Adenoid Cystic Carcinoma of Lobar Bronchial Origin: 20-Year Experience at a Single Institution

Background Pulmonary adenoid cystic carcinoma (ACC) is a rare type of lung malignancy. The prevalence of ACC of lobar bronchial origin is lower than that of other lung malignancies, and studies investigating it are lacking. This study aimed to evaluate survival of patients with ACC of the lobar bronchus after surgical resection and to explore its prognostic factors. Methods Between January 2000 and December 2019, 35 patients at the National Cancer Center/Cancer Hospital with a diagnosis of ACC of the lobar bronchus were included in the retrospective analysis. Results During a median follow-up period of 61 months (range, 10–194 months), the analysis showed a 5-year overall survival (OS) rate of 81.4%, a 5-year locoregional recurrence-free survival rate of 84.0%, and 5-year disease-free survival rate of 60.1%. The univariate analysis exclusively identified the surgical margin as a predictor of OS, and survival was significantly longer for the patients with negative surgical margins than for those with positive surgical margins (R0 vs. R1: 94.4% vs. 66.0%; p = 0.014). Adjuvant radiotherapy was administered to most of the patients with positive surgical margins, which might have contributed to prolonged OS (R0 vs. R1+RT: 94.4% vs. 66.7%, p = 0.173; R0 vs. R1+no RT: 94.4% vs. 62.5%, p = 0.007). Conclusions For ACC of lobar bronchial origin, complete resection is the radical treatment, and the OS rate was significantly higher for the R0 patients than for the R1 patients. Adjuvant radiotherapy for patients with R1 may prolong survival.