biostudies-literatureUnknown12(1)Korzets Y<h4>Background</h4>Menstrual and parity history might impact the risk for breast cancer. Data on the impact of these factors on other tumor characteristics are limited.<h4>Methods</h4>A single center retrospective cohort study comprising all women with estrogen receptor (ER) positive, human epidermal growth factor receptor 2 (HER2) negative, early breast cancer whose tumors were sent to OncotypeDX analysis. The prespecified subgroups were investigated: age of menarche (< 12 vs. ≥ 12 years), number of deliveries (0 vs. ≥ 1 childbirth and ≥ 5 childbirth vs. other), age of first delivery (≥ 30 years vs. younger age) and postmenopausal compared to premenopausal. The impact of age of menopause was also assessed categorically, using early (< 45 years) and late age of menopause (> 55 years). DiffDiscover. Oncology26https://www.ebi.ac.uk/biostudies/studies/S-EPMC8777527biostudies-literatureThe impact of endogenous estrogen exposures on the characteristics and outcomes of estrogen receptor positive, early breast cancer.PMC8777527Mutai RShochat TMoore AKorzets YYariv OGoldvaser HYerushalmi RfalseThe impact of endogenous estrogen exposures on the characteristics and outcomes of estrogen receptor positive, early breast cancer.<h4>Background</h4>Menstrual and parity history might impact the risk for breast cancer. Data on the impact of these factors on other tumor characteristics are limited.<h4>Methods</h4>A single center retrospective cohort study comprising all women with estrogen receptor (ER) positive, human epidermal growth factor receptor 2 (HER2) negative, early breast cancer whose tumors were sent to OncotypeDX analysis. The prespecified subgroups were investigated: age of menarche (< 12 vs. ≥ 12 years), number of deliveries (0 vs. ≥ 1 childbirth and ≥ 5 childbirth vs. other), age of first delivery (≥ 30 years vs. younger age) and postmenopausal compared to premenopausal. The impact of age of menopause was also assessed categorically, using early (< 45 years) and late age of menopause (> 55 years). Diff2021-01-01T00:00:00Z2021 Aug2025-04-18T17:08:54.301Z2025-04-07T04:44:02.083ZS-EPMC87775273520143410.1007/s12672-021-00420-x