Moderately Hypofractionated Radiotherapy Alone for Stage I-IIB Non-small Cell Lung Cancer.

Introduction: The optimal management of patients with early non-small cell lung cancer (NSCLC) not amenable to surgical resection or stereotactic body radiotherapy (SBRT) or those with hilar nodal involvement ineligible for surgery or concurrent chemoradiotherapy is unclear. This report describes survival outcomes and toxicity profiles of patients treated with hypofractionated radiotherapy (HRT) alone.

Methods: A total of 52 patients with Stage I-IIB NSCLC treated with HRT alone between 2010-2018 were reviewed. Patients were categorized as having ultracentral tumors if the planning target volume contacted or overlapped the proximal bronchial tree, esophagus, pulmonary vein or artery. Overall survival (OS) and progression-free survival (PFS) were estimated using the Kaplan-Meier method and the competing risk cumulative incidence of locoregional failure (LRF) and distant failure (DF) were estimated using death without failure as a competing risk. Pneumonitis and esophagitis rates were evaluated as per Acute Common Terminology Criteria for Adverse Events (CTCAE) version 4.0.

Results: Of the 52 patients analyzed, 50 patients were treated with radiotherapy alone to a dose of 70.2 Gy in 26 fractions, one patient was treated with 68 Gy in 25 fractions and one patient was treated with 65 Gy in 26 fractions. The median age was 72 (range 48-89), 42% of patients had an Eastern Cooperative Oncology Group (ECOG) performance status of 2-3, 46% were stage I and 54% were stage II. Hilar nodal involvement was present in 21% of patients and 74% of node-negative patients had ultracentral primary tumors. Median OS was 39.6 months and the median PFS was 21.0 months. Overall three-year cumulative incidence of LRF and DF were 32% and 34%, respectively. Grade 3 pneumonitis occurred in two (4%) patients. No grade 3+ acute esophagitis or grade 4-5 toxicities were observed.

Conclusion: Hypofractionated thoracic radiotherapy consisting of 70.2 Gy is well-tolerated and results in favorable locoregional control for stage I-IIB patients who are not candidates for SBRT, surgery, or concurrent chemoradiotherapy.