P85 Direct comparison of primary (neoadjuvant) endocrine therapy vs primary chemotherapy in postmenopausal women with ER-positive breast cancer

581 Background: While neoadjuvant chemotherapy (NACT) has been established as the standard of care for medically fit patients, there has been renewed interest in utilizing neoadjuvant endocrine therapy (NET) for the treatment of women with estrogen-receptor (ER) positive, HER-2 negative breast cancer. Rates of pCR are known to be low in this population, but there is inconsistent data regarding downstaging and long-term outcomes in a non-trial setting with NET vs NACT. Methods: A prospective institutional databaseof breast cancer patients treated with neoadjuvant therapy at the British Columbia Cancer Agency from 2012-2016 was analyzed to identify all medically fit patients with ER positive, HER2 negative breast cancer. Patients were then divided into two groups: those who received NET or NACT. Baseline characteristics were compared between groups. A matched analysis (age, stage and grade) was then performed to compare rates of downstaging, pCR and scores from a validated neoadjuvant therapy outcomes calculator (CPS+EG). Results: A total of 154 patients met eligibility criteria for this study. One hundred and six patients (69%) received NACT and 48 (31%) received NET. Women offered NACT were significantly younger (51 vs 64y, p < 0.001) than those offered endocrine therapy and presented with a higher clinical stage (LR 27.93, p = 0.002). According to multiple linear regression for downstaging, clinical stage followed by NACT were the most important predictors of downstaging. When matched for age, stage and grade, downstaging was significantly higher with NACT (31/48, 65%) as compared to NET (12/48, 25%), p < 0.001. Of these, 12.5% achieved pCR with NACT as compared to 2.1% with NET, LR 4.243, p = 0.039. No significant differences in CPS+EG scores were identified when comparing NACT to NET. Conclusions: Significantly higher rates of downstaging were achieved with NACT as compared to NET when patients were matched for age, stage and grade. Rates of pCR remain low for ER-positive breast cancer patients. Although not validated with the use of NET, CPS+EG scores predicting long-term outcomes were not significantly different with NET compared to NACT.

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Abstract P5-13-02: Neoadjuvant endocrine therapy for estrogen receptor (ER) positive breast cancer: Comprehensive systematic review and meta-analysis

10.1158/1538-7445.sabcs15-p5-13-02 ◽

2016 ◽

Author(s):

L Spring ◽

A Gupta ◽

KL Reynolds ◽

MA Gadd ◽

SJ Isakoff ◽

...

Keyword(s):

Breast Cancer ◽

Systematic Review ◽

Estrogen Receptor ◽

Endocrine Therapy ◽

Meta Analysis ◽

Neoadjuvant Endocrine Therapy ◽

Er Positive ◽

Positive Breast Cancer

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Adjuvant endocrine therapy for postmenopausal women with ER positive breast cancer: tailoring therapy based on tumors and patients

The Breast ◽

10.1016/s0960-9776(17)30096-6 ◽

2017 ◽

Vol 32 ◽

pp. S19-S20

Author(s):

H.J. Burstein

Keyword(s):

Breast Cancer ◽

Postmenopausal Women ◽

Endocrine Therapy ◽

Adjuvant Endocrine Therapy ◽

Er Positive ◽

Positive Breast Cancer

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Clinical validity of clinical treatment score 5 (CTS5) for estimating risk of late recurrence in unselected, non-trial patients with early oestrogen receptor-positive breast cancer

Breast Cancer Research and Treatment ◽

10.1007/s10549-020-06013-6 ◽

2020 ◽

Author(s):

Juliet Richman ◽

Alistair Ring ◽

Mitch Dowsett ◽

Ivana Sestak

Keyword(s):

Breast Cancer ◽

High Risk ◽

Postmenopausal Women ◽

Endocrine Therapy ◽

Oestrogen Receptor ◽

Premenopausal Women ◽

Clinical Validity ◽

Er Positive ◽

Extended Endocrine Therapy ◽

Positive Breast Cancer

Abstract Purpose Clinical Treatment Score at 5 years (CTS5) is a prognostic tool to estimate distant recurrence (DR) risk after 5 years of endocrine therapy for postmenopausal women with oestrogen receptor-positive (ER-positive) breast cancer. Methods The validity of CTS5 was tested in a retrospective cohort of patients diagnosed with early ER-positive breast cancer. The primary endpoint was DR in years 5–10. The primary analysis cohort consisted of postmenopausal women, with premenopausal women as a secondary analysis cohort. Cox regression models were used to determine the prognostic value of CTS5 and Kaplan–Meier curves were used with associated 10-year DR risks (%). Results 2428 women were included with a median follow-up of 13.4 years. The CTS5 was significantly prognostic in both postmenopausal (N = 1662, HR = 2.18 95% CI (1.78–2.67)) and premenopausal women (N = 766, HR = 1.84 95% CI (1.32–2.56)). The 10-year DR risks were 2.9% (1.9–4.5), 7.2% (5.3–9.9), and 12.9% (10.0–16.7) for low, intermediate and high risk in postmenopausal women and 3.8% (2.2–6.7), 6.9% (4.4–10.8), and 11.1% (7.4–16.5) in premenopausal women, respectively. The number of observed DRs was significantly greater than expected in those predicted to be at high risk by CTS5 but this discordance was lost when those receiving more than 60 months of endocrine therapy were excluded. Conclusions The CTS5 demonstrated clinical validity for predicting late DR within a large cohort of unselected postmenopausal patients but less so in premenopausal patients. Calibration of the CTS5 was good in patients who did not receive extended endocrine therapy. The CTS5 low-risk cohort has risk of DR so low as to not warrant extended endocrine therapy.

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