This is a non-interventional retrospective cohort study of premenopausal patients with HR+/HER2- breast cancer who are treated in the adjuvant setting with either Tamoxifen, Tamoxifen + Ovarial Function Suppression or Aromatase inhibitor + Ovarial Function Suppression.
The treatment landscape concerning the adjuvant endocrine therapy in premenopausal patients with early-stage hormone receptor positive (HRpos) breast cancer is quite heterogeneous and therapy recommendations can vary. Tamoxifen (TAM) is a common treatment option that does not require OFS, but research suggests that adding OFS to tamoxifen may improve outcomes. Aromatase inhibitors (AI) are another option, but they can only be used with OFS for premenopausal patients. Studies have shown that AI + OFS improves disease-free survival compared to TAM + OFS, but it may lead to additional side effects such as osteopenia and bone fractures. The CLEAR-B study aims to provide a detailed description of the therapy landscape in this therapeutic setting, including recurrence rates and overall survival with AI compared to TAM, as well as a comparison of the chosen therapies within prognostic subgroups. CLEAR-B is a retrospective cohort study, collecting data of premenopausal patients who were diagnosed with early-stage breast cancer between January 2016 and June 2019 in a certified breast cancer center. These patients had an intermediate or high risk of cancer recurrence, as defined by (neo)adjuvant chemotherapy, and/or pT≥2cm at the timepoint of definitive surgery and/or at least one positive lymph node at the time of definite surgery (pN+). The primary objective is to compare the invasive disease-free survival (iDFS) of patients who were treated with AI + OFS vs. those who were treated with TAM ± OFS. Additionally, the study will compare distant disease-free survival (DDFS) and overall survival (OS) between the two groups and perform subgroup analyses according to risk stratification (stage II and III). This study will be conducted at around 75 certified breast cancer centers and will enroll up to 3000 patients.
Study Type
OBSERVATIONAL
Enrollment
3,000
Department of Gynecology and Obstetrics, Erlangen University Hospital
Erlangen, Germany
RECRUITINGiDFS
The primary study aim is to show that aromatase inhibitor (AI) based treatments (AI arm) are not inferior to treatments based on tamoxifen (tamoxifen arm) in terms of invasive diseasefree survival (iDFS). iDFS will be assessed as time to event. Events for iDFS include: Invasive Ipsilateral Breast Tumor Recurrence (IBTR), Local/Regional Invasive Recurrence, Distant Recurrence, Death from BC, Death from Non-BC Cause, Death From unknown cause, Invasive Contralateral BC, Second Primary Invasive Cancer (non-breast)
Time frame: First start of adjuvant endocrine therapy until date of the above mentioned events up to 5 years
Comparison of iDFS
In case non-inferiority is confirmed, the superiority of Cohort AI+OFS over Cohort TAM will be tested with regard to iDFS. iDFS will be assessed as time to event. Events for iDFS include: Invasive Ipsilateral Breast Tumor Recurrence (IBTR), Local/Regional Invasive Recurrence, Distant Recurrence, Death from BC, Death from Non-BC Cause, Death From unknown cause, Invasive Contralateral BC, Second Primary Invasive Cancer (non-breast)
Time frame: First start of adjuvant endocrine therapy until date of the above mentioned events up to 5 years
Comparison of DDFS
To analyze the non-inferiority of the Cohort AI+OFS compared with the Cohort TAM with regard to distant disease-free survival (DDFS). DDFS will be assessed as time to event. Events for DDFS include distant recurrence, death from breast cancer, death from non-breast cancer cause, death from unknown cause.
Time frame: First start of adjuvant endocrine therapy until date of the above mentioned events up to 5 years
Comparison of OS
To analyze the non-inferiority of the Cohort AI+OFS compared with the Cohort TAM with regard to overall survival (OS). In case non-inferiority is confirmed, the superiority of Cohort AI+OFS over Cohort TAM will be tested with regard to OS. OS is defined as time from first start of adjuvant endocrine therapy until date of death due to any cause.
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Time frame: First start of adjuvant endocrine therapy until date of death up to 5 years
Comparison of iDFS in Cohort TAM
To compare patients within the Cohort TAM who were treated with OFS and those who were not treated with OFS. iDFS will be assessed as time to event. Events for iDFS include: Invasive Ipsilateral Breast Tumor Recurrence (IBTR), Local/Regional Invasive Recurrence, Distant Recurrence, Death from BC, Death from Non-BC Cause, Death From unknown cause, Invasive Contralateral BC, Second Primary Invasive Cancer (non-breast)
Time frame: First start of adjuvant endocrine therapy until date of the above mentioned events up to 5 years
Comparison of DDFS in Cohort TAM
To compare patients within the Cohort TAM who were treated with OFS and those who were not treated with OFS. DDFS will be assessed as time to event. Events for DDFS include distant recurrence, death from breast cancer, death from non-breast cancer cause, death from unknown cause.
Time frame: First start of adjuvant endocrine therapy until date of the above mentioned events up to 5 years
Comparison of OS in Cohort TAM
To compare patients within the Cohort TAM who were treated with OFS and those who were not treated with OFS. OS is defined as time from first start of adjuvant endocrine therapy until date of death due to any cause.
Time frame: First start of adjuvant endocrine therapy until date of death up to 5 years
Comparison of iDFS (TAM+OFS and AI+OFS)
To compare patients of Cohort AI+OFS with patients in Cohort TAM, who were treated with OFS with regard to iDFS. iDFS will be assessed as time to event. Events for iDFS include: Invasive Ipsilateral Breast Tumor Recurrence (IBTR), Local/Regional Invasive Recurrence, Distant Recurrence, Death from BC, Death from Non-BC Cause, Death From unknown cause, Invasive Contralateral BC, Second Primary Invasive Cancer (non-breast)
Time frame: First start of adjuvant endocrine therapy until date of the above mentioned events up to 5 years
Comparison of DDFS (TAM+OFS and AI+OFS)
To compare patients of Cohort AI+OFS with patients in Cohort TAM, who were treated with OFS with regard to DDFS. DDFS will be assessed as time to event. Events for DDFS include distant recurrence, death from breast cancer, death from non-breast cancer cause, death from unknown cause.
Time frame: First start of adjuvant endocrine therapy until date of the above mentioned events up to 5 years
Comparison of OS (TAM+OFS and AI+OFS)
To compare patients of Cohort AI+OFS with patients in Cohort TAM who were treated with OFS. OS is defined as time from first start of adjuvant endocrine therapy until date of death due to any cause.
Time frame: First start of adjuvant endocrine therapy until date of death up to 5 years
Comparison of iDFS (TAM-OFS and AI+OFS)
To compare patients of Cohort AI+OFS with patients in Cohort TAM, who were not treated with OFS with regard to iDFS. iDFS will be assessed as time to event. Events for iDFS include: Invasive Ipsilateral Breast Tumor Recurrence (IBTR), Local/Regional Invasive Recurrence, Distant Recurrence, Death from BC, Death from Non-BC Cause, Death From unknown cause, Invasive Contralateral BC, Second Primary Invasive Cancer (non-breast)
Time frame: First start of adjuvant endocrine therapy until date of the above mentioned events up to 5 years
Comparison of DDFS (TAM-OFS and AI+OFS)
To compare patients of Cohort AI+OFS with patients in Cohort TAM, who were not treated with OFS with regard to DDFS. DDFS will be assessed as time to event. Events for DDFS include distant recurrence, death from breast cancer, death from non-breast cancer cause, death from unknown cause.
Time frame: First start of adjuvant endocrine therapy until date of the above mentioned events up to 5 years
Comparison of OS (TAM-OFS and AI+OFS)
To compare patients of Cohort AI+OFS with patients in Cohort TAM who were not treated with OFS. OS is defined as time from first start of adjuvant endocrine therapy until date of death due to any cause.
Time frame: First start of adjuvant endocrine therapy until date of death up to 5 years
Influence of disease stage
To conduct multivariate analyses to estimate the influence of disease stage on prognosis.
Time frame: Baseline until onset of disease progression or death up to 5 years
Risk Factors
To conduct subgroup analyses for the survival outcomes (iDFS, DDFS, OS) according to risk stratification (stage II and stage III)
Time frame: Baseline until onset of disease progression or death up to 5 years
NATALEE Comparison
To compare patients who are matching the inclusion and exclusion criteria of the pivotal study NATALEE and who were treated in Cohort AI+OFS with patients matching the NATALEE population and who were treated in Cohort TAM.
Time frame: Baseline until onset of disease progression or death up to 5 years