Multimodality Treatment and Survival in Sinonasal Minor Salivary Gland Tumors

 

Objectives: To analyze the effect of the multimodality treatment on survival in sinonasal minor salivary gland tumors.

Study Design: A retrospective analysis of the National Cancer Database (NCDB) (2004–2014).

Methods: Adult patients with a clinical AJCC T1–T4a stage of sinonasal minor salivary gland tumors were isolated from the NCDB ([Fig. 1]). Kaplan–Meier log-rank tests and Cox multivariate regressions were performed to analyze the effect of multi-modality treatment. A subset analysis was also performed to analyze the effect of multi-modality treatment in patients with positive margins following surgical management.

Results: We identified 556 cases, of which 239 were within the nasal cavity, 282 maxillary sinus, and 35 ethmoid sinus. 293 (52.7%]) patients were treated with surgery and radiotherapy (RT), 160 (28.8%) were treated with surgery alone, and 52 (9.4%) were treated with surgery and chemoradiotherapy (CRT). No patients were treated with CT alone. Patients with ethmoid sinus cases were more likely to be older (p = 0.025), and nasal cavity cases were more likely to present at a lower AJCC T stage than the sinus cases (p < 0.001). Upon univariate (p = 0.008; [Fig. 2]) and multivariate Cox analysis, both maxillary sinus (HR: 1.610; 95% CI: 0.103–2.264; p = 0.014) and ethmoid sinus tumors (HR: 2.104; 95% CI: 1.139–3.890; p = 0.018) had decreased survival compared with nasal cavity tumors. With surgery and CRT as a reference, the only treatment modality associated with decreased survival was RT alone (HR: 3.213; 95% CI: 1.578–6.543; p = 0.001). Upon univariate analysis, negative margins were associated with increased survival compared with positive margins (log rank p < 0.001; [Fig. 3]). Within a subset analysis of patients with positive margins, the only factors associated with decreased survival was increased age, and moderately or poorly-differentiated tumors. When compared with triple modality treatment, neither surgery and RT nor surgery alone were associated with decreased survival in both univariate (log-rank p = 0.735; [Fig. 4]) and multivariate models.

Conclusion: To our knowledge, this is the largest analysis of sinonasal minor salivary gland tumors to date. Our analysis shows that, when controlling for demographic and oncologic factors, minor salivary gland tumors of the sinuses are associated with decreased survival. This may have to do with the difficulty of obtaining negative margins. The most common treatment was surgery and RT, consistent with NCCN guidelines, which recommends chemotherapy (CT) only in the most concerning cases. However, we found no difference in survival among most treatment modalities when compared with triple modality therapy, with the exception of RT alone. Although margins were prognostic within these cancers, we found no evidence that adjuvant RT or CRT provides any survival benefit. Though we were limited by the retrospective nature of this study, our data suggest that CT may not be necessary in many cases, and, in fact, surgery alone may be enough to treat the carefully selected patient.