Elderly breast cancer (BC) patients have been underrepresented in clinical trials whereas ∼60% of deaths from BC occur in women aged 65 years and older. The management of elderly women with early BC requires careful evaluation of risks and benefits of available treatment options. Clinical trials for elderly patients in the adjuvant setting are lacking, and efficacy results obtained in general population cannot be directly extrapolated to elderly patients without specific evidences. Therefore, we examined factors associated with the prescription of adjuvant chemotherapy (aCT) and the impact of this treatment on overall survival (OS) in a large cohort of patients aged 65 years and older.
Patients were retrospectively identified from a large cohort of 23,134 early BC patients who underwent primary surgery in 18 academic centres between 1990 and 2014. A binary logistic regression was built to identify the factors associated with aCT administration. The impact of aCT on OS was analysed using a multivariate Cox regression model including age, histology, grade, tumour size, lymphovascular invasion (LVI), nodal status and endocrine therapy (ET) and endocrine receptors (ER). A propensity score-based matching analysis was performed.
Of 6605 patients aged 65 years and older, 1493 received aCT (22.6%). Administration of aCT was predominantly associated with macroscopic lymph node involvement (LNi) and ER-negative status but common predictors, such as age < 80 years, ductal histology, tumour size ≥ 20mm, ET and tumour grade were also found as statistically significant. In a Cox model including age, histology, LVI, tumour size, LNi, ET, ER and grade, aCT was significantly associated with better OS (HR 0.71, 95% CI 0.58 to 0.86; p < 0.001). Ten-year OS estimates in case-matched patients for propensity score analysis were 76.8% (95% CI 76.6 to 77.1) in the aCT group vs. 61.5% (95% CI 61.3 to 61.7) without aCT (p < 0.0001). Interestingly, this benefit was maintained in the over-80s subgroup.
The factors associated with aCT use in the elderly are similar to those usually found in younger age groups. By highlighting an OS benefit, even in the “very old” subgroup, our results may help clarifying the role of aCT in elderly patients.
Clinical trial identification
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All authors have declared no conflicts of interest.