Electromagnetically navigated brachytherapy as a new treatment option for peripheral pulmonary tumors

This technical note describes the principles of navigated brachytherapy for treatment of peripheral non-small cell lung cancer (NSCLC).

In a prospective feasibility trial a first patient with medically inoperable NSCLC in the right upper lobe was treated with external-beam radiotherapy (50 Gy) and navigated endoluminal brachytherapy (15 Gy). Navigated bronchoscopy was performed with an electromagnetic navigation system for localization of a microsensor mounted on the tip of a dedicated catheter placed within the working channel of a bronchoscope. The probe can be actively guided by a steering mechanism to targeted lesions in the periphery of the lung. After successful localization of the NSCLC, endobronchial ultrasound (EBUS) was performed to confirm the exact position in the center of the lesion. A 6-F brachytherapy catheter was placed within the tumor. Primary 3-D-planned brachytherapy was performed on chest CTs acquired with the inserted catheter. High-dose-rate brachytherapy (370 GBq iridium-192) was applied as a boost three times a week (single dose 5 Gy) and provided highly conformal irradiations of the NSCLC including the draining bronchovascular bundle.

The brachytherapy catheter was tolerated well during treatment (5 days) and alimentation was possible without any problems. Repeated CTs showed stable positioning of the catheter. During follow-up (12 months), endoluminal ultrasound and CT demonstrated a partial remission while histology showed a complete remission of the tumor.

Navigated brachytherapy for peripheral pulmonary tumors not amenable to conventional bronchoscopy is feasible.