(P085) Oncologic and Functional Outcomes of Salivary Gland Tumors (SGTs) With Pathologically Proven Perineural Invasion (PNI)

Bryan M. Rabatic, PhD, MD, David Zaenger, MD, Joseph M. Kaminski, MD, Waleed F. Mourad, MD, PhD; Georgia Regents University

PURPOSE: To report the clinical outcomes and patterns of failure of salivary gland tumors (SGTs) with perineural invasion (PNI) status postmultimodality approach (ie, surgery, postoperative radiation therapy [RT], and chemotherapy).

MATERIALS: This is a single-institution retrospective study that was fully approved by our institutional review board (IRB). From March 1997–2010, a total of 62 patients with SGTs underwent the multimodality approach due to the presence of PNI ± other high-risk features (recurrent tumor, R1 or R2 resection, positive margins, multiple positive lymph nodes, and extracapsular extension). Intensity-modulated RT (IMRT) was utilized in 50% of the patients. RT fields included the tumor bed, ipsilateral neck, and occasionally the contralateral neck. The most common pathologically involved nerves (facial, V2, and V3) were included in the RT fields to the skull base. The median RT dose delivered was 63 Gy (range: 50–70 Gy at 1.8–2 Gy/fraction). A total of 53%, 34%, and 13% of cases were parotid, minor salivary, and submandibular gland primaries, respectively. Pathologically adenoid cystic carcinoma and adenocarcinoma were the most common histologies (39% and 24%, respectively).

RESULTS: The median age was 53 years (range: 20–78 yr). Males and Caucasians made up 50% and 50% of the population, respectively. With a median follow-up of 5 years (range: 1–10 yr), the 5-year actuarial disease-free survival (DFS), locoregional control (LRC), and distant control (DC) rates were 85%, 94%, and 91%, respectively. The median time to LR failure (LRF) and distant metastases (DMs) was 8 months (range: 6–16 mo) and 30 months (range: 18–60 mo), respectively. Late RT toxicity was grade ≤ 2 xerostomia (20%), altered taste (15%), trismus (6%), dysphagia (4%), and neck stiffness (2%).

CONCLUSIONS: A multimodality approach to SGTs with PNI provides excellent LRC. Further studies are warranted to identify the patients at higher risk of LRF and DMs to optimize their management.

Proceedings of the 97th Annual Meeting of the American Radium Society- americanradiumsociety.org