Hormone Receptor Positive HER-2 Negative Breast CancerNCT05878314
Impact of Endocrine Therapy, Menstrual Cycle, PAM50, Ki67 on Treatment Decisions in HR+ and HER2- Breast Cancer
An observational study of Hormone Receptor Positive HER-2 Negative Breast Cancer, run by University Hospital Tuebingen at 1 site in Germany.
Trial summary
PEAK is a prospective, multicenter, non-interventional investigator-initiated trial (IIT) that aims to investigate the influence of the menstrual cycle phase on Ki67 in patients who either receive Tamoxifen, Aromatase inhibitors ± gonadotropin-releasing hormone (GnRH)-Analogues or nothing or no preoperative endocrine… Read more about this study
- Who is it for?
- Ages 18 years and older, women only
- Conditions the study is for
- Hormone Receptor Positive HER-2 Negative Breast Cancer
- How many people
- 504 participants
- Where
- 1 siteGermany
- Study dates
- 25 Apr 2023to Apr 2035
- Phase
- Observational
- Are there results?
- Not yet: the study is under way
Key requirements
Who can take part, as listed by the sponsor. Only the study team can confirm whether you are eligible, so take this list to your doctor.
- Ages 18 years and older
- Women only
- No healthy volunteers
- Adult, Older adult
Study population: 252 premenopausal + 252 postmenopausal patients with early HR+/HER2 neg breast cancer receiving either * Tamoxifen (group A) * Aromatase inhibitor (+ GnRH if premenopausal) (group B) * nothing (group C) treatment during a window of opportunity of 2-3 weeks prior to surgery. Treatment will be assessed by investigators' choice and the three groups will be limited to 84 premenopausal/postmenopausal patients in each group)
Who may be able to join
- women ≥ 18 years of age
- histologically proven unilateral primary non-metastatic invasive breast cancer
- Estrogen receptor (ER)-/ or Progesterone receptor (PR)- positive and HER2-negative
- Ki67 from core biopsy is available
- no lymph-node involvement by clinical evaluation and ultrasound (cN0)
- not amendable to neoadjuvant chemotherapy
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- surgery or planned surgery at the Department for Women's Health, Tuebingen or Freiburg
- planned preoperative endocrine treatment with Tamoxifen, Aromatase inhibitors, Goserelin or nothing for 2 - 4 weeks
- written informed consent
Who cannot join
- ER-negative and PR-negative
- HER2-positive
- bilateral breast cancer
- preexisting cancer disease within the last 10 years
- preexisting invasive ipsi- or contralateral breast cancer (non-invasive ipsi- or contralateral breast cancer is not regarded as an exclusion criteria)
- any systemic breast cancer therapy before inclusion into the trial
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- indication for neoadjuvant chemotherapy
- any systemic therapy except Tamoxifen, Aromatase inhibitors, Goserelin before surgery
- locally advanced, inoperable or metastatic breast cancer
- pregnant or lactating patients
- inadequate general condition (not fit for chemotherapy)
- hormonal contraception within 6 months before inclusion
Trial locations and contacts
1 site in 1 country. Contact the study team or a site near you to ask about taking part.
Germany1 site, 1 recruiting
- Recruiting
Department of Women's Health
Tübingen, 72076
Dominik Dannehl, Dr., 07071 29 82211, Dominik.Dannehl@med.uni-tuebingen.de
About this study
Official title: Impact of Preoperative Endocrine Therapy, Menstrual Cycle, PAM50 Assessment and Ki67 Dynamics on Adjuvant Treatment Decisions in Hormone Receptor-positive and HER2-negative Patients With Early Breast Cancer
PEAK is a prospective, multicenter, non-interventional investigator-initiated trial (IIT) that aims to investigate the influence of the menstrual cycle phase on Ki67 in patients who either receive Tamoxifen, Aromatase inhibitors ± gonadotropin-releasing hormone (GnRH)-Analogues or nothing or no preoperative endocrine treatment as part of the clinical routine. The investigators moreover address the question whether PAM50 assessment in addition to Ki67 dynamics still impacts treatment recommendations.
Read the detailed description
Background of the study Chemotherapy and anti-hormonal therapies improve the chances of cure for patients with early-stage hormone receptor (HR)-positive/HER2-negative breast cancer. However, only a few patients benefit from chemotherapy, as classical tumor characteristics such as grading, tumor size, and lymph node involvement in the armpit have a prognostic value but do not allow predictions about the effectiveness of chemotherapy. New treatment concepts, such as gene expression tests and preoperative endocrine therapy, aim to identify patients with a high risk of recurrence and provide them with optimized treatment. Additionally, initial study results indicate that a woman's menstrual cycle could influence the tumor's growth rate. These hints need to be investigated in larger studies to understand how the growth rate of a tumor in different phases of the menstrual cycle can be interpreted.
Purpose of the study The main objective of the PEAK study is to investigate to what extent the menstrual cycle phase influences the tumor growth rate (biomarker Ki67). To make a scientifically sound statement, the growth rate of the tumor in postmenopausal patients must also be examined. In addition, the impact of preoperative anti-hormonal therapy, the dynamics of the growth marker Ki67, and the individual genetic risk (PAM50 gene test) on recommendations for adjuvant therapy in clinical routine should be evaluated. Furthermore, the influence of the aforementioned markers on established clinical-pathological risk factors and the spread of tumor cells should be assessed.
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
| Study group | Role | What they receive |
|---|---|---|
| Group A: Tamoxifen | Patients with early HR+/HER2- Breast cancer receiving Tamoxifen | |
| Group B: Aromatase Inhibitor (+GnRH if premenopausal) | Patients with early HR+/HER2- Breast cancer receiving Aromatase Inhibitor (+GnRH if premenopausal) | |
| Group C: Control group | no preoperative endocrine treatment |
What is being measured
The primary outcome is the main question the study is designed to answer.
Influence of the menstrual cycle on initial Ki67 in premenopausal women
The number of Ki67 positive cell nuclei will be estimated for the entire core biopsy in a semiquantitative evaluation in steps of 10% by a board certified pathologist as part of the clinical routine workup. Ki67 assessment will be conducted on breast core biopsy (I) and surgical specimen (II).
Measured: duration of therapy and follow-up data (10 years)
Secondary outcomes (1)
Influence of preoperative anti-hormonal therapy, dynamics of the growth marker Ki67 (evaluation of positive cell nuclei by pathologist), and individual genetic risk (PAM50 gene test) on recommendations for adjuvant therapy.
- breast biopsy, menstrual cycle assessment (questionnaire) and blood test for sexual hormones (follicle-stimulating hormone FSH, luteinizing hormone LH, Estrogen, Progesterone, Anti-Mullerian Hormone)
- PAM50 assessment from initial core biopsy (prognostic gene signature assay)
- determination of initial Ki67 (evaluation of positive cell nuclei by pathologist)
- 2 weeks of endocrine treatment or not (depending on group)
- preoperative menstrual cycle assessment (questionnaire) and blood test for sexual hormones (FSH, LH, Estrogen, Progesterone) in premenopausal patients
- surgery and determination of posttherapeutic Ki67 (evaluation of positive cell nuclei by pathologist)
- collection of clinical and pathological data
- assessment of therapy recommendation without knowledge of the PAM50 (Questionnaire for the investigator)
- assessment of therapy recommendation with knowledge of the PAM50 (Questionnaire for the investigator)
Measured: duration of therapy and follow-up data (10 years)
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted26 May 2023
- Study start25 Apr 2023
- Primary completionApr 2027 (estimated)
- Study completionApr 2035 (estimated)
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Other trials for Hormone Receptor Positive HER-2 Negative Breast CancerStudies of the same condition, open and under way.
- More trials run by University Hospital TuebingenThe sponsor's other registered studies.
- What the trial phases meanHow a treatment moves from first tests in people to approval.
More details
For doctors and researchers: how the study is designed, who runs it, and its registry IDs.
Study design
- Study type
- Observational
- Observational model
- Cohort
- Time perspective
- Prospective
- Enrolment
- 504 participants (estimated)
Sponsor and investigators
- Lead sponsor
- University Hospital Tuebingen
- Sponsor type
- University, hospital or other
- Collaborators
- University Hospital Ulm, University Hospital Freiburg
- Responsible party
- Sponsor
- Investigators
- Dominik Dannehl, Dr., Principal investigator, University Hospital Tuebingen
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT05878314
- Sponsor's protocol ID
- BZ_PEAK
- Status last verified
- Feb 2026
- First submitted
- 4 May 2023
- Last updated
- 10 Feb 2026
- Results posted
- No
- Data monitoring committee
- No
- FDA-regulated drug
- No
- FDA-regulated device
- No
- Individual data sharing
- No
Study at a glance
From the registry record, last updated by the sponsor on 10 Feb 2026. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- Impact of Preoperative Endocrine Therapy, Menstrual Cycle, PAM50 Assessment and Ki67 Dynamics on Adjuvant Treatment Decisions in Hormone Receptor-positive and HER2-negative Patients With Early Breast Cancer
- ClinicalTrials.gov ID
- NCT05878314
- Acronym / sponsor ID
- BZ_PEAK
- Study type
- Observational
- Recruitment status
- Recruiting
- Enrolment
- 504 participants (estimated)
- Lead sponsor
- University Hospital TuebingenUniversity, hospital or other
- Collaborators
- University Hospital Ulm, University Hospital Freiburg
- Study start
- 25 Apr 2023 (actual)
- Primary completion
- Apr 2027 (estimated)
- Study completion
- Apr 2035 (estimated)
- First posted
- 26 May 2023 (actual)
- Results
- Not posted in the source record
Clinical summary
The research question as the sponsor registered it. This describes what the study plans to test, not what it found.
PEAK is a prospective, multicenter, non-interventional investigator-initiated trial (IIT) that aims to investigate the influence of the menstrual cycle phase on Ki67 in patients who either receive Tamoxifen, Aromatase inhibitors ± gonadotropin-releasing hormone (GnRH)-Analogues or nothing or no preoperative endocrine treatment as part of the clinical routine. The investigators moreover address the question whether PAM50 assessment in addition to Ki67 dynamics still impacts treatment recommendations.
Detailed description
Background of the study Chemotherapy and anti-hormonal therapies improve the chances of cure for patients with early-stage hormone receptor (HR)-positive/HER2-negative breast cancer. However, only a few patients benefit from chemotherapy, as classical tumor characteristics such as grading, tumor size, and lymph node involvement in the armpit have a prognostic value but do not allow predictions about the effectiveness of chemotherapy. New treatment concepts, such as gene expression tests and preoperative endocrine therapy, aim to identify patients with a high risk of recurrence and provide them with optimized treatment. Additionally, initial study results indicate that a woman's menstrual cycle could influence the tumor's growth rate. These hints need to be investigated in larger studies to understand how the growth rate of a tumor in different phases of the menstrual cycle can be interpreted.
Purpose of the study The main objective of the PEAK study is to investigate to what extent the menstrual cycle phase influences the tumor growth rate (biomarker Ki67). To make a scientifically sound statement, the growth rate of the tumor in postmenopausal patients must also be examined. In addition, the impact of preoperative anti-hormonal therapy, the dynamics of the growth marker Ki67, and the individual genetic risk (PAM50 gene test) on recommendations for adjuvant therapy in clinical routine should be evaluated. Furthermore, the influence of the aforementioned markers on established clinical-pathological risk factors and the spread of tumor cells should be assessed.
Study design
- Observational model
- Cohort
- Time perspective
- Prospective
- Number of arms
- 3
| Arm | Type | Receives |
|---|---|---|
| Group A: Tamoxifen | – | –Patients with early HR+/HER2- Breast cancer receiving Tamoxifen |
| Group B: Aromatase Inhibitor (+GnRH if premenopausal) | – | –Patients with early HR+/HER2- Breast cancer receiving Aromatase Inhibitor (+GnRH if premenopausal) |
| Group C: Control group | – | –no preoperative endocrine treatment |
Who may qualify
- Ages
- 18 years and older
- Sex
- Female only
- Healthy volunteers
- Not accepted
- Age groups
- Adult, Older adult
- Study population
- 252 premenopausal + 252 postmenopausal patients with early HR+/HER2 neg breast cancer receiving either * Tamoxifen (group A) * Aromatase inhibitor (+ GnRH if premenopausal) (group B) * nothing (group C) treatment during a window of opportunity of 2-3 weeks prior to surgery. Treatment will be assessed by investigators' choice and the three groups will be limited to 84 premenopausal/postmenopausal patients in each group)
Key inclusion criteria (9 listed)
- women ≥ 18 years of age
- histologically proven unilateral primary non-metastatic invasive breast cancer
- Estrogen receptor (ER)-/ or Progesterone receptor (PR)- positive and HER2-negative
- Ki67 from core biopsy is available
- no lymph-node involvement by clinical evaluation and ultrasound (cN0)
Key exclusion criteria (12 listed)
- ER-negative and PR-negative
- HER2-positive
- bilateral breast cancer
- preexisting cancer disease within the last 10 years
- preexisting invasive ipsi- or contralateral breast cancer (non-invasive ipsi- or contralateral breast cancer is not regarded as an exclusion criteria)
Eligibility is decided by the study team after screening; this overview does not establish that a patient qualifies. Full inclusion and exclusion criteria.
Primary outcome
Influence of the menstrual cycle on initial Ki67 in premenopausal women
Time frame: duration of therapy and follow-up data (10 years)
The number of Ki67 positive cell nuclei will be estimated for the entire core biopsy in a semiquantitative evaluation in steps of 10% by a board certified pathologist as part of the clinical routine workup. Ki67 assessment will be conducted on breast core biopsy (I) and surgical specimen (II).
1 secondary outcome
Influence of preoperative anti-hormonal therapy, dynamics of the growth marker Ki67 (evaluation of positive cell nuclei by pathologist), and individual genetic risk (PAM50 gene test) on recommendations for adjuvant therapy.
Time frame: duration of therapy and follow-up data (10 years)
Results and safety
This study is still under way. Results are not available in the source record yet.
Research links
- Official record on ClinicalTrials.govLast updated by the sponsor 10 Feb 2026.
- Individual participant dataSharing planned: No
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Referral and contact
AzTrials does not enrol participants or take referrals. Contact the study team or a site listed below; they decide who can take part.
Dominik Dannehl, Dr. principal investigator
University Hospital Tuebingen
1 site in 1 country: see every site and its status.
Questions about this trial
What is this clinical trial studying?
An observational study of Hormone Receptor Positive HER-2 Negative Breast Cancer, run by University Hospital Tuebingen at 1 site in Germany.
The full registered description is in the About this study section and the official record.
Who may be eligible to take part?
The sponsor lists 9 inclusion and 12 exclusion criteria. Eligibility is decided by the study team after screening, so read the full criteria and contact a listed site.
Is this clinical trial currently recruiting?
The record says: looking for participants now, as of the sponsor's last update on 10 Feb 2026. Status can change between updates, so confirm with the study contact before making plans.
Where is the study taking place?
The record lists 1 site in Germany. Whether a site is taking part right now should be confirmed with that site. See every site.
What are the possible benefits and risks?
They depend on the study and the treatment, and no study can promise a benefit. The study team explains the known risks during informed consent, before anyone joins; the record itself does not list them.
Are results available for this study?
This study is still under way. Results are not available in the source record yet.
How can a doctor refer a patient or contact the research team?
Contact Dominik Dannehl, Dr. (07071 29 82211, Dominik.Dannehl@med.uni-tuebingen.de), or a site near the patient. AzTrials does not enrol participants or take referrals.
What does the primary outcome measure?
Influence of the menstrual cycle on initial Ki67 in premenopausal women (time frame: duration of therapy and follow-up data (10 years)). It is what the study was designed to measure, not a finding.
Where can I read the original study information?
Does a listing mean the treatment is approved or proven to work?
No. A listing means the study is registered. It does not show that the treatment is safe, works, or is approved by a regulator.
How often is this information updated?
AzTrials copies changed records from ClinicalTrials.gov every night and reloads the whole registry every week. The sponsor last updated this record on 10 Feb 2026.