Twice-daily thoracic radiotherapy for patients with locally advanced or oligometastatic non-small cell lung cancer: A single-center observational study.

Abstract

e21070 Background: Radiotherapy is standard treatment for locally advanced or oligometastatic non-small cell lung cancer (NSCLC). Once-daily thoracic radiotherapy of 60～66 Gy in 30～33 fractions is considered to be the most effective schedule in the past. The aim of this study was to investigate whether twice-daily thoracic radiotherapy improves survival and reduces toxicity. Methods: Patients aged 18 years and older with treatment-naive confirmed locally advanced or oligometastatic NSCLC, Eastern Cooperative Oncology Group (ECOG) performance status 0-2, and measurable disease according to the Response Evaluation Criteria in Solid Tumors version 1.1 were eligible. Participants received thoracic radiotherapy of 40～80 Gy(2～4Gy/fraction, bid) and 30～60 Gy (1.5～2.0Gy/fraction, bid) to the primary lung tumour and positive lymph node metastases respectively. Patients received 2-4 cycles of chemotherapy or oral targeted drugs if the driver genes is positive. Results: In total, 124 patients were included in this study between February 2016 to March 2020. The median patient age was 61 years old and 113(91.1%) patients were male. The patient group included 72 patients with stage IIB～IIIC, and 52 patients with stage IV disease. Histological diagnosis was squamous cell carcinoma in 68 patients, adenocarcinoma in 56 patients. Median follow-up was 24.8 months (range 1.5-59.7months). The 1, 2, 3-year OS were 83.1% and 70.6%, 60.6%, respectively. The incidence of ≥Grade 2 radiation pneumonitis and esophagitis were was 25.6% and 15.2%, respectively. The most common grade 3-4 adverse events were leukopenia (17 [13.7%]), thrombocytopenia (5 [4.0%]), anaemia (15[12.0%]) and lymphopenia (30[24.2%]). None of the patients experienced fatal bronchopulmonary hemorrhage or tracheal fistula. Conclusions: Twice-daily thoracic radiotherapy is feasible and well tolerated for locally advanced or oligometastatic NSCLC. It needs to be further confirmed by large randomized controlled clinical studies. Clinical trial information: ChiCTR2100055096.