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ICAR SINONASAL TUMORS

1 Classification and staging RMS utilizes unique staging systems that are distinct from those used for other soft tissue sarcomas. The most com monly used are the Intergroup Rhabdomyosarcoma Study Group (IRSG) systems, which utilize clinicopathologic stages to categorize patients into prognostic groups. 1224,1225 For head and neck RMS, consideration is also given to the specific location of the primary tumor. This is divided into parameningeal (PM), non-parameningeal (non-PM), and orbital. PM head and neck sites include the nasal cavity and paranasal sinuses, as well as the nasopharynx, para pharyngeal space, ITF, PPF, middle ear, and mastoid cavity. Recent studies have suggested that not all subsites within PM RMS carry similar prognosis and have suggested sub dividing favorable and unfavorable PM sites. Unfavorable PM sites include the paranasal sinuses, ITF, and PPF. The nasal cavity and non-PM head and neck and orbital RMS, on the other hand, are generally associated with more favorable prognosis. The IRSG defined four clinical risk groups based on extent of disease and resection in the Intergroup Rhab domyosarcoma Study-I (IRS-I) clinical trial 1226,1227 : - Clinical Group 1: localized disease without regional metastases that is completely excised (R0 resection); - Clinical Group 2: grossly resected tumor with micro scopic residual disease (R1 resection) and/or presence of pathologically positive regional lymph node disease that is completely resected; - Clinical Group 3: incompletely resected tumor (R2 resec tion) or biopsy with gross residual disease; - Clinical Group 4: distant metastases. IRSG has also proposed a pretreatment staging system based on primary tumor site, tumor size, regional lymph node status, and metastatic disease. 1228 In this staging sys tem, sinonasal RMS without distant metastases would fall into stage 2 or 3 as it is an unfavorable site. Clinical trials of RMS have utilized combinations of IRSG clinical risk group, IRSG stage, TNM stage, and size to separate tumors into specific treatment arms.

study by Siddiqui et al., the timing of surgery (i.e., pri mary vs. salvage) was not available in the database review, further limiting interpretation. 1229 Some groups have advocated for primary surgery for resectable tumors that would result in minimal functional or cosmetic deficits and against initial aggressive surgical management. 1224,1230 Siddiqui et al. noted a survival dif ference according to IRSG group: 85.7%, 80%, 40%, and 24.4% for groups 1–4, respectively ( p = 0.047). 1229 These data demonstrate that there is generally favorable OS with select tumors resected with clear margins (i.e., IRSG group 1), though this was not found to be an independent prog nosticator on multivariate analysis. Furthermore, there are likely few patients who present with surgically resectable tumors; in the Siddiqui et al. study, which utilizes the NCDB database, there were only 13 total IRSG group 1 or 2 patients out of 157 patients total. 1229 Clinical trials have similarly shown that a majority of sinonasal RMS tumors are IRSG group 3. 1225,1226,1231 It is also worth noting that many of the surgical advances that have allowed for mini mally invasive endoscopic approaches may not be possible in young children due to anatomic limitations. Role of surgery in pediatric rhabdomyosarcoma

Aggregate grade of evidence

C (Level 4: three studies)

Benefit

Possibility of additional survival benefit with upfront or salvage surgery. Risk of surgical complications including anesthetic risks, blood loss, infection, CSF leak, and orbital injury. Potential for significant morbidity and disfigurement for locally advanced tumors. Additional cost of surgery and perioperative care.

Harm

Cost

Benefits–harm assessment

Balance of benefits and harms.

Value

Minimally invasive endoscopic approaches are limited by pediatric sinonasal anatomy. Studies do not differentiate between upfront and salvage surgery.

judgments

Policy level Option. Intervention There is limited evidence to support routine upfront surgical intervention. May consider in salvage setting.

2 Role of surgery in pediatric rhabdomyosarcoma

While there are several clinical trials in RMS, none have examined the role of surgery as randomization typically starts after initial surgery or biopsy, and current evidence is based on retrospective studies (Table XXIII.A.1). These studies did not show a survival benefit with surgery. Inter pretation of this is limited as both studies did not have clear selection criteria for surgery and were retrospective. In the

3 Role of radiation therapy in pediatric rhabdomyosarcoma In clinical trials of pediatric RMS, the majority of para meningeal tumors have been treated with RT in combi nation with chemotherapy. The timing, dose, and frac-