Twice-Daily Thoracic Radiotherapy for Patients with Locally Advanced or Oligometastatic Non-Small Cell Lung Cancer: A Single-Center Observational Study

Abstract

<h3>Purpose/Objective(s)</h3> Radiotherapy is standard treatment for locally advanced or oligometastatic non-small cell lung cancer (NSCLC). Once-daily thoracic radiotherapy of 60ཞ66 Gy in 30ཞ33 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. <h3>Materials/Methods</h3> 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 40ཞ80 Gy (2ཞ4Gy/fraction, bid) and 30ཞ60 Gy (1.5ཞ2.0Gy/fraction, bid) to the primary lung tumor and positive lymph node metastases respectively. Patients received 2-4 cycles of chemotherapy or oral targeted drugs if the driver genes are positive. <h3>Results</h3> 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 IIBཞIIIC, 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 was 25.6% and 15.2%, respectively. The most common grade 3-4 adverse events were leukopenia (17 [13.7%]), thrombocytopenia (5 [4.0%]), anemia (15[12.0%]) and lymphopenia (30[24.2%]). None of the patients experienced fatal bronchopulmonary hemorrhage or tracheal fistula. <h3>Conclusion</h3> 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.