Navigated Superselective Intrabronchial Brachytherapy for peripheral lung cancer: an old technique plays a new role

<bold>Background:</bold> For early stage non-surgical Peripheral Lung Cancer（PLC）, SBRT（stereotactic body radiation therapy） carries a high risk of radiation pneumonia, and IGRT（image guided radiotherapy） mostly relies on percutaneous puncture. <bold>Objectives:</bold> To explore the safety and effectiveness of Navigated Superselective Intrabronchial Brachytherapy(NSIB) in the treatment of PLC. <bold>Methods:</bold> Six patients with PLCs successfully underwent treatment with NSIB following pathway planning, and were subsequently followed up to assess survival and treatment-related toxicities. <bold>Results:</bold> The endobronchial applicators were successfully placed inside the tumors of all patients using advanced navigation techniques according to the pre-treatment plan, and brachytherapy was delivered at curative doses after evaluation using radiotherapy planning software. None of the patients showed local progression of the treated lesions during the follow-up for a duration ranging from 11 months to 35 months, with a median follow-up time of 23 months. The patient with the longest follow-up, nearly 3 years, exhibited a stable condition. After undergoing endobronchial brachytherapy, patients predominantly experienced localized fibrosis as indicated. No significant alterations in cardiopulmonary function were detected during the follow-up, and no other adverse effects were found. <bold>Conclusion:</bold> The use of endobronchial brachytherapy for the curative treatment of PLCs is feasible. Furthermore, the development of novel bronchial navigation techniques has the potential to broaden the application of endobronchial brachytherapy.