P19.11 Endobronchial Brachytherapy as Curative Therapy for Postoperative Intrabronchial Oligometastasis in Non-Small Cell Lung Cancer

Abstract

Lung cancer is a major health problem and a leading cause of cancer mortality worldwide. Although intratracheal/bronchial oligometastasis is a very rare type of recurrence after surgery of lung cancer, such patients often suffer with symptoms of respiratory tract obstruction, including cough, bloody sputum and dyspnea. Surgical intervention might be difficult to perform due to reduced postoperative general condition and invasiveness associated with reoperation. In such cases of medically inoperable intratracheal/bronchial oligometastasis, endobronchial brachytherapy (EBB) plays an important role as curative treatment. We present 3 cases with recurrent intrabronchial oligometastasis who were curatively treated with a combination of external beam radiotherapy (ERBT) and EBB from May 2013 to October 2018. Patient characteristics are listed in Table1. In accordance with the present Japanese guideline1) for curative EBB, our radiation schedule is composed of 40 Gy of EBRT and 18 Gy in three fractions of EBB. We use a special source-centralizing applicator for EBB developed by Nomoto Y et al.2) to avoid eccentric distribution of the radiation dose and to protect the mucosal membrane of the bronchus from high-dose irradiation. EBB was performed in cooperation with radiologists under mild sedation without hospitalization. There were no complications in all cases using the applicator. Local control was confirmed by bronchoscopic evaluation in all cases. All patients are alive after 17, 24 and 78 months of follow-up, respectively, without evidence of recurrence. In the case of adenocarcinoma (Case 1), two metastatic lung cancers were discovered in the untreated lobe 3 years after EBB and cured by partial wedge resection. As both cases (Case 2,3) of squamous cell carcinoma were intrabronchial metastasis on the operated side which was accompanied with intrathoracic adhesions, the endobronchial brachytherapy was beneficial to avoid extreme invasive redo-surgery. Although good therapeutic result was also obtained in the case of adenocarcinoma (Case 1), it might be a subject for future debate whether local therapy with radiation or systemic therapy such as molecular targeted drugs should be ideal.