(14) Evaluating The Mortality in Women with Newly Diagnosed Early-Stage Breast Cancer Comparing Surgery Against Primary Endocrine Therapy

Saturday, August 27, 2022

8:00 AM – 6:00 PM CEST

Location: Hall C

Publication Number: 688

Presenting Author(s)

Yubo Wang
– The University of Manchester, Manchester, Lancashire, United Kingdom

Co-Author(s)

Douglas Steinke, PhD, FISPE
– University of Manchester, Manchester, Lancashire, United Kingdom
Sean Gavan
– Research Fellow, Manchester Centre for Health Economics, England, United Kingdom
Li-Chia Chen
– Senior Lecturer, University of Manchester, England, United Kingdom

Background: With an increasing number of postmenopausal women diagnosed with early-stage breast cancer at age>70 years, primary endocrine therapy (PET) has been widely used as an alternative to surgery for treating older women with breast cancer. However, limited randomised controlled trials assess the comparative effectiveness between PET and surgery.

Objectives: The cohort study compared the mortality outcome between surgery and PET in women with breast cancer.

Methods: Women aged ≥50 years with a newly diagnosed, early-stage breast cancer were identified from Clinical Practice Research Datalink (Gold and Aurum) linking to Hospital Episode Statistics, Cancer Registry, and national death registration from 2000 to 2016 in England and followed from the date of diagnosis to death before 2019. In both older (≥70 years) and younger (50-69 years) groups, propensity scores derived from age (by 5-year intervals), Hospital Risk Frailty Score (3 levels) and Charlson Comorbidity Index (3 levels) and Index of Multiple Deprivation (5 levels), were used to match patients receiving PET or surgery by inverse probability of weight. All-cause and breast cancer-specific mortality were analysed by Kaplan-Meier survival analysis and Cox regression, adjusted for the above propensity score as doubly robust estimations, and presented in Hazard Ratio (HR) and 95% confidence intervals (95%CI).

Results: Most women with breast cancer (58,804) were diagnosed at a younger age (61%). The proportion of patients receiving surgery and PET differed between younger (93% vs. 7%) and older groups (70% vs. 30%). The 10-year overall survival was higher in surgery than PET in both younger (29% vs 8%) and older (0.8% vs 0.04%) groups. PET incurred a significantly higher risk of all-cause mortality in younger (HR: 2.72; 95%CI: 2.36, 3.14) and older (HR: 2.48; 95%CI: 2.31, 2.67) groups. Likewise, PET has a higher risk of breast cancer specific mortality in younger (HR: 3.27, 95%CI: 2.75, 3.90) and older (HR: 3.62, 95%CI: 3.20, 4.07) groups.

Conclusions: Despite the high proportion of PET used in older women with early-stage breast cancer, surgery is superior to PET in reducing mortality for women with early breast cancer, regardless of age. Further research is needed to optimise clinical decisions in allocating frail, unfit fro surgery patients to PET.