Analyzing The Impact Of Primary Tumor Pet Metrics And Clinical Features On Outcomes In Locally Advanced Sinonasal Malignancy

We analyzed a retrospective cohort of patients with sinonasal malignancy to assess whether tumor PET metrics, in addition to clinical features, could predict for locoregional or distant control. An institutional database of patients with sinonasal malignancy from 2006-2016 was retrospectively reviewed. Clinical characteristics included stage, histology, smoking history of 10 pack years, and surgical margin status. Treatment modalities included surgical resection, chemotherapy, and radiation (RT). PET metric data including metabolic tumor volume (MTV), total lesion glycolysis (TLG), maximum standardized uptake value (SUVmax), and standard deviation of SUV (SD SUV) were obtained using a commercial semi-automatic gradient-based contouring algorithm for primary tumors on pre-treatment PET scans. Local and regional recurrences and distant metastases were recorded based on imaging and/or pathologic specimens. The time to death, locoregional, and distant failures were calculated from date of diagnosis. Actuarial survival curves were calculated using the Kaplan-Meier method, and comparisons between subgroups were performed using the log-rank test. Thirty-six patients with sinonasal malignancy were identified. Squamous cell carcinoma was the most common histology in 69% of patients. Maxillary sinus and nasal cavity were the two most common primary sites in 91% of patients. Sixty-four percent of patients had Stage IVA or higher disease. All patients received RT either definitively or in the adjuvant setting, Twenty-four patients underwent upfront surgery and 16 patients received chemotherapy (4 neoadjuvant, 16 concurrent with RT). With a median follow-up of 35 months, 13 patients experienced locoregional recurrence, with 5 of these patients having persistent disease. Eight patients underwent salvage surgery, of those, 6 recurred following salvage. Nine patients developed distant metastases, and 6 patients died. Of the 8 patients treated with upfront definitive chemoradiation, 4 remained free of disease and 1 was salvaged with surgery. Three-year actuarial rates for locoregional control and overall survival were 59.6% (95% CI: 39.6-74.8%) and 80.5% (95% CI: 58.7-91.5%), respectively. Median MTV, TLG, SUVmax, and SD SUV were 27.53, 209.63, 12.74 and 2.27, respectively. MTV>median was a significant predictor for distant metastasis, with 25% of patients developing distant metastases compared to 0% of patients with MTV < median (p=0.012). On univariate analysis, smoking status was a significant predictor for locoregional control (p =0.045). MTV is a significant predictor for distant control and smoking predicts for locoregional control in patients with locally advanced sinonasal malignancy. Further study of PET metrics and their predictive value for outcomes in sinonasal malignancy is warranted.