.

Results implicating direct effects of tryptophan and serotonin on objective hot flashes will help guide the development of improved interventions for alleviating hot flashes in women with breast cancer. These interventions may target the central serotonin system either behaviorally (e.g., diet) or pharmacologically (e.g., alternative drug therapeutics). If direct manipulation of tryptophan and serotonin does not affect hot flashes, these findings will be equally as useful in guiding future research on non-serotonin related etiologies and interventions. Findings from this study will ultimately be used to eradicate hot flashes as a frequent, severe and bothersome breast cancer treatment related condition, thereby, improving quality of life for all women with breast cancer.

Study Type

Interventional

Enrollment (Actual)

28

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 Locations

    • Indiana
      • Indianapolis, Indiana, United States, 46202
        • Indiana University Cancer Center

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

18 years and older (Adult, Older Adult)

Accepts Healthy Volunteers

No

Genders Eligible for Study

Female

Description

Inclusion Criteria:

  • At least 18 years of age
  • Willing and able to provide informed consent
  • Reporting daily hot flashes
  • Able to read, write, and speak English
  • Postmenopausal to limit sample variability (> 12 months amenorrhea)
  • Greater then 1 month but < 5 years post-treatment (surgery, radiation, chemotherapy) for non-metastatic breast cancer.
  • These criteria allow inclusion of women successfully treated for recurrent breast cancer since there is no known reason to exclude them. Menopausal status is assessed using self-reports due to problems in reliably measuring follicle-stimulating hormone levels and estradiol in tamoxifen users.

Exclusion Criteria:

  • Exclusion criteria are current depression, history of migraines or hepatitis, abnormal chemistry profile (e.g., sodium, potassium, glucose), or a positive urine drug screen for illegal substances.

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: Basic Science
  • Allocation: Randomized
  • Interventional Model: Crossover Assignment
  • Masking: Double

Arms and Interventions

Participant Group / Arm
Intervention / Treatment
Experimental: Acute tryptophan depletion
Full-strength tryptophan depletion
L-alanine (5.5g), L-arginine (4.9g), L-cysteine (2.7g), glycine (3.2g), L-histidine (3.2g), L-isoleucine (8.0g), L-leucine (13.5g), L-lysine (11.0g), L-methionine (3.0g), L-phenylalanine (5.7g), L-proline (12.2g), L-serine (6.9g), L-threonine (6.9g), L-tyrosine (6.9g), L-valine (8.9g)
Active Comparator: Control
Half-strength tryptophan depletion drink used as a control
L-alanine (1.4g), L-arginine (1.2g), L-cysteine (0.7g), glycine (0.8g), L-histidine (0.8g), L-isoleucine (2.0g), L-leucine (3.4g), L-lysine (2.8g), L-methionine (0.8g), L-phenylalanine (1.4g), L-proline (3.1g), L-serine (1.7g), L-threonine (1.7g), L-tyrosine (1.7g), L-valine (2.2g), and fillers (7.95g).

What is the study measuring?

Primary Outcome Measures

Outcome Measure
Measure Description
Time Frame
Serum Tryptophan Levels
Time Frame: baseline, 1 hour, 2 hours, 3 hours, 4 hours, 5 hours, 6 hours, 7 hours, 8 hours
Mean serum tryptophan levels (blood draw) at the end of the nadir period.
baseline, 1 hour, 2 hours, 3 hours, 4 hours, 5 hours, 6 hours, 7 hours, 8 hours
Objective Subject Hot Flash Frequency
Time Frame: One 24 hour monitoring session per week for 8 weeks
Mean of the 24 hour monitoring sessions for each patient based on one 24 hour monitoring session after each intervention using an electronic monitor.
One 24 hour monitoring session per week for 8 weeks

Collaborators and Investigators

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

Investigators

  • Principal Investigator: Janet S Carpenter, PhD, Indiana University School of Medicine

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.

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

July 1, 2005

Primary Completion (Actual)

October 1, 2007

Study Completion (Actual)

November 1, 2008

Study Registration Dates

First Submitted

September 14, 2005

First Submitted That Met QC Criteria

September 27, 2005

First Posted (Estimate)

September 29, 2005

Study Record Updates

Last Update Posted (Estimate)

April 14, 2015

Last Update Submitted That Met QC Criteria

March 24, 2015

Last Verified

March 1, 2015

More Information

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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