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What is the appropriate timing for endoscopic and radiographic surveillance following treatment for sinonasal malignancies?

BACKGROUND Sinonasal malignancies are rare, representing only 3% of all head and neck neoplasms and approximately 1% of all malignancies. Given this low incidence and the diversity of pathologies, standardized protocols for post-treatment surveillance are lacking. Due to their advanced stage at presentation, sinonasal malignancies often have a poor prognosis, with recurrence rates ranging from 27% to 56%. Whereas the majority of recurrences occur within 2 to 3 years post-treatment, certain malignancies, such adenoid cystic carcinoma, olfactory neuroblastoma, and melanoma, have a propensity to recur much later. The majority of recurrences occur locally and represent the leading cause of diseasespecific mortality. Several factors, including complex anatomy, treatment-related changes, distortion due to resection and reconstruction, and sinonasal inflammation complicate surveillance for recurrence. Due to these unique aspects, accepted surveillance guidelines for head and neck malignancies may not be directly applicable for sinonasal malignancies. Accordingly, distinct guidelines for post-treatment endoscopic and radiographic surveillance are needed. LITERATURE REVIEW The current available evidence is limited at best. Whereas surveillance protocols have been better defined in the management of head and neck squamous cell carcinoma, the limited incidence and varied pathologies in sinonasal carcinomas have hindered the development of standardized protocols for post-treatment surveillance. Despite differences in tumor biology, treatment modalities and anatomical subsites, current clinical practice relies significantly on data published on general head and neck malignancies. Khalili and colleagues retrospectively evaluated the efficacy of endoscopic and imaging surveillance in patients with sinonasal malignancies. In this study, endoscopic follow-up was completed every 1 to 3 months for the first 2 years, 3 to 6 months for the next 3 years, and annually beyond year 5, whereas imaging was obtained every 3 to 6 months for the first 2 years, and at 6 months to yearly intervals afterward. In their review of 100 patients, 30 patients recurred, with 22 patients (73%) recurring locally; regional and distant metastasis represented 17% and 10% of recurrences, respectively. The majority of patients (63%) recurred within 2 years. Seventy-seven percent of recurrences were diagnosed with imaging, whereas only 17% and 3% were identified via endoscopy or physical examination, respectively. Although the specificity of endoscopy and imaging was similar at 89% and 90%, respectively, imaging had a significantly higher sensitivity (75% vs. 25%), accuracy (86% vs. 73%), and negative predictive value (92% vs. 78%) with P values <.05. However, identification of recurrence by endoscopy was critical, as it resulted in better prognosis, likely due to the superficial nature of these recurrences, thus making them amenable to reresection. The positive predictive value (PPV) was higher for imaging than nasal endoscopy, but the difference was not significant (72% vs. 43%, P 5 .07). Out of the imaging modalities, magnetic resonance imaging (MRI) had the highest PPV at 84%, significantly higher than computed tomography (CT) (44%) and positron emission tomography (PET)/CT (46%). However, PET/CT was critical in diagnosing distant recurrences in cases of mucosal melanoma. Furthermore, the presence of From the Department of Otolaryngology–Head and Neck Surgery (A.K.P.), University of South Florida, Tampa, Florida; Leonard Davis Institute of Health Economics (A.K.P.) and Department of Otorhinolaryngology–Head and Neck Surgery (E.C.K., N.D.A.), University of Pennsylvania, Philadelphia, Pennsylvania; Department of Head and Neck Surgery (M.A.S.), Jonsson Comprehensive Cancer Center (M.A.S.), and University of California Los Angeles Head and Neck Cancer Program (M.A.S.), University of California, Los Angeles Medical Center, Los Angeles, California; and the Department of Otorhinolaryngology–Head and Neck Surgery (B.A.T.), Rush University Medical Center, Chicago, Illinois, U.S.A.