This study aimed to analyze the long-term outcomes of hypofractionated whole-breast irradiation (WBI) (HF-WBI) compared with those of conventionally fractionated WBI (CF-WBI) for early breast cancer treated with breast-conservation surgery (BCS) and adjuvant WBI in Taiwan. This study included patients treated at our institution between 2012 and 2016. All patients with early breast cancer received BCS (pT1-2, pN0, M0) and adjuvant WBI through one of two treatment schemes. Propensity score matching analysis was conducted to create comparable cohorts. The major result is ipsilateral breast tumor recurrence (IBTR) rates and overall survival rates. A total of 869 patients with early-stage breast cancer received adjuvant HF-WBI or CF-WBI were included. After matching, 718 patients were separated into two groups of the same number. With a median follow-up of 66 months, seven cases of IBTR were noted (three for CF, four for HF). There were no significant differences between the HF-WBI and CF-WBI groups in 5-year IBTR rates (0.9% vs 0.6%, P = 0.3887, 95% CI [0.25-7.79]) and 5-year overall survival rates (98.1% vs 98.9%, P = 0.4702, 95% CI [0.32-3.49]). In our institution, the use of HF-WBI increased significantly from 5% before 2012 (Q3) to 92% in 2016 (Q4). There was no significant difference in grade 1-2 toxicity between the two treatment groups. Fewer cases of grade 3 skin toxicity noted in the HF-WBI group (zero vs four events). HF-WBI had similar IBTR, OS and toxicity to CF-WBI.

A 54-year-old woman presented to an outpatient clinic with a recurrence of triple-negative breast cancer and multiple bone metastases. The patient had a large mass lesion of 10 cm on the sternum. She received the immune checkpoint inhibitors pembrolizumab and taxane. Initially, the patient responded excellently to treatment, but stopped pembrolizumab for grade IV skin toxicity with multiple ulcerative wounds over the bilateral leg and trunk. The lesions abated following administration of antibiotics and oral prednisolone for two months. After that, she was referred to the radiation oncology department for further treatment. She received radiotherapy for the sternum mass but stopped radiation at 42Gy/21 fractions for severe dyspnea and fever. Blood sampling found leukocytosis with neutrophil predominance. Chest radiography showed bilateral lung infiltration. Pulmonary CT scan yielded bilateral lung patchy consolidation compatible with radiation isodose-line. Bronchial lavage showed positive Pneumocystis jiroveci PCR. Dyspnea improved after titrating methylprednisolone within two days. The patient recovered well with TMP-SMX and glucocorticoids after the initiation of therapy.