Efficacy and safety of adjuvant therapies in older patients with breast cancer: a systematic review and meta-analysis of real-world data

Background: Insufficient data available for older patients with breast cancer complicates decision-making regarding optimal treatment. A systematic review that uses real-world data is required for assessing the effectiveness and potential adverse effects of various therapies for this age group of patients. Methods: Databases of PubMed, Embase, and Cochrane Library were searched. We included clinical studies that evaluated various treatments for geriatric breast cancer, including adjuvant radiation therapy, hypofractionated radiation therapy (hypo-RT) and accelerated and partial breast irradiation (APBI), endocrine therapy, chemotherapy, and targeted therapy. Results: A total of 71 studies were retrieved. Adjuvant radiation therapy significantly improved overall survival (OS) compared with no radiation [hazard ratio (HR) = 0.60, 95% confidence interval (CI) 0.54–0.67]. The pooled estimates of OS for hypo-RT and APBI demonstrated no inferiority compared with conventional radiation. Both endocrine treatment (HR = 0.63, 95% CI 0.43–0.92) and chemotherapy (HR = 0.76, 95% CI 0.65–0.88) significantly increased OS compared with no treatment. Trastuzumab monotherapy significantly enhanced OS compared with no trastuzumab use (HR = 0.23, 95% CI 0.07–0.73). Conclusion: Despite concerns about potential complications during treatment in older patients, proactive therapies significantly increase their survival rates. For patients who are frailer, hypo-RT and APBI offer survival rates comparable to traditional modalities. Additionally, targeted therapy as a monotherapy holds promise as a viable option for patients with HER2-positive breast cancer who cannot undergo chemotherapy. Therefore, by conducting thorough general assessments and clinical evaluations, the side effects of postoperative treatments can be effectively managed. © The Author(s), under exclusive licence to The Japanese Breast Cancer Society 2024.