## 1 Introduction  
Chronic rhinosinuisitis with nasal polyps (CRSwNP) is a persistent inflammatory disorder of the upper airways, characterized by a diffuse involvement of both nasal fossae and the paranasal sinuses. It accounts for 25-30% of all chronic rhinosinuisitis (CRS) cases and it considerably impairs patients' quality of life (QoL) [1]. CRSwNP is a multifactorial disease associated with genetic factors, immune system abnormalities, anatomical variations. The disease process is further complicated by its interaction with external environmental factors, such as airborne pollutants and allergens, but also microbial agents such as viruses, bacteria, and fungi. These intrinsic factors highlight the complexity of its pathophysiology. In this regard, CRSwNP is predominantly driven by a type 2 inflammatory response, a pattern that is especially prevalent in Western populations, characterized by elevated levels of interleukin (IL)-4, IL-5, and IL-13, elevated tissual eosinophils, macrophages, type 2 innate lymphoid cells, and mast cells [2; 3; 4; 5]. Furthermore, it has been observed that CRSwNP is frequently associated with type 2 driven comorbid condition, such as asthma, allergies to inhalants, and non-steroidal anti-inflammatory drugs (NSAIDs) intolerance, presenting with a greater impact on patients' quality of life and a poorer response to conventional treatments [6].  
At present, endoscopic examination remains a cornerstone in CRSwNP evaluation, both for diagnostic and follow-up purposes, allowing for the assessment of the disease burden and its response to medical and surgical treatment through a direct visualization of the nasal mucosa and its associated inflammatory changes. Key endoscopic features include mucus characteristics, such as viscosity and color, as well as nasal polyps (NP) volume and distribution, both considered as indicative of the underlying inflammatory endotype and disease severity [7]. In this regard, several scores have been proposed to standardize endoscopic finding, with the \"nasal polyp score (NPS)\" [8] and the \"modified Lund-Kennedy endoscopic score (M-LKS)\" (Figure 1) being two of the most largely adopted all over the globe [9]. These scores are validated for clinical and research use and have been proved to be reliable in detecting rhinological conditions changes over time, including the effects of both medical and surgical intervention [10].  
Over the past years, the management of severe uncontrolled CRSwNP has undergone a notable shift with the introduction of humanized monoclonal antibodies targeting specifically type 2 inflammation pathway. In particular, several real-life setting studies published in the literature have demonstrated the remarkable effectiveness of dupilumab in CRSwNP management [3; 11]. It has been largely established that biologic drugs substantially improve both clinician- and patient-reported outcome measures (CROMs and PROMs, respectively) with benefits becoming evident as early as week four of treatment [12]. Despite the significant effectiveness of biologic therapies, a considerable variability in the degree of response to such therapies is observed, which are currently classified into three categories (poor, moderate and excellent response) according to EUFOREA 2023 criteria [13]. In this regard, the reduction in polyp size, mostly evaluated by means of NPS, despite being one of the main criteria identified in the EUFOREA 2023 guidelines [13], does not consider other relevant endoscopic features of CRSwNP such as mucosal edema or nasal discharges.  
The aim of the present study is therefore to compare M-LKS and NPS accuracy in evaluating CRSwNP response to dupilumab therapy.  
Figure 1: (**A**) nasal polyp score (NPS) description; (**B**) modified Lund–Kennedy endoscopic score (M-LKS) description.