Adenoid cystic carcinoma of parotid gland treated with surgery and radiotherapy: long-term outcomes, QoL assessment and review of the literature

Abstract

To assess outcomes, toxicity and quality-of-life (QoL) of patients with parotid gland adenoid cystic carcinoma (PGACC) treated by surgery and postoperative radiotherapy. Between 1995 and 2010, 46 patients with PGACC were treated with parotidectomy±neck dissection followed by radiotherapy. Endpoints were loco-regional control (LRC), distant metastasis-free (DMFS), disease-free (DFS), cause-specific (CSS), and overall survival (OS), late toxicity, and QoL. After a median follow-up of 58 months (range 4-171), the 5-year Kaplan-Meier estimates of LRC, DMFS, DFS, CSS, and OS were 88%, 78%, 75%, 80%, and 67%, respectively and the 8-year rates were 88%, 75%, 72%, 77%, and 64%, respectively. On multivariate analysis, T-stage, N-stage, tumor grade, and perineural invasion correlate significantly with DMFS and DFS. The overall 5-year cumulative incidence of grade ≥2 late toxicity was 9%. QoL-scores deteriorate during and shortly after treatment but returned in all scales to almost baseline levels within 6 months. Excellent LRC rates were achieved in patients with PGACC treated by surgery and postoperative radiotherapy with low rate of late side-effects and preservation of good QoL. Despite the effective local therapy, 9 of 46 patients (20%) failed distantly. Because effective treatment strategies for this problem are lacking, prospective trials are needed to determine the role of adjuvant systemic or targeted therapy in patients at high risk of DM.