Radiotherapy in elderly patients with breast cancer: a literature review of acute and late toxicity

Radiotherapy (RT) induced toxicity in elderly patients is not well documented in the available literature due to the inhomogeneous and fragmentary data. Aim of this study was to review literature data on acute and late toxicity in elderly breast cancer patients treated with RT. The primary endpoint was RT-related acute and late toxicity in elderly breast cancer (BC) patients. The secondary endpoint was RT interruption rate in this patients' population. All studies reporting RT-related acute and/or late toxicity in elderly women with breast cancer were included. All types of RT settings were included and no restriction was applied regarding other primary/adjuvant associated treatment. A bibliographic search was performed on PubMed. Only articles in English were considered while no chronological limitation was applied. Twenty-two studies were included in this analysis: 12 retrospective, 5 prospective observational trials, 1 phase III trial sub-analysis, and 4 phase I-II trials. Thirteen studies reported results about whole breast irradiation (WBI) delivered by external beams (EB) RT ± boost on the tumor bed. Nine studies reported results about accelerated partial breast irradiation (APBI) based on EB RT (2 studies), intraoperative RT (IORT: 2 studies), and brachytherapy (BRT: 2 studies); three studies compared different treatment techniques. Overall, reported acute grade (G) ≥3 toxicity ranged from 0.0% to 10.5% and late toxicity from 0.0% to 13.0%. RT discontinuation/interruption rates ranged between 0.0% and 2.0%. Acute G ≥3 toxicity rates were 2.0%, 6.7%, and 5.2% with EB-APBI, BRT, and IORT, respectively. Late G ≥3 toxicity with EB-APBI was 2.8%. No late G ≥3 toxicity was recorded in studies reporting on BRT and IORT. With WBI, the overall rates of G ≥3 toxicity were 3.0% (acute) and 1.8% (late). Higher toxicity rates were observed with weekly hypofractionation. None of the studies directly comparing age subgroups found age-related differences. Our findings suggest that RT of breast cancer is well tolerated even in elderly patients with toxicity rates comparable to those of the general population. Given these considerations, RT omission in elderly patients with breast cancer should be carefully evaluated limiting this option to very selected critical patients.