Postoperative concurrent chemoradiation (CCRT) for non-squamous cell carcinoma (NSCCA) of head and neck.

Abstract

e17582 Background: Surgery is the mainstay of treatment for resectable non-metastatic NSCCA of head and neck. Postoperative radiation (RT) is delivered to patients (pt) with high risk for recurrence. Unlike the squamous cell counterpart where survival advantage from adding chemotherapy (CMT) as a radio-sensitizer is evident, the benefit of CCRT is uncertain in NSCCA pt. We hypothesized that CCRT would improve disease free survival (DFS), comparing to RT alone. Methods: NSCCA of head and neck pt who underwent curative surgery and RT at Siriraj hospital from 2006 to 2015 were included in this retrospective study. Patients with residual tumor after surgery or neuroendocrine histology were excluded. The primary outcome was DFS. The secondary outcome was overall survival (OS). Results: We included 139 pt, 99 (71.2%) had RT while 40 (28.8%) had CCRT. Baseline characteristics, including age, gender, primary site, histology and radiation dose were similar between 2 groups. Salivary gland was the most common primary site (67.6%). The most common histology was adenoid cystic carcinoma (35.3%), followed by mucoepidermoid carcinoma (25.9%). Patients who received RT alone had earlier stage (Stage I 29.3%, Stage IVa 14.1%), compared to CCRT group (Stage I 7.7%, Stage IVa 38.5%), p = 0.003. High risk features (positive margin, extranodal extension or ≥ 2 cervical lymph nodes metastasis) were found in 42% and 62% of pt with RT and CCRT, respectively (p = 0.03). In CCRT group, 92% of pt received cisplatin every 3 weeks during RT period. With the median follow-up time of 54.9 months, 3-year DFS was 79.4% and 79.5% in RT and CCRT groups, respectively (p = 0.22). There was no significant difference in 3-year OS between RT and CCRT groups (89.2% vs 89.9%, p = 0.76). Among pt with high-risk features (n = 67, 48.2%), 3-year DFS and OS were not significantly different between treatment groups. However, among pt without high-risk features, 3-year DFS in RT group was significantly higher than CCRT group (84.8% vs 79.0%, p = 0.04). Conclusions: This study demonstrates no survival benefit from adding concurrent CMT to RT following curative surgery in NSCCA of head and neck. Moreover, addition of CMT may be detrimental in pt without high-risk features.