xRead - Nasal Obstruction (September 2024) Full Articles

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ICAR SINONASAL TUMORS

D Order of imaging and biopsy Given the proximity of the sinonasal cavity to the orbit and the intracranial space, it is important to evaluate sinonasal lesions for potential invasions into these adjacent spaces. This is usually done with a combination of CT and MRI, which are superior for evaluating bony anatomy and soft tissue, respectively. The details of imaging for sinonasal tumors will be discussed in Section IX. When consider ing biopsy for sinonasal tumors, classic teaching describes obtaining both a CT and MRI prior to considering a biopsy. No specific studies have examined the necessity of CT and MRI prior to a sinonasal biopsy. This approach is based on expert opinion, with the goal of avoiding potential conse quences of performing a biopsy on an ill-defined sinonasal lesion and causing intracranial, intraorbital, or bleeding complications. There may be cases where a biopsy could be considered prior to bimodal imaging, to avoid delays in diagnosis and treatment initiation. The goal of imaging prior to tissue sampling is to allow the clinician to evaluate the barriers of the nasal cavity and the extent of the lesion. When this is possible without imaging, it may be appropriate to con sider a biopsy prior to bimodal imaging. Sinonasal lesions located inferiorly in the nasal cavity, with clear separation from the entire skull base and orbit, may not necessitate imaging prior to biopsy. Similarly, lesions that can be com pletely visualized with endoscopy and have an identifiable and accessible attachment site may not require imaging prior to biopsy. Clinicians should also consider whether a biopsy obtained prior to imaging may impact the subse quent imaging and radiologic interpretation. For example, packing or cautery within the sinonasal cavity as well as an inflammatory reaction from the biopsy can complicate the interpretation of sinonasal imaging. Clinicians should include these considerations in their assessment of the appropriateness of a preimaging biopsy. These consider ations are based on expert opinion only, and clinicians should be cautious when considering a biopsy prior to complete imaging to avoid potential complications and patient harm. Aggregate grade of evidence : D (Level 5: expert opinion, reasoning from first principles) VIII RESECTABILITY A Resectability of sinonasal tumors In the context of treatment planning, the term resectable refers to the ability to surgically extirpate tumor in an oncologically acceptable manner, while avoiding signifi cant morbidity, deterioration of QOL, or mortality. Tumors

are generally considered unresectable if their location or involvement of critical structures prevents the surgeon from achieving GTR with negative surgical margins. A critical evaluation of resectability is frequently necessary in SNM due to their characteristically late stage of pre sentation and proximity of sinonasal subsites to critical neurovascular structures (e.g., carotid artery, cavernous sinus) as well as orbital and intracranial contents (e.g., dura, brain parenchyma). The American Joint Committee on Cancer (AJCC) staging guidelines attempt to delineate locally advanced tumors as resectable (T4a) or unre sectable (T4b). 158 Tumors arising from the nasal cavity, maxillary sinus, or ethmoid sinus are staged T4b if they involve the orbital apex, dura, brain parenchyma, middle cranial fossa, cranial nerves other than V2, nasopharynx, or clivus. As an oncological principle, surgical extirpation is rarely considered acceptable in the presence of known distant metastases, unless the pathology tends toward indolent behavior (e.g., ACC) and there is potential for significant local morbidity (e.g., pain, fungating wound, threat to vision). In a review of the NCDB for SNM, Robin et al. found that increasing T stage was inversely correlated with the likelihood of achieving GTR with negative margins. The odds ratio for obtaining negative margins in T4-staged tumors is 0.189, compared to 0.824 in T2-staged tumors, though this was partially mitigated by the use of neoad juvant CRT (OR 2.641). 159 Furthermore, studies of large SNM cohorts demonstrate that a negative margin resec tion is an independent predictor of OS, DSS, and rates of local recurrence compared to those with positive surgical margins remaining. 160 When stratifying positive margins as either microscopically positive or macroscopically pos itive (grossly visible at the resection margins), Jafari et al. found a sequential deterioration in median OS for negative margins, micro-positive margins, macro-positive margins, and nonsurgical therapy (90.5, 56.7, 38.4, and 36.4 months, respectively). 161 For these reasons, current National Comprehensive Cancer Network (NCCN) guide lines recommend RT (with or without concurrent systemic therapy) or IC for unresectable tumors for patients with performance status 0–1. 162 Despite this guidance, there is disagreement regarding the absolute contraindications to resection of sinonasal tumors due to substantial variability in surgeon expe rience, institutional preference, and the emergence of EEAs, which allow for higher resolution visualization and decreased postoperative morbidity. The evolution of endonasal surgery also leads to heterogeneity in study designs that tend to incorporate open, endoscopic, and combined approaches. Randomized clinical trials or robust prospective studies specifically evaluating surgery as the primary modality of treating classically unresectable