Spontaneous regression following endobronchial ultrasound-guided transbronchial needle aspiration in lung cancer patients.

Spontaneous regression (SR) is defined as a complete or partial, temporary or permanent disappearance of a tumor without anticancer treatment, which potentially develops after surgery or biopsy for primary and metastatic tumors despite unknown incidence rate. Here, we report the incidence rate of SR after endobronchial ultrasound-guided transbronchial nodal needle aspiration (EBUS-TBNA) in lung cancer patients. Among 96 patients evaluable with chest CT before and after EBUS-TBNA, SR was found in three patients (3.1%). With regards to patient characteristics, two patients had small cell lung cancer (SCLC), and one patient had adenocarcinoma. All patients had stage 3 disease with a bulky N2 stage and a history of smoking. Two patients also had interstitial lung disease. Notably, SR was observed not only at the biopsied site, but also at the non-biopsied site. Our results indicate that SR can develop following EBUS-TBNA in a substantial proportion of lung cancer patients.