Cancer
Conditions
Interventions
Morning Afternoon Tamoxifen Administration
Evening Night Tamoxifen Administration
Sponsors
Kafr ElSheikh University
Eligibility
Sex/Gender
Female
Inclusion criteria
Inclusion criteria: Female, aged =18 years at time of tamoxifen initiation Histologically confirmed invasive breast carcinoma (ductal or lobular) ER-positive (Allred score =6, or =10% positive nuclei by IHC) and/or PR-positive HER2-negative (IHC 0/1+, or IHC 2+ with negative FISH/CISH) High-risk disease: pN1-3 (=1 positive axillary node), tumour grade 3, Ki-67 =20%, or Oncotype DX Recurrence Score =26 Completed primary surgical treatment (BCS or mastectomy) with curative intent Received adjuvant tamoxifen 20 mg/day for a minimum of 24 consecutive months Documented consistent tamoxifen administration time (morning/afternoon or evening/night) for =24 months, extractable from pharmacy records, nursing medication administration records, or structured EMR entries Minimum 24 months of oncological follow-up from tamoxifen initiation
Exclusion criteria
Exclusion criteria: Stage IV (metastatic) disease at diagnosis Concurrent or prior malignancy within 5 years (except DCIS or non-melanoma skin cancer) Use of aromatase inhibitors in lieu of or sequentially before tamoxifen within the same adjuvant treatment period under study Strong CYP2D6 inhibitor use (fluoxetine, paroxetine, bupropion) concurrently with tamoxifen Night-shift workers with documented circadian disruption Pregnancy or planned pregnancy during tamoxifen treatment Incomplete administration time documentation (<6 months of consistent, time-stamped records) Participation in a contemporaneous interventional clinical trial affecting endocrine therapy
Design outcomes
Primary
| Measure | Time frame |
|---|---|
| 5-year Disease-Free Survival (DFS) — time from tamoxifen initiation to first event: local/regional recurrence, distant metastasis, contralateral breast cancer, second primary cancer, or death from any cause | — |
Secondary
| Measure | Time frame |
|---|---|
| 5-year Overall Survival (OS) — time from tamoxifen initiation to death from any cause;Distant Metastasis-Free Survival (DMFS) — time from tamoxifen initiation to first distant metastatic event or death;Locoregional Recurrence Rate (LRR) — proportion with ipsilateral breast/chest wall or regional nodal recurrence;Medication Adherence Rate — proportion of prescribed tamoxifen doses dispensed (medication possession ratio, MPR), stratified by administration-time group | — |
Countries
Egypt
Contacts
Public ContactHagar Elmekawy
Lecturer of clinical pharmacy Department of Clinical Pharmacy Faculty of Pharmacy
Outcome results
None listed