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Breast CancerPhase 2LESSNCT05297617

Deescalation of Endocrine Therapy Duration in Women With HR+ HER2- Breast Cancer at Very Low Risk

A Phase 2 study testing Anti-aromatase inhibitor in people with Breast Cancer, run by UNICANCER at 2 sites in France.

Recruiting

Looking for participants now. Contact the study team or a site below to ask about taking part.

Sites and contacts
Official record
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Trial summary

Hormone therapy is recommended for five years in all patients with hormone receptor-positive breast cancer, but there is no consensus on its duration in low-risk tumours and especially in postmenopausal women. Read more about this study

Who is it for?
Ages 51 years and older, women only
Conditions the study is for
Breast Cancer
What is being tested?
Anti-aromatase inhibitor
Could I receive a placebo?
No, everyone receives an active treatment
How many people
696 participants
Where
2 sitesFrance
Study dates
12 Oct 2022to Nov 2035
Phase
Phase 2
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 51 years and older
  • Women only
  • No healthy volunteers
  • Adult, Older adult

Who may be able to join

  • Postmenopausal women: Postmenopausal status is defined by any of the following:
  • Prior bilateral oophorectomy
  • Age ≥60 years
  • Age >50 and <60 years and amenorrheic for at least 12 months, and follicle-stimulating hormone (FSH) and estradiol in the postmenopausal range
  • Eastern Cooperative Oncology Group (ECOG) performance status 0-1
  • Women with histologically proven invasive unilateral breast cancer Note: In case of a multifocal invasive tumor, all lesions (maximum 3 infiltrating lesions allowed) must be of identical phenotype and low biological risk
Show all 19Show fewer
  • M0: Not clinically nor radiologically detectable metastases at time of inclusion
  • Primary tumor completely resected and adequate axillary surgery performed, according to current standards
  • IHC expression of the estrogen receptor and/or progesterone receptor ≥50%
  • HER2 negative according to ASCO criteria in immunohistochemistry and/or genomic analysis (HER2 negativity is defined as IHC 0-1+, or [IHC 2+ and FISH or CISH nonamplified])
  • No indication of adjuvant chemotherapy
  • pT1 (tumor ≤20 mm), pN0, Grade 1 or Grade 2 OR pT2 (tumor ≤30 mm) and pN0, Grade 1 or Grade 2
  • Note 1: patient with Grade 2 pT2pN0 tumor must be aged under 70 years of age and should receive a genomic test as part of standard care (RIHN reimbursement)
  • Patient considered has having a luminal A ultralow risk of metastatic recurrence (i.e.less than 5% risk of metastatic relapse at 10 years) according to MammaPrint® and Blueprint® tests.
  • Note 1: To be eligible, MammaPrint index score should be > +0.355
  • Patients eligible to receive or have recently started (with a maximum of 4 months of adjuvant hormone therapy prior to enrollment) an adjuvant hormone therapy (letrozole, anastrozole, or exemestane)
  • Patient is willing and able to comply with the protocol for the duration of the study including scheduled visits, treatment plan, laboratory tests and other study procedures
  • Patients must be affiliated to a Social Security System (or equivalent)
  • Patient must have signed a written informed consent form prior to any trial specific procedures. When the patient is physically unable to give their written consent, a trusted person of their choice, independent from the investigator or the sponsor, can confirm in writing the patient's consent.

Who cannot join

  • Patients who received a neo-adjuvant hormone therapy, a neo-adjuvant or adjuvant chemotherapy or preoperative medical treatment
  • Any local or regional recurrence or metastatic disease
  • Non-invasive carcinoma
  • Bilateral breast cancer (except in case of contralateral DCIS), or history of other invasive ipsi- or contralateral breast cancer
  • Patients with a history of another malignancy, except for properly treated cervical carcinoma in situ, and non-melanoma cancer of the skin
  • Women with high-risk breast cancer predisposing deleterious germline mutations
Show all 11Show fewer
  • Contra-indications to the administration of anti-aromatase inhibitors
  • Patients enrolled in another therapeutic study within 30 days prior to inclusion
  • Patients with any other disease or illness, which requires hospitalization or is incompatible with the trial treatment
  • Patients unwilling or unable to comply with trial obligations for geographic, social, physical or psychological reasons, or who are unable to understand the purpose and procedures of the trial
  • Persons deprived of their liberty or under protective custody or guardianship

Trial locations and contacts

2 sites in 1 country. Contact the study team or a site near you to ask about taking part.

Clara GUYONNEAU, PharmD contact

0685167111

c-guyonneau@unicancer.fr

France2 sites, 2 recruiting

  • Centre Hospitalier Universitaire de Limoges

    Limoges, 87042

    Elise DELUCHE, MD

    elise.deluche@chu-limoges.fr

    Recruiting

  • Institute Gustave Roussy

    Villejuif, 94805

    Fabrice ANDRE, Pr/MD

    FABRICE.ANDRE@gustaveroussy.fr

    Not yet recruiting

Other trials in France

About this study

Official title: Single-arm Study to De-escalate Adjuvant Endocrine Therapy Duration in Women With HR+ HER2- Breast Cancer at Very Low Risk of Metastasis

Hormone therapy is recommended for five years in all patients with hormone receptor-positive breast cancer, but there is no consensus on its duration in low-risk tumours and especially in postmenopausal women. Adjuvant endocrine therapy (ET) is associated with substantial side effects and long-term decreased quality of life.

Moreover, while it has been shown that ET provides a real benefit in reducing the relapse rate over time, the deterioration in quality of life may also have a negative effect on patient adherence to treatment. It is therefore important to offer treatment to women with low-risk cancer less intensive treatment strategies. If recent trials tested longer durations as compared to 5 years for high-risk cancers, older trials have tested shorter durations. The 5-year duration appeared at that time as the gold standard because of optimal benefit-risk ratios of tamoxifen among high-risk patients. However shorter treatments of 2-3 years were already associated with substantial benefits and may be enough for very low risk patients.

Read the detailed description

Adjuvant ET is the cornerstone treatment of localized hormone-receptor positive breast cancer, with demonstrated benefits on overall survival (30-40% relative decrease in mortality) but also on the risk of local and contralateral relapse (43-50% relative decrease). While the relative benefit of 5 years ET is identical for small tumors as compared to larger ones, the absolute benefit is much lower, and the risk-benefit ratio may therefore become very questionable given the frequent and impactful side effects of ET. If recent trials tested longer durations as compared to 5 years for high-risk cancers, older trials have tested shorter durations. Five years appeared at that time as the gold standard because of optimal benefit-risk ratios of tamoxifen among rather high-risk patients. However shorter treatments of 2-3 years were already associated with substantial benefits and may be enough for very low risk patients. The purpose of this study is to demonstrate that adjuvant hormone therapy limited to 2 years of antiaromatase in postmenopausal women with a good prognosis can ensure very high survival without metastatic relapse and allows a reduction of side effects and a better quality of life. The 5-year DMFS was excellent in patients with low risk Luminal A tumors who received endocrine therapy.

Conditions
Breast Cancer
Being tested
Anti-aromatase inhibitor
Medical subject headings
Breast Neoplasms

What participants receive

What participants receive. In a randomised study each person is assigned to one group by chance.

  • Anti-aromatase inhibitorDrug

    Treatment will be either:

    • Letrozole, given per os, 2.5 mg daily
    • Anastrozole, given per os, 1 mg daily
    • Exemestane, given per os, 25 mg daily
Study groups in NCT05297617
Study groupRoleWhat they receive
Aromatase inhibitorExperimentalPatient will receive standard endocrine therapy (single agent aromatase inhibitors) for a maximum of 2 years.
Receives: Drug: Anti-aromatase inhibitor

What is being measured

The primary outcome is the main question the study is designed to answer.

  1. Distant relapse-free interval (DRFI)

    Distant relapse-free interval (DRFI) is defined as the time from date of beginning of hormonotherapy to the date of first event of distant recurrence or breast cancer related death

    Measured: From date of beginning of hormonotherapy to onset of metastases or death, up to 5-years.

Secondary outcomes (13)

  1. Distant Disease-Free Survival (DDFS)

    DDFS is defined as the time from date of beginning of hormonotherapy to the date of first event of distant recurrence, death from any cause or secondary non-breast cancer.

    Measured: From date of beginning of hormonotherapy to the date of first event of distant recurrence, death from any cause or secondary non-breast cancer up to 10 years

  2. Invasive disease free survival (iDFS)

    Invasive disease free survival is defined as duration of time from date of registration until first appearance of invasive local, regional, or distant recurrence (including invasive ipsilateral breast cancer recurrence), invasive contralateral breast cancer, second primary non breast invasive cancer (excluding non-melanoma skin cancer), or death from any cause.

    Measured: From date of beginning of hormonotherapy to onset of invasive event, second cancer, or death, up to 10 years.

  3. Invasive breast cancer-free survival (iBCFS)

    Invasive disease free survival is defined as the delay between date of inclusion and first appearance of invasive local, regional, or distant recurrence (including invasive ipsilateral breast cancer recurrence), invasive contralateral breast cancer, or death from any cause.

    Measured: From date of beginning of hormonotherapy to onset of invasive event or death, up to 10 years.

  4. Breast cancer-specific survival (BCSS)

    Breast cancer-specific survival is defined as the time from inclusion to death from breast cancer.

    Measured: From date of beginning of hormonotherapy to death from breast cancer, up to 10 years.

  5. Overall survival (OS)

    The overall survival is the length of time from inclusion to death from any cause.

    Measured: From date of beginning of hormonotherapy to death from any cause, up to 10 years.

  6. Quality of life (QoL) questionnaire - Core 30 (QLQ-C30)

    Developed by the EORTC, this self-reported questionnaire assesses the health-related quality of life of cancer patients in clinical trials. The questionnaire includes five functional scales (physical, everyday activity, cognitive, emotional, and social), three symptom scales (fatigue, pain, nausea and vomiting), a health/quality of life overall scale, and a number of additional elements assessing common symptoms (including dyspnea, loss of appetite, insomnia, constipation, and diarrhea), as well as, the perceived financial impact of the disease. All of the scales and single-item measures range in score from 0 to 100. A high scale score represents a higher response level.

    Measured: At baseline, 1 year, 2 years, 3 years, 4 years, 5 years

  7. Quality of life (QoL) questionnaire - EORTC QLQ-BR23/QLQ-BR45

    This EORTC breast cancer specific questionnaire is intended to supplement the QLQ-C30.

    The QLQ-BR23 contains 23 items incorporating five multi-item scales to assess systemic therapy side effects, arm symptoms, breast symptoms, body image and sexual functioning. In addition, single items assess sexual enjoyment, hair loss and future perspective. All items are rated on a four-point Likert-type scale (1 = "not at all", 2 = "a little", 3 = "quite a bit", and 4 = "very much"), and are linearly transformed to a 0-100 scale. For all items but sexual functioning and sexual enjoyment, higher scores indicate more severe symptoms. The QLQ-BR-23 was updated and 22 new questions were added to provide a more accurate and comprehensive assessment of the impact of new and scalable treatments on patients'QoL

    Measured: At baseline, 1 year, 2 years, 3 years, 4 years, 5 years

  8. Quality of life (QoL) questionnaire - Cancer related fatigue (QLQ-FA12)

    This EORTC cancer related fatigue questionnaire is intended to supplement the QLQ-C30.

    The QLQ-FA12 contains 12 items organized in three subscales: physical fatigue (5 items), emotional fatigue (3 items), and cognitive fatigue (2 items). The remaining two items serve as global indicators for interference of fatigue with daily activities and social sequelae of fatigue.

    All items are rated on a four-point Likert-type scale (1 = "not at all", 2 = "a little", 3 = "quite a bit", and 4 = "very much"), and are linearly transformed to a 0-100 scale with higher scores indicating greater degree of fatigue.

    Measured: At baseline, 1 year, 2 years, 3 years, 4 years, 5 years

  9. Hospital anxiety and depression scale (HADS)

    The HADS is a 14 items questionnaire: 7 items related to anxiety and 7 items related to depression scored on a scale. Scores for items in each subscale of the HADS are summed to produce an anxiety score (HADS-A) or a depression score (HADS-D), or can be added to produce a total score corresponding to emotional distress (HADS-T). Each item is rated on a 4-point Likert scale (1 = "not at all", 2 = "a little", 3 = "quite a bit", and 4 = "very much"), for a total score ranging from 0-21 for each subscale. The entire scale (emotional distress) range from 0 to 42, with higher scores indicating more distress.

    Measured: At baseline, 1 year, 2 years, 3 years, 4 years, 5 years

  10. Functional Assessment of Cancer Therapy - Cognitive Function (FACT-Cog)

    The FACT-Cog is a self-assessment questionnaire to estimate memory, attention, concentration, language, and thinking abilities of patients before, during, and after chemotherapy. This questionnaire, composed of 37 items consists of four subscales: cognitive impairments perceived by the patient (20 items), comments from others (4 items), cognitive abilities perceived by the patient (9 items), and impact on quality of life (4 items). The Perceived Cognitive Impairments and the Comments from Others subscales are rated on 5-point Likerttype scale (from 0 = "Never" to 4 = "Several times a day"). An intensity 5-point Likert-type scale (from 0 "Not at all" to 4 "Very much") is used to rate perceived cognitive abilities and the impact on quality of life. For all subscales, a higher score represents better cognitive functioning or quality of life.

    Measured: At baseline, 1 year, 2 years, 3 years, 4 years, 5 years

  11. Impact of Cancer (including fear of recidivism)

    The Impact of Cancer Version 2 (IOCv2) is a 47-item questionnaire. The first 37 items are intended to measure 4 positive (Altruism/Empathy, Health Awareness, Meaning of Cancer, and Positive SelfEvaluation) and 4 negative (Appearance Concerns, Body Change Concerns, Life Interferences, and Worry) subscales, which total to two summary scores (Positive and Negative Impact). The 10 additional items constitute conditional dimensions applicable to subsets of survivors assessing employment concerns, relationship concerns for individuals with a partner, and relationship concerns for those without a partner. All items are scored on a five-point scale (1 = "strongly disagree", 2 = disagree, 3 = neutral, 4 = agree, and 5 = "strongly agree"). Higher scores on the positive impact indicate greater positive impacts, while higher scores on the negative impact indicate greater negative impacts.

    Measured: At baseline, 1 year, 2 years, 3 years, 4 years, 5 years

  12. Geriatric Core Dataset (G-CODE)

    The G-CODE was developed by the DIalog for personALization of management in geriatric OncoloGy (DIALOG) intergroup to assess the general health status of the older patient.

    The G-Code contains 10 tools incorporating seven scales to assess social environment, functional status, mobility, nutritional status, cognitive status, depressive mood, and comorbidities. The total scale range 0-62. High score indicate better condition.

    Measured: At baseline, 1 year, 2 years, 3 years, 4 years, 5 years

  13. Evaluate the safety of the treatment in the study population

    The National Cancer Institute-Common Terminology Criteria for Adverse Events version 5 (NCI-CTCAE v5.0) is widely accepted in the community of oncology research as the leading rating scale for adverse events. This scale, divided into 5 grades (1 = "mild", 2 = "moderate", 3 = "severe", 4 = "life-threatening", and 5 = "death") determined by the investigator, will make it possible to assess the severity of the disorders.

    Measured: Throughout study completion, up to 10 years.

Timeline

From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.

  1. First posted28 Mar 2022
  2. Study start12 Oct 2022
  3. Primary completion12 Nov 2030 (estimated)
  4. Study completionNov 2035 (estimated)

Resources

More details

For doctors and researchers: how the study is designed, who runs it, and its registry IDs.

Study design
Study type
Interventional
Phase
Phase 2
Primary purpose
Treatment
Allocation
Not applicable
Intervention model
Single group
Model description
This is a prospective, national, multicenter, single-arm, interventional, non-threshold crossing phase II study evaluating a therapeutic de-escalation that limits adjuvant hormone therapy to 2 years of aromatase inhibitor
Masking
None (open label)
Enrolment
696 participants (estimated)
IDs, dates and publications
ClinicalTrials.gov ID
NCT05297617
Sponsor's protocol ID
UC-BCG-2103
Other IDs
2021-002889-41, 2024-514480-26-00
Acronym
LESS
Status last verified
Jun 2026
First submitted
16 Mar 2022
Last updated
21 Jul 2026
Results posted
No
Data monitoring committee
No
FDA-regulated drug
No
FDA-regulated device
No
Individual data sharing
No

Questions about this trial

What is this clinical trial studying?

A Phase 2 study testing Anti-aromatase inhibitor in people with Breast Cancer, run by UNICANCER at 2 sites in France.

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 19 inclusion and 11 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 21 Jul 2026. Status can change between updates, so confirm with the study contact before making plans.

Where is the study taking place?

The record lists 2 sites in France. 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.

What does this phase mean?

Phase 2 studies give the treatment to a larger group to see whether it has the intended effect and to keep checking safety.

Not every study follows the same path, and some studies (observational studies, device studies) have no phase.

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 Clara GUYONNEAU, PharmD (0685167111, c-guyonneau@unicancer.fr), or a site near the patient. AzTrials does not enrol participants or take referrals.

What does the primary outcome measure?

Distant relapse-free interval (DRFI) (time frame: From date of beginning of hormonotherapy to onset of metastases or death, up to 5-years.). It is what the study was designed to measure, not a finding.

Where can I read the original study information?

On the ClinicalTrials.gov record for NCT05297617.

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 21 Jul 2026.

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