Prognostic Impact of Adverse Pathologic Features in Sinonasal Squamous Cell Carcinoma

Background Sinonasal squamous cell carcinomas (SCC) are rare and poorly characterized. In mucosal SCC of the head and neck, positive margins, high grade, perineural invasion (PNI), and lymphovascular invasion (LVI) are considered adverse pathologic features. However, the prognostic impact of these features in sinonasal SCC is not clearly understood, due to the rarity of these tumors and the heterogeneity of previously reported cohorts, which often group multiple histopathologic types of sinonasal malignancies.

Methods All patients treated surgically for sinonasal SCC between January 2006 and December 2013 at our tertiary care institution were identified. Clinical and pathologic data for these patients were collected retrospectively from patient charts. Kaplan–Meier curves and Cox proportional hazards models were used to determine the association of adverse pathologic features, including T-stage, positive margins, high grade, PNI, and LVI, with overall (OS) and disease-free survival (DFS).

Results Forty-eight patients were identified. Mean age at surgery was 65.8 years (range: 19–95 years), and mean follow-up time was 40.7 months (range 0–116 months). Eighteen patients (38%) had T1–T3 disease, while 30 patients (63%) had locally advanced T4 disease. Only four patients (8.3%) had nodal disease at presentation. At 2, 5, and 10 years, respectively, OS was 71, 54, and 48%, while DFS was 64, 51, and 45%, respectively. Twelve patients (25%) experienced local recurrences, with mean time to recurrence of 15.3 months. Twenty-five patients (52%) had positive margins (grossly or microscopically), 24 (50%) had high-grade tumors, 18 (38%) had PNI, and 15 (31%) had LVI. Thirty-eight patients (79%) received adjuvant radiation with or without chemotherapy. In the Kaplan–Meier analysis, T4 disease, high grade, and LVI were associated with poorer OS and DFS. In the univariate analysis, T4 disease (risk ratio [RR] = 2.7) and high grade (RR = 2.4) had a significant association with DFS, while T4 disease, high grade, and LVI all showed a trend toward a significant association with OS. In the multivariate analysis, high grade (RR = 3.1) and LVI (RR = 3.7) had a significant association with OS and DFS.

Conclusion Our single-institution experience of 48 patients suggests that high grade and LVI are the only pathologic features that are independently associated with survival outcomes in sinonasal SCC. Consistent with prior literature, we find that PNI and positive margins do not have a significant impact.