Abstract P1-08-16: The influence of patient fitness on the likelihood of receiving primary surgery in older women with breast cancer: A population based cohort study
Authors: Jauhari Y , Gannon M , Medina J , Horgan K , Dodwell D , Cromwell D 
Published: May 2019

Abstract
Introduction: There is evidence of variation in the patterns of treatment of older women with breast cancer (BC). As women age, there are less similarities in terms of their functional ability, physiology and social wellbeing. This multifaceted relationship between disease and ageing makes the interpretation of age-related differences in BC management and outcomes at a population level complex. Measuring frailty is as an emerging concept and offers a way to standardise how characteristics of ageing are used in BC.
Objective: We compared the primary treatment patterns of women aged ≥70yrs compared to those aged 50–69yrs, with early invasive BC (EIBC; stage 1-3A); using a novel measure of frailty in addition to commonly used patient fitness measures.
Methods: Women aged ≥50yrs, diagnosed with unilateral EIBC in England and Wales between 01/01/2014 and 31/12/2016; were identified by linkage of several national datasets. Patient fitness was measured by the reported WHO performance status (WHO PS), a calculated Charlson comorbidity score (CCS) and a developed frailty measure based on the electronic Frailty Index (eFI). Multilevel logistic regression was used to account for clustering in the data.
Results: Among 126,111 women aged ≥50yrs with BC, 88,028 had EIBC: 88% in women aged 50-69yrs and 75% in women aged ≥70yrs. Table 1 describes the proportion of women who received surgery by age and measures of fitness. Overall, older women were less likely to undergo primary surgery, regardless of fitness. For each measure of fitness, fewer women in both age groups underwent surgery as their levels of fitness decreased; the magnitude of this change was greater for women aged ≥70yrs. Older women were also less likely to receive BCS for tumours &lt;5cm, compared to women aged 50-69yrs.
Receipt of surgery in women aged ≥50years with EIBC according to CCS, eFi and WHO PS status, by age at diagnosisMeasure of fitness50-69 years70+years No. of patients% having surgeryNo. of patients% having surgeryNumber of women5481796%2343687%Charlson comorbidity score04861697%2343687%1345495%439067%1+106389%309645%Unknown168462%228914%eFIFit5250697%570789%Mild frailty56489%236947%Moderate to severe frailty6362%66921%Unknown168462%228914%WHO performance status01507397%570788%1137293%226474%219885%91146%3-411652%79517%Unknown3805896%2353476%
The association between independent factors of ageing and fitness, and 'no surgery' remained after accounting for case-mix differences and clustering within geographical region. Compared to women aged 50–69yrs, there was strong regional variation in the adjusted rate of surgical treatment for EIBC in women aged ≥70yrs.
Discussion: Older women are less likely to undergo surgery for EIBC. Even a minor decrease in fitness levels significantly impacts the likelihood of receiving surgery in women ≥70yrs; such a pattern is not observed in women aged 50–69yrs. Long-term follow up of these women will enable further understanding of the implications of this variability in practice on outcomes. We also acknowledge poor data completion for the WHO PS, and propose that eFI is suitable replacement measure of fitness in older patients with BC.
Citation Format: Jauhari Y, Gannon M, Medina J, Horgan K, Dodwell D, Cromwell D. The influence of patient fitness on the likelihood of receiving primary surgery in older women with breast cancer: A population based cohort study [abstract]. In: Proceedings of the 2018 San Antonio Breast Cancer Symposium; 2018 Dec 4-8; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2019;79(4 Suppl):Abstract nr P1-08-16.