Leuprolide and Goserelin for Ovarian Function Suppression in Pre- or Peri-menopausal Women With Breast Cancer, OFS Trial

Proportion of participants with ultrasensitive estradiol concentration > 10 pg/ml

Time frame · During the first 24 weeks of therapy

Analyses will primarily be descriptive reporting the overall and by treatment group proportions of women with ultrasensitive estradiol concentration and the corresponding exact binomial 95% confidence intervals over the first 24 weeks of gonadotropin releasing hormone agonist (GnRHa) therapy.

Proportion of participants with ultrasensitive estradiol concentration > 10 pg/ml

Time frame · At 4 weeks after initial GnRHa treatment administration

Will be described with corresponding 95% confidence intervals overall and by treatment group.

Proportion of participants with ultrasensitive estradiol concentration > 10 pg/ml

Time frame · Any time after 4 weeks of initial GnRHa treatment administration, assessed cycle 3 day 1-cycle 7 day 1 (cycle length = 28 days)

Will be described with corresponding 95% confidence intervals overall and by treatment group.

Change in Functional Assessment of Cancer Therapy-(FACT)-Endocrine Subscale (ES) Trial Outcome Index

Time frame · Up to 24 weeks

Will use linear mixed-effects models with fixed effects for study group, time, and their interaction. For each outcome, a random intercept for each participant will be included to account for within-subject correlation. This approach allows for estimation of longitudinal trends in FACT-ES scores and assessment of whether changes over time differ between treatment arms. Missing data will be handled using maximum likelihood estimation under the assumption of missing at random (MAR).

Change in FACT-ES Endocrine Symptom Subscale

Time frame · Up to 24 weeks

Will use linear mixed-effects models with fixed effects for study group, time, and their interaction. For each outcome, a random intercept for each participant will be included to account for within-subject correlation. This approach allows for estimation of longitudinal trends in FACT-ES scores and assessment of whether changes over time differ between treatment arms. Missing data will be handled using maximum likelihood estimation under the assumption of MAR.

Percentage of participants reporting discomfort of 6/10 or higher on the Discomfort of Injection questionnaire

Time frame · At the day following initial GnRHa injection

Will be described by study arm and with corresponding exact binomial 95% confidence intervals.

Percentage of participants reporting discomfort of 6/10 or higher on the Discomfort of Injection questionnaire

Time frame · Before administration of the second GnRHa injection

Will be described by study arm and with corresponding exact binomial 95% confidence intervals.

Receipt of GnRHa therapy within ± 1 day of planned dosing

Time frame · Up to 24 weeks

Planned dosing should be given every 28 days. The proportion of patients who receive GnRHa therapy within ± 1 day of planned dosing will be reported overall and by study arm with corresponding exact binomial 95% confidence intervals.

Incidence of adverse events (AEs)

Time frame · Up to 24 weeks

AEs will be graded and described using National Cancer Institute Common Terminology Criteria for Adverse Events version 5.0. Will be reported using descriptive statistics for each GnRHa study arm.