Sinonasal undifferentiated carcinoma (SNUC) is a rare but aggressive tumour with very poor prognosis. There are currently no well-established clinical trials to guide therapy and the impact of various treatment modalities on survival is not well defined. We aim to provide an updated systematic review on current treatment modalities on survival outcomes.

Individual patient data were extracted, and survival data pooled in a one-stage meta-analysis. Descriptive statistics were analysed using the Kaplan-Meier method. Patient-level comparisons stratified by treatment modalities, adjusted for demographics, were conducted using shared-frailty Cox regression.

Participants include all patients diagnosed with SNUC based on histological evidence. We looked at the overall cumulative survival outcome for different treatment modalities and overall survival by treatment modality in low versus high stage SNUC patients.

Seventeen studies were identified, comprising 208 patients from 1993 to 2020. There was no significant difference in cumulative overall survival in low versus high stage patients, and no significant difference in outcomes by treatment modality. The overall cumulative survival of SNUC is 30% at 95 months. Among patients treated with various combinations of treatment modalities, patients with chemoradiotherapy had the highest cumulative survival of 42% at 40 months. Definitive chemoradiotherapy was associated with improved disease survival rate. Regardless of tumour stage, patients should be treated early and aggressively, with no superiority of one treatment regimen over another. Trimodality treatment does not confer survival advantage over bimodality treatment.